PATCH: allow ':/<oneline prefix>' notation to specify a specific file

Although the rev-parse documentation claims that the tree-ish:path/to/file
syntax is applicable to all tree-ish forms this is not so when using the
:/ "oneline prefix" syntax introduced in v1.5.0.1-227-g28a4d94.

This patch allows git show ":/PATCH: allow":sha1_name.c to show the
change to the file changed by this patch.

Signed-off-by: Eric Raible <redacted>
---
 sha1_name.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/sha1_name.c b/sha1_name.c
index b0b2167..a1acfcd 100644
--- a/sha1_name.c
+++ b/sha1_name.c

@@ -684,6 +684,7 @@ int get_sha1_with_mode(const char *name, unsigned

char *sha1, unsigned *mode)
 	int ret, bracket_depth;
 	int namelen = strlen(name);
 	const char *cp;
+	char *copy, *colon;

 	*mode = S_IFINVALID;
 	ret = get_sha1_1(name, namelen, sha1);

@@ -697,8 +698,18 @@ int get_sha1_with_mode(const char *name, unsigned

char *sha1, unsigned *mode)
 		int stage = 0;
 		struct cache_entry *ce;
 		int pos;
-		if (namelen > 2 && name[1] == '/')
-			return get_sha1_oneline(name + 2, sha1);
+		if (namelen > 2 && name[1] == '/') {
+			name += 2;
+			colon = strrchr(name, ':');
+			if (!get_sha1_oneline(name, sha1) || !colon)
+				return 0;
+			copy = xstrdup(name);
+			*(colon = strrchr(copy, ':')) = '\0';
+			ret = get_sha1_oneline(copy, sha1) ||
+				get_tree_entry(sha1, colon+1, sha1, mode);
+			free(copy);
+			return ret;
+		}
 		if (namelen < 3 ||
 		    name[2] != ':' ||
 		    name[1] < '0' || '3' < name[1])
-- 
1.5.6.1.1356.g3be5f.dirty

Hi,

is there a reason you break the mail thread quite a couple of times?  It 
makes it really hard to follow when you get 300+ mails a day.

Thankyouverymuch,
Dscho