diff: --full-index

A new option, --full-index, is introduced to diff family.  This
causes the full object name of pre- and post-images to appear on
the index line of patch formatted output, to be used in
conjunction with --allow-binary-replacement option of git-apply.

Signed-off-by: Junio C Hamano <junkio@cox.net>

3 files changed, 16 insertions, 7 deletions

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 8eef86e47..6b496ede2 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -13,6 +13,11 @@
 --name-status::
 	Show only names and status of changed files.
 
+--full-index::
+	Instead of the first handful characters, show full
+	object name of pre- and post-image blob on the "index"
+	line when generating a patch format output.	
+
 -B::
 	Break complete rewrite changes into pairs of delete and create.
 
diff --git a/diff.c b/diff.c
index fca61f32f..0391e8c42 100644
--- a/diff.c
+++ b/diff.c
@@ -650,7 +650,7 @@ static void diff_fill_sha1_info(struct diff_filespec *one)
 		memset(one->sha1, 0, 20);
 }
 
-static void run_diff(struct diff_filepair *p)
+static void run_diff(struct diff_filepair *p, struct diff_options *o)
 {
 	const char *pgm = external_diff();
 	char msg[PATH_MAX*2+300], *xfrm_msg;
@@ -713,11 +713,11 @@ static void run_diff(struct diff_filepair *p)
 
 	if (memcmp(one->sha1, two->sha1, 20)) {
 		char one_sha1[41];
+		const char *index_fmt = o->full_index ? "index %s..%s" : "index %.7s..%.7s";
 		memcpy(one_sha1, sha1_to_hex(one->sha1), 41);
 
 		len += snprintf(msg + len, sizeof(msg) - len,
-				"index %.7s..%.7s", one_sha1,
-				sha1_to_hex(two->sha1));
+				index_fmt, one_sha1, sha1_to_hex(two->sha1));
 		if (one->mode == two->mode)
 			len += snprintf(msg + len, sizeof(msg) - len,
 					" %06o", one->mode);
@@ -794,6 +794,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		options->line_termination = 0;
 	else if (!strncmp(arg, "-l", 2))
 		options->rename_limit = strtoul(arg+2, NULL, 10);
+	else if (!strcmp(arg, "--full-index"))
+		options->full_index = 1;
 	else if (!strcmp(arg, "--name-only"))
 		options->output_format = DIFF_FORMAT_NAME;
 	else if (!strcmp(arg, "--name-status"))
@@ -1022,7 +1024,7 @@ int diff_unmodified_pair(struct diff_filepair *p)
 	return 0;
 }
 
-static void diff_flush_patch(struct diff_filepair *p)
+static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
 {
 	if (diff_unmodified_pair(p))
 		return;
@@ -1031,7 +1033,7 @@ static void diff_flush_patch(struct diff_filepair *p)
 	    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
 		return; /* no tree diffs in patch format */ 
 
-	run_diff(p);
+	run_diff(p, o);
 }
 
 int diff_queue_is_empty(void)
@@ -1163,7 +1165,7 @@ void diff_flush(struct diff_options *options)
 			die("internal error in diff-resolve-rename-copy");
 		switch (diff_output_format) {
 		case DIFF_FORMAT_PATCH:
-			diff_flush_patch(p);
+			diff_flush_patch(p, options);
 			break;
 		case DIFF_FORMAT_RAW:
 		case DIFF_FORMAT_NAME_STATUS:
diff --git a/diff.h b/diff.h
index 12590791c..9b2e1e62b 100644
--- a/diff.h
+++ b/diff.h
@@ -32,7 +32,8 @@ struct diff_options {
 	const char *orderfile;
 	const char *pickaxe;
 	unsigned recursive:1,
-		 tree_in_recursive:1;
+		 tree_in_recursive:1,
+		 full_index:1;
 	int break_opt;
 	int detect_rename;
 	int find_copies_harder;
@@ -96,6 +97,7 @@ extern void diffcore_std_no_resolve(struct diff_options *);
 "  -u            synonym for -p.\n" \
 "  --name-only   show only names of changed files.\n" \
 "  --name-status show names and status of changed files.\n" \
+"  --full-index  show full object name on index ines.\n" \
 "  -R            swap input file pairs.\n" \
 "  -B            detect complete rewrites.\n" \
 "  -M            detect renames.\n" \