Add support for "commit name decorations" to log family of commands

This adds "--decorate" as a log option, which prints out the ref names
of any commits that are shown.

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

builtin-log.c

@@ -13,16 +13,43 @@
 #include "tag.h"
 #include "reflog-walk.h"
 #include "patch-ids.h"
+#include "refs.h"
 
 static int default_show_root = 1;
 
 /* this is in builtin-diff.c */
 void add_head(struct rev_info *revs);
 
+static void add_name_decoration(const char *prefix, const char *name, struct object *obj)
+{
+	int plen = strlen(prefix);
+	int nlen = strlen(name);
+	struct name_decoration *res = xmalloc(sizeof(struct name_decoration) + plen + nlen);
+	memcpy(res->name, prefix, plen);
+	memcpy(res->name + plen, name, nlen + 1);
+	res->next = add_decoration(&name_decoration, obj, res);
+}
+
+static int add_ref_decoration(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
+{
+	struct object *obj = parse_object(sha1);
+	if (!obj)
+		return 0;
+	add_name_decoration("", refname, obj);
+	while (obj->type == OBJ_TAG) {
+		obj = ((struct tag *)obj)->tagged;
+		if (!obj)
+			break;
+		add_name_decoration("tag: ", refname, obj);
+	}
+	return 0;
+}
+
 static void cmd_log_init(int argc, const char **argv, const char *prefix,
 		      struct rev_info *rev)
 {
 	int i;
+	int decorate = 0;
 
 	rev->abbrev = DEFAULT_ABBREV;
 	rev->commit_format = CMIT_FMT_DEFAULT;
@@ -39,8 +66,11 @@ static void cmd_log_init(int argc, const char **argv, const char *prefix,
 				git_log_output_encoding = xstrdup(arg);
 			else
 				git_log_output_encoding = "";
-		}
-		else
+		} else if (!strcmp(arg, "--decorate")) {
+			if (!decorate)
+				for_each_ref(add_ref_decoration, NULL);
+			decorate = 1;
+		} else
 			die("unrecognized argument: %s", arg);
 	}
 }

commit.h

@@ -3,6 +3,7 @@
 
 #include "object.h"
 #include "tree.h"
+#include "decorate.h"
 
 struct commit_list {
 	struct commit *item;
@@ -21,6 +22,13 @@ struct commit {
 extern int save_commit_buffer;
 extern const char *commit_type;
 
+/* While we can decorate any object with a name, it's only used for commits.. */
+extern struct decoration name_decoration;
+struct name_decoration {
+	struct name_decoration *next;
+	char name[1];
+};
+
 struct commit *lookup_commit(const unsigned char *sha1);
 struct commit *lookup_commit_reference(const unsigned char *sha1);
 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,

log-tree.c

@@ -4,6 +4,8 @@
 #include "log-tree.h"
 #include "reflog-walk.h"
 
+struct decoration name_decoration = { "object names" };
+
 static void show_parents(struct commit *commit, int abbrev)
 {
 	struct commit_list *p;
@@ -13,6 +15,23 @@ static void show_parents(struct commit *commit, int abbrev)
 	}
 }
 
+static void show_decorations(struct commit *commit)
+{
+	const char *prefix;
+	struct name_decoration *decoration;
+
+	decoration = lookup_decoration(&name_decoration, &commit->object);
+	if (!decoration)
+		return;
+	prefix = " (";
+	while (decoration) {
+		printf("%s%s", prefix, decoration->name);
+		prefix = ", ";
+		decoration = decoration->next;
+	}
+	putchar(')');
+}
+
 /*
  * Search for "^[-A-Za-z]+: [^@]+@" pattern. It usually matches
  * Signed-off-by: and Acked-by: lines.
@@ -136,6 +155,7 @@ void show_log(struct rev_info *opt, const char *sep)
 		fputs(diff_unique_abbrev(commit->object.sha1, abbrev_commit), stdout);
 		if (opt->parents)
 			show_parents(commit, abbrev_commit);
+		show_decorations(commit);
 		putchar(opt->diffopt.line_termination);
 		return;
 	}
@@ -240,6 +260,7 @@ void show_log(struct rev_info *opt, const char *sep)
 			printf(" (from %s)",
 			       diff_unique_abbrev(parent->object.sha1,
 						  abbrev_commit));
+		show_decorations(commit);
 		printf("%s",
 		       diff_get_color(opt->diffopt.color_diff, DIFF_RESET));
 		putchar(opt->commit_format == CMIT_FMT_ONELINE ? ' ' : '\n');