From a1b475eeb40dc29246d4ce7465474479639769d0 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 18 Jun 2012 11:30:15 -0700
Subject: sha1_name.c: indentation fix

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 03ffc2caaa..5b0c845d85 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -103,10 +103,10 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 		}
 		if (first < num) {
 			const unsigned char *now, *next;
-		       now = nth_packed_object_sha1(p, first);
+			now = nth_packed_object_sha1(p, first);
 			if (match_sha(len, match, now)) {
 				next = nth_packed_object_sha1(p, first+1);
-			       if (!next|| !match_sha(len, match, next)) {
+				if (!next|| !match_sha(len, match, next)) {
 					/* unique within this pack */
 					if (!found) {
 						found_sha1 = now;
-- 
cgit v1.2.1


From f01cc14c3c70cfd820114505d2ddc153c28f6f89 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 10:19:35 -0700
Subject: sha1_name.c: hide get_sha1_with_context_1() ugliness

There is no outside caller that cares about the "only-to-die" ugliness.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 5b0c845d85..10932bfe1d 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -992,16 +992,6 @@ static void diagnose_invalid_index_path(int stage,
 }
 
 
-int get_sha1_with_mode_1(const char *name, unsigned char *sha1, unsigned *mode,
-			 int only_to_die, const char *prefix)
-{
-	struct object_context oc;
-	int ret;
-	ret = get_sha1_with_context_1(name, sha1, &oc, only_to_die, prefix);
-	*mode = oc.mode;
-	return ret;
-}
-
 static char *resolve_relative_path(const char *rel)
 {
 	if (prefixcmp(rel, "./") && prefixcmp(rel, "../"))
@@ -1019,9 +1009,9 @@ static char *resolve_relative_path(const char *rel)
 			   rel);
 }
 
-int get_sha1_with_context_1(const char *name, unsigned char *sha1,
-			    struct object_context *oc,
-			    int only_to_die, const char *prefix)
+static int get_sha1_with_context_1(const char *name, unsigned char *sha1,
+				   struct object_context *oc,
+				   int only_to_die, const char *prefix)
 {
 	int ret, bracket_depth;
 	int namelen = strlen(name);
@@ -1134,3 +1124,18 @@ int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 	}
 	return ret;
 }
+
+int get_sha1_with_mode_1(const char *name, unsigned char *sha1, unsigned *mode,
+			 int only_to_die, const char *prefix)
+{
+	struct object_context oc;
+	int ret;
+	ret = get_sha1_with_context_1(name, sha1, &oc, only_to_die, prefix);
+	*mode = oc.mode;
+	return ret;
+}
+
+int get_sha1_with_context(const char *str, unsigned char *sha1, struct object_context *orc)
+{
+	return get_sha1_with_context_1(str, sha1, orc, 0, NULL);
+}
-- 
cgit v1.2.1


From 8c135ea260a84ef71899c8bd23bb39425288f9fe Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 11:01:25 -0700
Subject: sha1_name.c: get rid of get_sha1_with_mode_1()

The only external caller is setup.c that tries to give a nicer error
message when an object name is misspelt (e.g. "HEAD:cashe.h").
Retire it and give the caller a dedicated and more intuitive API
function maybe_die_on_misspelt_object_name().

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 10932bfe1d..df583c25bc 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1125,12 +1125,24 @@ static int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 	return ret;
 }
 
-int get_sha1_with_mode_1(const char *name, unsigned char *sha1, unsigned *mode,
-			 int only_to_die, const char *prefix)
+/*
+ * Call this function when you know "name" given by the end user must
+ * name an object but it doesn't; the function _may_ die with a better
+ * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
+ * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
+ * you have a chance to diagnose the error further.
+ */
+void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
 {
 	struct object_context oc;
-	int ret;
-	ret = get_sha1_with_context_1(name, sha1, &oc, only_to_die, prefix);
+	unsigned char sha1[20];
+	get_sha1_with_context_1(name, sha1, &oc, 1, prefix);
+}
+
+int get_sha1_with_mode(const char *str, unsigned char *sha1, unsigned *mode)
+{
+	struct object_context oc;
+	int ret = get_sha1_with_context_1(str, sha1, &oc, 0, NULL);
 	*mode = oc.mode;
 	return ret;
 }
-- 
cgit v1.2.1


From 249c8f4a164c8502f8274c505a48b9c686f458d0 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 12:56:44 -0700
Subject: sha1_name.c: get rid of get_sha1_with_mode()

There are only two callers, and they will benefit from being able to
pass disambiguation hints to underlying get_sha1_with_context() API
once it happens.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 8 --------
 1 file changed, 8 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index df583c25bc..e63459bd51 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1139,14 +1139,6 @@ void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
 	get_sha1_with_context_1(name, sha1, &oc, 1, prefix);
 }
 
-int get_sha1_with_mode(const char *str, unsigned char *sha1, unsigned *mode)
-{
-	struct object_context oc;
-	int ret = get_sha1_with_context_1(str, sha1, &oc, 0, NULL);
-	*mode = oc.mode;
-	return ret;
-}
-
 int get_sha1_with_context(const char *str, unsigned char *sha1, struct object_context *orc)
 {
 	return get_sha1_with_context_1(str, sha1, orc, 0, NULL);
-- 
cgit v1.2.1


From 274ac009f4613a14d2114259e40c6b523d9b7160 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 18 Jun 2012 11:41:03 -0700
Subject: sha1_name.c: clarify what "fake" is for in
 find_short_object_filename()

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index e63459bd51..9bb657deb3 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -17,6 +17,13 @@ static int find_short_object_filename(int len, const char *name, unsigned char *
 	static struct alternate_object_database *fakeent;
 
 	if (!fakeent) {
+		/*
+		 * Create a "fake" alternate object database that
+		 * points to our own object database, to make it
+		 * easier to get a temporary working space in
+		 * alt->name/alt->base while iterating over the
+		 * object databases including our own.
+		 */
 		const char *objdir = get_object_directory();
 		int objdir_len = strlen(objdir);
 		int entlen = objdir_len + 43;
-- 
cgit v1.2.1


From 1b27c2f01af398706acf554794644daaf6bc8835 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 18 Jun 2012 11:50:36 -0700
Subject: sha1_name.c: rename "now" to "current"

This variable points at the element we are currently looking at, and
does not have anything to do with the current time which the name
"now" implies.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 9bb657deb3..c5c4591f98 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -93,11 +93,11 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 		last = num;
 		while (first < last) {
 			uint32_t mid = (first + last) / 2;
-			const unsigned char *now;
+			const unsigned char *current;
 			int cmp;
 
-			now = nth_packed_object_sha1(p, mid);
-			cmp = hashcmp(match, now);
+			current = nth_packed_object_sha1(p, mid);
+			cmp = hashcmp(match, current);
 			if (!cmp) {
 				first = mid;
 				break;
@@ -109,17 +109,17 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 			last = mid;
 		}
 		if (first < num) {
-			const unsigned char *now, *next;
-			now = nth_packed_object_sha1(p, first);
-			if (match_sha(len, match, now)) {
+			const unsigned char *current, *next;
+			current = nth_packed_object_sha1(p, first);
+			if (match_sha(len, match, current)) {
 				next = nth_packed_object_sha1(p, first+1);
 				if (!next|| !match_sha(len, match, next)) {
 					/* unique within this pack */
 					if (!found) {
-						found_sha1 = now;
+						found_sha1 = current;
 						found++;
 					}
-					else if (hashcmp(found_sha1, now)) {
+					else if (hashcmp(found_sha1, current)) {
 						found = 2;
 						break;
 					}
-- 
cgit v1.2.1


From f703e6ea5e3bc7ff39b3ef6d3a21208fb63dfabd Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 18 Jun 2012 13:10:38 -0700
Subject: sha1_name.c: refactor find_short_packed_object()

Extract the logic to find object(s) that match a given prefix inside
a single pack into a separate helper function, and give it a bit more
comment.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 103 +++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 56 insertions(+), 47 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index c5c4591f98..7bef45fcea 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -78,6 +78,59 @@ static int match_sha(unsigned len, const unsigned char *a, const unsigned char *
 	return 1;
 }
 
+static int unique_in_pack(int len,
+			  const unsigned char *match,
+			  struct packed_git *p,
+			  const unsigned char **found_sha1,
+			  int seen_so_far)
+{
+	uint32_t num, last, i, first = 0;
+	const unsigned char *current = NULL;
+
+	open_pack_index(p);
+	num = p->num_objects;
+	last = num;
+	while (first < last) {
+		uint32_t mid = (first + last) / 2;
+		const unsigned char *current;
+		int cmp;
+
+		current = nth_packed_object_sha1(p, mid);
+		cmp = hashcmp(match, current);
+		if (!cmp) {
+			first = mid;
+			break;
+		}
+		if (cmp > 0) {
+			first = mid+1;
+			continue;
+		}
+		last = mid;
+	}
+
+	/*
+	 * At this point, "first" is the location of the lowest object
+	 * with an object name that could match "match".  See if we have
+	 * 0, 1 or more objects that actually match(es).
+	 */
+	for (i = first; i < num; i++) {
+		current = nth_packed_object_sha1(p, first);
+		if (!match_sha(len, match, current))
+			break;
+
+		/* current matches */
+		if (!seen_so_far) {
+			*found_sha1 = current;
+			seen_so_far++;
+		} else if (seen_so_far) {
+			/* is it the same as the one previously found elsewhere? */
+			if (hashcmp(*found_sha1, current))
+				return 2; /* definitely not unique */
+		}
+	}
+	return seen_so_far;
+}
+
 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
 {
 	struct packed_git *p;
@@ -85,53 +138,9 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 	int found = 0;
 
 	prepare_packed_git();
-	for (p = packed_git; p && found < 2; p = p->next) {
-		uint32_t num, last;
-		uint32_t first = 0;
-		open_pack_index(p);
-		num = p->num_objects;
-		last = num;
-		while (first < last) {
-			uint32_t mid = (first + last) / 2;
-			const unsigned char *current;
-			int cmp;
-
-			current = nth_packed_object_sha1(p, mid);
-			cmp = hashcmp(match, current);
-			if (!cmp) {
-				first = mid;
-				break;
-			}
-			if (cmp > 0) {
-				first = mid+1;
-				continue;
-			}
-			last = mid;
-		}
-		if (first < num) {
-			const unsigned char *current, *next;
-			current = nth_packed_object_sha1(p, first);
-			if (match_sha(len, match, current)) {
-				next = nth_packed_object_sha1(p, first+1);
-				if (!next|| !match_sha(len, match, next)) {
-					/* unique within this pack */
-					if (!found) {
-						found_sha1 = current;
-						found++;
-					}
-					else if (hashcmp(found_sha1, current)) {
-						found = 2;
-						break;
-					}
-				}
-				else {
-					/* not even unique within this pack */
-					found = 2;
-					break;
-				}
-			}
-		}
-	}
+	for (p = packed_git; p && found < 2; p = p->next)
+		found = unique_in_pack(len, match, p, &found_sha1, found);
+
 	if (found == 1)
 		hashcpy(sha1, found_sha1);
 	return found;
-- 
cgit v1.2.1


From 1703f9aa0b87d52278489029d538ef1a4aa37432 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 20 Jun 2012 22:35:43 -0700
Subject: sha1_name.c: correct misnamed "canonical" and "res"

These are hexadecimal and binary representation of the short object
name given to the callchain as its input.  Rename them with _pfx
suffix to make it clear they are prefixes, and call them hex and bin
respectively.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 7bef45fcea..db8ac83a12 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -9,7 +9,7 @@
 
 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
 
-static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
+static int find_short_object_filename(int len, const char *hex_pfx, unsigned char *sha1)
 {
 	struct alternate_object_database *alt;
 	char hex[40];
@@ -34,18 +34,18 @@ static int find_short_object_filename(int len, const char *name, unsigned char *
 	}
 	fakeent->next = alt_odb_list;
 
-	sprintf(hex, "%.2s", name);
+	sprintf(hex, "%.2s", hex_pfx);
 	for (alt = fakeent; alt && found < 2; alt = alt->next) {
 		struct dirent *de;
 		DIR *dir;
-		sprintf(alt->name, "%.2s/", name);
+		sprintf(alt->name, "%.2s/", hex_pfx);
 		dir = opendir(alt->base);
 		if (!dir)
 			continue;
 		while ((de = readdir(dir)) != NULL) {
 			if (strlen(de->d_name) != 38)
 				continue;
-			if (memcmp(de->d_name, name + 2, len - 2))
+			if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 				continue;
 			if (!found) {
 				memcpy(hex + 2, de->d_name, 38);
@@ -79,7 +79,7 @@ static int match_sha(unsigned len, const unsigned char *a, const unsigned char *
 }
 
 static int unique_in_pack(int len,
-			  const unsigned char *match,
+			  const unsigned char *bin_pfx,
 			  struct packed_git *p,
 			  const unsigned char **found_sha1,
 			  int seen_so_far)
@@ -96,7 +96,7 @@ static int unique_in_pack(int len,
 		int cmp;
 
 		current = nth_packed_object_sha1(p, mid);
-		cmp = hashcmp(match, current);
+		cmp = hashcmp(bin_pfx, current);
 		if (!cmp) {
 			first = mid;
 			break;
@@ -110,12 +110,12 @@ static int unique_in_pack(int len,
 
 	/*
 	 * At this point, "first" is the location of the lowest object
-	 * with an object name that could match "match".  See if we have
+	 * with an object name that could match "bin_pfx".  See if we have
 	 * 0, 1 or more objects that actually match(es).
 	 */
 	for (i = first; i < num; i++) {
 		current = nth_packed_object_sha1(p, first);
-		if (!match_sha(len, match, current))
+		if (!match_sha(len, bin_pfx, current))
 			break;
 
 		/* current matches */
@@ -131,7 +131,7 @@ static int unique_in_pack(int len,
 	return seen_so_far;
 }
 
-static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
+static int find_short_packed_object(int len, const unsigned char *bin_pfx, unsigned char *sha1)
 {
 	struct packed_git *p;
 	const unsigned char *found_sha1 = NULL;
@@ -139,7 +139,7 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 
 	prepare_packed_git();
 	for (p = packed_git; p && found < 2; p = p->next)
-		found = unique_in_pack(len, match, p, &found_sha1, found);
+		found = unique_in_pack(len, bin_pfx, p, &found_sha1, found);
 
 	if (found == 1)
 		hashcpy(sha1, found_sha1);
@@ -149,15 +149,15 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 #define SHORT_NAME_NOT_FOUND (-1)
 #define SHORT_NAME_AMBIGUOUS (-2)
 
-static int find_unique_short_object(int len, char *canonical,
-				    unsigned char *res, unsigned char *sha1)
+static int find_unique_short_object(int len, char *hex_pfx,
+				    unsigned char *bin_pfx, unsigned char *sha1)
 {
 	int has_unpacked, has_packed;
 	unsigned char unpacked_sha1[20], packed_sha1[20];
 
 	prepare_alt_odb();
-	has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
-	has_packed = find_short_packed_object(len, res, packed_sha1);
+	has_unpacked = find_short_object_filename(len, hex_pfx, unpacked_sha1);
+	has_packed = find_short_packed_object(len, bin_pfx, packed_sha1);
 	if (!has_unpacked && !has_packed)
 		return SHORT_NAME_NOT_FOUND;
 	if (1 < has_unpacked || 1 < has_packed)
@@ -177,13 +177,13 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			  int quietly)
 {
 	int i, status;
-	char canonical[40];
-	unsigned char res[20];
+	char hex_pfx[40];
+	unsigned char bin_pfx[20];
 
 	if (len < MINIMUM_ABBREV || len > 40)
 		return -1;
-	hashclr(res);
-	memset(canonical, 'x', 40);
+	hashclr(bin_pfx);
+	memset(hex_pfx, 'x', 40);
 	for (i = 0; i < len ;i++) {
 		unsigned char c = name[i];
 		unsigned char val;
@@ -197,15 +197,15 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 		}
 		else
 			return -1;
-		canonical[i] = c;
+		hex_pfx[i] = c;
 		if (!(i & 1))
 			val <<= 4;
-		res[i >> 1] |= val;
+		bin_pfx[i >> 1] |= val;
 	}
 
-	status = find_unique_short_object(i, canonical, res, sha1);
+	status = find_unique_short_object(i, hex_pfx, bin_pfx, sha1);
 	if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
-		return error("short SHA1 %.*s is ambiguous.", len, canonical);
+		return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 	return status;
 }
 
-- 
cgit v1.2.1


From a78fafe74a4f8c416c35ca07b3ba28375475ae96 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 20 Jun 2012 22:07:36 -0700
Subject: sha1_name.c: restructure disambiguation of short names

We try to find zero, one or more matches from loose objects and
packed objects independently and then decide if the given short
object name is unique across them.

Instead, introduce a "struct disambiguate_state" that keeps track of
what we have found so far, that can be one of:

 - We have seen one object that _could_ be what we are looking for;
 - We have also checked that object for additional constraints (if any),
   and found that the object satisfies it;
 - We have also checked that object for additional constraints (if any),
   and found that the object does not satisfy it; or
 - We have seen more than one objects that satisfy the constraints.

and pass it to the enumeration functions for loose and packed
objects.  The disambiguation state can optionally take a callback
function that takes a candidate object name and reports if the
object satisifies additional criteria (e.g. when the caller knows
that the short name must refer to a commit, this mechanism can be
used to check the type of the given object).

Compared to the earlier attempt, this round avoids the optional
check if there is only one candidate that matches the short name in
the first place.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 172 +++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 112 insertions(+), 60 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index db8ac83a12..2e2dbb8664 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -9,11 +9,67 @@
 
 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
 
-static int find_short_object_filename(int len, const char *hex_pfx, unsigned char *sha1)
+typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
+
+struct disambiguate_state {
+	disambiguate_hint_fn fn;
+	void *cb_data;
+	unsigned char candidate[20];
+	unsigned candidate_exists:1;
+	unsigned candidate_checked:1;
+	unsigned candidate_ok:1;
+	unsigned disambiguate_fn_used:1;
+	unsigned ambiguous:1;
+};
+
+static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
+{
+	if (!ds->candidate_exists) {
+		/* this is the first candidate */
+		hashcpy(ds->candidate, current);
+		ds->candidate_exists = 1;
+		return;
+	} else if (!hashcmp(ds->candidate, current)) {
+		/* the same as what we already have seen */
+		return;
+	}
+
+	if (!ds->fn) {
+		/* cannot disambiguate between ds->candidate and current */
+		ds->ambiguous = 1;
+		return;
+	}
+
+	if (!ds->candidate_checked) {
+		ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
+		ds->disambiguate_fn_used = 1;
+		ds->candidate_checked = 1;
+	}
+
+	if (!ds->candidate_ok) {
+		/* discard the candidate; we know it does not satisify fn */
+		hashcpy(ds->candidate, current);
+		ds->candidate_checked = 0;
+		return;
+	}
+
+	/* if we reach this point, we know ds->candidate satisfies fn */
+	if (ds->fn(current, ds->cb_data)) {
+		/*
+		 * if both current and candidate satisfy fn, we cannot
+		 * disambiguate.
+		 */
+		ds->candidate_ok = 0;
+		ds->ambiguous = 1;
+	}
+
+	/* otherwise, current can be discarded and candidate is still good */
+}
+
+static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
 {
 	struct alternate_object_database *alt;
 	char hex[40];
-	int found = 0;
 	static struct alternate_object_database *fakeent;
 
 	if (!fakeent) {
@@ -35,32 +91,27 @@ static int find_short_object_filename(int len, const char *hex_pfx, unsigned cha
 	fakeent->next = alt_odb_list;
 
 	sprintf(hex, "%.2s", hex_pfx);
-	for (alt = fakeent; alt && found < 2; alt = alt->next) {
+	for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 		struct dirent *de;
 		DIR *dir;
 		sprintf(alt->name, "%.2s/", hex_pfx);
 		dir = opendir(alt->base);
 		if (!dir)
 			continue;
-		while ((de = readdir(dir)) != NULL) {
+
+		while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
+			unsigned char sha1[20];
+
 			if (strlen(de->d_name) != 38)
 				continue;
 			if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 				continue;
-			if (!found) {
-				memcpy(hex + 2, de->d_name, 38);
-				found++;
-			}
-			else if (memcmp(hex + 2, de->d_name, 38)) {
-				found = 2;
-				break;
-			}
+			memcpy(hex + 2, de->d_name, 38);
+			if (!get_sha1_hex(hex, sha1))
+				update_candidates(ds, sha1);
 		}
 		closedir(dir);
 	}
-	if (found == 1)
-		return get_sha1_hex(hex, sha1) == 0;
-	return found;
 }
 
 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
@@ -78,11 +129,10 @@ static int match_sha(unsigned len, const unsigned char *a, const unsigned char *
 	return 1;
 }
 
-static int unique_in_pack(int len,
+static void unique_in_pack(int len,
 			  const unsigned char *bin_pfx,
-			  struct packed_git *p,
-			  const unsigned char **found_sha1,
-			  int seen_so_far)
+			   struct packed_git *p,
+			   struct disambiguate_state *ds)
 {
 	uint32_t num, last, i, first = 0;
 	const unsigned char *current = NULL;
@@ -113,63 +163,58 @@ static int unique_in_pack(int len,
 	 * with an object name that could match "bin_pfx".  See if we have
 	 * 0, 1 or more objects that actually match(es).
 	 */
-	for (i = first; i < num; i++) {
-		current = nth_packed_object_sha1(p, first);
+	for (i = first; i < num && !ds->ambiguous; i++) {
+		current = nth_packed_object_sha1(p, i);
 		if (!match_sha(len, bin_pfx, current))
 			break;
-
-		/* current matches */
-		if (!seen_so_far) {
-			*found_sha1 = current;
-			seen_so_far++;
-		} else if (seen_so_far) {
-			/* is it the same as the one previously found elsewhere? */
-			if (hashcmp(*found_sha1, current))
-				return 2; /* definitely not unique */
-		}
+		update_candidates(ds, current);
 	}
-	return seen_so_far;
 }
 
-static int find_short_packed_object(int len, const unsigned char *bin_pfx, unsigned char *sha1)
+static void find_short_packed_object(int len, const unsigned char *bin_pfx,
+				     struct disambiguate_state *ds)
 {
 	struct packed_git *p;
-	const unsigned char *found_sha1 = NULL;
-	int found = 0;
 
 	prepare_packed_git();
-	for (p = packed_git; p && found < 2; p = p->next)
-		found = unique_in_pack(len, bin_pfx, p, &found_sha1, found);
-
-	if (found == 1)
-		hashcpy(sha1, found_sha1);
-	return found;
+	for (p = packed_git; p && !ds->ambiguous; p = p->next)
+		unique_in_pack(len, bin_pfx, p, ds);
 }
 
 #define SHORT_NAME_NOT_FOUND (-1)
 #define SHORT_NAME_AMBIGUOUS (-2)
 
-static int find_unique_short_object(int len, char *hex_pfx,
-				    unsigned char *bin_pfx, unsigned char *sha1)
+static int finish_object_disambiguation(struct disambiguate_state *ds,
+					unsigned char *sha1)
 {
-	int has_unpacked, has_packed;
-	unsigned char unpacked_sha1[20], packed_sha1[20];
+	if (ds->ambiguous)
+		return SHORT_NAME_AMBIGUOUS;
 
-	prepare_alt_odb();
-	has_unpacked = find_short_object_filename(len, hex_pfx, unpacked_sha1);
-	has_packed = find_short_packed_object(len, bin_pfx, packed_sha1);
-	if (!has_unpacked && !has_packed)
+	if (!ds->candidate_exists)
 		return SHORT_NAME_NOT_FOUND;
-	if (1 < has_unpacked || 1 < has_packed)
-		return SHORT_NAME_AMBIGUOUS;
-	if (has_unpacked != has_packed) {
-		hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
-		return 0;
-	}
-	/* Both have unique ones -- do they match? */
-	if (hashcmp(packed_sha1, unpacked_sha1))
-		return SHORT_NAME_AMBIGUOUS;
-	hashcpy(sha1, packed_sha1);
+
+	if (!ds->candidate_checked)
+		/*
+		 * If this is the only candidate, there is no point
+		 * calling the disambiguation hint callback.
+		 *
+		 * On the other hand, if the current candidate
+		 * replaced an earlier candidate that did _not_ pass
+		 * the disambiguation hint callback, then we do have
+		 * more than one objects that match the short name
+		 * given, so we should make sure this one matches;
+		 * otherwise, if we discovered this one and the one
+		 * that we previously discarded in the reverse order,
+		 * we would end up showing different results in the
+		 * same repository!
+		 */
+		ds->candidate_ok = (!ds->disambiguate_fn_used ||
+				    ds->fn(ds->candidate, ds->cb_data));
+
+	if (!ds->candidate_ok)
+		return SHORT_NAME_NOT_FOUND;
+
+	hashcpy(sha1, ds->candidate);
 	return 0;
 }
 
@@ -179,6 +224,7 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 	int i, status;
 	char hex_pfx[40];
 	unsigned char bin_pfx[20];
+	struct disambiguate_state ds;
 
 	if (len < MINIMUM_ABBREV || len > 40)
 		return -1;
@@ -203,7 +249,13 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 		bin_pfx[i >> 1] |= val;
 	}
 
-	status = find_unique_short_object(i, hex_pfx, bin_pfx, sha1);
+	prepare_alt_odb();
+
+	memset(&ds, 0, sizeof(ds));
+	find_short_object_filename(len, hex_pfx, &ds);
+	find_short_packed_object(len, bin_pfx, &ds);
+	status = finish_object_disambiguation(&ds, sha1);
+
 	if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 		return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 	return status;
-- 
cgit v1.2.1


From c005e98612c3ba896415cfa56df67ae8b240cc85 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 3 Jul 2012 11:01:03 -0700
Subject: get_sha1(): fix error status regression

In finish_object_disambiguation(), if the candidate hasn't been
checked, there are two cases:

 - It is the first and only object that match the prefix; or
 - It replaced another object that matched the prefix but that
   object did not satisfy ds->fn() callback.

And the former case we set ds->candidate_ok to true without doing
anything else, while for the latter we check the candidate, which
may set ds->candidate_ok to false.

At this point in the code, ds->candidate_ok can be false only if
this last-round check found that the candidate does not pass the
check, because the state after update_candidates() returns cannot
satisfy

    !ds->ambiguous && ds->candidate_exists && ds->candidate_checked

and !ds->canidate_ok at the same time.

Hence, when we execute this "return", we know we have seen more than
one object that match the prefix (and none of them satisfied ds->fn),
meaning that we should say "the short name is ambiguous", not "there
is no object that matches the prefix".

Noticed by Jeff King.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 2e2dbb8664..c824bdd3eb 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -212,7 +212,7 @@ static int finish_object_disambiguation(struct disambiguate_state *ds,
 				    ds->fn(ds->candidate, ds->cb_data));
 
 	if (!ds->candidate_ok)
-		return SHORT_NAME_NOT_FOUND;
+		return SHORT_NAME_AMBIGUOUS;
 
 	hashcpy(sha1, ds->candidate);
 	return 0;
-- 
cgit v1.2.1


From 37c00e5590605c9d3ba76b6c9d7a94ac0356f703 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 18 Jun 2012 11:32:03 -0700
Subject: sha1_name.c: allow get_short_sha1() to take other flags

Instead of a separate "int quietly" argument, make it take "unsigned
flags" so that we can pass other options to it.

The bit assignment of this flag word is exposed in cache.h because
the mechanism will be exposed to callers of the higher layer in
later commits in this series.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index c824bdd3eb..793d80cbf9 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -219,12 +219,13 @@ static int finish_object_disambiguation(struct disambiguate_state *ds,
 }
 
 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
-			  int quietly)
+			  unsigned flags)
 {
 	int i, status;
 	char hex_pfx[40];
 	unsigned char bin_pfx[20];
 	struct disambiguate_state ds;
+	int quietly = !!(flags & GET_SHA1_QUIETLY);
 
 	if (len < MINIMUM_ABBREV || len > 40)
 		return -1;
@@ -272,7 +273,7 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
 		return hex;
 	while (len < 40) {
 		unsigned char sha1_ret[20];
-		status = get_short_sha1(hex, len, sha1_ret, 1);
+		status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 		if (exists
 		    ? !status
 		    : status == SHORT_NAME_NOT_FOUND) {
@@ -603,7 +604,7 @@ static int get_describe_name(const char *name, int len, unsigned char *sha1)
 			if (ch == 'g' && cp[-1] == '-') {
 				cp++;
 				len -= cp - name;
-				return get_short_sha1(cp, len, sha1, 1);
+				return get_short_sha1(cp, len, sha1, GET_SHA1_QUIETLY);
 			}
 		}
 	}
-- 
cgit v1.2.1


From aa1dec9ef6ff184792520eb4539af1555c01604c Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 20 Jun 2012 23:03:09 -0700
Subject: sha1_name.c: teach get_short_sha1() a commit-only option

When the caller knows that the parameter is meant to name a commit,
e.g. "56789a" in describe name "v1.2.3-4-g56789a", pass that as a
hint so that lower level can use it to disambiguate objects when
there is only one commit whose name begins with 56789a even if there
are objects of other types whose names share the same prefix.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 793d80cbf9..174d3df9b3 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -218,6 +218,12 @@ static int finish_object_disambiguation(struct disambiguate_state *ds,
 	return 0;
 }
 
+static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	int kind = sha1_object_info(sha1, NULL);
+	return kind == OBJ_COMMIT;
+}
+
 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			  unsigned flags)
 {
@@ -253,6 +259,9 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 	prepare_alt_odb();
 
 	memset(&ds, 0, sizeof(ds));
+	if (flags & GET_SHA1_COMMIT)
+		ds.fn = disambiguate_commit_only;
+
 	find_short_object_filename(len, hex_pfx, &ds);
 	find_short_packed_object(len, bin_pfx, &ds);
 	status = finish_object_disambiguation(&ds, sha1);
-- 
cgit v1.2.1


From 6269b6b676310d9fa2560da49be618372b39acf4 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 18 Jun 2012 13:45:56 -0700
Subject: sha1_name.c: get_describe_name() by definition groks only commits

Teach get_describe_name() to pass the disambiguation hint down the
callchain to get_short_sha1().

Also add tests to show various syntactic elements that we could take
advantage of the object type information to help disambiguration of
abbreviated object names.  Many of them are marked as broken, and
some of them will be fixed in later patches in this series.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 174d3df9b3..caef6e5e62 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -603,6 +603,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 {
 	const char *cp;
+	unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 
 	for (cp = name + len - 1; name + 2 <= cp; cp--) {
 		char ch = *cp;
@@ -613,7 +614,7 @@ static int get_describe_name(const char *name, int len, unsigned char *sha1)
 			if (ch == 'g' && cp[-1] == '-') {
 				cp++;
 				len -= cp - name;
-				return get_short_sha1(cp, len, sha1, GET_SHA1_QUIETLY);
+				return get_short_sha1(cp, len, sha1, flags);
 			}
 		}
 	}
-- 
cgit v1.2.1


From e48ba200be908f02a3fb30adcbb8000b7100cb32 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 09:46:50 -0700
Subject: sha1_name.c: get_sha1_1() takes lookup flags

This is to pass the disambiguation hints from the caller down the
callchain.  Nothing is changed in this step, as everybody just
passes 0 in the flag.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index caef6e5e62..8feb9b553a 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -333,7 +333,7 @@ static inline int upstream_mark(const char *string, int len)
 	return 0;
 }
 
-static int get_sha1_1(const char *name, int len, unsigned char *sha1);
+static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 {
@@ -370,7 +370,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 		ret = interpret_branch_name(str+at, &buf);
 		if (ret > 0) {
 			/* substitute this branch name and restart */
-			return get_sha1_1(buf.buf, buf.len, sha1);
+			return get_sha1_1(buf.buf, buf.len, sha1, 0);
 		} else if (ret == 0) {
 			return -1;
 		}
@@ -440,7 +440,7 @@ static int get_parent(const char *name, int len,
 		      unsigned char *result, int idx)
 {
 	unsigned char sha1[20];
-	int ret = get_sha1_1(name, len, sha1);
+	int ret = get_sha1_1(name, len, sha1, 0);
 	struct commit *commit;
 	struct commit_list *p;
 
@@ -473,7 +473,7 @@ static int get_nth_ancestor(const char *name, int len,
 	struct commit *commit;
 	int ret;
 
-	ret = get_sha1_1(name, len, sha1);
+	ret = get_sha1_1(name, len, sha1, 0);
 	if (ret)
 		return ret;
 	commit = lookup_commit_reference(sha1);
@@ -554,7 +554,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 	else
 		return -1;
 
-	if (get_sha1_1(name, sp - name - 2, outer))
+	if (get_sha1_1(name, sp - name - 2, outer, 0))
 		return -1;
 
 	o = parse_object(outer);
@@ -621,7 +621,7 @@ static int get_describe_name(const char *name, int len, unsigned char *sha1)
 	return -1;
 }
 
-static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 {
 	int ret, has_suffix;
 	const char *cp;
@@ -1098,7 +1098,7 @@ static int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 
 	memset(oc, 0, sizeof(*oc));
 	oc->mode = S_IFINVALID;
-	ret = get_sha1_1(name, namelen, sha1);
+	ret = get_sha1_1(name, namelen, sha1, 0);
 	if (!ret)
 		return ret;
 	/* sha1:path --> object name of path in ent sha1
@@ -1176,7 +1176,7 @@ static int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 			strncpy(object_name, name, cp-name);
 			object_name[cp-name] = '\0';
 		}
-		if (!get_sha1_1(name, cp-name, tree_sha1)) {
+		if (!get_sha1_1(name, cp-name, tree_sha1, 0)) {
 			const char *filename = cp+1;
 			char *new_filename = NULL;
 
-- 
cgit v1.2.1


From e2643617d75e53e5a69278f8d7382553d1c14cf0 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 10:00:40 -0700
Subject: sha1_name.c: many short names can only be committish

We know that the token "$name" that appear in "$name^{commit}",
"$name^4", "$name~4" etc. can only name a committish (either a
commit or a tag that peels to a commit).  Teach get_short_sha1() to
take advantage of that knowledge when disambiguating an abbreviated
SHA-1 given as an object name.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 8feb9b553a..215bb016f3 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -224,6 +224,24 @@ static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unu
 	return kind == OBJ_COMMIT;
 }
 
+static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	struct object *obj;
+	int kind;
+
+	kind = sha1_object_info(sha1, NULL);
+	if (kind == OBJ_COMMIT)
+		return 1;
+	if (kind != OBJ_TAG)
+		return 0;
+
+	/* We need to do this the hard way... */
+	obj = deref_tag(lookup_object(sha1), NULL, 0);
+	if (obj && obj->type == OBJ_COMMIT)
+		return 1;
+	return 0;
+}
+
 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			  unsigned flags)
 {
@@ -261,6 +279,8 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 	memset(&ds, 0, sizeof(ds));
 	if (flags & GET_SHA1_COMMIT)
 		ds.fn = disambiguate_commit_only;
+	else if (flags & GET_SHA1_COMMITTISH)
+		ds.fn = disambiguate_committish_only;
 
 	find_short_object_filename(len, hex_pfx, &ds);
 	find_short_packed_object(len, bin_pfx, &ds);
@@ -440,7 +460,7 @@ static int get_parent(const char *name, int len,
 		      unsigned char *result, int idx)
 {
 	unsigned char sha1[20];
-	int ret = get_sha1_1(name, len, sha1, 0);
+	int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 	struct commit *commit;
 	struct commit_list *p;
 
@@ -473,7 +493,7 @@ static int get_nth_ancestor(const char *name, int len,
 	struct commit *commit;
 	int ret;
 
-	ret = get_sha1_1(name, len, sha1, 0);
+	ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 	if (ret)
 		return ret;
 	commit = lookup_commit_reference(sha1);
@@ -519,6 +539,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 	unsigned char outer[20];
 	const char *sp;
 	unsigned int expected_type = 0;
+	unsigned lookup_flags = 0;
 	struct object *o;
 
 	/*
@@ -554,7 +575,10 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 	else
 		return -1;
 
-	if (get_sha1_1(name, sp - name - 2, outer, 0))
+	if (expected_type == OBJ_COMMIT)
+		lookup_flags = GET_SHA1_COMMITTISH;
+
+	if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 		return -1;
 
 	o = parse_object(outer);
@@ -666,7 +690,7 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned l
 	if (!ret)
 		return 0;
 
-	return get_short_sha1(name, len, sha1, 0);
+	return get_short_sha1(name, len, sha1, lookup_flags);
 }
 
 /*
-- 
cgit v1.2.1


From 33bd598c3902c40c5a10a68aeaa3004484239258 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 10:32:11 -0700
Subject: sha1_name.c: teach lookup context to get_sha1_with_context()

The function takes user input string and returns the object name
(binary SHA-1) with mode bits and path when the object was looked
up in a tree.

Additionally give hints to help disambiguation of abbreviated object
names when the caller knows what it is looking for.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 215bb016f3..c045be8e13 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -996,7 +996,7 @@ int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
 int get_sha1(const char *name, unsigned char *sha1)
 {
 	struct object_context unused;
-	return get_sha1_with_context(name, sha1, &unused);
+	return get_sha1_with_context(name, 0, sha1, &unused);
 }
 
 /* Must be called only when object_name:filename doesn't exist. */
@@ -1112,20 +1112,24 @@ static char *resolve_relative_path(const char *rel)
 			   rel);
 }
 
-static int get_sha1_with_context_1(const char *name, unsigned char *sha1,
-				   struct object_context *oc,
-				   int only_to_die, const char *prefix)
+static int get_sha1_with_context_1(const char *name,
+				   unsigned flags,
+				   const char *prefix,
+				   unsigned char *sha1,
+				   struct object_context *oc)
 {
 	int ret, bracket_depth;
 	int namelen = strlen(name);
 	const char *cp;
+	int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
 
 	memset(oc, 0, sizeof(*oc));
 	oc->mode = S_IFINVALID;
-	ret = get_sha1_1(name, namelen, sha1, 0);
+	ret = get_sha1_1(name, namelen, sha1, flags);
 	if (!ret)
 		return ret;
-	/* sha1:path --> object name of path in ent sha1
+	/*
+	 * sha1:path --> object name of path in ent sha1
 	 * :path -> object name of absolute path in index
 	 * :./path -> object name of path relative to cwd in index
 	 * :[0-3]:path -> object name of path in index at stage
@@ -1239,10 +1243,10 @@ void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
 {
 	struct object_context oc;
 	unsigned char sha1[20];
-	get_sha1_with_context_1(name, sha1, &oc, 1, prefix);
+	get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
 }
 
-int get_sha1_with_context(const char *str, unsigned char *sha1, struct object_context *orc)
+int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
 {
-	return get_sha1_with_context_1(str, sha1, orc, 0, NULL);
+	return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
 }
-- 
cgit v1.2.1


From cd74e4733db3e2353077bdc7021caa70bed2a483 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 12:04:52 -0700
Subject: sha1_name.c: introduce get_sha1_committish()

Many callers know that the user meant to name a committish by
syntactical positions where the object name appears.  Calling this
function allows the machinery to disambiguate shorter-than-unique
abbreviated object names between committish and others.

Note that this does NOT error out when the named object is not a
committish. It is merely to give a hint to the disambiguation
machinery.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index c045be8e13..9e13d60bfa 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -872,7 +872,7 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
 		struct strbuf sb;
 		strbuf_init(&sb, dots - name);
 		strbuf_add(&sb, name, dots - name);
-		st = get_sha1(sb.buf, sha1_tmp);
+		st = get_sha1_committish(sb.buf, sha1_tmp);
 		strbuf_release(&sb);
 	}
 	if (st)
@@ -881,7 +881,7 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
 	if (!one)
 		return -1;
 
-	if (get_sha1(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
+	if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 		return -1;
 	two = lookup_commit_reference_gently(sha1_tmp, 0);
 	if (!two)
@@ -999,6 +999,23 @@ int get_sha1(const char *name, unsigned char *sha1)
 	return get_sha1_with_context(name, 0, sha1, &unused);
 }
 
+/*
+ * Many callers know that the user meant to name a committish by
+ * syntactical positions where the object name appears.  Calling this
+ * function allows the machinery to disambiguate shorter-than-unique
+ * abbreviated object names between committish and others.
+ *
+ * Note that this does NOT error out when the named object is not a
+ * committish. It is merely to give a hint to the disambiguation
+ * machinery.
+ */
+int get_sha1_committish(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
+				     sha1, &unused);
+}
+
 /* Must be called only when object_name:filename doesn't exist. */
 static void diagnose_invalid_sha1_path(const char *prefix,
 				       const char *filename,
-- 
cgit v1.2.1


From daba53aeaf6565b4bbdd6783c659480453ec3c5e Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 2 Jul 2012 23:35:05 -0700
Subject: sha1_name.c: add support for disambiguating other types

This teaches the revision parser that in "$name:$path" (used for a
blob object name), "$name" must be a tree-ish.

There are many more places where we know what types of objects are
called for.  This patch adds support for "commit", "treeish", "tree",
and "blob", which could be used in the following contexts:

 - "git apply --build-fake-ancestor" reads the "index" lines from
   the patch; they must name blob objects (not even "blob-ish");

 - "git commit-tree" reads a tree object name (not "tree-ish"), and
   zero or more commit object names (not "committish");

 - "git reset $rev" wants a committish; "git reset $rev -- $path"
   wants a treeish.

They will come in later patches in the series.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 65 insertions(+), 1 deletion(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 9e13d60bfa..18fac921dd 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -242,6 +242,36 @@ static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data
 	return 0;
 }
 
+static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	int kind = sha1_object_info(sha1, NULL);
+	return kind == OBJ_TREE;
+}
+
+static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	struct object *obj;
+	int kind;
+
+	kind = sha1_object_info(sha1, NULL);
+	if (kind == OBJ_TREE || kind == OBJ_COMMIT)
+		return 1;
+	if (kind != OBJ_TAG)
+		return 0;
+
+	/* We need to do this the hard way... */
+	obj = deref_tag(lookup_object(sha1), NULL, 0);
+	if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
+		return 1;
+	return 0;
+}
+
+static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	int kind = sha1_object_info(sha1, NULL);
+	return kind == OBJ_BLOB;
+}
+
 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			  unsigned flags)
 {
@@ -281,6 +311,12 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 		ds.fn = disambiguate_commit_only;
 	else if (flags & GET_SHA1_COMMITTISH)
 		ds.fn = disambiguate_committish_only;
+	else if (flags & GET_SHA1_TREE)
+		ds.fn = disambiguate_tree_only;
+	else if (flags & GET_SHA1_TREEISH)
+		ds.fn = disambiguate_treeish_only;
+	else if (flags & GET_SHA1_BLOB)
+		ds.fn = disambiguate_blob_only;
 
 	find_short_object_filename(len, hex_pfx, &ds);
 	find_short_packed_object(len, bin_pfx, &ds);
@@ -1016,6 +1052,34 @@ int get_sha1_committish(const char *name, unsigned char *sha1)
 				     sha1, &unused);
 }
 
+int get_sha1_treeish(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_TREEISH,
+				     sha1, &unused);
+}
+
+int get_sha1_commit(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_COMMIT,
+				     sha1, &unused);
+}
+
+int get_sha1_tree(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_TREE,
+				     sha1, &unused);
+}
+
+int get_sha1_blob(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_BLOB,
+				     sha1, &unused);
+}
+
 /* Must be called only when object_name:filename doesn't exist. */
 static void diagnose_invalid_sha1_path(const char *prefix,
 				       const char *filename,
@@ -1221,7 +1285,7 @@ static int get_sha1_with_context_1(const char *name,
 			strncpy(object_name, name, cp-name);
 			object_name[cp-name] = '\0';
 		}
-		if (!get_sha1_1(name, cp-name, tree_sha1, 0)) {
+		if (!get_sha1_1(name, cp-name, tree_sha1, GET_SHA1_TREEISH)) {
 			const char *filename = cp+1;
 			char *new_filename = NULL;
 
-- 
cgit v1.2.1


From 957d74062c1f0e92368aeda335e27d2d61f584f6 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 3 Jul 2012 14:21:59 -0700
Subject: rev-parse --disambiguate=<prefix>

The new option allows you to feed an ambiguous prefix and enumerate
all the objects that share it as a prefix of their object names.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 50 insertions(+), 9 deletions(-)

(limited to 'sha1_name.c')

diff --git a/sha1_name.c b/sha1_name.c
index 18fac921dd..8bc20c54b1 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -20,10 +20,15 @@ struct disambiguate_state {
 	unsigned candidate_ok:1;
 	unsigned disambiguate_fn_used:1;
 	unsigned ambiguous:1;
+	unsigned always_call_fn:1;
 };
 
 static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
 {
+	if (ds->always_call_fn) {
+		ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
+		return;
+	}
 	if (!ds->candidate_exists) {
 		/* this is the first candidate */
 		hashcpy(ds->candidate, current);
@@ -272,17 +277,12 @@ static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unuse
 	return kind == OBJ_BLOB;
 }
 
-static int get_short_sha1(const char *name, int len, unsigned char *sha1,
-			  unsigned flags)
+static int prepare_prefixes(const char *name, int len,
+			    unsigned char *bin_pfx,
+			    char *hex_pfx)
 {
-	int i, status;
-	char hex_pfx[40];
-	unsigned char bin_pfx[20];
-	struct disambiguate_state ds;
-	int quietly = !!(flags & GET_SHA1_QUIETLY);
+	int i;
 
-	if (len < MINIMUM_ABBREV || len > 40)
-		return -1;
 	hashclr(bin_pfx);
 	memset(hex_pfx, 'x', 40);
 	for (i = 0; i < len ;i++) {
@@ -303,6 +303,22 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			val <<= 4;
 		bin_pfx[i >> 1] |= val;
 	}
+	return 0;
+}
+
+static int get_short_sha1(const char *name, int len, unsigned char *sha1,
+			  unsigned flags)
+{
+	int status;
+	char hex_pfx[40];
+	unsigned char bin_pfx[20];
+	struct disambiguate_state ds;
+	int quietly = !!(flags & GET_SHA1_QUIETLY);
+
+	if (len < MINIMUM_ABBREV || len > 40)
+		return -1;
+	if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
+		return -1;
 
 	prepare_alt_odb();
 
@@ -327,6 +343,31 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 	return status;
 }
 
+
+int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
+{
+	char hex_pfx[40];
+	unsigned char bin_pfx[20];
+	struct disambiguate_state ds;
+	int len = strlen(prefix);
+
+	if (len < MINIMUM_ABBREV || len > 40)
+		return -1;
+	if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
+		return -1;
+
+	prepare_alt_odb();
+
+	memset(&ds, 0, sizeof(ds));
+	ds.always_call_fn = 1;
+	ds.cb_data = cb_data;
+	ds.fn = fn;
+
+	find_short_object_filename(len, hex_pfx, &ds);
+	find_short_packed_object(len, bin_pfx, &ds);
+	return ds.ambiguous;
+}
+
 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 {
 	int status, exists;
-- 
cgit v1.2.1