[PATCH 06/10] add ref_abbrev_matches_full_with_rev_parse_rules() comparing abbrev with full ref name

[Steffen Prohaska <prohaska@zib.de>]

ref_abbrev_matches_full_with_rev_parse_rules(abbrev_name, full_name)
expands abbrev_name according to the rules documented in
git-rev-parse and compares the expanded name with full_name. It
reports a match by returning 0.

This function makes the rules for resolving refs to sha1s available
for string comparison. Before this change, the rules were buried in
get_sha1*() and dwim_ref().

The function name is very long to make the rule set used
explicit. We have a different set of rules for matching refspecs.
It would be a good thing to unify all different rule sets. But
this commit doesn't address this challenge. It only makes the
git-rev-parse rules available for string comparison.

ref_abbrev_matches_full_with_rev_parse_rules() will be used for
matching refspecs in git-send-pack.

Thanks to Daniel Barkalow <barkalow@iabervon.org> for pointing
out that ref_matches_abbrev in remote.c solves a similar problem
and care should be take to avoid confusion.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 cache.h     |    1 +
 sha1_name.c |   14 ++++++++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/cache.h b/cache.h
index 27485d3..bb10ade 100644
--- a/cache.h
+++ b/cache.h
@@ -405,6 +405,7 @@ extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 extern int read_ref(const char *filename, unsigned char *sha1);
 extern const char *resolve_ref(const char *path, unsigned char *sha1, int, int *);
+extern int ref_abbrev_matches_full_with_rev_parse_rules(const char *abbrev_name, const char *full_name);
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
 
diff --git a/sha1_name.c b/sha1_name.c
index 2d727d5..944e318 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -249,6 +249,20 @@ static const char *ref_fmt[] = {
 	NULL
 };
 
+int ref_abbrev_matches_full_with_rev_parse_rules(const char *abbrev_name, const char *full_name)
+{
+	const char **p;
+	const int abbrev_name_len = strlen(abbrev_name);
+
+	for (p = ref_fmt; *p; p++) {
+		if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 {
 	const char **p, *r;
-- 
1.5.3.4.439.ge8b49