Merge branch 'jk/unused-function'
[gitweb.git] / refs / packed-backend.c
index dab8a85d9a67870d45e160e66ab382991a181eae..c01c7f5901a6f3bd0fd5fa638bfc286fa7e5f1d8 100644 (file)
@@ -5,6 +5,7 @@
 #include "packed-backend.h"
 #include "../iterator.h"
 #include "../lockfile.h"
+#include "../chdir-notify.h"
 
 enum mmap_strategy {
        /*
@@ -68,17 +69,21 @@ struct snapshot {
        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.
+        * The contents of the `packed-refs` file:
+        *
+        * - buf -- a pointer to the start of the memory
+        * - start -- a pointer to the first byte of actual references
+        *   (i.e., after the header line, if one is present)
+        * - eof -- a pointer just past the end of the reference
+        *   contents
+        *
+        * If the `packed-refs` file was already sorted, `buf` points
+        * at the mmapped contents of the file. If not, it points at
+        * heap-allocated memory containing the contents, sorted. If
+        * there were no contents (e.g., because the file didn't
+        * exist), `buf`, `start`, and `eof` are all NULL.
         */
-       char *buf, *eof;
-
-       /* The size of the header line, if any; otherwise, 0: */
-       size_t header_len;
+       char *buf, *start, *eof;
 
        /*
         * What is the peeled state of the `packed-refs` file that
@@ -169,8 +174,7 @@ static void clear_snapshot_buffer(struct snapshot *snapshot)
        } else {
                free(snapshot->buf);
        }
-       snapshot->buf = snapshot->eof = NULL;
-       snapshot->header_len = 0;
+       snapshot->buf = snapshot->start = snapshot->eof = NULL;
 }
 
 /*
@@ -199,6 +203,8 @@ struct ref_store *packed_ref_store_create(const char *path,
        refs->store_flags = store_flags;
 
        refs->path = xstrdup(path);
+       chdir_notify_reparent("packed-refs", &refs->path);
+
        return ref_store;
 }
 
@@ -215,13 +221,13 @@ static struct packed_ref_store *packed_downcast(struct ref_store *ref_store,
        struct packed_ref_store *refs;
 
        if (ref_store->be != &refs_be_packed)
-               die("BUG: ref_store is type \"%s\" not \"packed\" in %s",
+               BUG("ref_store is type \"%s\" not \"packed\" in %s",
                    ref_store->be->name, caller);
 
        refs = (struct packed_ref_store *)ref_store;
 
        if ((refs->store_flags & required_flags) != required_flags)
-               die("BUG: unallowed operation (%s), requires %x, has %x\n",
+               BUG("unallowed operation (%s), requires %x, has %x\n",
                    caller, required_flags, refs->store_flags);
 
        return refs;
@@ -268,8 +274,8 @@ struct snapshot_record {
 static int cmp_packed_ref_records(const void *v1, const void *v2)
 {
        const struct snapshot_record *e1 = v1, *e2 = v2;
-       const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1;
-       const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1;
+       const char *r1 = e1->start + the_hash_algo->hexsz + 1;
+       const char *r2 = e2->start + the_hash_algo->hexsz + 1;
 
        while (1) {
                if (*r1 == '\n')
@@ -291,7 +297,7 @@ static int cmp_packed_ref_records(const void *v1, const void *v2)
  */
 static int cmp_record_to_refname(const char *rec, const char *refname)
 {
-       const char *r1 = rec + GIT_SHA1_HEXSZ + 1;
+       const char *r1 = rec + the_hash_algo->hexsz + 1;
        const char *r2 = refname;
 
        while (1) {
@@ -319,13 +325,14 @@ static void sort_snapshot(struct snapshot *snapshot)
        size_t len, i;
        char *new_buffer, *dst;
 
-       pos = snapshot->buf + snapshot->header_len;
+       pos = snapshot->start;
        eof = snapshot->eof;
-       len = eof - pos;
 
-       if (!len)
+       if (pos == eof)
                return;
 
+       len = eof - pos;
+
        /*
         * Initialize records based on a crude estimate of the number
         * of references in the file (we'll grow it below if needed):
@@ -337,7 +344,7 @@ static void sort_snapshot(struct snapshot *snapshot)
                if (!eol)
                        /* The safety check should prevent this. */
                        BUG("unterminated line found in packed-refs");
-               if (eol - pos < GIT_SHA1_HEXSZ + 2)
+               if (eol - pos < the_hash_algo->hexsz + 2)
                        die_invalid_line(snapshot->refs->path,
                                         pos, eof - pos);
                eol++;
@@ -391,9 +398,8 @@ static void sort_snapshot(struct snapshot *snapshot)
         * place:
         */
        clear_snapshot_buffer(snapshot);
-       snapshot->buf = new_buffer;
+       snapshot->buf = snapshot->start = new_buffer;
        snapshot->eof = new_buffer + len;
-       snapshot->header_len = 0;
 
 cleanup:
        free(records);
@@ -442,23 +448,26 @@ static const char *find_end_of_record(const char *p, const char *end)
  */
 static void verify_buffer_safe(struct snapshot *snapshot)
 {
-       const char *buf = snapshot->buf + snapshot->header_len;
+       const char *start = snapshot->start;
        const char *eof = snapshot->eof;
        const char *last_line;
 
-       if (buf == eof)
+       if (start == eof)
                return;
 
-       last_line = find_start_of_record(buf, eof - 1);
-       if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2)
+       last_line = find_start_of_record(start, eof - 1);
+       if (*(eof - 1) != '\n' || eof - last_line < the_hash_algo->hexsz + 2)
                die_invalid_line(snapshot->refs->path,
                                 last_line, eof - last_line);
 }
 
+#define SMALL_FILE_SIZE (32*1024)
+
 /*
  * Depending on `mmap_strategy`, either mmap or read the contents of
  * the `packed-refs` file into the snapshot. Return 1 if the file
- * existed and was read, or 0 if the file was absent. Die on errors.
+ * existed and was read, or 0 if the file was absent or empty. Die on
+ * errors.
  */
 static int load_contents(struct snapshot *snapshot)
 {
@@ -489,24 +498,24 @@ static int load_contents(struct snapshot *snapshot)
                die_errno("couldn't stat %s", snapshot->refs->path);
        size = xsize_t(st.st_size);
 
-       switch (mmap_strategy) {
-       case MMAP_NONE:
+       if (!size) {
+               close(fd);
+               return 0;
+       } else if (mmap_strategy == MMAP_NONE || size <= SMALL_FILE_SIZE) {
                snapshot->buf = xmalloc(size);
                bytes_read = read_in_full(fd, snapshot->buf, size);
                if (bytes_read < 0 || bytes_read != size)
                        die_errno("couldn't read %s", snapshot->refs->path);
-               snapshot->eof = snapshot->buf + size;
                snapshot->mmapped = 0;
-               break;
-       case MMAP_TEMPORARY:
-       case MMAP_OK:
+       } else {
                snapshot->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
-               snapshot->eof = snapshot->buf + size;
                snapshot->mmapped = 1;
-               break;
        }
        close(fd);
 
+       snapshot->start = snapshot->buf;
+       snapshot->eof = snapshot->buf + size;
+
        return 1;
 }
 
@@ -515,9 +524,11 @@ static int load_contents(struct snapshot *snapshot)
  * `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.
+ * inserted, or `snapshot->eof` (which might be NULL) if it would be
+ * inserted at the end of the file. 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 `snapshot->buf` must
  * be sorted.
@@ -539,7 +550,7 @@ static const char *find_reference_location(struct snapshot *snapshot,
         * preceding records all have reference names that come
         * *before* `refname`.
         */
-       const char *lo = snapshot->buf + snapshot->header_len;
+       const char *lo = snapshot->start;
 
        /*
         * A pointer to a the first character of a record whose
@@ -547,7 +558,7 @@ static const char *find_reference_location(struct snapshot *snapshot,
         */
        const char *hi = snapshot->eof;
 
-       while (lo < hi) {
+       while (lo != hi) {
                const char *mid, *rec;
                int cmp;
 
@@ -616,9 +627,7 @@ static struct snapshot *create_snapshot(struct packed_ref_store *refs)
 
        /* If the file has a header line, process it: */
        if (snapshot->buf < snapshot->eof && *snapshot->buf == '#') {
-               struct strbuf tmp = STRBUF_INIT;
-               char *p;
-               const char *eol;
+               char *tmp, *p, *eol;
                struct string_list traits = STRING_LIST_INIT_NODUP;
 
                eol = memchr(snapshot->buf, '\n',
@@ -628,9 +637,9 @@ static struct snapshot *create_snapshot(struct packed_ref_store *refs)
                                              snapshot->buf,
                                              snapshot->eof - snapshot->buf);
 
-               strbuf_add(&tmp, snapshot->buf, eol - snapshot->buf);
+               tmp = xmemdupz(snapshot->buf, eol - snapshot->buf);
 
-               if (!skip_prefix(tmp.buf, "# pack-refs with:", (const char **)&p))
+               if (!skip_prefix(tmp, "# pack-refs with:", (const char **)&p))
                        die_invalid_line(refs->path,
                                         snapshot->buf,
                                         snapshot->eof - snapshot->buf);
@@ -647,10 +656,10 @@ static struct snapshot *create_snapshot(struct packed_ref_store *refs)
                /* perhaps other traits later as well */
 
                /* The "+ 1" is for the LF character. */
-               snapshot->header_len = eol + 1 - snapshot->buf;
+               snapshot->start = eol + 1;
 
                string_list_clear(&traits, 0);
-               strbuf_release(&tmp);
+               free(tmp);
        }
 
        verify_buffer_safe(snapshot);
@@ -671,13 +680,12 @@ static struct snapshot *create_snapshot(struct packed_ref_store *refs)
                 * We don't want to leave the file mmapped, so we are
                 * forced to make a copy now:
                 */
-               size_t size = snapshot->eof -
-                       (snapshot->buf + snapshot->header_len);
+               size_t size = snapshot->eof - snapshot->start;
                char *buf_copy = xmalloc(size);
 
-               memcpy(buf_copy, snapshot->buf + snapshot->header_len, size);
+               memcpy(buf_copy, snapshot->start, size);
                clear_snapshot_buffer(snapshot);
-               snapshot->buf = buf_copy;
+               snapshot->buf = snapshot->start = buf_copy;
                snapshot->eof = buf_copy + size;
        }
 
@@ -716,7 +724,7 @@ static struct snapshot *get_snapshot(struct packed_ref_store *refs)
 }
 
 static int packed_read_raw_ref(struct ref_store *ref_store,
-                              const char *refname, unsigned char *sha1,
+                              const char *refname, struct object_id *oid,
                               struct strbuf *referent, unsigned int *type)
 {
        struct packed_ref_store *refs =
@@ -734,7 +742,7 @@ static int packed_read_raw_ref(struct ref_store *ref_store,
                return -1;
        }
 
-       if (get_sha1_hex(rec, sha1))
+       if (get_oid_hex(rec, oid))
                die_invalid_line(refs->path, rec, snapshot->eof - rec);
 
        *type = REF_ISPACKED;
@@ -744,7 +752,7 @@ static int packed_read_raw_ref(struct ref_store *ref_store,
 /*
  * This value is set in `base.flags` if the peeled value of the
  * current reference is known. In that case, `peeled` contains the
- * correct peeled value for the reference, which might be `null_sha1`
+ * correct peeled value for the reference, which might be `null_oid`
  * if the reference is not a tag or if it is broken.
  */
 #define REF_KNOWS_PEELED 0x40
@@ -788,7 +796,7 @@ static int next_record(struct packed_ref_iterator *iter)
 
        iter->base.flags = REF_ISPACKED;
 
-       if (iter->eof - p < GIT_SHA1_HEXSZ + 2 ||
+       if (iter->eof - p < the_hash_algo->hexsz + 2 ||
            parse_oid_hex(p, &iter->oid, &p) ||
            !isspace(*p++))
                die_invalid_line(iter->snapshot->refs->path,
@@ -818,7 +826,7 @@ static int next_record(struct packed_ref_iterator *iter)
 
        if (iter->pos < iter->eof && *iter->pos == '^') {
                p = iter->pos + 1;
-               if (iter->eof - p < GIT_SHA1_HEXSZ + 1 ||
+               if (iter->eof - p < the_hash_algo->hexsz + 1 ||
                    parse_oid_hex(p, &iter->peeled, &p) ||
                    *p++ != '\n')
                        die_invalid_line(iter->snapshot->refs->path,
@@ -880,7 +888,7 @@ static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
        } else if ((iter->base.flags & (REF_ISBROKEN | REF_ISSYMREF))) {
                return -1;
        } else {
-               return !!peel_object(iter->oid.hash, peeled->hash);
+               return !!peel_object(&iter->oid, peeled);
        }
 }
 
@@ -924,7 +932,12 @@ static struct ref_iterator *packed_ref_iterator_begin(
         */
        snapshot = get_snapshot(refs);
 
-       if (!snapshot->buf)
+       if (prefix && *prefix)
+               start = find_reference_location(snapshot, prefix, 0);
+       else
+               start = snapshot->start;
+
+       if (start == snapshot->eof)
                return empty_ref_iterator_begin();
 
        iter = xcalloc(1, sizeof(*iter));
@@ -934,11 +947,6 @@ static struct ref_iterator *packed_ref_iterator_begin(
        iter->snapshot = snapshot;
        acquire_snapshot(snapshot);
 
-       if (prefix && *prefix)
-               start = find_reference_location(snapshot, prefix, 0);
-       else
-               start = snapshot->buf + snapshot->header_len;
-
        iter->pos = start;
        iter->eof = snapshot->eof;
        strbuf_init(&iter->refname_buf, 0);
@@ -961,11 +969,11 @@ static struct ref_iterator *packed_ref_iterator_begin(
  * by the failing call to `fprintf()`.
  */
 static int write_packed_entry(FILE *fh, const char *refname,
-                             const unsigned char *sha1,
-                             const unsigned char *peeled)
+                             const struct object_id *oid,
+                             const struct object_id *peeled)
 {
-       if (fprintf(fh, "%s %s\n", sha1_to_hex(sha1), refname) < 0 ||
-           (peeled && fprintf(fh, "^%s\n", sha1_to_hex(peeled)) < 0))
+       if (fprintf(fh, "%s %s\n", oid_to_hex(oid), refname) < 0 ||
+           (peeled && fprintf(fh, "^%s\n", oid_to_hex(peeled)) < 0))
                return -1;
 
        return 0;
@@ -1029,7 +1037,7 @@ void packed_refs_unlock(struct ref_store *ref_store)
                        "packed_refs_unlock");
 
        if (!is_lock_file_locked(&refs->lock))
-               die("BUG: packed_refs_unlock() called when not locked");
+               BUG("packed_refs_unlock() called when not locked");
        rollback_lock_file(&refs->lock);
 }
 
@@ -1082,7 +1090,7 @@ static int write_with_updates(struct packed_ref_store *refs,
        char *packed_refs_path;
 
        if (!is_lock_file_locked(&refs->lock))
-               die("BUG: write_with_updates() called while unlocked");
+               BUG("write_with_updates() called while unlocked");
 
        /*
         * If packed-refs is a symlink, we want to overwrite the
@@ -1152,7 +1160,7 @@ static int write_with_updates(struct packed_ref_store *refs,
                                                    "reference already exists",
                                                    update->refname);
                                        goto error;
-                               } else if (oidcmp(&update->old_oid, iter->oid)) {
+                               } else if (!oideq(&update->old_oid, iter->oid)) {
                                        strbuf_addf(err, "cannot update ref '%s': "
                                                    "is at %s but expected %s",
                                                    update->refname,
@@ -1203,8 +1211,8 @@ static int write_with_updates(struct packed_ref_store *refs,
                        int peel_error = ref_iterator_peel(iter, &peeled);
 
                        if (write_packed_entry(out, iter->refname,
-                                              iter->oid->hash,
-                                              peel_error ? NULL : peeled.hash))
+                                              iter->oid,
+                                              peel_error ? NULL : &peeled))
                                goto write_error;
 
                        if ((ok = ref_iterator_advance(iter)) != ITER_OK)
@@ -1220,12 +1228,12 @@ static int write_with_updates(struct packed_ref_store *refs,
                        i++;
                } else {
                        struct object_id peeled;
-                       int peel_error = peel_object(update->new_oid.hash,
-                                                    peeled.hash);
+                       int peel_error = peel_object(&update->new_oid,
+                                                    &peeled);
 
                        if (write_packed_entry(out, update->refname,
-                                              update->new_oid.hash,
-                                              peel_error ? NULL : peeled.hash))
+                                              &update->new_oid,
+                                              peel_error ? NULL : &peeled))
                                goto write_error;
 
                        i++;
@@ -1340,7 +1348,7 @@ int is_packed_transaction_needed(struct ref_store *ref_store,
                        continue;
 
                if (!refs_read_raw_ref(ref_store, update->refname,
-                                      oid.hash, &referent, &type) ||
+                                      &oid, &referent, &type) ||
                    errno != ENOENT) {
                        /*
                         * We have to actually delete that reference
@@ -1556,21 +1564,21 @@ static int packed_create_symref(struct ref_store *ref_store,
                               const char *refname, const char *target,
                               const char *logmsg)
 {
-       die("BUG: packed reference store does not support symrefs");
+       BUG("packed reference store does not support symrefs");
 }
 
 static int packed_rename_ref(struct ref_store *ref_store,
                            const char *oldrefname, const char *newrefname,
                            const char *logmsg)
 {
-       die("BUG: packed reference store does not support renaming references");
+       BUG("packed reference store does not support renaming references");
 }
 
 static int packed_copy_ref(struct ref_store *ref_store,
                           const char *oldrefname, const char *newrefname,
                           const char *logmsg)
 {
-       die("BUG: packed reference store does not support copying references");
+       BUG("packed reference store does not support copying references");
 }
 
 static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
@@ -1603,7 +1611,7 @@ static int packed_create_reflog(struct ref_store *ref_store,
                               const char *refname, int force_create,
                               struct strbuf *err)
 {
-       die("BUG: packed reference store does not support reflogs");
+       BUG("packed reference store does not support reflogs");
 }
 
 static int packed_delete_reflog(struct ref_store *ref_store,
@@ -1613,7 +1621,7 @@ static int packed_delete_reflog(struct ref_store *ref_store,
 }
 
 static int packed_reflog_expire(struct ref_store *ref_store,
-                               const char *refname, const unsigned char *sha1,
+                               const char *refname, const struct object_id *oid,
                                unsigned int flags,
                                reflog_expiry_prepare_fn prepare_fn,
                                reflog_expiry_should_prune_fn should_prune_fn,