Make the progress indicator smooth in threaded mode.

This adds lzma_get_progress() to liblzma and takes advantage
of it in xz.

lzma_get_progress() collects progress information from
the thread-specific structures so that fairly accurate
progress information is available to applications. Adding
a new function seemed to be a better way than making the
information directly available in lzma_stream (like total_in
and total_out are) because collecting the information requires
locking mutexes. It's waste of time to do it more often than
the up to date information is actually needed by an application.

1 files changed, 13 insertions, 7 deletions

diff --git a/src/xz/message.c b/src/xz/message.c
index bc16aedb..abdf0568 100644
--- a/src/xz/message.c
+++ b/src/xz/message.c
@@ -526,20 +526,26 @@ progress_elapsed(void)
 }
 
 
-/// Get information about position in the stream. This is currently simple,
-/// but it will become more complicated once we have multithreading support.
+/// Get how much uncompressed and compressed data has been processed.
 static void
 progress_pos(uint64_t *in_pos,
 		uint64_t *compressed_pos, uint64_t *uncompressed_pos)
 {
-	*in_pos = progress_strm->total_in;
+	uint64_t out_pos;
+	lzma_get_progress(progress_strm, in_pos, &out_pos);
+
+	// It cannot have processed more input than it has been given.
+	assert(*in_pos <= progress_strm->total_in);
+
+	// It cannot have produced more output than it claims to have ready.
+	assert(out_pos >= progress_strm->total_out);
 
 	if (opt_mode == MODE_COMPRESS) {
-		*compressed_pos = progress_strm->total_out;
-		*uncompressed_pos = progress_strm->total_in;
+		*compressed_pos = out_pos;
+		*uncompressed_pos = *in_pos;
 	} else {
-		*compressed_pos = progress_strm->total_in;
-		*uncompressed_pos = progress_strm->total_out;
+		*compressed_pos = *in_pos;
+		*uncompressed_pos = out_pos;
 	}
 
 	return;