[PATCH 18/30] packed-refs: write file format version 2
From: Derrick Stolee <derrickstolee@github.com>
TODO: add writing tests.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
refs/packed-backend.c | 3 +-
refs/packed-format-v2.c | 108 ++++++++++++++++++++++++++++++++++++++++
t/t3212-ref-formats.sh | 6 ++-
3 files changed, 115 insertions(+), 2 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 09f7b74584f..3429e63620a 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -790,7 +790,8 @@ static int write_with_updates(struct packed_ref_store *refs,
break;
case 2:
- ok = write_with_updates_v2(refs, updates, err);
+ /* Convert the normal error codes to ITER_DONE. */
+ ok = write_with_updates_v2(refs, updates, err) ? -2 : ITER_DONE;
break;
default:
diff --git a/refs/packed-format-v2.c b/refs/packed-format-v2.c
index ecf3cc93694..044cc9f629a 100644
--- a/refs/packed-format-v2.c
+++ b/refs/packed-format-v2.c
@@ -6,11 +6,30 @@
#include "../iterator.h"
#include "../lockfile.h"
#include "../chdir-notify.h"
+#include "../chunk-format.h"
+#include "../csum-file.h"
+
+#define OFFSET_IS_PEELED (((uint64_t)1) << 63)
+
+#define PACKED_REFS_SIGNATURE 0x50524546 /* "PREF" */
+#define CHREFS_CHUNKID_OFFSETS 0x524F4646 /* "ROFF" */
+#define CHREFS_CHUNKID_REFS 0x52454653 /* "REFS" */
struct write_packed_refs_v2_context {
struct packed_ref_store *refs;
struct string_list *updates;
struct strbuf *err;
+
+ struct hashfile *f;
+ struct chunkfile *cf;
+
+ /*
+ * As we stream the ref names to the refs chunk, store these
+ * values in-memory. These arrays are populated one for every ref.
+ */
+ uint64_t *offsets;
+ size_t nr;
+ size_t offsets_alloc;
};
struct write_packed_refs_v2_context *create_v2_context(struct packed_ref_store *refs,
@@ -24,15 +43,104 @@ struct write_packed_refs_v2_context *create_v2_context(struct packed_ref_store *
ctx->updates = updates;
ctx->err = err;
+ if (!fdopen_tempfile(refs->tempfile, "w")) {
+ strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s",
+ strerror(errno));
+ return ctx;
+ }
+
+ ctx->f = hashfd(refs->tempfile->fd, refs->tempfile->filename.buf);
+ ctx->cf = init_chunkfile(ctx->f);
+
return ctx;
}
+static int write_packed_entry_v2(const char *refname,
+ const struct object_id *oid,
+ const struct object_id *peeled,
+ void *write_data)
+{
+ struct write_packed_refs_v2_context *ctx = write_data;
+ size_t reflen = strlen(refname) + 1;
+ size_t i = ctx->nr;
+
+ ALLOC_GROW(ctx->offsets, i + 1, ctx->offsets_alloc);
+
+ /* Write entire ref, including null terminator. */
+ hashwrite(ctx->f, refname, reflen);
+ hashwrite(ctx->f, oid->hash, the_hash_algo->rawsz);
+ if (peeled)
+ hashwrite(ctx->f, peeled->hash, the_hash_algo->rawsz);
+
+ if (i)
+ ctx->offsets[i] = (ctx->offsets[i - 1] & (~OFFSET_IS_PEELED));
+ else
+ ctx->offsets[i] = 0;
+ ctx->offsets[i] += reflen + the_hash_algo->rawsz;
+
+ if (peeled) {
+ ctx->offsets[i] += the_hash_algo->rawsz;
+ ctx->offsets[i] |= OFFSET_IS_PEELED;
+ }
+
+ ctx->nr++;
+ return 0;
+}
+
+static int write_refs_chunk_refs(struct hashfile *f,
+ void *data)
+{
+ struct write_packed_refs_v2_context *ctx = data;
+ int ok;
+
+ trace2_region_enter("refs", "refs-chunk", the_repository);
+ ok = merge_iterator_and_updates(ctx->refs, ctx->updates, ctx->err,
+ write_packed_entry_v2, ctx);
+ trace2_region_leave("refs", "refs-chunk", the_repository);
+
+ return ok != ITER_DONE;
+}
+
+static int write_refs_chunk_offsets(struct hashfile *f,
+ void *data)
+{
+ struct write_packed_refs_v2_context *ctx = data;
+ size_t i;
+
+ trace2_region_enter("refs", "offsets", the_repository);
+ for (i = 0; i < ctx->nr; i++)
+ hashwrite_be64(f, ctx->offsets[i]);
+
+ trace2_region_leave("refs", "offsets", the_repository);
+ return 0;
+}
+
int write_packed_refs_v2(struct write_packed_refs_v2_context *ctx)
{
+ unsigned char file_hash[GIT_MAX_RAWSZ];
+
+ add_chunk(ctx->cf, CHREFS_CHUNKID_REFS, 0, write_refs_chunk_refs);
+ add_chunk(ctx->cf, CHREFS_CHUNKID_OFFSETS, 0, write_refs_chunk_offsets);
+
+ hashwrite_be32(ctx->f, PACKED_REFS_SIGNATURE);
+ hashwrite_be32(ctx->f, 2);
+ hashwrite_be32(ctx->f, the_hash_algo->format_id);
+
+ if (write_chunkfile(ctx->cf, CHUNKFILE_TRAILING_TOC, ctx))
+ goto failure;
+
+ finalize_hashfile(ctx->f, file_hash, FSYNC_COMPONENT_REFERENCE,
+ CSUM_HASH_IN_STREAM | CSUM_FSYNC);
+
return 0;
+
+failure:
+ return -1;
}
void free_v2_context(struct write_packed_refs_v2_context *ctx)
{
+ if (ctx->cf)
+ free_chunkfile(ctx->cf);
free(ctx);
}
diff --git a/t/t3212-ref-formats.sh b/t/t3212-ref-formats.sh
index cd1b399bbb8..03c713ac4f6 100755
--- a/t/t3212-ref-formats.sh
+++ b/t/t3212-ref-formats.sh
@@ -71,7 +71,11 @@ test_expect_success 'extensions.refFormat=files,packed-v2' '
# Refuse to parse a v1 packed-refs file.
cp ../.git/packed-refs .git/packed-refs &&
test_must_fail git rev-parse refs/tags/Q &&
- rm -f .git/packed-refs
+ rm -f .git/packed-refs &&
+
+ # Create a v2 packed-refs file
+ git pack-refs --all &&
+ test_path_exists .git/packed-refs
)
'
--
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Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>