[PATCH 04/17] add_to_alternates_file: don't add duplicate entries
- From
Jeff King <peff@peff.net>
- Date
- Aug 10, 2015, 09:34 UTC
- Message-ID
- <20150810093446.GD30981@sigill.intra.peff.net>
- In-Reply-To
- <20150810092731.GA9027@sigill.intra.peff.net>
The add_to_alternates_file function blindly uses hold_lock_file_for_append to copy the existing contents, and then adds the new line to it. This has two minor problems:
1. We might add duplicate entries, which are ugly and
inefficient. 2. We do not check that the file ends with a newline, in
which case we would bogusly append to the final line.
This is quite unlikely in practice, though, as we call
this function only from git-clone, so presumably we are
the only writers of the file (and we always add a
newline).Instead of using hold_lock_file_for_append, let's copy the file line by line, which ensures all records are properly terminated. If we see an extra line, we can simply abort the update (there is no point in even copying the rest, as we know that it would be identical to the original).
As a bonus, we also get rid of some calls to the static-buffer mkpath and git_path functions.
Signed-off-by: Jeff King <peff@peff.net> --- This is a polishing of the thread at:
http://thread.gmane.org/gmane.comp.version-control.git/270341
sha1_file.c | 47 +++++++++++++++++++++++++++++++++++++++------- t/t5700-clone-reference.sh | 5 +++++ 2 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/sha1_file.c b/sha1_file.c index 1cee438..3400b8b 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -404,13 +404,46 @@ void read_info_alternates(const char * relative_base, int depth) void add_to_alternates_file(const char *reference) { struct lock_file *lock = xcalloc(1, sizeof(struct lock_file)); - int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR); - const char *alt = mkpath("%s\n", reference); - write_or_die(fd, alt, strlen(alt)); - if (commit_lock_file(lock)) - die("could not close alternates file"); - if (alt_odb_tail) - link_alt_odb_entries(alt, strlen(alt), '\n', NULL, 0); + char *alts = git_pathdup("objects/info/alternates"); + FILE *in, *out; + + hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR); + out = fdopen_lock_file(lock, "w"); + if (!out) + die_errno("unable to fdopen alternates lockfile"); + + in = fopen(alts, "r"); + if (in) { + struct strbuf line = STRBUF_INIT; + int found = 0; + + while (strbuf_getline(&line, in, '\n') != EOF) { + if (!strcmp(reference, line.buf)) { + found = 1; + break; + } + fprintf_or_die(out, "%s\n", line.buf); + } + + strbuf_release(&line); + fclose(in); + + if (found) { + rollback_lock_file(lock); + lock = NULL; + } + } + else if (errno != ENOENT) + die_errno("unable to read alternates file"); + + if (lock) { + fprintf_or_die(out, "%s\n", reference); + if (commit_lock_file(lock)) + die_errno("unable to move new alternates file into place"); + if (alt_odb_tail) + link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0); + } + free(alts); } int foreach_alt_odb(alt_odb_fn fn, void *cb) diff --git a/t/t5700-clone-reference.sh b/t/t5700-clone-reference.sh index 51d131a..ef1779f 100755 --- a/t/t5700-clone-reference.sh +++ b/t/t5700-clone-reference.sh @@ -120,6 +120,11 @@ test_expect_success 'cloning with reference being subset of source (-l -s)' ' git clone -l -s --reference A B E ' +test_expect_success 'cloning with multiple references drops duplicates' ' + git clone -s --reference B --reference A --reference B A dups && + test_line_count = 2 dups/.git/objects/info/alternates +' + test_expect_success 'clone with reference from a tagged repository' ' ( cd A && git tag -a -m tagged HEAD
-- 2.5.0.414.g670f2a4