Teach revision walking machinery to walk multiple times sequencially

Previously it was not possible to iterate revisions twice using the
revision walking api. We add a reset_revision_walk() which clears the
used flags. This allows us to do multiple sequencial revision walks.

We add the appropriate calls to the existing submodule machinery doing
revision walks. This is done to avoid surprises if future code wants to
call these functions more than once during the processes lifetime.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/test-revision-walking.c b/test-revision-walking.c
new file mode 100644
index 0000000000..3ade02c72d
--- /dev/null
+++ b/test-revision-walking.c
@@ -0,0 +1,66 @@
+/*
+ * test-revision-walking.c: test revision walking API.
+ *
+ * (C) 2012 Heiko Voigt <hvoigt@hvoigt.net>
+ *
+ * This code is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "cache.h"
+#include "commit.h"
+#include "diff.h"
+#include "revision.h"
+
+static void print_commit(struct commit *commit)
+{
+	struct strbuf sb = STRBUF_INIT;
+	struct pretty_print_context ctx = {0};
+	ctx.date_mode = DATE_NORMAL;
+	format_commit_message(commit, " %m %s", &sb, &ctx);
+	printf("%s\n", sb.buf);
+	strbuf_release(&sb);
+}
+
+static int run_revision_walk(void)
+{
+	struct rev_info rev;
+	struct commit *commit;
+	const char *argv[] = {NULL, "--all", NULL};
+	int argc = ARRAY_SIZE(argv) - 1;
+	int got_revision = 0;
+
+	init_revisions(&rev, NULL);
+	setup_revisions(argc, argv, &rev, NULL);
+	if (prepare_revision_walk(&rev))
+		die("revision walk setup failed");
+
+	while ((commit = get_revision(&rev)) != NULL) {
+		print_commit(commit);
+		got_revision = 1;
+	}
+
+	reset_revision_walk();
+	return got_revision;
+}
+
+int main(int argc, char **argv)
+{
+	if (argc < 2)
+		return 1;
+
+	if (!strcmp(argv[1], "run-twice")) {
+		printf("1st\n");
+		if (!run_revision_walk())
+			return 1;
+		printf("2nd\n");
+		if (!run_revision_walk())
+			return 1;
+
+		return 0;
+	}
+
+	fprintf(stderr, "check usage\n");
+	return 1;
+}