#include "../cache.h"
+#include "../config.h"
#include "../refs.h"
#include "refs-internal.h"
#include "ref-cache.h"
#include "../iterator.h"
#include "../lockfile.h"
+enum mmap_strategy {
+ /*
+ * Don't use mmap() at all for reading `packed-refs`.
+ */
+ MMAP_NONE,
+
+ /*
+ * Can use mmap() for reading `packed-refs`, but the file must
+ * not remain mmapped. This is the usual option on Windows,
+ * where you cannot rename a new version of a file onto a file
+ * that is currently mmapped.
+ */
+ MMAP_TEMPORARY,
+
+ /*
+ * It is OK to leave the `packed-refs` file mmapped while
+ * arbitrary other code is running.
+ */
+ MMAP_OK
+};
+
+#if defined(NO_MMAP)
+static enum mmap_strategy mmap_strategy = MMAP_NONE;
+#elif defined(MMAP_PREVENTS_DELETE)
+static enum mmap_strategy mmap_strategy = MMAP_TEMPORARY;
+#else
+static enum mmap_strategy mmap_strategy = MMAP_OK;
+#endif
+
+struct packed_ref_store;
+
struct packed_ref_cache {
+ /*
+ * A back-pointer to the packed_ref_store with which this
+ * cache is associated:
+ */
+ struct packed_ref_store *refs;
+
struct ref_cache *cache;
+ /* Is the `packed-refs` file currently mmapped? */
+ int mmapped;
+
+ /*
+ * The contents of the `packed-refs` file. If the file was
+ * already sorted, this points at the mmapped contents of the
+ * file. If not, this points at heap-allocated memory
+ * containing the contents, sorted. If there were no contents
+ * (e.g., because the file didn't exist), `buf` and `eof` are
+ * both NULL.
+ */
+ char *buf, *eof;
+
+ /* The size of the header line, if any; otherwise, 0: */
+ size_t header_len;
+
+ /*
+ * What is the peeled state of this cache? (This is usually
+ * determined from the header of the "packed-refs" file.)
+ */
+ enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled;
+
/*
* Count of references to the data structure in this instance,
* including the pointer from files_ref_store::packed if any.
struct stat_validity validity;
};
-/*
- * 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_cache(packed_refs->cache);
- stat_validity_clear(&packed_refs->validity);
- free(packed_refs);
- return 1;
- } else {
- return 0;
- }
-}
-
/*
* A container for `packed-refs`-related data. It is not (yet) a
* `ref_store`.
struct tempfile tempfile;
};
+/*
+ * Increment the reference count of *packed_refs.
+ */
+static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
+{
+ packed_refs->referrers++;
+}
+
+/*
+ * If the buffer in `packed_refs` is active, then either munmap the
+ * memory and close the file, or free the memory. Then set the buffer
+ * pointers to NULL.
+ */
+static void release_packed_ref_buffer(struct packed_ref_cache *packed_refs)
+{
+ if (packed_refs->mmapped) {
+ if (munmap(packed_refs->buf,
+ packed_refs->eof - packed_refs->buf))
+ die_errno("error ummapping packed-refs file %s",
+ packed_refs->refs->path);
+ packed_refs->mmapped = 0;
+ } else {
+ free(packed_refs->buf);
+ }
+ packed_refs->buf = packed_refs->eof = NULL;
+ packed_refs->header_len = 0;
+}
+
+/*
+ * 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_cache(packed_refs->cache);
+ stat_validity_clear(&packed_refs->validity);
+ release_packed_ref_buffer(packed_refs);
+ free(packed_refs);
+ return 1;
+ } else {
+ return 0;
+ }
+}
+
struct ref_store *packed_ref_store_create(const char *path,
unsigned int store_flags)
{
return ref_store;
}
-/*
- * Die if refs is not the main ref store. caller is used in any
- * necessary error messages.
- */
-static void packed_assert_main_repository(struct packed_ref_store *refs,
- const char *caller)
-{
- if (refs->store_flags & REF_STORE_MAIN)
- return;
-
- die("BUG: operation %s only allowed for main ref store", caller);
-}
-
/*
* Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is
* not a `packed_ref_store`. Also die if `packed_ref_store` doesn't
if (refs->cache) {
struct packed_ref_cache *cache = refs->cache;
- if (is_lock_file_locked(&refs->lock))
- die("BUG: packed-ref cache cleared while locked");
refs->cache = NULL;
release_packed_ref_cache(cache);
}
}
-/* The length of a peeled reference line in packed-refs, including EOL: */
-#define PEELED_LINE_LENGTH 42
+static NORETURN void die_unterminated_line(const char *path,
+ const char *p, size_t len)
+{
+ if (len < 80)
+ die("unterminated line in %s: %.*s", path, (int)len, p);
+ else
+ die("unterminated line in %s: %.75s...", path, p);
+}
+
+static NORETURN void die_invalid_line(const char *path,
+ const char *p, size_t len)
+{
+ const char *eol = memchr(p, '\n', len);
+
+ if (!eol)
+ die_unterminated_line(path, p, len);
+ else if (eol - p < 80)
+ die("unexpected line in %s: %.*s", path, (int)(eol - p), p);
+ else
+ die("unexpected line in %s: %.75s...", path, p);
+
+}
/*
- * 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.
+ * An iterator over a packed-refs file that is currently mmapped.
*/
-static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
+struct mmapped_ref_iterator {
+ struct ref_iterator base;
+
+ struct packed_ref_cache *packed_refs;
+
+ /* The current position in the mmapped file: */
+ const char *pos;
+
+ /* The end of the mmapped file: */
+ const char *eof;
+
+ struct object_id oid, peeled;
+
+ struct strbuf refname_buf;
+};
+
+static int mmapped_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
- const char *ref;
+ struct mmapped_ref_iterator *iter =
+ (struct mmapped_ref_iterator *)ref_iterator;
+ const char *p = iter->pos, *eol;
- if (parse_oid_hex(line->buf, oid, &ref) < 0)
- return NULL;
- if (!isspace(*ref++))
- return NULL;
+ strbuf_reset(&iter->refname_buf);
- if (isspace(*ref))
- return NULL;
+ if (iter->pos == iter->eof)
+ return ref_iterator_abort(ref_iterator);
- if (line->buf[line->len - 1] != '\n')
- return NULL;
- line->buf[--line->len] = 0;
+ iter->base.flags = REF_ISPACKED;
+
+ if (iter->eof - p < GIT_SHA1_HEXSZ + 2 ||
+ parse_oid_hex(p, &iter->oid, &p) ||
+ !isspace(*p++))
+ die_invalid_line(iter->packed_refs->refs->path,
+ iter->pos, iter->eof - iter->pos);
+
+ eol = memchr(p, '\n', iter->eof - p);
+ if (!eol)
+ die_unterminated_line(iter->packed_refs->refs->path,
+ iter->pos, iter->eof - iter->pos);
+
+ strbuf_add(&iter->refname_buf, p, eol - p);
+ iter->base.refname = iter->refname_buf.buf;
+
+ if (check_refname_format(iter->base.refname, REFNAME_ALLOW_ONELEVEL)) {
+ if (!refname_is_safe(iter->base.refname))
+ die("packed refname is dangerous: %s",
+ iter->base.refname);
+ oidclr(&iter->oid);
+ iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN;
+ }
+ if (iter->packed_refs->peeled == PEELED_FULLY ||
+ (iter->packed_refs->peeled == PEELED_TAGS &&
+ starts_with(iter->base.refname, "refs/tags/")))
+ iter->base.flags |= REF_KNOWS_PEELED;
+
+ iter->pos = eol + 1;
+
+ if (iter->pos < iter->eof && *iter->pos == '^') {
+ p = iter->pos + 1;
+ if (iter->eof - p < GIT_SHA1_HEXSZ + 1 ||
+ parse_oid_hex(p, &iter->peeled, &p) ||
+ *p++ != '\n')
+ die_invalid_line(iter->packed_refs->refs->path,
+ iter->pos, iter->eof - iter->pos);
+ iter->pos = p;
+
+ /*
+ * Regardless of what the file header said, we
+ * definitely know the value of *this* reference. But
+ * we suppress it if the reference is broken:
+ */
+ if ((iter->base.flags & REF_ISBROKEN)) {
+ oidclr(&iter->peeled);
+ iter->base.flags &= ~REF_KNOWS_PEELED;
+ } else {
+ iter->base.flags |= REF_KNOWS_PEELED;
+ }
+ } else {
+ oidclr(&iter->peeled);
+ }
+
+ return ITER_OK;
+}
+
+static int mmapped_ref_iterator_peel(struct ref_iterator *ref_iterator,
+ struct object_id *peeled)
+{
+ struct mmapped_ref_iterator *iter =
+ (struct mmapped_ref_iterator *)ref_iterator;
+
+ if ((iter->base.flags & REF_KNOWS_PEELED)) {
+ oidcpy(peeled, &iter->peeled);
+ return is_null_oid(&iter->peeled) ? -1 : 0;
+ } else if ((iter->base.flags & (REF_ISBROKEN | REF_ISSYMREF))) {
+ return -1;
+ } else {
+ return !!peel_object(iter->oid.hash, peeled->hash);
+ }
+}
+
+static int mmapped_ref_iterator_abort(struct ref_iterator *ref_iterator)
+{
+ struct mmapped_ref_iterator *iter =
+ (struct mmapped_ref_iterator *)ref_iterator;
+
+ release_packed_ref_cache(iter->packed_refs);
+ strbuf_release(&iter->refname_buf);
+ base_ref_iterator_free(ref_iterator);
+ return ITER_DONE;
+}
+
+static struct ref_iterator_vtable mmapped_ref_iterator_vtable = {
+ mmapped_ref_iterator_advance,
+ mmapped_ref_iterator_peel,
+ mmapped_ref_iterator_abort
+};
+
+struct ref_iterator *mmapped_ref_iterator_begin(
+ struct packed_ref_cache *packed_refs,
+ const char *pos, const char *eof)
+{
+ struct mmapped_ref_iterator *iter = xcalloc(1, sizeof(*iter));
+ struct ref_iterator *ref_iterator = &iter->base;
+
+ if (!packed_refs->buf)
+ return empty_ref_iterator_begin();
+
+ base_ref_iterator_init(ref_iterator, &mmapped_ref_iterator_vtable, 1);
+
+ iter->packed_refs = packed_refs;
+ acquire_packed_ref_cache(iter->packed_refs);
+ iter->pos = pos;
+ iter->eof = eof;
+ strbuf_init(&iter->refname_buf, 0);
+
+ iter->base.oid = &iter->oid;
+
+ return ref_iterator;
+}
+
+struct packed_ref_entry {
+ const char *start;
+ size_t len;
+};
+
+static int cmp_packed_ref_entries(const void *v1, const void *v2)
+{
+ const struct packed_ref_entry *e1 = v1, *e2 = v2;
+ const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1;
+ const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1;
+
+ while (1) {
+ if (*r1 == '\n')
+ return *r2 == '\n' ? 0 : -1;
+ if (*r1 != *r2) {
+ if (*r2 == '\n')
+ return 1;
+ else
+ return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1;
+ }
+ r1++;
+ r2++;
+ }
+}
+
+/*
+ * Compare a packed-refs record pointed to by `rec` to the specified
+ * NUL-terminated refname.
+ */
+static int cmp_entry_to_refname(const char *rec, const char *refname)
+{
+ const char *r1 = rec + GIT_SHA1_HEXSZ + 1;
+ const char *r2 = refname;
+
+ while (1) {
+ if (*r1 == '\n')
+ return *r2 ? -1 : 0;
+ if (!*r2)
+ return 1;
+ if (*r1 != *r2)
+ return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1;
+ r1++;
+ r2++;
+ }
+}
+
+/*
+ * `packed_refs->buf` is not known to be sorted. Check whether it is,
+ * and if not, sort it into new memory and munmap/free the old
+ * storage.
+ */
+static void sort_packed_refs(struct packed_ref_cache *packed_refs)
+{
+ struct packed_ref_entry *entries = NULL;
+ size_t alloc = 0, nr = 0;
+ int sorted = 1;
+ const char *pos, *eof, *eol;
+ size_t len, i;
+ char *new_buffer, *dst;
+
+ pos = packed_refs->buf + packed_refs->header_len;
+ eof = packed_refs->eof;
+ len = eof - pos;
+
+ if (!len)
+ return;
+
+ /*
+ * Initialize entries based on a crude estimate of the number
+ * of references in the file (we'll grow it below if needed):
+ */
+ ALLOC_GROW(entries, len / 80 + 20, alloc);
+
+ while (pos < eof) {
+ eol = memchr(pos, '\n', eof - pos);
+ if (!eol)
+ /* The safety check should prevent this. */
+ BUG("unterminated line found in packed-refs");
+ if (eol - pos < GIT_SHA1_HEXSZ + 2)
+ die_invalid_line(packed_refs->refs->path,
+ pos, eof - pos);
+ eol++;
+ if (eol < eof && *eol == '^') {
+ /*
+ * Keep any peeled line together with its
+ * reference:
+ */
+ const char *peeled_start = eol;
+
+ eol = memchr(peeled_start, '\n', eof - peeled_start);
+ if (!eol)
+ /* The safety check should prevent this. */
+ BUG("unterminated peeled line found in packed-refs");
+ eol++;
+ }
+
+ ALLOC_GROW(entries, nr + 1, alloc);
+ entries[nr].start = pos;
+ entries[nr].len = eol - pos;
+ nr++;
+
+ if (sorted &&
+ nr > 1 &&
+ cmp_packed_ref_entries(&entries[nr - 2],
+ &entries[nr - 1]) >= 0)
+ sorted = 0;
+
+ pos = eol;
+ }
+
+ if (sorted)
+ goto cleanup;
+
+ /* We need to sort the memory. First we sort the entries array: */
+ QSORT(entries, nr, cmp_packed_ref_entries);
+
+ /*
+ * Allocate a new chunk of memory, and copy the old memory to
+ * the new in the order indicated by `entries` (not bothering
+ * with the header line):
+ */
+ new_buffer = xmalloc(len);
+ for (dst = new_buffer, i = 0; i < nr; i++) {
+ memcpy(dst, entries[i].start, entries[i].len);
+ dst += entries[i].len;
+ }
+
+ /*
+ * Now munmap the old buffer and use the sorted buffer in its
+ * place:
+ */
+ release_packed_ref_buffer(packed_refs);
+ packed_refs->buf = new_buffer;
+ packed_refs->eof = new_buffer + len;
+ packed_refs->header_len = 0;
+
+cleanup:
+ free(entries);
+}
+
+/*
+ * Return a pointer to the start of the record that contains the
+ * character `*p` (which must be within the buffer). If no other
+ * record start is found, return `buf`.
+ */
+static const char *find_start_of_record(const char *buf, const char *p)
+{
+ while (p > buf && (p[-1] != '\n' || p[0] == '^'))
+ p--;
+ return p;
+}
+
+/*
+ * Return a pointer to the start of the record following the record
+ * that contains `*p`. If none is found before `end`, return `end`.
+ */
+static const char *find_end_of_record(const char *p, const char *end)
+{
+ while (++p < end && (p[-1] != '\n' || p[0] == '^'))
+ ;
+ return p;
+}
+
+/*
+ * We want to be able to compare mmapped reference records quickly,
+ * without totally parsing them. We can do so because the records are
+ * LF-terminated, and the refname should start exactly (GIT_SHA1_HEXSZ
+ * + 1) bytes past the beginning of the record.
+ *
+ * But what if the `packed-refs` file contains garbage? We're willing
+ * to tolerate not detecting the problem, as long as we don't produce
+ * totally garbled output (we can't afford to check the integrity of
+ * the whole file during every Git invocation). But we do want to be
+ * sure that we never read past the end of the buffer in memory and
+ * perform an illegal memory access.
+ *
+ * Guarantee that minimum level of safety by verifying that the last
+ * record in the file is LF-terminated, and that it has at least
+ * (GIT_SHA1_HEXSZ + 1) characters before the LF. Die if either of
+ * these checks fails.
+ */
+static void verify_buffer_safe(struct packed_ref_cache *packed_refs)
+{
+ const char *buf = packed_refs->buf + packed_refs->header_len;
+ const char *eof = packed_refs->eof;
+ const char *last_line;
+
+ if (buf == eof)
+ return;
+
+ last_line = find_start_of_record(buf, eof - 1);
+ if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2)
+ die_invalid_line(packed_refs->refs->path,
+ last_line, eof - last_line);
+}
+
+/*
+ * Depending on `mmap_strategy`, either mmap or read the contents of
+ * the `packed-refs` file into the `packed_refs` instance. Return 1 if
+ * the file existed and was read, or 0 if the file was absent. Die on
+ * errors.
+ */
+static int load_contents(struct packed_ref_cache *packed_refs)
+{
+ int fd;
+ struct stat st;
+ size_t size;
+ ssize_t bytes_read;
+
+ fd = open(packed_refs->refs->path, O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT) {
+ /*
+ * This is OK; it just means that no
+ * "packed-refs" file has been written yet,
+ * which is equivalent to it being empty,
+ * which is its state when initialized with
+ * zeros.
+ */
+ return 0;
+ } else {
+ die_errno("couldn't read %s", packed_refs->refs->path);
+ }
+ }
+
+ stat_validity_update(&packed_refs->validity, fd);
+
+ if (fstat(fd, &st) < 0)
+ die_errno("couldn't stat %s", packed_refs->refs->path);
+ size = xsize_t(st.st_size);
+
+ switch (mmap_strategy) {
+ case MMAP_NONE:
+ packed_refs->buf = xmalloc(size);
+ bytes_read = read_in_full(fd, packed_refs->buf, size);
+ if (bytes_read < 0 || bytes_read != size)
+ die_errno("couldn't read %s", packed_refs->refs->path);
+ packed_refs->eof = packed_refs->buf + size;
+ packed_refs->mmapped = 0;
+ break;
+ case MMAP_TEMPORARY:
+ case MMAP_OK:
+ packed_refs->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ packed_refs->eof = packed_refs->buf + size;
+ packed_refs->mmapped = 1;
+ break;
+ }
+ close(fd);
- return ref;
+ return 1;
}
/*
- * Read from `packed_refs_file` into a newly-allocated
+ * Find the place in `cache->buf` where the start of the record for
+ * `refname` starts. If `mustexist` is true and the reference doesn't
+ * exist, then return NULL. If `mustexist` is false and the reference
+ * doesn't exist, then return the point where that reference would be
+ * inserted. In the latter mode, `refname` doesn't have to be a proper
+ * reference name; for example, one could search for "refs/replace/"
+ * to find the start of any replace references.
+ *
+ * The record is sought using a binary search, so `cache->buf` must be
+ * sorted.
+ */
+static const char *find_reference_location(struct packed_ref_cache *cache,
+ const char *refname, int mustexist)
+{
+ /*
+ * This is not *quite* a garden-variety binary search, because
+ * the data we're searching is made up of records, and we
+ * always need to find the beginning of a record to do a
+ * comparison. A "record" here is one line for the reference
+ * itself and zero or one peel lines that start with '^'. Our
+ * loop invariant is described in the next two comments.
+ */
+
+ /*
+ * A pointer to the character at the start of a record whose
+ * preceding records all have reference names that come
+ * *before* `refname`.
+ */
+ const char *lo = cache->buf + cache->header_len;
+
+ /*
+ * A pointer to a the first character of a record whose
+ * reference name comes *after* `refname`.
+ */
+ const char *hi = cache->eof;
+
+ while (lo < hi) {
+ const char *mid, *rec;
+ int cmp;
+
+ mid = lo + (hi - lo) / 2;
+ rec = find_start_of_record(lo, mid);
+ cmp = cmp_entry_to_refname(rec, refname);
+ if (cmp < 0) {
+ lo = find_end_of_record(mid, hi);
+ } else if (cmp > 0) {
+ hi = rec;
+ } else {
+ return rec;
+ }
+ }
+
+ if (mustexist)
+ return NULL;
+ else
+ return lo;
+}
+
+/*
+ * Read from the `packed-refs` file into a newly-allocated
* `packed_ref_cache` and return it. The return value will already
* have its reference count incremented.
*
* A comment line of the form "# pack-refs with: " may contain zero or
* more traits. We interpret the traits as follows:
*
- * No traits:
+ * Neither `peeled` nor `fully-peeled`:
*
* Probably no references are peeled. But if the file contains a
* peeled value for a reference, we will use it.
*
- * peeled:
+ * `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:
+ * `fully-peeled`:
*
* All references in the file that can be peeled are peeled.
* Inversely (and this is more important), any references in the
* 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).
+ *
+ * `sorted`:
+ *
+ * The references in this file are known to be sorted by refname.
*/
-static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
+static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
{
- FILE *f;
struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
- struct ref_entry *last = NULL;
- struct strbuf line = STRBUF_INIT;
- enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
struct ref_dir *dir;
+ struct ref_iterator *iter;
+ int sorted = 0;
+ int ok;
+ packed_refs->refs = refs;
acquire_packed_ref_cache(packed_refs);
packed_refs->cache = create_ref_cache(NULL, NULL);
packed_refs->cache->root->flag &= ~REF_INCOMPLETE;
+ packed_refs->peeled = PEELED_NONE;
- f = fopen(packed_refs_file, "r");
- if (!f) {
- if (errno == ENOENT) {
- /*
- * This is OK; it just means that no
- * "packed-refs" file has been written yet,
- * which is equivalent to it being empty.
- */
- return packed_refs;
- } else {
- die_errno("couldn't read %s", packed_refs_file);
- }
+ if (!load_contents(packed_refs))
+ return packed_refs;
+
+ /* If the file has a header line, process it: */
+ if (packed_refs->buf < packed_refs->eof && *packed_refs->buf == '#') {
+ struct strbuf tmp = STRBUF_INIT;
+ char *p;
+ const char *eol;
+ struct string_list traits = STRING_LIST_INIT_NODUP;
+
+ eol = memchr(packed_refs->buf, '\n',
+ packed_refs->eof - packed_refs->buf);
+ if (!eol)
+ die_unterminated_line(refs->path,
+ packed_refs->buf,
+ packed_refs->eof - packed_refs->buf);
+
+ strbuf_add(&tmp, packed_refs->buf, eol - packed_refs->buf);
+
+ if (!skip_prefix(tmp.buf, "# pack-refs with:", (const char **)&p))
+ die_invalid_line(refs->path,
+ packed_refs->buf,
+ packed_refs->eof - packed_refs->buf);
+
+ string_list_split_in_place(&traits, p, ' ', -1);
+
+ if (unsorted_string_list_has_string(&traits, "fully-peeled"))
+ packed_refs->peeled = PEELED_FULLY;
+ else if (unsorted_string_list_has_string(&traits, "peeled"))
+ packed_refs->peeled = PEELED_TAGS;
+
+ sorted = unsorted_string_list_has_string(&traits, "sorted");
+
+ /* perhaps other traits later as well */
+
+ /* The "+ 1" is for the LF character. */
+ packed_refs->header_len = eol + 1 - packed_refs->buf;
+
+ string_list_clear(&traits, 0);
+ strbuf_release(&tmp);
}
- stat_validity_update(&packed_refs->validity, fileno(f));
+ verify_buffer_safe(packed_refs);
- dir = get_ref_dir(packed_refs->cache->root);
- while (strbuf_getwholeline(&line, f, '\n') != EOF) {
- struct object_id oid;
- 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;
- }
+ if (!sorted) {
+ sort_packed_refs(packed_refs);
- refname = parse_ref_line(&line, &oid);
- if (refname) {
- int flag = REF_ISPACKED;
+ /*
+ * Reordering the records might have moved a short one
+ * to the end of the buffer, so verify the buffer's
+ * safety again:
+ */
+ verify_buffer_safe(packed_refs);
+ }
- if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
- if (!refname_is_safe(refname))
- die("packed refname is dangerous: %s", refname);
- oidclr(&oid);
- flag |= REF_BAD_NAME | REF_ISBROKEN;
- }
- last = create_ref_entry(refname, &oid, flag);
- if (peeled == PEELED_FULLY ||
- (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
- last->flag |= REF_KNOWS_PEELED;
- add_ref_entry(dir, last);
- continue;
- }
- if (last &&
- line.buf[0] == '^' &&
- line.len == PEELED_LINE_LENGTH &&
- line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
- !get_oid_hex(line.buf + 1, &oid)) {
- oidcpy(&last->u.value.peeled, &oid);
- /*
- * Regardless of what the file header said,
- * we definitely know the value of *this*
- * reference:
- */
- last->flag |= REF_KNOWS_PEELED;
- }
+ if (mmap_strategy != MMAP_OK && packed_refs->mmapped) {
+ /*
+ * We don't want to leave the file mmapped, so we are
+ * forced to make a copy now:
+ */
+ size_t size = packed_refs->eof -
+ (packed_refs->buf + packed_refs->header_len);
+ char *buf_copy = xmalloc(size);
+
+ memcpy(buf_copy, packed_refs->buf + packed_refs->header_len, size);
+ release_packed_ref_buffer(packed_refs);
+ packed_refs->buf = buf_copy;
+ packed_refs->eof = buf_copy + size;
+ }
+
+ dir = get_ref_dir(packed_refs->cache->root);
+ iter = mmapped_ref_iterator_begin(
+ packed_refs,
+ packed_refs->buf + packed_refs->header_len,
+ packed_refs->eof);
+ while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
+ struct ref_entry *entry =
+ create_ref_entry(iter->refname, iter->oid, iter->flags);
+
+ if ((iter->flags & REF_KNOWS_PEELED))
+ ref_iterator_peel(iter, &entry->u.value.peeled);
+ add_ref_entry(dir, entry);
}
- fclose(f);
- strbuf_release(&line);
+ if (ok != ITER_DONE)
+ die("error reading packed-refs file %s", refs->path);
return packed_refs;
}
validate_packed_ref_cache(refs);
if (!refs->cache)
- refs->cache = read_packed_refs(refs->path);
+ refs->cache = read_packed_refs(refs);
return refs->cache;
}
return get_packed_ref_dir(get_packed_ref_cache(refs));
}
-/*
- * Add or overwrite a reference in the in-memory packed reference
- * cache. This may only be called while the packed-refs file is locked
- * (see packed_refs_lock()). To actually write the packed-refs file,
- * call commit_packed_refs().
- */
-void add_packed_ref(struct ref_store *ref_store,
- const char *refname, const struct object_id *oid)
-{
- struct packed_ref_store *refs =
- packed_downcast(ref_store, REF_STORE_WRITE,
- "add_packed_ref");
- struct ref_dir *packed_refs;
- struct ref_entry *packed_entry;
-
- if (!is_lock_file_locked(&refs->lock))
- die("BUG: packed refs not locked");
-
- if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
- die("Reference has invalid format: '%s'", refname);
-
- packed_refs = get_packed_refs(refs);
- packed_entry = find_ref_entry(packed_refs, refname);
- if (packed_entry) {
- /* Overwrite the existing entry: */
- oidcpy(&packed_entry->u.value.oid, oid);
- packed_entry->flag = REF_ISPACKED;
- oidclr(&packed_entry->u.value.peeled);
- } else {
- packed_entry = create_ref_entry(refname, oid, REF_ISPACKED);
- add_ref_entry(packed_refs, packed_entry);
- }
-}
-
/*
* Return the ref_entry for the given refname from the packed
* references. If it does not exist, return NULL.
const char *prefix, unsigned int flags)
{
struct packed_ref_store *refs;
+ struct packed_ref_cache *packed_refs;
+ const char *start;
struct packed_ref_iterator *iter;
struct ref_iterator *ref_iterator;
unsigned int required_flags = REF_STORE_READ;
iter = xcalloc(1, sizeof(*iter));
ref_iterator = &iter->base;
- base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable);
+ base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1);
/*
* Note that get_packed_ref_cache() internally checks whether
* the packed-ref cache is up to date with what is on disk,
* and re-reads it if not.
*/
+ iter->cache = packed_refs = get_packed_ref_cache(refs);
+ acquire_packed_ref_cache(packed_refs);
- iter->cache = get_packed_ref_cache(refs);
- acquire_packed_ref_cache(iter->cache);
- iter->iter0 = cache_ref_iterator_begin(iter->cache->cache, prefix, 0);
+ if (prefix && *prefix)
+ start = find_reference_location(packed_refs, prefix, 0);
+ else
+ start = packed_refs->buf + packed_refs->header_len;
+
+ iter->iter0 = mmapped_ref_iterator_begin(
+ packed_refs, start, packed_refs->eof);
iter->flags = flags;
+ if (prefix && *prefix)
+ /* Stop iteration after we've gone *past* prefix: */
+ ref_iterator = prefix_ref_iterator_begin(ref_iterator, prefix, 0);
+
return ref_iterator;
}
"packed_refs_lock");
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);
*/
validate_packed_ref_cache(refs);
- packed_ref_cache = get_packed_ref_cache(refs);
- /* Increment the reference count to prevent it from being freed: */
- acquire_packed_ref_cache(packed_ref_cache);
+ /*
+ * Now make sure that the packed-refs file as it exists in the
+ * locked state is loaded into the cache:
+ */
+ get_packed_ref_cache(refs);
return 0;
}
if (!is_lock_file_locked(&refs->lock))
die("BUG: packed_refs_unlock() called when not locked");
rollback_lock_file(&refs->lock);
- release_packed_ref_cache(refs->cache);
}
int packed_refs_is_locked(struct ref_store *ref_store)
/*
* The packed-refs header line that we write out. Perhaps other
- * traits will be added later. The trailing space is required.
+ * traits will be added later.
+ *
+ * Note that earlier versions of Git used to parse these traits by
+ * looking for " trait " in the line. For this reason, the space after
+ * the colon and the trailing space are required.
*/
static const char PACKED_REFS_HEADER[] =
- "# pack-refs with: peeled fully-peeled \n";
+ "# pack-refs with: peeled fully-peeled sorted \n";
+
+static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
+{
+ /* Nothing to do. */
+ 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
- * packed_refs_lock()). Return zero on success. On errors, rollback
- * the lockfile, write an error message to `err`, and return a nonzero
- * value.
+ * Write the packed-refs from the cache to the packed-refs tempfile,
+ * incorporating any changes from `updates`. `updates` must be a
+ * sorted string list whose keys are the refnames and whose util
+ * values are `struct ref_update *`. On error, rollback the tempfile,
+ * write an error message to `err`, and return a nonzero value.
+ *
+ * The packfile must be locked before calling this function and will
+ * remain locked when it is done.
*/
-int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
+static int write_with_updates(struct packed_ref_store *refs,
+ struct string_list *updates,
+ struct strbuf *err)
{
- struct packed_ref_store *refs =
- packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
- "commit_packed_refs");
- struct packed_ref_cache *packed_ref_cache =
- get_packed_ref_cache(refs);
+ struct ref_iterator *iter = NULL;
+ size_t i;
int ok;
- int ret = -1;
- struct strbuf sb = STRBUF_INIT;
FILE *out;
- struct ref_iterator *iter;
+ struct strbuf sb = STRBUF_INIT;
+ char *packed_refs_path;
if (!is_lock_file_locked(&refs->lock))
- die("BUG: commit_packed_refs() called when unlocked");
+ die("BUG: write_with_updates() called while unlocked");
- strbuf_addf(&sb, "%s.new", refs->path);
+ /*
+ * If packed-refs is a symlink, we want to overwrite the
+ * symlinked-to file, not the symlink itself. Also, put the
+ * staging file next to it:
+ */
+ packed_refs_path = get_locked_file_path(&refs->lock);
+ strbuf_addf(&sb, "%s.new", packed_refs_path);
+ free(packed_refs_path);
if (create_tempfile(&refs->tempfile, sb.buf) < 0) {
strbuf_addf(err, "unable to create file %s: %s",
sb.buf, strerror(errno));
strbuf_release(&sb);
- goto out;
+ return -1;
}
strbuf_release(&sb);
goto error;
}
- if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) {
- strbuf_addf(err, "error writing to %s: %s",
- get_tempfile_path(&refs->tempfile), strerror(errno));
- goto error;
- }
+ if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0)
+ goto write_error;
- iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0);
- while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
- struct object_id peeled;
- int peel_error = ref_iterator_peel(iter, &peeled);
-
- if (write_packed_entry(out, iter->refname, iter->oid->hash,
- peel_error ? NULL : peeled.hash)) {
- strbuf_addf(err, "error writing to %s: %s",
- get_tempfile_path(&refs->tempfile),
- strerror(errno));
- ref_iterator_abort(iter);
- goto error;
+ /*
+ * We iterate in parallel through the current list of refs and
+ * the list of updates, processing an entry from at least one
+ * of the lists each time through the loop. When the current
+ * list of refs is exhausted, set iter to NULL. When the list
+ * of updates is exhausted, leave i set to updates->nr.
+ */
+ iter = packed_ref_iterator_begin(&refs->base, "",
+ DO_FOR_EACH_INCLUDE_BROKEN);
+ if ((ok = ref_iterator_advance(iter)) != ITER_OK)
+ iter = NULL;
+
+ i = 0;
+
+ while (iter || i < updates->nr) {
+ struct ref_update *update = NULL;
+ int cmp;
+
+ if (i >= updates->nr) {
+ cmp = -1;
+ } else {
+ update = updates->items[i].util;
+
+ if (!iter)
+ cmp = +1;
+ else
+ cmp = strcmp(iter->refname, update->refname);
+ }
+
+ if (!cmp) {
+ /*
+ * There is both an old value and an update
+ * for this reference. Check the old value if
+ * necessary:
+ */
+ if ((update->flags & REF_HAVE_OLD)) {
+ if (is_null_oid(&update->old_oid)) {
+ strbuf_addf(err, "cannot update ref '%s': "
+ "reference already exists",
+ update->refname);
+ goto error;
+ } else if (oidcmp(&update->old_oid, iter->oid)) {
+ strbuf_addf(err, "cannot update ref '%s': "
+ "is at %s but expected %s",
+ update->refname,
+ oid_to_hex(iter->oid),
+ oid_to_hex(&update->old_oid));
+ goto error;
+ }
+ }
+
+ /* Now figure out what to use for the new value: */
+ if ((update->flags & REF_HAVE_NEW)) {
+ /*
+ * The update takes precedence. Skip
+ * the iterator over the unneeded
+ * value.
+ */
+ if ((ok = ref_iterator_advance(iter)) != ITER_OK)
+ iter = NULL;
+ cmp = +1;
+ } else {
+ /*
+ * The update doesn't actually want to
+ * change anything. We're done with it.
+ */
+ i++;
+ cmp = -1;
+ }
+ } else if (cmp > 0) {
+ /*
+ * There is no old value but there is an
+ * update for this reference. Make sure that
+ * the update didn't expect an existing value:
+ */
+ if ((update->flags & REF_HAVE_OLD) &&
+ !is_null_oid(&update->old_oid)) {
+ strbuf_addf(err, "cannot update ref '%s': "
+ "reference is missing but expected %s",
+ update->refname,
+ oid_to_hex(&update->old_oid));
+ goto error;
+ }
+ }
+
+ if (cmp < 0) {
+ /* Pass the old reference through. */
+
+ struct object_id peeled;
+ int peel_error = ref_iterator_peel(iter, &peeled);
+
+ if (write_packed_entry(out, iter->refname,
+ iter->oid->hash,
+ peel_error ? NULL : peeled.hash))
+ goto write_error;
+
+ if ((ok = ref_iterator_advance(iter)) != ITER_OK)
+ iter = NULL;
+ } else if (is_null_oid(&update->new_oid)) {
+ /*
+ * The update wants to delete the reference,
+ * and the reference either didn't exist or we
+ * have already skipped it. So we're done with
+ * the update (and don't have to write
+ * anything).
+ */
+ i++;
+ } else {
+ struct object_id peeled;
+ int peel_error = peel_object(update->new_oid.hash,
+ peeled.hash);
+
+ if (write_packed_entry(out, update->refname,
+ update->new_oid.hash,
+ peel_error ? NULL : peeled.hash))
+ goto write_error;
+
+ i++;
}
}
if (ok != ITER_DONE) {
- strbuf_addf(err, "unable to rewrite packed-refs file: "
+ strbuf_addf(err, "unable to write packed-refs file: "
"error iterating over old contents");
goto error;
}
- if (rename_tempfile(&refs->tempfile, refs->path)) {
- strbuf_addf(err, "error replacing %s: %s",
- refs->path, strerror(errno));
- goto out;
+ if (close_tempfile(&refs->tempfile)) {
+ strbuf_addf(err, "error closing file %s: %s",
+ get_tempfile_path(&refs->tempfile),
+ strerror(errno));
+ strbuf_release(&sb);
+ return -1;
}
- ret = 0;
- goto out;
+ return 0;
+
+write_error:
+ strbuf_addf(err, "error writing to %s: %s",
+ get_tempfile_path(&refs->tempfile), strerror(errno));
error:
- delete_tempfile(&refs->tempfile);
+ if (iter)
+ ref_iterator_abort(iter);
-out:
- packed_refs_unlock(ref_store);
- return ret;
+ delete_tempfile(&refs->tempfile);
+ return -1;
}
-/*
- * 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(struct packed_ref_store *refs)
-{
- packed_assert_main_repository(refs, "rollback_packed_refs");
+struct packed_transaction_backend_data {
+ /* True iff the transaction owns the packed-refs lock. */
+ int own_lock;
- if (!is_lock_file_locked(&refs->lock))
- die("BUG: packed-refs not locked");
- packed_refs_unlock(&refs->base);
- clear_packed_ref_cache(refs);
-}
+ struct string_list updates;
+};
-/*
- * 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.
- */
-int repack_without_refs(struct ref_store *ref_store,
- struct string_list *refnames, struct strbuf *err)
+static void packed_transaction_cleanup(struct packed_ref_store *refs,
+ struct ref_transaction *transaction)
{
- struct packed_ref_store *refs =
- packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
- "repack_without_refs");
- struct ref_dir *packed;
- struct string_list_item *refname;
- int needs_repacking = 0, removed = 0;
-
- packed_assert_main_repository(refs, "repack_without_refs");
- assert(err);
-
- /* Look for a packed ref */
- for_each_string_list_item(refname, refnames) {
- if (get_packed_ref(refs, refname->string)) {
- needs_repacking = 1;
- break;
- }
- }
+ struct packed_transaction_backend_data *data = transaction->backend_data;
- /* Avoid locking if we have nothing to do */
- if (!needs_repacking)
- return 0; /* no refname exists in packed refs */
+ if (data) {
+ string_list_clear(&data->updates, 0);
- if (packed_refs_lock(&refs->base, 0, err))
- return -1;
+ if (is_tempfile_active(&refs->tempfile))
+ delete_tempfile(&refs->tempfile);
- packed = get_packed_refs(refs);
+ if (data->own_lock && is_lock_file_locked(&refs->lock)) {
+ packed_refs_unlock(&refs->base);
+ data->own_lock = 0;
+ }
- /* Remove refnames from the cache */
- for_each_string_list_item(refname, refnames)
- if (remove_entry_from_dir(packed, refname->string) != -1)
- removed = 1;
- if (!removed) {
- /*
- * All packed entries disappeared while we were
- * acquiring the lock.
- */
- rollback_packed_refs(refs);
- return 0;
+ free(data);
+ transaction->backend_data = NULL;
}
- /* Write what remains */
- return commit_packed_refs(&refs->base, err);
-}
-
-static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
-{
- /* Nothing to do. */
- return 0;
+ transaction->state = REF_TRANSACTION_CLOSED;
}
static int packed_transaction_prepare(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
- die("BUG: not implemented yet");
+ struct packed_ref_store *refs = packed_downcast(
+ ref_store,
+ REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
+ "ref_transaction_prepare");
+ struct packed_transaction_backend_data *data;
+ size_t i;
+ int ret = TRANSACTION_GENERIC_ERROR;
+
+ /*
+ * Note that we *don't* skip transactions with zero updates,
+ * because such a transaction might be executed for the side
+ * effect of ensuring that all of the references are peeled.
+ * If the caller wants to optimize away empty transactions, it
+ * should do so itself.
+ */
+
+ data = xcalloc(1, sizeof(*data));
+ string_list_init(&data->updates, 0);
+
+ transaction->backend_data = data;
+
+ /*
+ * Stick the updates in a string list by refname so that we
+ * can sort them:
+ */
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *update = transaction->updates[i];
+ struct string_list_item *item =
+ string_list_append(&data->updates, update->refname);
+
+ /* Store a pointer to update in item->util: */
+ item->util = update;
+ }
+ string_list_sort(&data->updates);
+
+ if (ref_update_reject_duplicates(&data->updates, err))
+ goto failure;
+
+ if (!is_lock_file_locked(&refs->lock)) {
+ if (packed_refs_lock(ref_store, 0, err))
+ goto failure;
+ data->own_lock = 1;
+ }
+
+ if (write_with_updates(refs, &data->updates, err))
+ goto failure;
+
+ transaction->state = REF_TRANSACTION_PREPARED;
+ return 0;
+
+failure:
+ packed_transaction_cleanup(refs, transaction);
+ return ret;
}
static int packed_transaction_abort(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
- die("BUG: not implemented yet");
+ struct packed_ref_store *refs = packed_downcast(
+ ref_store,
+ REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
+ "ref_transaction_abort");
+
+ packed_transaction_cleanup(refs, transaction);
+ return 0;
}
static int packed_transaction_finish(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
- die("BUG: not implemented yet");
+ struct packed_ref_store *refs = packed_downcast(
+ ref_store,
+ REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
+ "ref_transaction_finish");
+ int ret = TRANSACTION_GENERIC_ERROR;
+ char *packed_refs_path;
+
+ clear_packed_ref_cache(refs);
+
+ packed_refs_path = get_locked_file_path(&refs->lock);
+ if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
+ strbuf_addf(err, "error replacing %s: %s",
+ refs->path, strerror(errno));
+ goto cleanup;
+ }
+
+ ret = 0;
+
+cleanup:
+ free(packed_refs_path);
+ packed_transaction_cleanup(refs, transaction);
+ return ret;
}
static int packed_initial_transaction_commit(struct ref_store *ref_store,
static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
struct string_list *refnames, unsigned int flags)
{
- die("BUG: not implemented yet");
+ struct packed_ref_store *refs =
+ packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
+ struct strbuf err = STRBUF_INIT;
+ struct ref_transaction *transaction;
+ struct string_list_item *item;
+ int ret;
+
+ (void)refs; /* We need the check above, but don't use the variable */
+
+ if (!refnames->nr)
+ return 0;
+
+ /*
+ * Since we don't check the references' old_oids, the
+ * individual updates can't fail, so we can pack all of the
+ * updates into a single transaction.
+ */
+
+ transaction = ref_store_transaction_begin(ref_store, &err);
+ if (!transaction)
+ return -1;
+
+ for_each_string_list_item(item, refnames) {
+ if (ref_transaction_delete(transaction, item->string, NULL,
+ flags, msg, &err)) {
+ warning(_("could not delete reference %s: %s"),
+ item->string, err.buf);
+ strbuf_reset(&err);
+ }
+ }
+
+ ret = ref_transaction_commit(transaction, &err);
+
+ if (ret) {
+ 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);
+ }
+
+ ref_transaction_free(transaction);
+ strbuf_release(&err);
+ return ret;
}
static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)