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 {
unsigned char sha1[20];
unsigned char peeled[20];
};
+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;
*/
int sorted;
+ /* A pointer to the ref_cache that contains this ref_dir. */
+ struct ref_cache *ref_cache;
+
struct ref_entry **entries;
};
/* ISSYMREF=0x01, ISPACKED=0x02, and ISBROKEN=0x04 are public interfaces */
#define REF_KNOWS_PEELED 0x08
+
+/* ref_entry represents a directory of references */
#define REF_DIR 0x10
+/*
+ * Entry has not yet been read from disk (used only for REF_DIR
+ * entries representing loose references)
+ */
+#define REF_INCOMPLETE 0x20
+
/*
* 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. 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).
+ * 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
char name[FLEX_ARRAY];
};
+static void read_loose_refs(const char *dirname, struct ref_dir *dir);
+
+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);
+ 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)
static void free_ref_entry(struct ref_entry *entry)
{
- if (entry->flag & REF_DIR)
+ 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);
}
{
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;
}
/*
* 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(const char *dirname)
+static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
+ const char *dirname, size_t len,
+ int incomplete)
{
struct ref_entry *direntry;
- int len = strlen(dirname);
direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
- memcpy(direntry->name, dirname, len + 1);
- direntry->flag = REF_DIR;
+ 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 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_)
+{
+ struct string_slice *key = (struct string_slice *)key_;
+ struct ref_entry *ent = *(struct ref_entry **)ent_;
+ int entlen = strlen(ent->name);
+ int cmplen = key->len < entlen ? key->len : entlen;
+ int cmp = memcmp(key->str, ent->name, cmplen);
+ if (cmp)
+ return cmp;
+ return key->len - entlen;
+}
+
/*
* Return the entry with the given refname from the ref_dir
* (non-recursively), sorting dir if necessary. Return NULL if no
- * such entry is found.
+ * such entry is found. dir must already be complete.
*/
-static struct ref_entry *search_ref_dir(struct ref_dir *dir, const char *refname)
+static struct ref_entry *search_ref_dir(struct ref_dir *dir,
+ const char *refname, size_t len)
{
- struct ref_entry *e, **r;
- int len;
+ struct ref_entry **r;
+ struct string_slice key;
if (refname == NULL || !dir->nr)
return NULL;
sort_ref_dir(dir);
-
- len = strlen(refname) + 1;
- e = xmalloc(sizeof(struct ref_entry) + len);
- memcpy(e->name, refname, len);
-
- r = bsearch(&e, dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
-
- free(e);
+ key.len = len;
+ key.str = refname;
+ r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
+ ref_entry_cmp_sslice);
if (r == NULL)
return NULL;
* 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.
+ * directory cannot be found. dir must already be complete.
*/
-static struct ref_entry *search_for_subdir(struct ref_dir *dir,
- const char *subdirname, int mkdir)
+static struct ref_dir *search_for_subdir(struct ref_dir *dir,
+ const char *subdirname, size_t len,
+ int mkdir)
{
- struct ref_entry *entry = search_ref_dir(dir, subdirname);
+ struct ref_entry *entry = search_ref_dir(dir, subdirname, len);
if (!entry) {
if (!mkdir)
return NULL;
- entry = create_dir_entry(subdirname);
+ /*
+ * 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);
}
- assert(entry->flag & REF_DIR);
- return entry;
+ 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. 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.
+ * 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)
{
- struct strbuf dirname;
const char *slash;
- strbuf_init(&dirname, PATH_MAX);
for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
- struct ref_entry *entry;
- strbuf_add(&dirname,
- refname + dirname.len,
- (slash + 1) - (refname + dirname.len));
- entry = search_for_subdir(dir, dirname.buf, mkdir);
- if (!entry)
+ size_t dirnamelen = slash - refname + 1;
+ struct ref_dir *subdir;
+ subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
+ if (!subdir) {
+ dir = NULL;
break;
- dir = &entry->u.subdir;
+ }
+ dir = subdir;
}
- strbuf_release(&dirname);
return dir;
}
dir = find_containing_dir(dir, refname, 0);
if (!dir)
return NULL;
- entry = search_ref_dir(dir, refname);
+ entry = search_ref_dir(dir, refname, strlen(refname));
return (entry && !(entry->flag & REF_DIR)) ? entry : NULL;
}
struct ref_entry *entry = dir->entries[i];
int retval;
if (entry->flag & REF_DIR) {
- sort_ref_dir(&entry->u.subdir);
- retval = do_for_each_ref_in_dir(&entry->u.subdir, 0,
+ struct ref_dir *subdir = get_ref_dir(entry);
+ sort_ref_dir(subdir);
+ retval = do_for_each_ref_in_dir(subdir, 0,
base, fn, trim, flags, cb_data);
} else {
retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
if (cmp == 0) {
if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
/* Both are directories; descend them in parallel. */
- sort_ref_dir(&e1->u.subdir);
- sort_ref_dir(&e2->u.subdir);
+ 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_ref_in_dirs(
- &e1->u.subdir, &e2->u.subdir,
+ subdir1, subdir2,
base, fn, trim, flags, cb_data);
i1++;
i2++;
i2++;
}
if (e->flag & REF_DIR) {
- sort_ref_dir(&e->u.subdir);
+ struct ref_dir *subdir = get_ref_dir(e);
+ sort_ref_dir(subdir);
retval = do_for_each_ref_in_dir(
- &e->u.subdir, 0,
+ subdir, 0,
base, fn, trim, flags, cb_data);
} else {
retval = do_one_ref(base, fn, trim, flags, cb_data, e);
const char *packed_refs_file;
FILE *f;
- refs->packed = create_dir_entry("");
+ refs->packed = create_dir_entry(refs, "", 0, 0);
if (*refs->name)
packed_refs_file = git_path_submodule(refs->name, "packed-refs");
else
packed_refs_file = git_path("packed-refs");
f = fopen(packed_refs_file, "r");
if (f) {
- read_packed_refs(f, &refs->packed->u.subdir);
+ read_packed_refs(f, get_ref_dir(refs->packed));
fclose(f);
}
}
- return &refs->packed->u.subdir;
+ return get_ref_dir(refs->packed);
}
void add_packed_ref(const char *refname, const unsigned char *sha1)
}
/*
- * Read the loose references for refs from the namespace dirname.
- * dirname must end with '/'. dir must be the directory entry
- * corresponding to dirname.
+ * 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 get_ref_dir(struct ref_cache *refs, const char *dirname,
- struct ref_dir *dir)
+static void read_loose_refs(const char *dirname, struct ref_dir *dir)
{
+ struct ref_cache *refs = dir->ref_cache;
DIR *d;
const char *path;
struct dirent *de;
; /* silently ignore */
} else if (S_ISDIR(st.st_mode)) {
strbuf_addch(&refname, '/');
- get_ref_dir(refs, refname.buf,
- &search_for_subdir(dir, refname.buf, 1)->u.subdir);
+ add_entry_to_dir(dir,
+ create_dir_entry(refs, refname.buf,
+ refname.len, 1));
} else {
if (*refs->name) {
hashclr(sha1);
static struct ref_dir *get_loose_refs(struct ref_cache *refs)
{
if (!refs->loose) {
- refs->loose = create_dir_entry("");
- get_ref_dir(refs, "refs/",
- &search_for_subdir(&refs->loose->u.subdir,
- "refs/", 1)->u.subdir);
+ /*
+ * 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 &refs->loose->u.subdir;
+ return get_ref_dir(refs->loose);
}
/* We allow "recursive" symbolic refs. Only within reason, though */
return 0;
fprintf(d->fp, d->msg_fmt, refname);
+ fputc('\n', d->fp);
return 0;
}