sha1_file.c: the global packed_git variable static to the filesz/packed-git-static

This is a first step in making the codebase thread-safe.  By and
large, the operations which might benefit from threading are those
that work with pack files (e.g., checkout, blame), so the focus of
this patch is stop leaking the global list of pack files outside of
sha1_file.c.

The next step will be to control access to the list of pack files
with a mutex.  However, that alone is not enough to make pack file
access thread safe.  Even in a read-only operation, the window list
associated with each pack file will need to be controlled.
Additionally, the global counters in sha1_file.c will need to be
controlled.

This patch is a pure refactor with no functional changes, so it
shouldn't require any additional tests.  Adding the actual locks
will be a functional change, and will require additional tests.

[jc: with minimul style fixes before a full review]

Signed-off-by: Stefan Zager <szager@chromium.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 25 insertions, 19 deletions

diff --git a/builtin/count-objects.c b/builtin/count-objects.c
index a7f70cb858..c1a6a2c254 100644
--- a/builtin/count-objects.c
+++ b/builtin/count-objects.c
@@ -83,14 +83,32 @@ static char const * const count_objects_usage[] = {
 	NULL
 };
 
+struct pack_data {
+	unsigned long packed;
+	off_t size_pack;
+	unsigned long num_pack;
+};
+
+static int collect_pack_data(struct packed_git *p, void *data)
+{
+	struct pack_data *pd = (struct pack_data *) data;
+	if (p->pack_local && !open_pack_index(p)) {
+		pd->packed += p->num_objects;
+		pd->size_pack += p->pack_size + p->index_size;
+		pd->num_pack++;
+	}
+	return 0;
+}
+
 int cmd_count_objects(int argc, const char **argv, const char *prefix)
 {
 	int i, verbose = 0, human_readable = 0;
 	const char *objdir = get_object_directory();
 	int len = strlen(objdir);
 	char *path = xmalloc(len + 50);
-	unsigned long loose = 0, packed = 0, packed_loose = 0;
+	unsigned long loose = 0, packed_loose = 0;
 	off_t loose_size = 0;
+	struct pack_data pd = {0, 0, 0};
 	struct option opts[] = {
 		OPT__VERBOSE(&verbose, N_("be verbose")),
 		OPT_BOOL('H', "human-readable", &human_readable,
@@ -118,41 +136,29 @@ int cmd_count_objects(int argc, const char **argv, const char *prefix)
 		closedir(d);
 	}
 	if (verbose) {
-		struct packed_git *p;
-		unsigned long num_pack = 0;
-		off_t size_pack = 0;
 		struct strbuf loose_buf = STRBUF_INIT;
 		struct strbuf pack_buf = STRBUF_INIT;
 		struct strbuf garbage_buf = STRBUF_INIT;
-		if (!packed_git)
-			prepare_packed_git();
-		for (p = packed_git; p; p = p->next) {
-			if (!p->pack_local)
-				continue;
-			if (open_pack_index(p))
-				continue;
-			packed += p->num_objects;
-			size_pack += p->pack_size + p->index_size;
-			num_pack++;
-		}
+		prepare_packed_git();
+		foreach_packed_git(collect_pack_data, NULL, &pd);
 
 		if (human_readable) {
 			strbuf_humanise_bytes(&loose_buf, loose_size);
-			strbuf_humanise_bytes(&pack_buf, size_pack);
+			strbuf_humanise_bytes(&pack_buf, pd.size_pack);
 			strbuf_humanise_bytes(&garbage_buf, size_garbage);
 		} else {
 			strbuf_addf(&loose_buf, "%lu",
 				    (unsigned long)(loose_size / 1024));
 			strbuf_addf(&pack_buf, "%lu",
-				    (unsigned long)(size_pack / 1024));
+				    (unsigned long)(pd.size_pack / 1024));
 			strbuf_addf(&garbage_buf, "%lu",
 				    (unsigned long)(size_garbage / 1024));
 		}
 
 		printf("count: %lu\n", loose);
 		printf("size: %s\n", loose_buf.buf);
-		printf("in-pack: %lu\n", packed);
-		printf("packs: %lu\n", num_pack);
+		printf("in-pack: %lu\n", pd.packed);
+		printf("packs: %lu\n", pd.num_pack);
 		printf("size-pack: %s\n", pack_buf.buf);
 		printf("prune-packable: %lu\n", packed_loose);
 		printf("garbage: %lu\n", garbage);