Re: No progress from push when using bitmaps

[Jeff King <peff@peff.net>]

On Thu, Mar 13, 2014 at 06:07:54PM -0400, Jeff King wrote:

>   3. Use the regular "Writing objects" progress, but fake the object
>      count. We know we are writing M bytes with N objects. Bump the
>      counter by 1 for every M/N bytes we write.

Here is that strategy. I think it looks pretty nice, and it seamlessly
handles the case where you have extra objects to send on top of the
reused pack (we just keep the same progress meter counting up).

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 831dd05..f187859 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -709,7 +709,7 @@ static struct object_entry **compute_write_order(void)
 static off_t write_reused_pack(struct sha1file *f)
 {
 	unsigned char buffer[8192];
-	off_t to_write;
+	off_t to_write, total;
 	int fd;
 
 	if (!is_pack_valid(reuse_packfile))
@@ -726,7 +726,7 @@ static off_t write_reused_pack(struct sha1file *f)
 	if (reuse_packfile_offset < 0)
 		reuse_packfile_offset = reuse_packfile->pack_size - 20;
 
-	to_write = reuse_packfile_offset - sizeof(struct pack_header);
+	total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 
 	while (to_write) {
 		int read_pack = xread(fd, buffer, sizeof(buffer));
@@ -739,10 +739,23 @@ static off_t write_reused_pack(struct sha1file *f)
 
 		sha1write(f, buffer, read_pack);
 		to_write -= read_pack;
+
+		/*
+		 * We don't know the actual number of objects written,
+		 * only how many bytes written, how many bytes total, and
+		 * how many objects total. So we can fake it by pretending all
+		 * objects we are writing are the same size. This gives us a
+		 * smooth progress meter, and at the end it matches the true
+		 * answer.
+		 */
+		written = reuse_packfile_objects *
+				(((double)(total - to_write)) / total);
+		display_progress(progress_state, written);
 	}
 
 	close(fd);
-	written += reuse_packfile_objects;
+	written = reuse_packfile_objects;
+	display_progress(progress_state, written);
 	return reuse_packfile_offset - sizeof(struct pack_header);
 }