patchTeach fmt-patch to write individual files.

diff --git a/builtin-log.c b/builtin-log.c
index a39aed6..576703c 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -69,12 +69,65 @@ int cmd_log(int argc, const char **argv,
 	return cmd_log_wc(argc, argv, envp, &rev);
 }
 
+static int istitlechar(char c)
+{
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
+		(c >= '0' && c <= '9') || c == '.' || c == '_';
+}
+
+static void reopen_stdout(struct commit *commit, int nr)
+{
+	char filename[1024];
+	char *sol;
+	int len;
+
+
+	sprintf(filename, "%04d", nr);
+	len = strlen(filename);
+
+	sol = strstr(commit->buffer, "\n\n");
+	if (sol) {
+		int j, space = 1;
+
+		sol += 2;
+		/* strip [PATCH] or [PATCH blabla] */
+		if (!strncmp(sol, "[PATCH", 6)) {
+			char *eos = strchr(sol + 6, ']');
+			if (eos) {
+				while (isspace(*eos))
+					eos++;
+				sol = eos;
+			}
+		}
+
+		for (j = 0; len < 1024 - 6 && sol[j] && sol[j] != '\n'; j++) {
+			if (istitlechar(sol[j])) {
+				if (space) {
+					filename[len++] = '-';
+					space = 0;
+				}
+				filename[len++] = sol[j];
+				if (sol[j] == '.')
+					while (sol[j + 1] == '.')
+						j++;
+			} else
+				space = 1;
+		}
+		while (filename[len - 1] == '.' || filename[len - 1] == '-')
+			len--;
+	}
+	strcpy(filename + len, ".txt");
+	fprintf(stderr, "%s\n", filename);
+	freopen(filename, "w", stdout);
+}
+
 int cmd_format_patch(int argc, const char **argv, char **envp)
 {
 	struct commit *commit;
 	struct commit **list = NULL;
 	struct rev_info rev;
-	int nr = 0;
+	int nr = 0, total;
+	int use_stdout = 0;
 
 	init_revisions(&rev);
 	rev.commit_format = CMIT_FMT_EMAIL;
@@ -87,20 +140,37 @@ int cmd_format_patch(int argc, const cha
 	rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 	argc = setup_revisions(argc, argv, &rev, "HEAD");
 
+	while (argc > 1) {
+		if (!strcmp(argv[1], "--stdout"))
+			use_stdout = 1;
+		else
+			die ("unrecognized argument: %s", argv[1]);
+		argc--;
+		argv++;
+	}
+
 	prepare_revision_walk(&rev);
 	while ((commit = get_revision(&rev)) != NULL) {
+		/* ignore merges */
+		if (commit->parents && commit->parents->next)
+			continue;
 		nr++;
 		list = realloc(list, nr * sizeof(list[0]));
 		list[nr - 1] = commit;
 	}
+	total = nr;
 	while (0 <= --nr) {
 		int shown;
 		commit = list[nr];
+		if (!use_stdout)
+			reopen_stdout(commit, total - nr);
 		shown = log_tree_commit(&rev, commit);
 		free(commit->buffer);
 		commit->buffer = NULL;
 		if (shown)
 			printf("-- \n%s\n\n", git_version_string);
+		if (!use_stdout)
+			fclose(stdout);
 	}
 	free(list);
 	return 0;

diff --git a/log-tree.c b/log-tree.c
index d92abaf..6379d43 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -86,7 +86,7 @@ int log_tree_diff_flush(struct rev_info 
 	}
 
 	if (opt->loginfo && !opt->no_commit_id)
-		show_log(opt, opt->loginfo, opt->diffopt.with_stat ? "---\n" : "\n");
+		show_log(opt, opt->loginfo, opt->diffopt.with_stat ? "\n---\n\n" : "\n");
 	diff_flush(&opt->diffopt);
 	return 1;
 }
-- snap --

> > 	- git-format-patch outputs the commit_sha1 just before the first
> > 	  diff, which fmt-patch does not,
> 
> Which should be fine.

Yeah, I just wanted to mention it in case people rely on it.

> > 	- the file names are no longer output to stdout, but to stderr
> > 	  (since stdout is freopen()ed all the time), and
> 
> Which might be a bigger deal; I suspect people capture that while
> dumping patches into individual files, and do their
> postprocessing using the list of filenames.

I hoped it is not necessary to "FILE *realstdout = fdopen(dup(1));" but I 
can do it if this is wanted.

> > 	- "git fmt-patch HEAD^" does not work as expected: it outputs
> > 	  *all* commits reachable from HEAD^!
> 
> If we really wanted to handle this, you could do something like
> what builtin-diff does before letting the revision machinery
> start walking the revision tree.  Look at pending objects, and
> if you find only one UNINTERESTING commit, add_object the
> current HEAD there as well.  Personally I do not think it is
> worth it; rather we would probably want to standardize on rev-list
> syntax.

Well, I have to get used to add ".." after HEAD^, but that is probably not 
very difficult. I would like fmt-patch to error out without a range, 
though.

> Two major differences you forgot to mention.
> 
> One is that it does not do the "git cherry" filtering.  It is
> not a big deal for me personally, but some people may be
> depending on it.  I dunno.

Oops. I really did not think of that.

> Another is -o outdir, which should be trivial to add once you
> have implemented output switching with freopen().

Yes, this becomes easy now. I'll do that next.

Ciao,
Dscho