[PATCH] Add --diff-filter= output restriction to diff-* family.

This is a halfway between debugging aid and a helper to write an
ultra-smart merge scripts.  The new option takes a string that
consists of a list of "status" letters, and limits the diff
output to only those classes of changes, with two exceptions:

 - A broken pair (aka "complete rewrite"), does not match D
   (deleted) or N (created).  Use B to look for them.

 - The letter "A" in the diff-filter string does not match
   anything itself, but causes the entire diff that contains
   selected patches to be output (this behaviour is similar to
   that of --pickaxe-all for the -S option).

For example,

    $ git-rev-list HEAD |
      git-diff-tree --stdin -s -v -B -C --diff-filter=BCR

shows a list of commits that have complete rewrite, copy, or
rename.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff-cache.c

@@ -11,6 +11,7 @@ static const char *pickaxe = NULL;
 static int pickaxe_opts = 0;
 static int diff_break_opt = -1;
 static const char *orderfile = NULL;
+static const char *diff_filter = NULL;
 
 /* A file entry went away or appeared */
 static void show_file(const char *prefix, struct cache_entry *ce, unsigned char *sha1, unsigned int mode)
@@ -224,6 +225,10 @@ int main(int argc, const char **argv)
 			pickaxe = arg + 2;
 			continue;
 		}
+		if (!strncmp(arg, "--diff-filter=", 14)) {
+			diff_filter = arg + 14;
+			continue;
+		}
 		if (!strncmp(arg, "-O", 2)) {
 			orderfile = arg + 2;
 			continue;
@@ -263,7 +268,7 @@ int main(int argc, const char **argv)
 		     detect_rename, diff_score_opt,
 		     pickaxe, pickaxe_opts,
 		     diff_break_opt,
-		     orderfile);
-	diff_flush(diff_output_format, 1);
+		     orderfile, diff_filter);
+	diff_flush(diff_output_format);
 	return ret;
 }

diff-files.c

@@ -17,6 +17,7 @@ static const char *pickaxe = NULL;
 static int pickaxe_opts = 0;
 static int diff_break_opt = -1;
 static const char *orderfile = NULL;
+static const char *diff_filter = NULL;
 static int silent = 0;
 
 static void show_unmerge(const char *path)
@@ -59,6 +60,8 @@ int main(int argc, const char **argv)
 			pickaxe = argv[1] + 2;
 		else if (!strncmp(argv[1], "-O", 2))
 			orderfile = argv[1] + 2;
+		else if (!strncmp(argv[1], "--diff-filter=", 14))
+			diff_filter = argv[1] + 14;
 		else if (!strcmp(argv[1], "--pickaxe-all"))
 			pickaxe_opts = DIFF_PICKAXE_ALL;
 		else if (!strncmp(argv[1], "-B", 2)) {
@@ -131,7 +134,7 @@ int main(int argc, const char **argv)
 		     detect_rename, diff_score_opt,
 		     pickaxe, pickaxe_opts,
 		     diff_break_opt,
-		     orderfile);
-	diff_flush(diff_output_format, 1);
+		     orderfile, diff_filter);
+	diff_flush(diff_output_format);
 	return 0;
 }

diff-helper.c

@@ -8,17 +8,16 @@
 static const char *pickaxe = NULL;
 static int pickaxe_opts = 0;
 static const char *orderfile = NULL;
+static const char *diff_filter = NULL;
 static int line_termination = '\n';
 static int inter_name_termination = '\t';
 
 static void flush_them(int ac, const char **av)
 {
-	diffcore_std(av + 1,
-		     0, 0, /* no renames */
-		     pickaxe, pickaxe_opts,
-		     -1, /* no breaks */
-		     orderfile);
-	diff_flush(DIFF_FORMAT_PATCH, 0);
+	diffcore_std_no_resolve(av + 1,
+				pickaxe, pickaxe_opts,
+				orderfile, diff_filter);
+	diff_flush(DIFF_FORMAT_PATCH);
 }
 
 static const char *diff_helper_usage =
@@ -38,6 +37,10 @@ int main(int ac, const char **av) {
 		}
 		else if (!strcmp(av[1], "--pickaxe-all"))
 			pickaxe_opts = DIFF_PICKAXE_ALL;
+		else if (!strncmp(av[1], "--diff-filter=", 14))
+			diff_filter = av[1] + 14;
+		else if (!strncmp(av[1], "-O", 2))
+			orderfile = av[1] + 2;
 		else
 			usage(diff_helper_usage);
 		ac--; av++;

diff-stages.c

@@ -13,6 +13,7 @@ static const char *pickaxe = NULL;
 static int pickaxe_opts = 0;
 static int diff_break_opt = -1;
 static const char *orderfile = NULL;
+static const char *diff_filter = NULL;
 
 static char *diff_stages_usage =
 "git-diff-stages [-p] [-r] [-z] [-M] [-C] [-R] [-S<string>] [-O<orderfile>] <stage1> <stage2> [<path>...]";
@@ -50,6 +51,8 @@ int main(int ac, const char **av)
 			pickaxe = arg + 2;
 		else if (!strncmp(arg, "-O", 2))
 			orderfile = arg + 2;
+		else if (!strncmp(arg, "--diff-filter=", 14))
+			diff_filter = arg + 14;
 		else if (!strcmp(arg, "--pickaxe-all"))
 			pickaxe_opts = DIFF_PICKAXE_ALL;
 		else
@@ -106,7 +109,8 @@ int main(int ac, const char **av)
 		     detect_rename, diff_score_opt,
 		     pickaxe, pickaxe_opts,
 		     diff_break_opt,
-		     orderfile);
-	diff_flush(diff_output_format, 1);
+		     orderfile,
+		     diff_filter);
+	diff_flush(diff_output_format);
 	return 0;
 }

diff-tree.c

@@ -18,6 +18,7 @@ static const char *pickaxe = NULL;
 static int pickaxe_opts = 0;
 static int diff_break_opt = -1;
 static const char *orderfile = NULL;
+static const char *diff_filter = NULL;
 static const char *header = NULL;
 static const char *header_prefix = "";
 static enum cmit_fmt commit_format = CMIT_FMT_RAW;
@@ -272,9 +273,10 @@ static int call_diff_flush(void)
 		     detect_rename, diff_score_opt,
 		     pickaxe, pickaxe_opts,
 		     diff_break_opt,
-		     orderfile);
+		     orderfile,
+		     diff_filter);
 	if (diff_queue_is_empty()) {
-		diff_flush(DIFF_FORMAT_NO_OUTPUT, 0);
+		diff_flush(DIFF_FORMAT_NO_OUTPUT);
 		return 0;
 	}
 	if (header) {
@@ -285,7 +287,7 @@ static int call_diff_flush(void)
 		printf(fmt, header, 0);
 		header = NULL;
 	}
-	diff_flush(diff_output_format, 1);
+	diff_flush(diff_output_format);
 	return 1;
 }
 
@@ -468,6 +470,10 @@ int main(int argc, const char **argv)
 			orderfile = arg + 2;
 			continue;
 		}
+		if (!strncmp(arg, "--diff-filter=", 14)) {
+			diff_filter = arg + 14;
+			continue;
+		}
 		if (!strcmp(arg, "--pickaxe-all")) {
 			pickaxe_opts = DIFF_PICKAXE_ALL;
 			continue;

diff.c

@@ -921,7 +921,7 @@ static void diff_resolve_rename_copy(void)
 	diff_debug_queue("resolve-rename-copy done", q);
 }
 
-void diff_flush(int diff_output_style, int resolve_rename_copy)
+void diff_flush(int diff_output_style)
 {
 	struct diff_queue_struct *q = &diff_queued_diff;
 	int i;
@@ -930,8 +930,6 @@ void diff_flush(int diff_output_style, int resolve_rename_copy)
 
 	if (diff_output_style == DIFF_FORMAT_MACHINE)
 		line_termination = inter_name_termination = 0;
-	if (resolve_rename_copy)
-		diff_resolve_rename_copy();
 
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
@@ -958,11 +956,58 @@ void diff_flush(int diff_output_style, int resolve_rename_copy)
 	q->nr = q->alloc = 0;
 }
 
+static void diffcore_apply_filter(const char *filter)
+{
+	int i;
+	struct diff_queue_struct *q = &diff_queued_diff;
+	struct diff_queue_struct outq;
+	outq.queue = NULL;
+	outq.nr = outq.alloc = 0;
+
+	if (!filter)
+		return;
+
+	if (strchr(filter, 'A')) {
+		/* All-or-none */
+		int found;
+		for (i = found = 0; !found && i < q->nr; i++) {
+			struct diff_filepair *p = q->queue[i];
+			if ((p->broken_pair && strchr(filter, 'B')) ||
+			    (!p->broken_pair && strchr(filter, p->status)))
+				found++;
+		}
+		if (found)
+			return;
+
+		/* otherwise we will clear the whole queue
+		 * by copying the empty outq at the end of this
+		 * function, but first clear the current entries
+		 * in the queue.
+		 */
+		for (i = 0; i < q->nr; i++)
+			diff_free_filepair(q->queue[i]);
+	}
+	else {
+		/* Only the matching ones */
+		for (i = 0; i < q->nr; i++) {
+			struct diff_filepair *p = q->queue[i];
+			if ((p->broken_pair && strchr(filter, 'B')) ||
+			    (!p->broken_pair && strchr(filter, p->status)))
+				diff_q(&outq, p);
+			else
+				diff_free_filepair(p);
+		}
+	}
+	free(q->queue);
+	*q = outq;
+}
+
 void diffcore_std(const char **paths,
 		  int detect_rename, int rename_score,
 		  const char *pickaxe, int pickaxe_opts,
 		  int break_opt,
-		  const char *orderfile)
+		  const char *orderfile,
+		  const char *filter)
 {
 	if (paths && paths[0])
 		diffcore_pathspec(paths);
@@ -976,6 +1021,23 @@ void diffcore_std(const char **paths,
 		diffcore_pickaxe(pickaxe, pickaxe_opts);
 	if (orderfile)
 		diffcore_order(orderfile);
+	diff_resolve_rename_copy();
+	diffcore_apply_filter(filter);
+}
+
+
+void diffcore_std_no_resolve(const char **paths,
+			     const char *pickaxe, int pickaxe_opts,
+			     const char *orderfile,
+			     const char *filter)
+{
+	if (paths && paths[0])
+		diffcore_pathspec(paths);
+	if (pickaxe)
+		diffcore_pickaxe(pickaxe, pickaxe_opts);
+	if (orderfile)
+		diffcore_order(orderfile);
+	diffcore_apply_filter(filter);
 }
 
 void diff_addremove(int addremove, unsigned mode,

diff.h

@@ -47,7 +47,11 @@ extern void diffcore_std(const char **paths,
 			 int detect_rename, int rename_score,
 			 const char *pickaxe, int pickaxe_opts,
 			 int break_opt,
-			 const char *orderfile);
+			 const char *orderfile, const char *filter);
+
+extern void diffcore_std_no_resolve(const char **paths,
+				    const char *pickaxe, int pickaxe_opts,
+				    const char *orderfile, const char *filter);
 
 extern int diff_queue_is_empty(void);
 
@@ -56,6 +60,6 @@ extern int diff_queue_is_empty(void);
 #define DIFF_FORMAT_PATCH	2
 #define DIFF_FORMAT_NO_OUTPUT	3
 
-extern void diff_flush(int output_style, int resolve_rename_copy);
+extern void diff_flush(int output_style);
 
 #endif /* DIFF_H */