--- /dev/null
- status |= error("unable to commit reflog '%s' (%s)",
+#include "../cache.h"
+#include "../refs.h"
+#include "refs-internal.h"
+#include "../lockfile.h"
+#include "../object.h"
+#include "../dir.h"
+
+struct ref_lock {
+ char *ref_name;
+ char *orig_ref_name;
+ struct lock_file *lk;
+ struct object_id old_oid;
+};
+
+struct ref_entry;
+
+/*
+ * Information used (along with the information in ref_entry) to
+ * describe a single cached reference. This data structure only
+ * occurs embedded in a union in struct ref_entry, and only when
+ * (ref_entry->flag & REF_DIR) is zero.
+ */
+struct ref_value {
+ /*
+ * The name of the object to which this reference resolves
+ * (which may be a tag object). If REF_ISBROKEN, this is
+ * null. If REF_ISSYMREF, then this is the name of the object
+ * referred to by the last reference in the symlink chain.
+ */
+ struct object_id oid;
+
+ /*
+ * If REF_KNOWS_PEELED, then this field holds the peeled value
+ * of this reference, or null if the reference is known not to
+ * be peelable. See the documentation for peel_ref() for an
+ * exact definition of "peelable".
+ */
+ struct object_id peeled;
+};
+
+struct ref_cache;
+
+/*
+ * Information used (along with the information in ref_entry) to
+ * describe a level in the hierarchy of references. This data
+ * structure only occurs embedded in a union in struct ref_entry, and
+ * only when (ref_entry.flag & REF_DIR) is set. In that case,
+ * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
+ * in the directory have already been read:
+ *
+ * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
+ * or packed references, already read.
+ *
+ * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
+ * references that hasn't been read yet (nor has any of its
+ * subdirectories).
+ *
+ * Entries within a directory are stored within a growable array of
+ * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
+ * sorted are sorted by their component name in strcmp() order and the
+ * remaining entries are unsorted.
+ *
+ * Loose references are read lazily, one directory at a time. When a
+ * directory of loose references is read, then all of the references
+ * in that directory are stored, and REF_INCOMPLETE stubs are created
+ * for any subdirectories, but the subdirectories themselves are not
+ * read. The reading is triggered by get_ref_dir().
+ */
+struct ref_dir {
+ int nr, alloc;
+
+ /*
+ * Entries with index 0 <= i < sorted are sorted by name. New
+ * entries are appended to the list unsorted, and are sorted
+ * only when required; thus we avoid the need to sort the list
+ * after the addition of every reference.
+ */
+ int sorted;
+
+ /* A pointer to the ref_cache that contains this ref_dir. */
+ struct ref_cache *ref_cache;
+
+ struct ref_entry **entries;
+};
+
+/*
+ * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
+ * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
+ * public values; see refs.h.
+ */
+
+/*
+ * The field ref_entry->u.value.peeled of this value entry contains
+ * the correct peeled value for the reference, which might be
+ * null_sha1 if the reference is not a tag or if it is broken.
+ */
+#define REF_KNOWS_PEELED 0x10
+
+/* ref_entry represents a directory of references */
+#define REF_DIR 0x20
+
+/*
+ * Entry has not yet been read from disk (used only for REF_DIR
+ * entries representing loose references)
+ */
+#define REF_INCOMPLETE 0x40
+
+/*
+ * A ref_entry represents either a reference or a "subdirectory" of
+ * references.
+ *
+ * Each directory in the reference namespace is represented by a
+ * ref_entry with (flags & REF_DIR) set and containing a subdir member
+ * that holds the entries in that directory that have been read so
+ * far. If (flags & REF_INCOMPLETE) is set, then the directory and
+ * its subdirectories haven't been read yet. REF_INCOMPLETE is only
+ * used for loose reference directories.
+ *
+ * References are represented by a ref_entry with (flags & REF_DIR)
+ * unset and a value member that describes the reference's value. The
+ * flag member is at the ref_entry level, but it is also needed to
+ * interpret the contents of the value field (in other words, a
+ * ref_value object is not very much use without the enclosing
+ * ref_entry).
+ *
+ * Reference names cannot end with slash and directories' names are
+ * always stored with a trailing slash (except for the top-level
+ * directory, which is always denoted by ""). This has two nice
+ * consequences: (1) when the entries in each subdir are sorted
+ * lexicographically by name (as they usually are), the references in
+ * a whole tree can be generated in lexicographic order by traversing
+ * the tree in left-to-right, depth-first order; (2) the names of
+ * references and subdirectories cannot conflict, and therefore the
+ * presence of an empty subdirectory does not block the creation of a
+ * similarly-named reference. (The fact that reference names with the
+ * same leading components can conflict *with each other* is a
+ * separate issue that is regulated by verify_refname_available().)
+ *
+ * Please note that the name field contains the fully-qualified
+ * reference (or subdirectory) name. Space could be saved by only
+ * storing the relative names. But that would require the full names
+ * to be generated on the fly when iterating in do_for_each_ref(), and
+ * would break callback functions, who have always been able to assume
+ * that the name strings that they are passed will not be freed during
+ * the iteration.
+ */
+struct ref_entry {
+ unsigned char flag; /* ISSYMREF? ISPACKED? */
+ union {
+ struct ref_value value; /* if not (flags&REF_DIR) */
+ struct ref_dir subdir; /* if (flags&REF_DIR) */
+ } u;
+ /*
+ * The full name of the reference (e.g., "refs/heads/master")
+ * or the full name of the directory with a trailing slash
+ * (e.g., "refs/heads/"):
+ */
+ char name[FLEX_ARRAY];
+};
+
+static void read_loose_refs(const char *dirname, struct ref_dir *dir);
+static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
+static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
+ const char *dirname, size_t len,
+ int incomplete);
+static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+
+static struct ref_dir *get_ref_dir(struct ref_entry *entry)
+{
+ struct ref_dir *dir;
+ assert(entry->flag & REF_DIR);
+ dir = &entry->u.subdir;
+ if (entry->flag & REF_INCOMPLETE) {
+ read_loose_refs(entry->name, dir);
+
+ /*
+ * Manually add refs/bisect, which, being
+ * per-worktree, might not appear in the directory
+ * listing for refs/ in the main repo.
+ */
+ if (!strcmp(entry->name, "refs/")) {
+ int pos = search_ref_dir(dir, "refs/bisect/", 12);
+ if (pos < 0) {
+ struct ref_entry *child_entry;
+ child_entry = create_dir_entry(dir->ref_cache,
+ "refs/bisect/",
+ 12, 1);
+ add_entry_to_dir(dir, child_entry);
+ read_loose_refs("refs/bisect",
+ &child_entry->u.subdir);
+ }
+ }
+ entry->flag &= ~REF_INCOMPLETE;
+ }
+ return dir;
+}
+
+static struct ref_entry *create_ref_entry(const char *refname,
+ const unsigned char *sha1, int flag,
+ int check_name)
+{
+ int len;
+ struct ref_entry *ref;
+
+ if (check_name &&
+ check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
+ die("Reference has invalid format: '%s'", refname);
+ len = strlen(refname) + 1;
+ ref = xmalloc(sizeof(struct ref_entry) + len);
+ hashcpy(ref->u.value.oid.hash, sha1);
+ oidclr(&ref->u.value.peeled);
+ memcpy(ref->name, refname, len);
+ ref->flag = flag;
+ return ref;
+}
+
+static void clear_ref_dir(struct ref_dir *dir);
+
+static void free_ref_entry(struct ref_entry *entry)
+{
+ if (entry->flag & REF_DIR) {
+ /*
+ * Do not use get_ref_dir() here, as that might
+ * trigger the reading of loose refs.
+ */
+ clear_ref_dir(&entry->u.subdir);
+ }
+ free(entry);
+}
+
+/*
+ * Add a ref_entry to the end of dir (unsorted). Entry is always
+ * stored directly in dir; no recursion into subdirectories is
+ * done.
+ */
+static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
+{
+ ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
+ dir->entries[dir->nr++] = entry;
+ /* optimize for the case that entries are added in order */
+ if (dir->nr == 1 ||
+ (dir->nr == dir->sorted + 1 &&
+ strcmp(dir->entries[dir->nr - 2]->name,
+ dir->entries[dir->nr - 1]->name) < 0))
+ dir->sorted = dir->nr;
+}
+
+/*
+ * Clear and free all entries in dir, recursively.
+ */
+static void clear_ref_dir(struct ref_dir *dir)
+{
+ int i;
+ for (i = 0; i < dir->nr; i++)
+ free_ref_entry(dir->entries[i]);
+ free(dir->entries);
+ dir->sorted = dir->nr = dir->alloc = 0;
+ dir->entries = NULL;
+}
+
+/*
+ * Create a struct ref_entry object for the specified dirname.
+ * dirname is the name of the directory with a trailing slash (e.g.,
+ * "refs/heads/") or "" for the top-level directory.
+ */
+static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
+ const char *dirname, size_t len,
+ int incomplete)
+{
+ struct ref_entry *direntry;
+ direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
+ memcpy(direntry->name, dirname, len);
+ direntry->name[len] = '\0';
+ direntry->u.subdir.ref_cache = ref_cache;
+ direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
+ return direntry;
+}
+
+static int ref_entry_cmp(const void *a, const void *b)
+{
+ struct ref_entry *one = *(struct ref_entry **)a;
+ struct ref_entry *two = *(struct ref_entry **)b;
+ return strcmp(one->name, two->name);
+}
+
+static void sort_ref_dir(struct ref_dir *dir);
+
+struct string_slice {
+ size_t len;
+ const char *str;
+};
+
+static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
+{
+ const struct string_slice *key = key_;
+ const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
+ int cmp = strncmp(key->str, ent->name, key->len);
+ if (cmp)
+ return cmp;
+ return '\0' - (unsigned char)ent->name[key->len];
+}
+
+/*
+ * Return the index of the entry with the given refname from the
+ * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
+ * no such entry is found. dir must already be complete.
+ */
+static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
+{
+ struct ref_entry **r;
+ struct string_slice key;
+
+ if (refname == NULL || !dir->nr)
+ return -1;
+
+ sort_ref_dir(dir);
+ key.len = len;
+ key.str = refname;
+ r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
+ ref_entry_cmp_sslice);
+
+ if (r == NULL)
+ return -1;
+
+ return r - dir->entries;
+}
+
+/*
+ * Search for a directory entry directly within dir (without
+ * recursing). Sort dir if necessary. subdirname must be a directory
+ * name (i.e., end in '/'). If mkdir is set, then create the
+ * directory if it is missing; otherwise, return NULL if the desired
+ * directory cannot be found. dir must already be complete.
+ */
+static struct ref_dir *search_for_subdir(struct ref_dir *dir,
+ const char *subdirname, size_t len,
+ int mkdir)
+{
+ int entry_index = search_ref_dir(dir, subdirname, len);
+ struct ref_entry *entry;
+ if (entry_index == -1) {
+ if (!mkdir)
+ return NULL;
+ /*
+ * Since dir is complete, the absence of a subdir
+ * means that the subdir really doesn't exist;
+ * therefore, create an empty record for it but mark
+ * the record complete.
+ */
+ entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
+ add_entry_to_dir(dir, entry);
+ } else {
+ entry = dir->entries[entry_index];
+ }
+ return get_ref_dir(entry);
+}
+
+/*
+ * If refname is a reference name, find the ref_dir within the dir
+ * tree that should hold refname. If refname is a directory name
+ * (i.e., ends in '/'), then return that ref_dir itself. dir must
+ * represent the top-level directory and must already be complete.
+ * Sort ref_dirs and recurse into subdirectories as necessary. If
+ * mkdir is set, then create any missing directories; otherwise,
+ * return NULL if the desired directory cannot be found.
+ */
+static struct ref_dir *find_containing_dir(struct ref_dir *dir,
+ const char *refname, int mkdir)
+{
+ const char *slash;
+ for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+ size_t dirnamelen = slash - refname + 1;
+ struct ref_dir *subdir;
+ subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
+ if (!subdir) {
+ dir = NULL;
+ break;
+ }
+ dir = subdir;
+ }
+
+ return dir;
+}
+
+/*
+ * Find the value entry with the given name in dir, sorting ref_dirs
+ * and recursing into subdirectories as necessary. If the name is not
+ * found or it corresponds to a directory entry, return NULL.
+ */
+static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
+{
+ int entry_index;
+ struct ref_entry *entry;
+ dir = find_containing_dir(dir, refname, 0);
+ if (!dir)
+ return NULL;
+ entry_index = search_ref_dir(dir, refname, strlen(refname));
+ if (entry_index == -1)
+ return NULL;
+ entry = dir->entries[entry_index];
+ return (entry->flag & REF_DIR) ? NULL : entry;
+}
+
+/*
+ * Remove the entry with the given name from dir, recursing into
+ * subdirectories as necessary. If refname is the name of a directory
+ * (i.e., ends with '/'), then remove the directory and its contents.
+ * If the removal was successful, return the number of entries
+ * remaining in the directory entry that contained the deleted entry.
+ * If the name was not found, return -1. Please note that this
+ * function only deletes the entry from the cache; it does not delete
+ * it from the filesystem or ensure that other cache entries (which
+ * might be symbolic references to the removed entry) are updated.
+ * Nor does it remove any containing dir entries that might be made
+ * empty by the removal. dir must represent the top-level directory
+ * and must already be complete.
+ */
+static int remove_entry(struct ref_dir *dir, const char *refname)
+{
+ int refname_len = strlen(refname);
+ int entry_index;
+ struct ref_entry *entry;
+ int is_dir = refname[refname_len - 1] == '/';
+ if (is_dir) {
+ /*
+ * refname represents a reference directory. Remove
+ * the trailing slash; otherwise we will get the
+ * directory *representing* refname rather than the
+ * one *containing* it.
+ */
+ char *dirname = xmemdupz(refname, refname_len - 1);
+ dir = find_containing_dir(dir, dirname, 0);
+ free(dirname);
+ } else {
+ dir = find_containing_dir(dir, refname, 0);
+ }
+ if (!dir)
+ return -1;
+ entry_index = search_ref_dir(dir, refname, refname_len);
+ if (entry_index == -1)
+ return -1;
+ entry = dir->entries[entry_index];
+
+ memmove(&dir->entries[entry_index],
+ &dir->entries[entry_index + 1],
+ (dir->nr - entry_index - 1) * sizeof(*dir->entries)
+ );
+ dir->nr--;
+ if (dir->sorted > entry_index)
+ dir->sorted--;
+ free_ref_entry(entry);
+ return dir->nr;
+}
+
+/*
+ * Add a ref_entry to the ref_dir (unsorted), recursing into
+ * subdirectories as necessary. dir must represent the top-level
+ * directory. Return 0 on success.
+ */
+static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
+{
+ dir = find_containing_dir(dir, ref->name, 1);
+ if (!dir)
+ return -1;
+ add_entry_to_dir(dir, ref);
+ return 0;
+}
+
+/*
+ * Emit a warning and return true iff ref1 and ref2 have the same name
+ * and the same sha1. Die if they have the same name but different
+ * sha1s.
+ */
+static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
+{
+ if (strcmp(ref1->name, ref2->name))
+ return 0;
+
+ /* Duplicate name; make sure that they don't conflict: */
+
+ if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
+ /* This is impossible by construction */
+ die("Reference directory conflict: %s", ref1->name);
+
+ if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
+ die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
+
+ warning("Duplicated ref: %s", ref1->name);
+ return 1;
+}
+
+/*
+ * Sort the entries in dir non-recursively (if they are not already
+ * sorted) and remove any duplicate entries.
+ */
+static void sort_ref_dir(struct ref_dir *dir)
+{
+ int i, j;
+ struct ref_entry *last = NULL;
+
+ /*
+ * This check also prevents passing a zero-length array to qsort(),
+ * which is a problem on some platforms.
+ */
+ if (dir->sorted == dir->nr)
+ return;
+
+ qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
+
+ /* Remove any duplicates: */
+ for (i = 0, j = 0; j < dir->nr; j++) {
+ struct ref_entry *entry = dir->entries[j];
+ if (last && is_dup_ref(last, entry))
+ free_ref_entry(entry);
+ else
+ last = dir->entries[i++] = entry;
+ }
+ dir->sorted = dir->nr = i;
+}
+
+/* Include broken references in a do_for_each_ref*() iteration: */
+#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
+
+/*
+ * Return true iff the reference described by entry can be resolved to
+ * an object in the database. Emit a warning if the referred-to
+ * object does not exist.
+ */
+static int ref_resolves_to_object(struct ref_entry *entry)
+{
+ if (entry->flag & REF_ISBROKEN)
+ return 0;
+ if (!has_sha1_file(entry->u.value.oid.hash)) {
+ error("%s does not point to a valid object!", entry->name);
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * current_ref is a performance hack: when iterating over references
+ * using the for_each_ref*() functions, current_ref is set to the
+ * current reference's entry before calling the callback function. If
+ * the callback function calls peel_ref(), then peel_ref() first
+ * checks whether the reference to be peeled is the current reference
+ * (it usually is) and if so, returns that reference's peeled version
+ * if it is available. This avoids a refname lookup in a common case.
+ */
+static struct ref_entry *current_ref;
+
+typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
+
+struct ref_entry_cb {
+ const char *base;
+ int trim;
+ int flags;
+ each_ref_fn *fn;
+ void *cb_data;
+};
+
+/*
+ * Handle one reference in a do_for_each_ref*()-style iteration,
+ * calling an each_ref_fn for each entry.
+ */
+static int do_one_ref(struct ref_entry *entry, void *cb_data)
+{
+ struct ref_entry_cb *data = cb_data;
+ struct ref_entry *old_current_ref;
+ int retval;
+
+ if (!starts_with(entry->name, data->base))
+ return 0;
+
+ if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
+ !ref_resolves_to_object(entry))
+ return 0;
+
+ /* Store the old value, in case this is a recursive call: */
+ old_current_ref = current_ref;
+ current_ref = entry;
+ retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
+ entry->flag, data->cb_data);
+ current_ref = old_current_ref;
+ return retval;
+}
+
+/*
+ * Call fn for each reference in dir that has index in the range
+ * offset <= index < dir->nr. Recurse into subdirectories that are in
+ * that index range, sorting them before iterating. This function
+ * does not sort dir itself; it should be sorted beforehand. fn is
+ * called for all references, including broken ones.
+ */
+static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
+ each_ref_entry_fn fn, void *cb_data)
+{
+ int i;
+ assert(dir->sorted == dir->nr);
+ for (i = offset; i < dir->nr; i++) {
+ struct ref_entry *entry = dir->entries[i];
+ int retval;
+ if (entry->flag & REF_DIR) {
+ struct ref_dir *subdir = get_ref_dir(entry);
+ sort_ref_dir(subdir);
+ retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
+ } else {
+ retval = fn(entry, cb_data);
+ }
+ if (retval)
+ return retval;
+ }
+ return 0;
+}
+
+/*
+ * Call fn for each reference in the union of dir1 and dir2, in order
+ * by refname. Recurse into subdirectories. If a value entry appears
+ * in both dir1 and dir2, then only process the version that is in
+ * dir2. The input dirs must already be sorted, but subdirs will be
+ * sorted as needed. fn is called for all references, including
+ * broken ones.
+ */
+static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
+ struct ref_dir *dir2,
+ each_ref_entry_fn fn, void *cb_data)
+{
+ int retval;
+ int i1 = 0, i2 = 0;
+
+ assert(dir1->sorted == dir1->nr);
+ assert(dir2->sorted == dir2->nr);
+ while (1) {
+ struct ref_entry *e1, *e2;
+ int cmp;
+ if (i1 == dir1->nr) {
+ return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
+ }
+ if (i2 == dir2->nr) {
+ return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
+ }
+ e1 = dir1->entries[i1];
+ e2 = dir2->entries[i2];
+ cmp = strcmp(e1->name, e2->name);
+ if (cmp == 0) {
+ if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
+ /* Both are directories; descend them in parallel. */
+ struct ref_dir *subdir1 = get_ref_dir(e1);
+ struct ref_dir *subdir2 = get_ref_dir(e2);
+ sort_ref_dir(subdir1);
+ sort_ref_dir(subdir2);
+ retval = do_for_each_entry_in_dirs(
+ subdir1, subdir2, fn, cb_data);
+ i1++;
+ i2++;
+ } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
+ /* Both are references; ignore the one from dir1. */
+ retval = fn(e2, cb_data);
+ i1++;
+ i2++;
+ } else {
+ die("conflict between reference and directory: %s",
+ e1->name);
+ }
+ } else {
+ struct ref_entry *e;
+ if (cmp < 0) {
+ e = e1;
+ i1++;
+ } else {
+ e = e2;
+ i2++;
+ }
+ if (e->flag & REF_DIR) {
+ struct ref_dir *subdir = get_ref_dir(e);
+ sort_ref_dir(subdir);
+ retval = do_for_each_entry_in_dir(
+ subdir, 0, fn, cb_data);
+ } else {
+ retval = fn(e, cb_data);
+ }
+ }
+ if (retval)
+ return retval;
+ }
+}
+
+/*
+ * Load all of the refs from the dir into our in-memory cache. The hard work
+ * of loading loose refs is done by get_ref_dir(), so we just need to recurse
+ * through all of the sub-directories. We do not even need to care about
+ * sorting, as traversal order does not matter to us.
+ */
+static void prime_ref_dir(struct ref_dir *dir)
+{
+ int i;
+ for (i = 0; i < dir->nr; i++) {
+ struct ref_entry *entry = dir->entries[i];
+ if (entry->flag & REF_DIR)
+ prime_ref_dir(get_ref_dir(entry));
+ }
+}
+
+struct nonmatching_ref_data {
+ const struct string_list *skip;
+ const char *conflicting_refname;
+};
+
+static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
+{
+ struct nonmatching_ref_data *data = vdata;
+
+ if (data->skip && string_list_has_string(data->skip, entry->name))
+ return 0;
+
+ data->conflicting_refname = entry->name;
+ return 1;
+}
+
+/*
+ * Return 0 if a reference named refname could be created without
+ * conflicting with the name of an existing reference in dir.
+ * See verify_refname_available for more information.
+ */
+static int verify_refname_available_dir(const char *refname,
+ const struct string_list *extras,
+ const struct string_list *skip,
+ struct ref_dir *dir,
+ struct strbuf *err)
+{
+ const char *slash;
+ const char *extra_refname;
+ int pos;
+ struct strbuf dirname = STRBUF_INIT;
+ int ret = -1;
+
+ /*
+ * For the sake of comments in this function, suppose that
+ * refname is "refs/foo/bar".
+ */
+
+ assert(err);
+
+ strbuf_grow(&dirname, strlen(refname) + 1);
+ for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+ /* Expand dirname to the new prefix, not including the trailing slash: */
+ strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
+
+ /*
+ * We are still at a leading dir of the refname (e.g.,
+ * "refs/foo"; if there is a reference with that name,
+ * it is a conflict, *unless* it is in skip.
+ */
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+ if (pos >= 0 &&
+ (!skip || !string_list_has_string(skip, dirname.buf))) {
+ /*
+ * We found a reference whose name is
+ * a proper prefix of refname; e.g.,
+ * "refs/foo", and is not in skip.
+ */
+ strbuf_addf(err, "'%s' exists; cannot create '%s'",
+ dirname.buf, refname);
+ goto cleanup;
+ }
+ }
+
+ if (extras && string_list_has_string(extras, dirname.buf) &&
+ (!skip || !string_list_has_string(skip, dirname.buf))) {
+ strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+ refname, dirname.buf);
+ goto cleanup;
+ }
+
+ /*
+ * Otherwise, we can try to continue our search with
+ * the next component. So try to look up the
+ * directory, e.g., "refs/foo/". If we come up empty,
+ * we know there is nothing under this whole prefix,
+ * but even in that case we still have to continue the
+ * search for conflicts with extras.
+ */
+ strbuf_addch(&dirname, '/');
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+ if (pos < 0) {
+ /*
+ * There was no directory "refs/foo/",
+ * so there is nothing under this
+ * whole prefix. So there is no need
+ * to continue looking for conflicting
+ * references. But we need to continue
+ * looking for conflicting extras.
+ */
+ dir = NULL;
+ } else {
+ dir = get_ref_dir(dir->entries[pos]);
+ }
+ }
+ }
+
+ /*
+ * We are at the leaf of our refname (e.g., "refs/foo/bar").
+ * There is no point in searching for a reference with that
+ * name, because a refname isn't considered to conflict with
+ * itself. But we still need to check for references whose
+ * names are in the "refs/foo/bar/" namespace, because they
+ * *do* conflict.
+ */
+ strbuf_addstr(&dirname, refname + dirname.len);
+ strbuf_addch(&dirname, '/');
+
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+
+ if (pos >= 0) {
+ /*
+ * We found a directory named "$refname/"
+ * (e.g., "refs/foo/bar/"). It is a problem
+ * iff it contains any ref that is not in
+ * "skip".
+ */
+ struct nonmatching_ref_data data;
+
+ data.skip = skip;
+ data.conflicting_refname = NULL;
+ dir = get_ref_dir(dir->entries[pos]);
+ sort_ref_dir(dir);
+ if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
+ strbuf_addf(err, "'%s' exists; cannot create '%s'",
+ data.conflicting_refname, refname);
+ goto cleanup;
+ }
+ }
+ }
+
+ extra_refname = find_descendant_ref(dirname.buf, extras, skip);
+ if (extra_refname)
+ strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+ refname, extra_refname);
+ else
+ ret = 0;
+
+cleanup:
+ strbuf_release(&dirname);
+ return ret;
+}
+
+struct packed_ref_cache {
+ struct ref_entry *root;
+
+ /*
+ * Count of references to the data structure in this instance,
+ * including the pointer from ref_cache::packed if any. The
+ * data will not be freed as long as the reference count is
+ * nonzero.
+ */
+ unsigned int referrers;
+
+ /*
+ * Iff the packed-refs file associated with this instance is
+ * currently locked for writing, this points at the associated
+ * lock (which is owned by somebody else). The referrer count
+ * is also incremented when the file is locked and decremented
+ * when it is unlocked.
+ */
+ struct lock_file *lock;
+
+ /* The metadata from when this packed-refs cache was read */
+ struct stat_validity validity;
+};
+
+/*
+ * Future: need to be in "struct repository"
+ * when doing a full libification.
+ */
+static struct ref_cache {
+ struct ref_cache *next;
+ struct ref_entry *loose;
+ struct packed_ref_cache *packed;
+ /*
+ * The submodule name, or "" for the main repo. We allocate
+ * length 1 rather than FLEX_ARRAY so that the main ref_cache
+ * is initialized correctly.
+ */
+ char name[1];
+} ref_cache, *submodule_ref_caches;
+
+/* Lock used for the main packed-refs file: */
+static struct lock_file packlock;
+
+/*
+ * Increment the reference count of *packed_refs.
+ */
+static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
+{
+ packed_refs->referrers++;
+}
+
+/*
+ * Decrease the reference count of *packed_refs. If it goes to zero,
+ * free *packed_refs and return true; otherwise return false.
+ */
+static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
+{
+ if (!--packed_refs->referrers) {
+ free_ref_entry(packed_refs->root);
+ stat_validity_clear(&packed_refs->validity);
+ free(packed_refs);
+ return 1;
+ } else {
+ return 0;
+ }
+}
+
+static void clear_packed_ref_cache(struct ref_cache *refs)
+{
+ if (refs->packed) {
+ struct packed_ref_cache *packed_refs = refs->packed;
+
+ if (packed_refs->lock)
+ die("internal error: packed-ref cache cleared while locked");
+ refs->packed = NULL;
+ release_packed_ref_cache(packed_refs);
+ }
+}
+
+static void clear_loose_ref_cache(struct ref_cache *refs)
+{
+ if (refs->loose) {
+ free_ref_entry(refs->loose);
+ refs->loose = NULL;
+ }
+}
+
+static struct ref_cache *create_ref_cache(const char *submodule)
+{
+ int len;
+ struct ref_cache *refs;
+ if (!submodule)
+ submodule = "";
+ len = strlen(submodule) + 1;
+ refs = xcalloc(1, sizeof(struct ref_cache) + len);
+ memcpy(refs->name, submodule, len);
+ return refs;
+}
+
+/*
+ * Return a pointer to a ref_cache for the specified submodule. For
+ * the main repository, use submodule==NULL. The returned structure
+ * will be allocated and initialized but not necessarily populated; it
+ * should not be freed.
+ */
+static struct ref_cache *get_ref_cache(const char *submodule)
+{
+ struct ref_cache *refs;
+
+ if (!submodule || !*submodule)
+ return &ref_cache;
+
+ for (refs = submodule_ref_caches; refs; refs = refs->next)
+ if (!strcmp(submodule, refs->name))
+ return refs;
+
+ refs = create_ref_cache(submodule);
+ refs->next = submodule_ref_caches;
+ submodule_ref_caches = refs;
+ return refs;
+}
+
+/* The length of a peeled reference line in packed-refs, including EOL: */
+#define PEELED_LINE_LENGTH 42
+
+/*
+ * The packed-refs header line that we write out. Perhaps other
+ * traits will be added later. The trailing space is required.
+ */
+static const char PACKED_REFS_HEADER[] =
+ "# pack-refs with: peeled fully-peeled \n";
+
+/*
+ * Parse one line from a packed-refs file. Write the SHA1 to sha1.
+ * Return a pointer to the refname within the line (null-terminated),
+ * or NULL if there was a problem.
+ */
+static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
+{
+ const char *ref;
+
+ /*
+ * 42: the answer to everything.
+ *
+ * In this case, it happens to be the answer to
+ * 40 (length of sha1 hex representation)
+ * +1 (space in between hex and name)
+ * +1 (newline at the end of the line)
+ */
+ if (line->len <= 42)
+ return NULL;
+
+ if (get_sha1_hex(line->buf, sha1) < 0)
+ return NULL;
+ if (!isspace(line->buf[40]))
+ return NULL;
+
+ ref = line->buf + 41;
+ if (isspace(*ref))
+ return NULL;
+
+ if (line->buf[line->len - 1] != '\n')
+ return NULL;
+ line->buf[--line->len] = 0;
+
+ return ref;
+}
+
+/*
+ * Read f, which is a packed-refs file, into dir.
+ *
+ * A comment line of the form "# pack-refs with: " may contain zero or
+ * more traits. We interpret the traits as follows:
+ *
+ * No traits:
+ *
+ * Probably no references are peeled. But if the file contains a
+ * peeled value for a reference, we will use it.
+ *
+ * peeled:
+ *
+ * References under "refs/tags/", if they *can* be peeled, *are*
+ * peeled in this file. References outside of "refs/tags/" are
+ * probably not peeled even if they could have been, but if we find
+ * a peeled value for such a reference we will use it.
+ *
+ * fully-peeled:
+ *
+ * All references in the file that can be peeled are peeled.
+ * Inversely (and this is more important), any references in the
+ * file for which no peeled value is recorded is not peelable. This
+ * trait should typically be written alongside "peeled" for
+ * compatibility with older clients, but we do not require it
+ * (i.e., "peeled" is a no-op if "fully-peeled" is set).
+ */
+static void read_packed_refs(FILE *f, struct ref_dir *dir)
+{
+ struct ref_entry *last = NULL;
+ struct strbuf line = STRBUF_INIT;
+ enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
+
+ while (strbuf_getwholeline(&line, f, '\n') != EOF) {
+ unsigned char sha1[20];
+ const char *refname;
+ const char *traits;
+
+ if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
+ if (strstr(traits, " fully-peeled "))
+ peeled = PEELED_FULLY;
+ else if (strstr(traits, " peeled "))
+ peeled = PEELED_TAGS;
+ /* perhaps other traits later as well */
+ continue;
+ }
+
+ refname = parse_ref_line(&line, sha1);
+ if (refname) {
+ int flag = REF_ISPACKED;
+
+ if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+ if (!refname_is_safe(refname))
+ die("packed refname is dangerous: %s", refname);
+ hashclr(sha1);
+ flag |= REF_BAD_NAME | REF_ISBROKEN;
+ }
+ last = create_ref_entry(refname, sha1, flag, 0);
+ if (peeled == PEELED_FULLY ||
+ (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
+ last->flag |= REF_KNOWS_PEELED;
+ add_ref(dir, last);
+ continue;
+ }
+ if (last &&
+ line.buf[0] == '^' &&
+ line.len == PEELED_LINE_LENGTH &&
+ line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
+ !get_sha1_hex(line.buf + 1, sha1)) {
+ hashcpy(last->u.value.peeled.hash, sha1);
+ /*
+ * Regardless of what the file header said,
+ * we definitely know the value of *this*
+ * reference:
+ */
+ last->flag |= REF_KNOWS_PEELED;
+ }
+ }
+
+ strbuf_release(&line);
+}
+
+/*
+ * Get the packed_ref_cache for the specified ref_cache, creating it
+ * if necessary.
+ */
+static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
+{
+ char *packed_refs_file;
+
+ if (*refs->name)
+ packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");
+ else
+ packed_refs_file = git_pathdup("packed-refs");
+
+ if (refs->packed &&
+ !stat_validity_check(&refs->packed->validity, packed_refs_file))
+ clear_packed_ref_cache(refs);
+
+ if (!refs->packed) {
+ FILE *f;
+
+ refs->packed = xcalloc(1, sizeof(*refs->packed));
+ acquire_packed_ref_cache(refs->packed);
+ refs->packed->root = create_dir_entry(refs, "", 0, 0);
+ f = fopen(packed_refs_file, "r");
+ if (f) {
+ stat_validity_update(&refs->packed->validity, fileno(f));
+ read_packed_refs(f, get_ref_dir(refs->packed->root));
+ fclose(f);
+ }
+ }
+ free(packed_refs_file);
+ return refs->packed;
+}
+
+static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
+{
+ return get_ref_dir(packed_ref_cache->root);
+}
+
+static struct ref_dir *get_packed_refs(struct ref_cache *refs)
+{
+ return get_packed_ref_dir(get_packed_ref_cache(refs));
+}
+
+/*
+ * Add a reference to the in-memory packed reference cache. This may
+ * only be called while the packed-refs file is locked (see
+ * lock_packed_refs()). To actually write the packed-refs file, call
+ * commit_packed_refs().
+ */
+static void add_packed_ref(const char *refname, const unsigned char *sha1)
+{
+ struct packed_ref_cache *packed_ref_cache =
+ get_packed_ref_cache(&ref_cache);
+
+ if (!packed_ref_cache->lock)
+ die("internal error: packed refs not locked");
+ add_ref(get_packed_ref_dir(packed_ref_cache),
+ create_ref_entry(refname, sha1, REF_ISPACKED, 1));
+}
+
+/*
+ * Read the loose references from the namespace dirname into dir
+ * (without recursing). dirname must end with '/'. dir must be the
+ * directory entry corresponding to dirname.
+ */
+static void read_loose_refs(const char *dirname, struct ref_dir *dir)
+{
+ struct ref_cache *refs = dir->ref_cache;
+ DIR *d;
+ struct dirent *de;
+ int dirnamelen = strlen(dirname);
+ struct strbuf refname;
+ struct strbuf path = STRBUF_INIT;
+ size_t path_baselen;
+
+ if (*refs->name)
+ strbuf_git_path_submodule(&path, refs->name, "%s", dirname);
+ else
+ strbuf_git_path(&path, "%s", dirname);
+ path_baselen = path.len;
+
+ d = opendir(path.buf);
+ if (!d) {
+ strbuf_release(&path);
+ return;
+ }
+
+ strbuf_init(&refname, dirnamelen + 257);
+ strbuf_add(&refname, dirname, dirnamelen);
+
+ while ((de = readdir(d)) != NULL) {
+ unsigned char sha1[20];
+ struct stat st;
+ int flag;
+
+ if (de->d_name[0] == '.')
+ continue;
+ if (ends_with(de->d_name, ".lock"))
+ continue;
+ strbuf_addstr(&refname, de->d_name);
+ strbuf_addstr(&path, de->d_name);
+ if (stat(path.buf, &st) < 0) {
+ ; /* silently ignore */
+ } else if (S_ISDIR(st.st_mode)) {
+ strbuf_addch(&refname, '/');
+ add_entry_to_dir(dir,
+ create_dir_entry(refs, refname.buf,
+ refname.len, 1));
+ } else {
+ int read_ok;
+
+ if (*refs->name) {
+ hashclr(sha1);
+ flag = 0;
+ read_ok = !resolve_gitlink_ref(refs->name,
+ refname.buf, sha1);
+ } else {
+ read_ok = !read_ref_full(refname.buf,
+ RESOLVE_REF_READING,
+ sha1, &flag);
+ }
+
+ if (!read_ok) {
+ hashclr(sha1);
+ flag |= REF_ISBROKEN;
+ } else if (is_null_sha1(sha1)) {
+ /*
+ * It is so astronomically unlikely
+ * that NULL_SHA1 is the SHA-1 of an
+ * actual object that we consider its
+ * appearance in a loose reference
+ * file to be repo corruption
+ * (probably due to a software bug).
+ */
+ flag |= REF_ISBROKEN;
+ }
+
+ if (check_refname_format(refname.buf,
+ REFNAME_ALLOW_ONELEVEL)) {
+ if (!refname_is_safe(refname.buf))
+ die("loose refname is dangerous: %s", refname.buf);
+ hashclr(sha1);
+ flag |= REF_BAD_NAME | REF_ISBROKEN;
+ }
+ add_entry_to_dir(dir,
+ create_ref_entry(refname.buf, sha1, flag, 0));
+ }
+ strbuf_setlen(&refname, dirnamelen);
+ strbuf_setlen(&path, path_baselen);
+ }
+ strbuf_release(&refname);
+ strbuf_release(&path);
+ closedir(d);
+}
+
+static struct ref_dir *get_loose_refs(struct ref_cache *refs)
+{
+ if (!refs->loose) {
+ /*
+ * Mark the top-level directory complete because we
+ * are about to read the only subdirectory that can
+ * hold references:
+ */
+ refs->loose = create_dir_entry(refs, "", 0, 0);
+ /*
+ * Create an incomplete entry for "refs/":
+ */
+ add_entry_to_dir(get_ref_dir(refs->loose),
+ create_dir_entry(refs, "refs/", 5, 1));
+ }
+ return get_ref_dir(refs->loose);
+}
+
+/* We allow "recursive" symbolic refs. Only within reason, though */
+#define MAXDEPTH 5
+#define MAXREFLEN (1024)
+
+/*
+ * Called by resolve_gitlink_ref_recursive() after it failed to read
+ * from the loose refs in ref_cache refs. Find <refname> in the
+ * packed-refs file for the submodule.
+ */
+static int resolve_gitlink_packed_ref(struct ref_cache *refs,
+ const char *refname, unsigned char *sha1)
+{
+ struct ref_entry *ref;
+ struct ref_dir *dir = get_packed_refs(refs);
+
+ ref = find_ref(dir, refname);
+ if (ref == NULL)
+ return -1;
+
+ hashcpy(sha1, ref->u.value.oid.hash);
+ return 0;
+}
+
+static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
+ const char *refname, unsigned char *sha1,
+ int recursion)
+{
+ int fd, len;
+ char buffer[128], *p;
+ char *path;
+
+ if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
+ return -1;
+ path = *refs->name
+ ? git_pathdup_submodule(refs->name, "%s", refname)
+ : git_pathdup("%s", refname);
+ fd = open(path, O_RDONLY);
+ free(path);
+ if (fd < 0)
+ return resolve_gitlink_packed_ref(refs, refname, sha1);
+
+ len = read(fd, buffer, sizeof(buffer)-1);
+ close(fd);
+ if (len < 0)
+ return -1;
+ while (len && isspace(buffer[len-1]))
+ len--;
+ buffer[len] = 0;
+
+ /* Was it a detached head or an old-fashioned symlink? */
+ if (!get_sha1_hex(buffer, sha1))
+ return 0;
+
+ /* Symref? */
+ if (strncmp(buffer, "ref:", 4))
+ return -1;
+ p = buffer + 4;
+ while (isspace(*p))
+ p++;
+
+ return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
+}
+
+int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
+{
+ int len = strlen(path), retval;
+ char *submodule;
+ struct ref_cache *refs;
+
+ while (len && path[len-1] == '/')
+ len--;
+ if (!len)
+ return -1;
+ submodule = xstrndup(path, len);
+ refs = get_ref_cache(submodule);
+ free(submodule);
+
+ retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
+ return retval;
+}
+
+/*
+ * Return the ref_entry for the given refname from the packed
+ * references. If it does not exist, return NULL.
+ */
+static struct ref_entry *get_packed_ref(const char *refname)
+{
+ return find_ref(get_packed_refs(&ref_cache), refname);
+}
+
+/*
+ * A loose ref file doesn't exist; check for a packed ref. The
+ * options are forwarded from resolve_safe_unsafe().
+ */
+static int resolve_missing_loose_ref(const char *refname,
+ int resolve_flags,
+ unsigned char *sha1,
+ int *flags)
+{
+ struct ref_entry *entry;
+
+ /*
+ * The loose reference file does not exist; check for a packed
+ * reference.
+ */
+ entry = get_packed_ref(refname);
+ if (entry) {
+ hashcpy(sha1, entry->u.value.oid.hash);
+ if (flags)
+ *flags |= REF_ISPACKED;
+ return 0;
+ }
+ /* The reference is not a packed reference, either. */
+ if (resolve_flags & RESOLVE_REF_READING) {
+ errno = ENOENT;
+ return -1;
+ } else {
+ hashclr(sha1);
+ return 0;
+ }
+}
+
+/* This function needs to return a meaningful errno on failure */
+static const char *resolve_ref_1(const char *refname,
+ int resolve_flags,
+ unsigned char *sha1,
+ int *flags,
+ struct strbuf *sb_refname,
+ struct strbuf *sb_path,
+ struct strbuf *sb_contents)
+{
+ int depth = MAXDEPTH;
+ int bad_name = 0;
+
+ if (flags)
+ *flags = 0;
+
+ if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+ if (flags)
+ *flags |= REF_BAD_NAME;
+
+ if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
+ !refname_is_safe(refname)) {
+ errno = EINVAL;
+ return NULL;
+ }
+ /*
+ * dwim_ref() uses REF_ISBROKEN to distinguish between
+ * missing refs and refs that were present but invalid,
+ * to complain about the latter to stderr.
+ *
+ * We don't know whether the ref exists, so don't set
+ * REF_ISBROKEN yet.
+ */
+ bad_name = 1;
+ }
+ for (;;) {
+ const char *path;
+ struct stat st;
+ char *buf;
+ int fd;
+
+ if (--depth < 0) {
+ errno = ELOOP;
+ return NULL;
+ }
+
+ strbuf_reset(sb_path);
+ strbuf_git_path(sb_path, "%s", refname);
+ path = sb_path->buf;
+
+ /*
+ * We might have to loop back here to avoid a race
+ * condition: first we lstat() the file, then we try
+ * to read it as a link or as a file. But if somebody
+ * changes the type of the file (file <-> directory
+ * <-> symlink) between the lstat() and reading, then
+ * we don't want to report that as an error but rather
+ * try again starting with the lstat().
+ */
+ stat_ref:
+ if (lstat(path, &st) < 0) {
+ if (errno != ENOENT)
+ return NULL;
+ if (resolve_missing_loose_ref(refname, resolve_flags,
+ sha1, flags))
+ return NULL;
+ if (bad_name) {
+ hashclr(sha1);
+ if (flags)
+ *flags |= REF_ISBROKEN;
+ }
+ return refname;
+ }
+
+ /* Follow "normalized" - ie "refs/.." symlinks by hand */
+ if (S_ISLNK(st.st_mode)) {
+ strbuf_reset(sb_contents);
+ if (strbuf_readlink(sb_contents, path, 0) < 0) {
+ if (errno == ENOENT || errno == EINVAL)
+ /* inconsistent with lstat; retry */
+ goto stat_ref;
+ else
+ return NULL;
+ }
+ if (starts_with(sb_contents->buf, "refs/") &&
+ !check_refname_format(sb_contents->buf, 0)) {
+ strbuf_swap(sb_refname, sb_contents);
+ refname = sb_refname->buf;
+ if (flags)
+ *flags |= REF_ISSYMREF;
+ if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
+ hashclr(sha1);
+ return refname;
+ }
+ continue;
+ }
+ }
+
+ /* Is it a directory? */
+ if (S_ISDIR(st.st_mode)) {
+ errno = EISDIR;
+ return NULL;
+ }
+
+ /*
+ * Anything else, just open it and try to use it as
+ * a ref
+ */
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ /* inconsistent with lstat; retry */
+ goto stat_ref;
+ else
+ return NULL;
+ }
+ strbuf_reset(sb_contents);
+ if (strbuf_read(sb_contents, fd, 256) < 0) {
+ int save_errno = errno;
+ close(fd);
+ errno = save_errno;
+ return NULL;
+ }
+ close(fd);
+ strbuf_rtrim(sb_contents);
+
+ /*
+ * Is it a symbolic ref?
+ */
+ if (!starts_with(sb_contents->buf, "ref:")) {
+ /*
+ * Please note that FETCH_HEAD has a second
+ * line containing other data.
+ */
+ if (get_sha1_hex(sb_contents->buf, sha1) ||
+ (sb_contents->buf[40] != '\0' && !isspace(sb_contents->buf[40]))) {
+ if (flags)
+ *flags |= REF_ISBROKEN;
+ errno = EINVAL;
+ return NULL;
+ }
+ if (bad_name) {
+ hashclr(sha1);
+ if (flags)
+ *flags |= REF_ISBROKEN;
+ }
+ return refname;
+ }
+ if (flags)
+ *flags |= REF_ISSYMREF;
+ buf = sb_contents->buf + 4;
+ while (isspace(*buf))
+ buf++;
+ strbuf_reset(sb_refname);
+ strbuf_addstr(sb_refname, buf);
+ refname = sb_refname->buf;
+ if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
+ hashclr(sha1);
+ return refname;
+ }
+ if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
+ if (flags)
+ *flags |= REF_ISBROKEN;
+
+ if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
+ !refname_is_safe(buf)) {
+ errno = EINVAL;
+ return NULL;
+ }
+ bad_name = 1;
+ }
+ }
+}
+
+const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
+ unsigned char *sha1, int *flags)
+{
+ static struct strbuf sb_refname = STRBUF_INIT;
+ struct strbuf sb_contents = STRBUF_INIT;
+ struct strbuf sb_path = STRBUF_INIT;
+ const char *ret;
+
+ ret = resolve_ref_1(refname, resolve_flags, sha1, flags,
+ &sb_refname, &sb_path, &sb_contents);
+ strbuf_release(&sb_path);
+ strbuf_release(&sb_contents);
+ return ret;
+}
+
+/*
+ * Peel the entry (if possible) and return its new peel_status. If
+ * repeel is true, re-peel the entry even if there is an old peeled
+ * value that is already stored in it.
+ *
+ * It is OK to call this function with a packed reference entry that
+ * might be stale and might even refer to an object that has since
+ * been garbage-collected. In such a case, if the entry has
+ * REF_KNOWS_PEELED then leave the status unchanged and return
+ * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
+ */
+static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
+{
+ enum peel_status status;
+
+ if (entry->flag & REF_KNOWS_PEELED) {
+ if (repeel) {
+ entry->flag &= ~REF_KNOWS_PEELED;
+ oidclr(&entry->u.value.peeled);
+ } else {
+ return is_null_oid(&entry->u.value.peeled) ?
+ PEEL_NON_TAG : PEEL_PEELED;
+ }
+ }
+ if (entry->flag & REF_ISBROKEN)
+ return PEEL_BROKEN;
+ if (entry->flag & REF_ISSYMREF)
+ return PEEL_IS_SYMREF;
+
+ status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
+ if (status == PEEL_PEELED || status == PEEL_NON_TAG)
+ entry->flag |= REF_KNOWS_PEELED;
+ return status;
+}
+
+int peel_ref(const char *refname, unsigned char *sha1)
+{
+ int flag;
+ unsigned char base[20];
+
+ if (current_ref && (current_ref->name == refname
+ || !strcmp(current_ref->name, refname))) {
+ if (peel_entry(current_ref, 0))
+ return -1;
+ hashcpy(sha1, current_ref->u.value.peeled.hash);
+ return 0;
+ }
+
+ if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
+ return -1;
+
+ /*
+ * If the reference is packed, read its ref_entry from the
+ * cache in the hope that we already know its peeled value.
+ * We only try this optimization on packed references because
+ * (a) forcing the filling of the loose reference cache could
+ * be expensive and (b) loose references anyway usually do not
+ * have REF_KNOWS_PEELED.
+ */
+ if (flag & REF_ISPACKED) {
+ struct ref_entry *r = get_packed_ref(refname);
+ if (r) {
+ if (peel_entry(r, 0))
+ return -1;
+ hashcpy(sha1, r->u.value.peeled.hash);
+ return 0;
+ }
+ }
+
+ return peel_object(base, sha1);
+}
+
+/*
+ * Call fn for each reference in the specified ref_cache, omitting
+ * references not in the containing_dir of base. fn is called for all
+ * references, including broken ones. If fn ever returns a non-zero
+ * value, stop the iteration and return that value; otherwise, return
+ * 0.
+ */
+static int do_for_each_entry(struct ref_cache *refs, const char *base,
+ each_ref_entry_fn fn, void *cb_data)
+{
+ struct packed_ref_cache *packed_ref_cache;
+ struct ref_dir *loose_dir;
+ struct ref_dir *packed_dir;
+ int retval = 0;
+
+ /*
+ * We must make sure that all loose refs are read before accessing the
+ * packed-refs file; this avoids a race condition in which loose refs
+ * are migrated to the packed-refs file by a simultaneous process, but
+ * our in-memory view is from before the migration. get_packed_ref_cache()
+ * takes care of making sure our view is up to date with what is on
+ * disk.
+ */
+ loose_dir = get_loose_refs(refs);
+ if (base && *base) {
+ loose_dir = find_containing_dir(loose_dir, base, 0);
+ }
+ if (loose_dir)
+ prime_ref_dir(loose_dir);
+
+ packed_ref_cache = get_packed_ref_cache(refs);
+ acquire_packed_ref_cache(packed_ref_cache);
+ packed_dir = get_packed_ref_dir(packed_ref_cache);
+ if (base && *base) {
+ packed_dir = find_containing_dir(packed_dir, base, 0);
+ }
+
+ if (packed_dir && loose_dir) {
+ sort_ref_dir(packed_dir);
+ sort_ref_dir(loose_dir);
+ retval = do_for_each_entry_in_dirs(
+ packed_dir, loose_dir, fn, cb_data);
+ } else if (packed_dir) {
+ sort_ref_dir(packed_dir);
+ retval = do_for_each_entry_in_dir(
+ packed_dir, 0, fn, cb_data);
+ } else if (loose_dir) {
+ sort_ref_dir(loose_dir);
+ retval = do_for_each_entry_in_dir(
+ loose_dir, 0, fn, cb_data);
+ }
+
+ release_packed_ref_cache(packed_ref_cache);
+ return retval;
+}
+
+/*
+ * Call fn for each reference in the specified ref_cache for which the
+ * refname begins with base. If trim is non-zero, then trim that many
+ * characters off the beginning of each refname before passing the
+ * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
+ * broken references in the iteration. If fn ever returns a non-zero
+ * value, stop the iteration and return that value; otherwise, return
+ * 0.
+ */
+static int do_for_each_ref(struct ref_cache *refs, const char *base,
+ each_ref_fn fn, int trim, int flags, void *cb_data)
+{
+ struct ref_entry_cb data;
+ data.base = base;
+ data.trim = trim;
+ data.flags = flags;
+ data.fn = fn;
+ data.cb_data = cb_data;
+
+ if (ref_paranoia < 0)
+ ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
+ if (ref_paranoia)
+ data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
+
+ return do_for_each_entry(refs, base, do_one_ref, &data);
+}
+
+static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
+{
+ struct object_id oid;
+ int flag;
+
+ if (submodule) {
+ if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
+ return fn("HEAD", &oid, 0, cb_data);
+
+ return 0;
+ }
+
+ if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
+ return fn("HEAD", &oid, flag, cb_data);
+
+ return 0;
+}
+
+int head_ref(each_ref_fn fn, void *cb_data)
+{
+ return do_head_ref(NULL, fn, cb_data);
+}
+
+int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
+{
+ return do_head_ref(submodule, fn, cb_data);
+}
+
+int for_each_ref(each_ref_fn fn, void *cb_data)
+{
+ return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
+}
+
+int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
+{
+ return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
+}
+
+int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
+{
+ return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
+}
+
+int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
+{
+ unsigned int flag = 0;
+
+ if (broken)
+ flag = DO_FOR_EACH_INCLUDE_BROKEN;
+ return do_for_each_ref(&ref_cache, prefix, fn, 0, flag, cb_data);
+}
+
+int for_each_ref_in_submodule(const char *submodule, const char *prefix,
+ each_ref_fn fn, void *cb_data)
+{
+ return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
+}
+
+int for_each_replace_ref(each_ref_fn fn, void *cb_data)
+{
+ return do_for_each_ref(&ref_cache, git_replace_ref_base, fn,
+ strlen(git_replace_ref_base), 0, cb_data);
+}
+
+int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
+{
+ struct strbuf buf = STRBUF_INIT;
+ int ret;
+ strbuf_addf(&buf, "%srefs/", get_git_namespace());
+ ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
+ strbuf_release(&buf);
+ return ret;
+}
+
+int for_each_rawref(each_ref_fn fn, void *cb_data)
+{
+ return do_for_each_ref(&ref_cache, "", fn, 0,
+ DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
+}
+
+static void unlock_ref(struct ref_lock *lock)
+{
+ /* Do not free lock->lk -- atexit() still looks at them */
+ if (lock->lk)
+ rollback_lock_file(lock->lk);
+ free(lock->ref_name);
+ free(lock->orig_ref_name);
+ free(lock);
+}
+
+/*
+ * Verify that the reference locked by lock has the value old_sha1.
+ * Fail if the reference doesn't exist and mustexist is set. Return 0
+ * on success. On error, write an error message to err, set errno, and
+ * return a negative value.
+ */
+static int verify_lock(struct ref_lock *lock,
+ const unsigned char *old_sha1, int mustexist,
+ struct strbuf *err)
+{
+ assert(err);
+
+ if (read_ref_full(lock->ref_name,
+ mustexist ? RESOLVE_REF_READING : 0,
+ lock->old_oid.hash, NULL)) {
+ int save_errno = errno;
+ strbuf_addf(err, "can't verify ref %s", lock->ref_name);
+ errno = save_errno;
+ return -1;
+ }
+ if (hashcmp(lock->old_oid.hash, old_sha1)) {
+ strbuf_addf(err, "ref %s is at %s but expected %s",
+ lock->ref_name,
+ sha1_to_hex(lock->old_oid.hash),
+ sha1_to_hex(old_sha1));
+ errno = EBUSY;
+ return -1;
+ }
+ return 0;
+}
+
+static int remove_empty_directories(struct strbuf *path)
+{
+ /*
+ * we want to create a file but there is a directory there;
+ * if that is an empty directory (or a directory that contains
+ * only empty directories), remove them.
+ */
+ return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
+}
+
+/*
+ * Locks a ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
+static struct ref_lock *lock_ref_sha1_basic(const char *refname,
+ const unsigned char *old_sha1,
+ const struct string_list *extras,
+ const struct string_list *skip,
+ unsigned int flags, int *type_p,
+ struct strbuf *err)
+{
+ struct strbuf ref_file = STRBUF_INIT;
+ struct strbuf orig_ref_file = STRBUF_INIT;
+ const char *orig_refname = refname;
+ struct ref_lock *lock;
+ int last_errno = 0;
+ int type, lflags;
+ int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
+ int resolve_flags = 0;
+ int attempts_remaining = 3;
+
+ assert(err);
+
+ lock = xcalloc(1, sizeof(struct ref_lock));
+
+ if (mustexist)
+ resolve_flags |= RESOLVE_REF_READING;
+ if (flags & REF_DELETING) {
+ resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
+ if (flags & REF_NODEREF)
+ resolve_flags |= RESOLVE_REF_NO_RECURSE;
+ }
+
+ refname = resolve_ref_unsafe(refname, resolve_flags,
+ lock->old_oid.hash, &type);
+ if (!refname && errno == EISDIR) {
+ /*
+ * we are trying to lock foo but we used to
+ * have foo/bar which now does not exist;
+ * it is normal for the empty directory 'foo'
+ * to remain.
+ */
+ strbuf_git_path(&orig_ref_file, "%s", orig_refname);
+ if (remove_empty_directories(&orig_ref_file)) {
+ last_errno = errno;
+ if (!verify_refname_available_dir(orig_refname, extras, skip,
+ get_loose_refs(&ref_cache), err))
+ strbuf_addf(err, "there are still refs under '%s'",
+ orig_refname);
+ goto error_return;
+ }
+ refname = resolve_ref_unsafe(orig_refname, resolve_flags,
+ lock->old_oid.hash, &type);
+ }
+ if (type_p)
+ *type_p = type;
+ if (!refname) {
+ last_errno = errno;
+ if (last_errno != ENOTDIR ||
+ !verify_refname_available_dir(orig_refname, extras, skip,
+ get_loose_refs(&ref_cache), err))
+ strbuf_addf(err, "unable to resolve reference %s: %s",
+ orig_refname, strerror(last_errno));
+
+ goto error_return;
+ }
+ /*
+ * If the ref did not exist and we are creating it, make sure
+ * there is no existing packed ref whose name begins with our
+ * refname, nor a packed ref whose name is a proper prefix of
+ * our refname.
+ */
+ if (is_null_oid(&lock->old_oid) &&
+ verify_refname_available_dir(refname, extras, skip,
+ get_packed_refs(&ref_cache), err)) {
+ last_errno = ENOTDIR;
+ goto error_return;
+ }
+
+ lock->lk = xcalloc(1, sizeof(struct lock_file));
+
+ lflags = 0;
+ if (flags & REF_NODEREF) {
+ refname = orig_refname;
+ lflags |= LOCK_NO_DEREF;
+ }
+ lock->ref_name = xstrdup(refname);
+ lock->orig_ref_name = xstrdup(orig_refname);
+ strbuf_git_path(&ref_file, "%s", refname);
+
+ retry:
+ switch (safe_create_leading_directories_const(ref_file.buf)) {
+ case SCLD_OK:
+ break; /* success */
+ case SCLD_VANISHED:
+ if (--attempts_remaining > 0)
+ goto retry;
+ /* fall through */
+ default:
+ last_errno = errno;
+ strbuf_addf(err, "unable to create directory for %s",
+ ref_file.buf);
+ goto error_return;
+ }
+
+ if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
+ last_errno = errno;
+ if (errno == ENOENT && --attempts_remaining > 0)
+ /*
+ * Maybe somebody just deleted one of the
+ * directories leading to ref_file. Try
+ * again:
+ */
+ goto retry;
+ else {
+ unable_to_lock_message(ref_file.buf, errno, err);
+ goto error_return;
+ }
+ }
+ if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
+ last_errno = errno;
+ goto error_return;
+ }
+ goto out;
+
+ error_return:
+ unlock_ref(lock);
+ lock = NULL;
+
+ out:
+ strbuf_release(&ref_file);
+ strbuf_release(&orig_ref_file);
+ errno = last_errno;
+ return lock;
+}
+
+/*
+ * Write an entry to the packed-refs file for the specified refname.
+ * If peeled is non-NULL, write it as the entry's peeled value.
+ */
+static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
+ unsigned char *peeled)
+{
+ fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
+ if (peeled)
+ fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
+}
+
+/*
+ * An each_ref_entry_fn that writes the entry to a packed-refs file.
+ */
+static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
+{
+ enum peel_status peel_status = peel_entry(entry, 0);
+
+ if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
+ error("internal error: %s is not a valid packed reference!",
+ entry->name);
+ write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
+ peel_status == PEEL_PEELED ?
+ entry->u.value.peeled.hash : NULL);
+ return 0;
+}
+
+/*
+ * Lock the packed-refs file for writing. Flags is passed to
+ * hold_lock_file_for_update(). Return 0 on success. On errors, set
+ * errno appropriately and return a nonzero value.
+ */
+static int lock_packed_refs(int flags)
+{
+ static int timeout_configured = 0;
+ static int timeout_value = 1000;
+
+ struct packed_ref_cache *packed_ref_cache;
+
+ if (!timeout_configured) {
+ git_config_get_int("core.packedrefstimeout", &timeout_value);
+ timeout_configured = 1;
+ }
+
+ if (hold_lock_file_for_update_timeout(
+ &packlock, git_path("packed-refs"),
+ flags, timeout_value) < 0)
+ return -1;
+ /*
+ * Get the current packed-refs while holding the lock. If the
+ * packed-refs file has been modified since we last read it,
+ * this will automatically invalidate the cache and re-read
+ * the packed-refs file.
+ */
+ packed_ref_cache = get_packed_ref_cache(&ref_cache);
+ packed_ref_cache->lock = &packlock;
+ /* Increment the reference count to prevent it from being freed: */
+ acquire_packed_ref_cache(packed_ref_cache);
+ return 0;
+}
+
+/*
+ * Write the current version of the packed refs cache from memory to
+ * disk. The packed-refs file must already be locked for writing (see
+ * lock_packed_refs()). Return zero on success. On errors, set errno
+ * and return a nonzero value
+ */
+static int commit_packed_refs(void)
+{
+ struct packed_ref_cache *packed_ref_cache =
+ get_packed_ref_cache(&ref_cache);
+ int error = 0;
+ int save_errno = 0;
+ FILE *out;
+
+ if (!packed_ref_cache->lock)
+ die("internal error: packed-refs not locked");
+
+ out = fdopen_lock_file(packed_ref_cache->lock, "w");
+ if (!out)
+ die_errno("unable to fdopen packed-refs descriptor");
+
+ fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
+ do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
+ 0, write_packed_entry_fn, out);
+
+ if (commit_lock_file(packed_ref_cache->lock)) {
+ save_errno = errno;
+ error = -1;
+ }
+ packed_ref_cache->lock = NULL;
+ release_packed_ref_cache(packed_ref_cache);
+ errno = save_errno;
+ return error;
+}
+
+/*
+ * Rollback the lockfile for the packed-refs file, and discard the
+ * in-memory packed reference cache. (The packed-refs file will be
+ * read anew if it is needed again after this function is called.)
+ */
+static void rollback_packed_refs(void)
+{
+ struct packed_ref_cache *packed_ref_cache =
+ get_packed_ref_cache(&ref_cache);
+
+ if (!packed_ref_cache->lock)
+ die("internal error: packed-refs not locked");
+ rollback_lock_file(packed_ref_cache->lock);
+ packed_ref_cache->lock = NULL;
+ release_packed_ref_cache(packed_ref_cache);
+ clear_packed_ref_cache(&ref_cache);
+}
+
+struct ref_to_prune {
+ struct ref_to_prune *next;
+ unsigned char sha1[20];
+ char name[FLEX_ARRAY];
+};
+
+struct pack_refs_cb_data {
+ unsigned int flags;
+ struct ref_dir *packed_refs;
+ struct ref_to_prune *ref_to_prune;
+};
+
+/*
+ * An each_ref_entry_fn that is run over loose references only. If
+ * the loose reference can be packed, add an entry in the packed ref
+ * cache. If the reference should be pruned, also add it to
+ * ref_to_prune in the pack_refs_cb_data.
+ */
+static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
+{
+ struct pack_refs_cb_data *cb = cb_data;
+ enum peel_status peel_status;
+ struct ref_entry *packed_entry;
+ int is_tag_ref = starts_with(entry->name, "refs/tags/");
+
+ /* Do not pack per-worktree refs: */
+ if (ref_type(entry->name) != REF_TYPE_NORMAL)
+ return 0;
+
+ /* ALWAYS pack tags */
+ if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
+ return 0;
+
+ /* Do not pack symbolic or broken refs: */
+ if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
+ return 0;
+
+ /* Add a packed ref cache entry equivalent to the loose entry. */
+ peel_status = peel_entry(entry, 1);
+ if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
+ die("internal error peeling reference %s (%s)",
+ entry->name, oid_to_hex(&entry->u.value.oid));
+ packed_entry = find_ref(cb->packed_refs, entry->name);
+ if (packed_entry) {
+ /* Overwrite existing packed entry with info from loose entry */
+ packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
+ oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
+ } else {
+ packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
+ REF_ISPACKED | REF_KNOWS_PEELED, 0);
+ add_ref(cb->packed_refs, packed_entry);
+ }
+ oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
+
+ /* Schedule the loose reference for pruning if requested. */
+ if ((cb->flags & PACK_REFS_PRUNE)) {
+ int namelen = strlen(entry->name) + 1;
+ struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
+ hashcpy(n->sha1, entry->u.value.oid.hash);
+ memcpy(n->name, entry->name, namelen); /* includes NUL */
+ n->next = cb->ref_to_prune;
+ cb->ref_to_prune = n;
+ }
+ return 0;
+}
+
+/*
+ * Remove empty parents, but spare refs/ and immediate subdirs.
+ * Note: munges *name.
+ */
+static void try_remove_empty_parents(char *name)
+{
+ char *p, *q;
+ int i;
+ p = name;
+ for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
+ while (*p && *p != '/')
+ p++;
+ /* tolerate duplicate slashes; see check_refname_format() */
+ while (*p == '/')
+ p++;
+ }
+ for (q = p; *q; q++)
+ ;
+ while (1) {
+ while (q > p && *q != '/')
+ q--;
+ while (q > p && *(q-1) == '/')
+ q--;
+ if (q == p)
+ break;
+ *q = '\0';
+ if (rmdir(git_path("%s", name)))
+ break;
+ }
+}
+
+/* make sure nobody touched the ref, and unlink */
+static void prune_ref(struct ref_to_prune *r)
+{
+ struct ref_transaction *transaction;
+ struct strbuf err = STRBUF_INIT;
+
+ if (check_refname_format(r->name, 0))
+ return;
+
+ transaction = ref_transaction_begin(&err);
+ if (!transaction ||
+ ref_transaction_delete(transaction, r->name, r->sha1,
+ REF_ISPRUNING, NULL, &err) ||
+ ref_transaction_commit(transaction, &err)) {
+ ref_transaction_free(transaction);
+ error("%s", err.buf);
+ strbuf_release(&err);
+ return;
+ }
+ ref_transaction_free(transaction);
+ strbuf_release(&err);
+ try_remove_empty_parents(r->name);
+}
+
+static void prune_refs(struct ref_to_prune *r)
+{
+ while (r) {
+ prune_ref(r);
+ r = r->next;
+ }
+}
+
+int pack_refs(unsigned int flags)
+{
+ struct pack_refs_cb_data cbdata;
+
+ memset(&cbdata, 0, sizeof(cbdata));
+ cbdata.flags = flags;
+
+ lock_packed_refs(LOCK_DIE_ON_ERROR);
+ cbdata.packed_refs = get_packed_refs(&ref_cache);
+
+ do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
+ pack_if_possible_fn, &cbdata);
+
+ if (commit_packed_refs())
+ die_errno("unable to overwrite old ref-pack file");
+
+ prune_refs(cbdata.ref_to_prune);
+ return 0;
+}
+
+/*
+ * Rewrite the packed-refs file, omitting any refs listed in
+ * 'refnames'. On error, leave packed-refs unchanged, write an error
+ * message to 'err', and return a nonzero value.
+ *
+ * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
+ */
+static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
+{
+ struct ref_dir *packed;
+ struct string_list_item *refname;
+ int ret, needs_repacking = 0, removed = 0;
+
+ assert(err);
+
+ /* Look for a packed ref */
+ for_each_string_list_item(refname, refnames) {
+ if (get_packed_ref(refname->string)) {
+ needs_repacking = 1;
+ break;
+ }
+ }
+
+ /* Avoid locking if we have nothing to do */
+ if (!needs_repacking)
+ return 0; /* no refname exists in packed refs */
+
+ if (lock_packed_refs(0)) {
+ unable_to_lock_message(git_path("packed-refs"), errno, err);
+ return -1;
+ }
+ packed = get_packed_refs(&ref_cache);
+
+ /* Remove refnames from the cache */
+ for_each_string_list_item(refname, refnames)
+ if (remove_entry(packed, refname->string) != -1)
+ removed = 1;
+ if (!removed) {
+ /*
+ * All packed entries disappeared while we were
+ * acquiring the lock.
+ */
+ rollback_packed_refs();
+ return 0;
+ }
+
+ /* Write what remains */
+ ret = commit_packed_refs();
+ if (ret)
+ strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
+ strerror(errno));
+ return ret;
+}
+
+static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
+{
+ assert(err);
+
+ if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
+ /*
+ * loose. The loose file name is the same as the
+ * lockfile name, minus ".lock":
+ */
+ char *loose_filename = get_locked_file_path(lock->lk);
+ int res = unlink_or_msg(loose_filename, err);
+ free(loose_filename);
+ if (res)
+ return 1;
+ }
+ return 0;
+}
+
+int delete_refs(struct string_list *refnames)
+{
+ struct strbuf err = STRBUF_INIT;
+ int i, result = 0;
+
+ if (!refnames->nr)
+ return 0;
+
+ result = repack_without_refs(refnames, &err);
+ if (result) {
+ /*
+ * If we failed to rewrite the packed-refs file, then
+ * it is unsafe to try to remove loose refs, because
+ * doing so might expose an obsolete packed value for
+ * a reference that might even point at an object that
+ * has been garbage collected.
+ */
+ if (refnames->nr == 1)
+ error(_("could not delete reference %s: %s"),
+ refnames->items[0].string, err.buf);
+ else
+ error(_("could not delete references: %s"), err.buf);
+
+ goto out;
+ }
+
+ for (i = 0; i < refnames->nr; i++) {
+ const char *refname = refnames->items[i].string;
+
+ if (delete_ref(refname, NULL, 0))
+ result |= error(_("could not remove reference %s"), refname);
+ }
+
+out:
+ strbuf_release(&err);
+ return result;
+}
+
+/*
+ * People using contrib's git-new-workdir have .git/logs/refs ->
+ * /some/other/path/.git/logs/refs, and that may live on another device.
+ *
+ * IOW, to avoid cross device rename errors, the temporary renamed log must
+ * live into logs/refs.
+ */
+#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
+
+static int rename_tmp_log(const char *newrefname)
+{
+ int attempts_remaining = 4;
+ struct strbuf path = STRBUF_INIT;
+ int ret = -1;
+
+ retry:
+ strbuf_reset(&path);
+ strbuf_git_path(&path, "logs/%s", newrefname);
+ switch (safe_create_leading_directories_const(path.buf)) {
+ case SCLD_OK:
+ break; /* success */
+ case SCLD_VANISHED:
+ if (--attempts_remaining > 0)
+ goto retry;
+ /* fall through */
+ default:
+ error("unable to create directory for %s", newrefname);
+ goto out;
+ }
+
+ if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
+ if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
+ /*
+ * rename(a, b) when b is an existing
+ * directory ought to result in ISDIR, but
+ * Solaris 5.8 gives ENOTDIR. Sheesh.
+ */
+ if (remove_empty_directories(&path)) {
+ error("Directory not empty: logs/%s", newrefname);
+ goto out;
+ }
+ goto retry;
+ } else if (errno == ENOENT && --attempts_remaining > 0) {
+ /*
+ * Maybe another process just deleted one of
+ * the directories in the path to newrefname.
+ * Try again from the beginning.
+ */
+ goto retry;
+ } else {
+ error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
+ newrefname, strerror(errno));
+ goto out;
+ }
+ }
+ ret = 0;
+out:
+ strbuf_release(&path);
+ return ret;
+}
+
+int verify_refname_available(const char *newname,
+ struct string_list *extras,
+ struct string_list *skip,
+ struct strbuf *err)
+{
+ struct ref_dir *packed_refs = get_packed_refs(&ref_cache);
+ struct ref_dir *loose_refs = get_loose_refs(&ref_cache);
+
+ if (verify_refname_available_dir(newname, extras, skip,
+ packed_refs, err) ||
+ verify_refname_available_dir(newname, extras, skip,
+ loose_refs, err))
+ return -1;
+
+ return 0;
+}
+
+static int write_ref_to_lockfile(struct ref_lock *lock,
+ const unsigned char *sha1, struct strbuf *err);
+static int commit_ref_update(struct ref_lock *lock,
+ const unsigned char *sha1, const char *logmsg,
+ int flags, struct strbuf *err);
+
+int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
+{
+ unsigned char sha1[20], orig_sha1[20];
+ int flag = 0, logmoved = 0;
+ struct ref_lock *lock;
+ struct stat loginfo;
+ int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+ const char *symref = NULL;
+ struct strbuf err = STRBUF_INIT;
+
+ if (log && S_ISLNK(loginfo.st_mode))
+ return error("reflog for %s is a symlink", oldrefname);
+
+ symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
+ orig_sha1, &flag);
+ if (flag & REF_ISSYMREF)
+ return error("refname %s is a symbolic ref, renaming it is not supported",
+ oldrefname);
+ if (!symref)
+ return error("refname %s not found", oldrefname);
+
+ if (!rename_ref_available(oldrefname, newrefname))
+ return 1;
+
+ if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
+ return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
+ oldrefname, strerror(errno));
+
+ if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
+ error("unable to delete old %s", oldrefname);
+ goto rollback;
+ }
+
+ if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
+ delete_ref(newrefname, sha1, REF_NODEREF)) {
+ if (errno==EISDIR) {
+ struct strbuf path = STRBUF_INIT;
+ int result;
+
+ strbuf_git_path(&path, "%s", newrefname);
+ result = remove_empty_directories(&path);
+ strbuf_release(&path);
+
+ if (result) {
+ error("Directory not empty: %s", newrefname);
+ goto rollback;
+ }
+ } else {
+ error("unable to delete existing %s", newrefname);
+ goto rollback;
+ }
+ }
+
+ if (log && rename_tmp_log(newrefname))
+ goto rollback;
+
+ logmoved = log;
+
+ lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
+ if (!lock) {
+ error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+ strbuf_release(&err);
+ goto rollback;
+ }
+ hashcpy(lock->old_oid.hash, orig_sha1);
+
+ if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
+ commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
+ error("unable to write current sha1 into %s: %s", newrefname, err.buf);
+ strbuf_release(&err);
+ goto rollback;
+ }
+
+ return 0;
+
+ rollback:
+ lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
+ if (!lock) {
+ error("unable to lock %s for rollback: %s", oldrefname, err.buf);
+ strbuf_release(&err);
+ goto rollbacklog;
+ }
+
+ flag = log_all_ref_updates;
+ log_all_ref_updates = 0;
+ if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
+ commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
+ error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
+ strbuf_release(&err);
+ }
+ log_all_ref_updates = flag;
+
+ rollbacklog:
+ if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+ error("unable to restore logfile %s from %s: %s",
+ oldrefname, newrefname, strerror(errno));
+ if (!logmoved && log &&
+ rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
+ error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
+ oldrefname, strerror(errno));
+
+ return 1;
+}
+
+static int close_ref(struct ref_lock *lock)
+{
+ if (close_lock_file(lock->lk))
+ return -1;
+ return 0;
+}
+
+static int commit_ref(struct ref_lock *lock)
+{
+ if (commit_lock_file(lock->lk))
+ return -1;
+ return 0;
+}
+
+/*
+ * Create a reflog for a ref. If force_create = 0, the reflog will
+ * only be created for certain refs (those for which
+ * should_autocreate_reflog returns non-zero. Otherwise, create it
+ * regardless of the ref name. Fill in *err and return -1 on failure.
+ */
+static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
+{
+ int logfd, oflags = O_APPEND | O_WRONLY;
+
+ strbuf_git_path(logfile, "logs/%s", refname);
+ if (force_create || should_autocreate_reflog(refname)) {
+ if (safe_create_leading_directories(logfile->buf) < 0) {
+ strbuf_addf(err, "unable to create directory for %s: "
+ "%s", logfile->buf, strerror(errno));
+ return -1;
+ }
+ oflags |= O_CREAT;
+ }
+
+ logfd = open(logfile->buf, oflags, 0666);
+ if (logfd < 0) {
+ if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
+ return 0;
+
+ if (errno == EISDIR) {
+ if (remove_empty_directories(logfile)) {
+ strbuf_addf(err, "There are still logs under "
+ "'%s'", logfile->buf);
+ return -1;
+ }
+ logfd = open(logfile->buf, oflags, 0666);
+ }
+
+ if (logfd < 0) {
+ strbuf_addf(err, "unable to append to %s: %s",
+ logfile->buf, strerror(errno));
+ return -1;
+ }
+ }
+
+ adjust_shared_perm(logfile->buf);
+ close(logfd);
+ return 0;
+}
+
+
+int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
+{
+ int ret;
+ struct strbuf sb = STRBUF_INIT;
+
+ ret = log_ref_setup(refname, &sb, err, force_create);
+ strbuf_release(&sb);
+ return ret;
+}
+
+static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
+ const unsigned char *new_sha1,
+ const char *committer, const char *msg)
+{
+ int msglen, written;
+ unsigned maxlen, len;
+ char *logrec;
+
+ msglen = msg ? strlen(msg) : 0;
+ maxlen = strlen(committer) + msglen + 100;
+ logrec = xmalloc(maxlen);
+ len = xsnprintf(logrec, maxlen, "%s %s %s\n",
+ sha1_to_hex(old_sha1),
+ sha1_to_hex(new_sha1),
+ committer);
+ if (msglen)
+ len += copy_reflog_msg(logrec + len - 1, msg) - 1;
+
+ written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
+ free(logrec);
+ if (written != len)
+ return -1;
+
+ return 0;
+}
+
+static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
+ const unsigned char *new_sha1, const char *msg,
+ struct strbuf *logfile, int flags,
+ struct strbuf *err)
+{
+ int logfd, result, oflags = O_APPEND | O_WRONLY;
+
+ if (log_all_ref_updates < 0)
+ log_all_ref_updates = !is_bare_repository();
+
+ result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
+
+ if (result)
+ return result;
+
+ logfd = open(logfile->buf, oflags);
+ if (logfd < 0)
+ return 0;
+ result = log_ref_write_fd(logfd, old_sha1, new_sha1,
+ git_committer_info(0), msg);
+ if (result) {
+ strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
+ strerror(errno));
+ close(logfd);
+ return -1;
+ }
+ if (close(logfd)) {
+ strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
+ strerror(errno));
+ return -1;
+ }
+ return 0;
+}
+
+static int log_ref_write(const char *refname, const unsigned char *old_sha1,
+ const unsigned char *new_sha1, const char *msg,
+ int flags, struct strbuf *err)
+{
+ return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
+ err);
+}
+
+int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+ const unsigned char *new_sha1, const char *msg,
+ int flags, struct strbuf *err)
+{
+ struct strbuf sb = STRBUF_INIT;
+ int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
+ err);
+ strbuf_release(&sb);
+ return ret;
+}
+
+/*
+ * Write sha1 into the open lockfile, then close the lockfile. On
+ * errors, rollback the lockfile, fill in *err and
+ * return -1.
+ */
+static int write_ref_to_lockfile(struct ref_lock *lock,
+ const unsigned char *sha1, struct strbuf *err)
+{
+ static char term = '\n';
+ struct object *o;
+ int fd;
+
+ o = parse_object(sha1);
+ if (!o) {
+ strbuf_addf(err,
+ "Trying to write ref %s with nonexistent object %s",
+ lock->ref_name, sha1_to_hex(sha1));
+ unlock_ref(lock);
+ return -1;
+ }
+ if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
+ strbuf_addf(err,
+ "Trying to write non-commit object %s to branch %s",
+ sha1_to_hex(sha1), lock->ref_name);
+ unlock_ref(lock);
+ return -1;
+ }
+ fd = get_lock_file_fd(lock->lk);
+ if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
+ write_in_full(fd, &term, 1) != 1 ||
+ close_ref(lock) < 0) {
+ strbuf_addf(err,
+ "Couldn't write %s", get_lock_file_path(lock->lk));
+ unlock_ref(lock);
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * Commit a change to a loose reference that has already been written
+ * to the loose reference lockfile. Also update the reflogs if
+ * necessary, using the specified lockmsg (which can be NULL).
+ */
+static int commit_ref_update(struct ref_lock *lock,
+ const unsigned char *sha1, const char *logmsg,
+ int flags, struct strbuf *err)
+{
+ clear_loose_ref_cache(&ref_cache);
+ if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
+ (strcmp(lock->ref_name, lock->orig_ref_name) &&
+ log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
+ char *old_msg = strbuf_detach(err, NULL);
+ strbuf_addf(err, "Cannot update the ref '%s': %s",
+ lock->ref_name, old_msg);
+ free(old_msg);
+ unlock_ref(lock);
+ return -1;
+ }
+ if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
+ /*
+ * Special hack: If a branch is updated directly and HEAD
+ * points to it (may happen on the remote side of a push
+ * for example) then logically the HEAD reflog should be
+ * updated too.
+ * A generic solution implies reverse symref information,
+ * but finding all symrefs pointing to the given branch
+ * would be rather costly for this rare event (the direct
+ * update of a branch) to be worth it. So let's cheat and
+ * check with HEAD only which should cover 99% of all usage
+ * scenarios (even 100% of the default ones).
+ */
+ unsigned char head_sha1[20];
+ int head_flag;
+ const char *head_ref;
+ head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
+ head_sha1, &head_flag);
+ if (head_ref && (head_flag & REF_ISSYMREF) &&
+ !strcmp(head_ref, lock->ref_name)) {
+ struct strbuf log_err = STRBUF_INIT;
+ if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
+ logmsg, 0, &log_err)) {
+ error("%s", log_err.buf);
+ strbuf_release(&log_err);
+ }
+ }
+ }
+ if (commit_ref(lock)) {
+ error("Couldn't set %s", lock->ref_name);
+ unlock_ref(lock);
+ return -1;
+ }
+
+ unlock_ref(lock);
+ return 0;
+}
+
+int create_symref(const char *ref_target, const char *refs_heads_master,
+ const char *logmsg)
+{
+ char *lockpath = NULL;
+ char ref[1000];
+ int fd, len, written;
+ char *git_HEAD = git_pathdup("%s", ref_target);
+ unsigned char old_sha1[20], new_sha1[20];
+ struct strbuf err = STRBUF_INIT;
+
+ if (logmsg && read_ref(ref_target, old_sha1))
+ hashclr(old_sha1);
+
+ if (safe_create_leading_directories(git_HEAD) < 0)
+ return error("unable to create directory for %s", git_HEAD);
+
+#ifndef NO_SYMLINK_HEAD
+ if (prefer_symlink_refs) {
+ unlink(git_HEAD);
+ if (!symlink(refs_heads_master, git_HEAD))
+ goto done;
+ fprintf(stderr, "no symlink - falling back to symbolic ref\n");
+ }
+#endif
+
+ len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
+ if (sizeof(ref) <= len) {
+ error("refname too long: %s", refs_heads_master);
+ goto error_free_return;
+ }
+ lockpath = mkpathdup("%s.lock", git_HEAD);
+ fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
+ if (fd < 0) {
+ error("Unable to open %s for writing", lockpath);
+ goto error_free_return;
+ }
+ written = write_in_full(fd, ref, len);
+ if (close(fd) != 0 || written != len) {
+ error("Unable to write to %s", lockpath);
+ goto error_unlink_return;
+ }
+ if (rename(lockpath, git_HEAD) < 0) {
+ error("Unable to create %s", git_HEAD);
+ goto error_unlink_return;
+ }
+ if (adjust_shared_perm(git_HEAD)) {
+ error("Unable to fix permissions on %s", lockpath);
+ error_unlink_return:
+ unlink_or_warn(lockpath);
+ error_free_return:
+ free(lockpath);
+ free(git_HEAD);
+ return -1;
+ }
+ free(lockpath);
+
+#ifndef NO_SYMLINK_HEAD
+ done:
+#endif
+ if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
+ log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
+ error("%s", err.buf);
+ strbuf_release(&err);
+ }
+
+ free(git_HEAD);
+ return 0;
+}
+
+int reflog_exists(const char *refname)
+{
+ struct stat st;
+
+ return !lstat(git_path("logs/%s", refname), &st) &&
+ S_ISREG(st.st_mode);
+}
+
+int delete_reflog(const char *refname)
+{
+ return remove_path(git_path("logs/%s", refname));
+}
+
+static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
+{
+ unsigned char osha1[20], nsha1[20];
+ char *email_end, *message;
+ unsigned long timestamp;
+ int tz;
+
+ /* old SP new SP name <email> SP time TAB msg LF */
+ if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
+ get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
+ get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
+ !(email_end = strchr(sb->buf + 82, '>')) ||
+ email_end[1] != ' ' ||
+ !(timestamp = strtoul(email_end + 2, &message, 10)) ||
+ !message || message[0] != ' ' ||
+ (message[1] != '+' && message[1] != '-') ||
+ !isdigit(message[2]) || !isdigit(message[3]) ||
+ !isdigit(message[4]) || !isdigit(message[5]))
+ return 0; /* corrupt? */
+ email_end[1] = '\0';
+ tz = strtol(message + 1, NULL, 10);
+ if (message[6] != '\t')
+ message += 6;
+ else
+ message += 7;
+ return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
+}
+
+static char *find_beginning_of_line(char *bob, char *scan)
+{
+ while (bob < scan && *(--scan) != '\n')
+ ; /* keep scanning backwards */
+ /*
+ * Return either beginning of the buffer, or LF at the end of
+ * the previous line.
+ */
+ return scan;
+}
+
+int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
+{
+ struct strbuf sb = STRBUF_INIT;
+ FILE *logfp;
+ long pos;
+ int ret = 0, at_tail = 1;
+
+ logfp = fopen(git_path("logs/%s", refname), "r");
+ if (!logfp)
+ return -1;
+
+ /* Jump to the end */
+ if (fseek(logfp, 0, SEEK_END) < 0)
+ return error("cannot seek back reflog for %s: %s",
+ refname, strerror(errno));
+ pos = ftell(logfp);
+ while (!ret && 0 < pos) {
+ int cnt;
+ size_t nread;
+ char buf[BUFSIZ];
+ char *endp, *scanp;
+
+ /* Fill next block from the end */
+ cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
+ if (fseek(logfp, pos - cnt, SEEK_SET))
+ return error("cannot seek back reflog for %s: %s",
+ refname, strerror(errno));
+ nread = fread(buf, cnt, 1, logfp);
+ if (nread != 1)
+ return error("cannot read %d bytes from reflog for %s: %s",
+ cnt, refname, strerror(errno));
+ pos -= cnt;
+
+ scanp = endp = buf + cnt;
+ if (at_tail && scanp[-1] == '\n')
+ /* Looking at the final LF at the end of the file */
+ scanp--;
+ at_tail = 0;
+
+ while (buf < scanp) {
+ /*
+ * terminating LF of the previous line, or the beginning
+ * of the buffer.
+ */
+ char *bp;
+
+ bp = find_beginning_of_line(buf, scanp);
+
+ if (*bp == '\n') {
+ /*
+ * The newline is the end of the previous line,
+ * so we know we have complete line starting
+ * at (bp + 1). Prefix it onto any prior data
+ * we collected for the line and process it.
+ */
+ strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
+ scanp = bp;
+ endp = bp + 1;
+ ret = show_one_reflog_ent(&sb, fn, cb_data);
+ strbuf_reset(&sb);
+ if (ret)
+ break;
+ } else if (!pos) {
+ /*
+ * We are at the start of the buffer, and the
+ * start of the file; there is no previous
+ * line, and we have everything for this one.
+ * Process it, and we can end the loop.
+ */
+ strbuf_splice(&sb, 0, 0, buf, endp - buf);
+ ret = show_one_reflog_ent(&sb, fn, cb_data);
+ strbuf_reset(&sb);
+ break;
+ }
+
+ if (bp == buf) {
+ /*
+ * We are at the start of the buffer, and there
+ * is more file to read backwards. Which means
+ * we are in the middle of a line. Note that we
+ * may get here even if *bp was a newline; that
+ * just means we are at the exact end of the
+ * previous line, rather than some spot in the
+ * middle.
+ *
+ * Save away what we have to be combined with
+ * the data from the next read.
+ */
+ strbuf_splice(&sb, 0, 0, buf, endp - buf);
+ break;
+ }
+ }
+
+ }
+ if (!ret && sb.len)
+ die("BUG: reverse reflog parser had leftover data");
+
+ fclose(logfp);
+ strbuf_release(&sb);
+ return ret;
+}
+
+int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
+{
+ FILE *logfp;
+ struct strbuf sb = STRBUF_INIT;
+ int ret = 0;
+
+ logfp = fopen(git_path("logs/%s", refname), "r");
+ if (!logfp)
+ return -1;
+
+ while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
+ ret = show_one_reflog_ent(&sb, fn, cb_data);
+ fclose(logfp);
+ strbuf_release(&sb);
+ return ret;
+}
+/*
+ * Call fn for each reflog in the namespace indicated by name. name
+ * must be empty or end with '/'. Name will be used as a scratch
+ * space, but its contents will be restored before return.
+ */
+static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
+{
+ DIR *d = opendir(git_path("logs/%s", name->buf));
+ int retval = 0;
+ struct dirent *de;
+ int oldlen = name->len;
+
+ if (!d)
+ return name->len ? errno : 0;
+
+ while ((de = readdir(d)) != NULL) {
+ struct stat st;
+
+ if (de->d_name[0] == '.')
+ continue;
+ if (ends_with(de->d_name, ".lock"))
+ continue;
+ strbuf_addstr(name, de->d_name);
+ if (stat(git_path("logs/%s", name->buf), &st) < 0) {
+ ; /* silently ignore */
+ } else {
+ if (S_ISDIR(st.st_mode)) {
+ strbuf_addch(name, '/');
+ retval = do_for_each_reflog(name, fn, cb_data);
+ } else {
+ struct object_id oid;
+
+ if (read_ref_full(name->buf, 0, oid.hash, NULL))
+ retval = error("bad ref for %s", name->buf);
+ else
+ retval = fn(name->buf, &oid, 0, cb_data);
+ }
+ if (retval)
+ break;
+ }
+ strbuf_setlen(name, oldlen);
+ }
+ closedir(d);
+ return retval;
+}
+
+int for_each_reflog(each_ref_fn fn, void *cb_data)
+{
+ int retval;
+ struct strbuf name;
+ strbuf_init(&name, PATH_MAX);
+ retval = do_for_each_reflog(&name, fn, cb_data);
+ strbuf_release(&name);
+ return retval;
+}
+
+static int ref_update_reject_duplicates(struct string_list *refnames,
+ struct strbuf *err)
+{
+ int i, n = refnames->nr;
+
+ assert(err);
+
+ for (i = 1; i < n; i++)
+ if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
+ strbuf_addf(err,
+ "Multiple updates for ref '%s' not allowed.",
+ refnames->items[i].string);
+ return 1;
+ }
+ return 0;
+}
+
+int ref_transaction_commit(struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ int ret = 0, i;
+ int n = transaction->nr;
+ struct ref_update **updates = transaction->updates;
+ struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
+ struct string_list_item *ref_to_delete;
+ struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
+
+ assert(err);
+
+ if (transaction->state != REF_TRANSACTION_OPEN)
+ die("BUG: commit called for transaction that is not open");
+
+ if (!n) {
+ transaction->state = REF_TRANSACTION_CLOSED;
+ return 0;
+ }
+
+ /* Fail if a refname appears more than once in the transaction: */
+ for (i = 0; i < n; i++)
+ string_list_append(&affected_refnames, updates[i]->refname);
+ string_list_sort(&affected_refnames);
+ if (ref_update_reject_duplicates(&affected_refnames, err)) {
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+
+ /*
+ * Acquire all locks, verify old values if provided, check
+ * that new values are valid, and write new values to the
+ * lockfiles, ready to be activated. Only keep one lockfile
+ * open at a time to avoid running out of file descriptors.
+ */
+ for (i = 0; i < n; i++) {
+ struct ref_update *update = updates[i];
+
+ if ((update->flags & REF_HAVE_NEW) &&
+ is_null_sha1(update->new_sha1))
+ update->flags |= REF_DELETING;
+ update->lock = lock_ref_sha1_basic(
+ update->refname,
+ ((update->flags & REF_HAVE_OLD) ?
+ update->old_sha1 : NULL),
+ &affected_refnames, NULL,
+ update->flags,
+ &update->type,
+ err);
+ if (!update->lock) {
+ char *reason;
+
+ ret = (errno == ENOTDIR)
+ ? TRANSACTION_NAME_CONFLICT
+ : TRANSACTION_GENERIC_ERROR;
+ reason = strbuf_detach(err, NULL);
+ strbuf_addf(err, "cannot lock ref '%s': %s",
+ update->refname, reason);
+ free(reason);
+ goto cleanup;
+ }
+ if ((update->flags & REF_HAVE_NEW) &&
+ !(update->flags & REF_DELETING)) {
+ int overwriting_symref = ((update->type & REF_ISSYMREF) &&
+ (update->flags & REF_NODEREF));
+
+ if (!overwriting_symref &&
+ !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {
+ /*
+ * The reference already has the desired
+ * value, so we don't need to write it.
+ */
+ } else if (write_ref_to_lockfile(update->lock,
+ update->new_sha1,
+ err)) {
+ char *write_err = strbuf_detach(err, NULL);
+
+ /*
+ * The lock was freed upon failure of
+ * write_ref_to_lockfile():
+ */
+ update->lock = NULL;
+ strbuf_addf(err,
+ "cannot update the ref '%s': %s",
+ update->refname, write_err);
+ free(write_err);
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ } else {
+ update->flags |= REF_NEEDS_COMMIT;
+ }
+ }
+ if (!(update->flags & REF_NEEDS_COMMIT)) {
+ /*
+ * We didn't have to write anything to the lockfile.
+ * Close it to free up the file descriptor:
+ */
+ if (close_ref(update->lock)) {
+ strbuf_addf(err, "Couldn't close %s.lock",
+ update->refname);
+ goto cleanup;
+ }
+ }
+ }
+
+ /* Perform updates first so live commits remain referenced */
+ for (i = 0; i < n; i++) {
+ struct ref_update *update = updates[i];
+
+ if (update->flags & REF_NEEDS_COMMIT) {
+ if (commit_ref_update(update->lock,
+ update->new_sha1, update->msg,
+ update->flags, err)) {
+ /* freed by commit_ref_update(): */
+ update->lock = NULL;
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ } else {
+ /* freed by commit_ref_update(): */
+ update->lock = NULL;
+ }
+ }
+ }
+
+ /* Perform deletes now that updates are safely completed */
+ for (i = 0; i < n; i++) {
+ struct ref_update *update = updates[i];
+
+ if (update->flags & REF_DELETING) {
+ if (delete_ref_loose(update->lock, update->type, err)) {
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+
+ if (!(update->flags & REF_ISPRUNING))
+ string_list_append(&refs_to_delete,
+ update->lock->ref_name);
+ }
+ }
+
+ if (repack_without_refs(&refs_to_delete, err)) {
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+ for_each_string_list_item(ref_to_delete, &refs_to_delete)
+ unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
+ clear_loose_ref_cache(&ref_cache);
+
+cleanup:
+ transaction->state = REF_TRANSACTION_CLOSED;
+
+ for (i = 0; i < n; i++)
+ if (updates[i]->lock)
+ unlock_ref(updates[i]->lock);
+ string_list_clear(&refs_to_delete, 0);
+ string_list_clear(&affected_refnames, 0);
+ return ret;
+}
+
+static int ref_present(const char *refname,
+ const struct object_id *oid, int flags, void *cb_data)
+{
+ struct string_list *affected_refnames = cb_data;
+
+ return string_list_has_string(affected_refnames, refname);
+}
+
+int initial_ref_transaction_commit(struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ int ret = 0, i;
+ int n = transaction->nr;
+ struct ref_update **updates = transaction->updates;
+ struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
+
+ assert(err);
+
+ if (transaction->state != REF_TRANSACTION_OPEN)
+ die("BUG: commit called for transaction that is not open");
+
+ /* Fail if a refname appears more than once in the transaction: */
+ for (i = 0; i < n; i++)
+ string_list_append(&affected_refnames, updates[i]->refname);
+ string_list_sort(&affected_refnames);
+ if (ref_update_reject_duplicates(&affected_refnames, err)) {
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+
+ /*
+ * It's really undefined to call this function in an active
+ * repository or when there are existing references: we are
+ * only locking and changing packed-refs, so (1) any
+ * simultaneous processes might try to change a reference at
+ * the same time we do, and (2) any existing loose versions of
+ * the references that we are setting would have precedence
+ * over our values. But some remote helpers create the remote
+ * "HEAD" and "master" branches before calling this function,
+ * so here we really only check that none of the references
+ * that we are creating already exists.
+ */
+ if (for_each_rawref(ref_present, &affected_refnames))
+ die("BUG: initial ref transaction called with existing refs");
+
+ for (i = 0; i < n; i++) {
+ struct ref_update *update = updates[i];
+
+ if ((update->flags & REF_HAVE_OLD) &&
+ !is_null_sha1(update->old_sha1))
+ die("BUG: initial ref transaction with old_sha1 set");
+ if (verify_refname_available(update->refname,
+ &affected_refnames, NULL,
+ err)) {
+ ret = TRANSACTION_NAME_CONFLICT;
+ goto cleanup;
+ }
+ }
+
+ if (lock_packed_refs(0)) {
+ strbuf_addf(err, "unable to lock packed-refs file: %s",
+ strerror(errno));
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+
+ for (i = 0; i < n; i++) {
+ struct ref_update *update = updates[i];
+
+ if ((update->flags & REF_HAVE_NEW) &&
+ !is_null_sha1(update->new_sha1))
+ add_packed_ref(update->refname, update->new_sha1);
+ }
+
+ if (commit_packed_refs()) {
+ strbuf_addf(err, "unable to commit packed-refs file: %s",
+ strerror(errno));
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+
+cleanup:
+ transaction->state = REF_TRANSACTION_CLOSED;
+ string_list_clear(&affected_refnames, 0);
+ return ret;
+}
+
+struct expire_reflog_cb {
+ unsigned int flags;
+ reflog_expiry_should_prune_fn *should_prune_fn;
+ void *policy_cb;
+ FILE *newlog;
+ unsigned char last_kept_sha1[20];
+};
+
+static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+ const char *email, unsigned long timestamp, int tz,
+ const char *message, void *cb_data)
+{
+ struct expire_reflog_cb *cb = cb_data;
+ struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
+
+ if (cb->flags & EXPIRE_REFLOGS_REWRITE)
+ osha1 = cb->last_kept_sha1;
+
+ if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
+ message, policy_cb)) {
+ if (!cb->newlog)
+ printf("would prune %s", message);
+ else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
+ printf("prune %s", message);
+ } else {
+ if (cb->newlog) {
+ fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
+ sha1_to_hex(osha1), sha1_to_hex(nsha1),
+ email, timestamp, tz, message);
+ hashcpy(cb->last_kept_sha1, nsha1);
+ }
+ if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
+ printf("keep %s", message);
+ }
+ return 0;
+}
+
+int reflog_expire(const char *refname, const unsigned char *sha1,
+ unsigned int flags,
+ reflog_expiry_prepare_fn prepare_fn,
+ reflog_expiry_should_prune_fn should_prune_fn,
+ reflog_expiry_cleanup_fn cleanup_fn,
+ void *policy_cb_data)
+{
+ static struct lock_file reflog_lock;
+ struct expire_reflog_cb cb;
+ struct ref_lock *lock;
+ char *log_file;
+ int status = 0;
+ int type;
+ struct strbuf err = STRBUF_INIT;
+
+ memset(&cb, 0, sizeof(cb));
+ cb.flags = flags;
+ cb.policy_cb = policy_cb_data;
+ cb.should_prune_fn = should_prune_fn;
+
+ /*
+ * The reflog file is locked by holding the lock on the
+ * reference itself, plus we might need to update the
+ * reference if --updateref was specified:
+ */
+ lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
+ if (!lock) {
+ error("cannot lock ref '%s': %s", refname, err.buf);
+ strbuf_release(&err);
+ return -1;
+ }
+ if (!reflog_exists(refname)) {
+ unlock_ref(lock);
+ return 0;
+ }
+
+ log_file = git_pathdup("logs/%s", refname);
+ if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
+ /*
+ * Even though holding $GIT_DIR/logs/$reflog.lock has
+ * no locking implications, we use the lock_file
+ * machinery here anyway because it does a lot of the
+ * work we need, including cleaning up if the program
+ * exits unexpectedly.
+ */
+ if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
+ struct strbuf err = STRBUF_INIT;
+ unable_to_lock_message(log_file, errno, &err);
+ error("%s", err.buf);
+ strbuf_release(&err);
+ goto failure;
+ }
+ cb.newlog = fdopen_lock_file(&reflog_lock, "w");
+ if (!cb.newlog) {
+ error("cannot fdopen %s (%s)",
+ get_lock_file_path(&reflog_lock), strerror(errno));
+ goto failure;
+ }
+ }
+
+ (*prepare_fn)(refname, sha1, cb.policy_cb);
+ for_each_reflog_ent(refname, expire_reflog_ent, &cb);
+ (*cleanup_fn)(cb.policy_cb);
+
+ if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
+ /*
+ * It doesn't make sense to adjust a reference pointed
+ * to by a symbolic ref based on expiring entries in
+ * the symbolic reference's reflog. Nor can we update
+ * a reference if there are no remaining reflog
+ * entries.
+ */
+ int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
+ !(type & REF_ISSYMREF) &&
+ !is_null_sha1(cb.last_kept_sha1);
+
+ if (close_lock_file(&reflog_lock)) {
+ status |= error("couldn't write %s: %s", log_file,
+ strerror(errno));
+ } else if (update &&
+ (write_in_full(get_lock_file_fd(lock->lk),
+ sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
+ write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
+ close_ref(lock) < 0)) {
+ status |= error("couldn't write %s",
+ get_lock_file_path(lock->lk));
+ rollback_lock_file(&reflog_lock);
+ } else if (commit_lock_file(&reflog_lock)) {
++ status |= error("unable to write reflog '%s' (%s)",
+ log_file, strerror(errno));
+ } else if (update && commit_ref(lock)) {
+ status |= error("couldn't set %s", lock->ref_name);
+ }
+ }
+ free(log_file);
+ unlock_ref(lock);
+ return status;
+
+ failure:
+ rollback_lock_file(&reflog_lock);
+ free(log_file);
+ unlock_ref(lock);
+ return -1;
+}