[PATCH] RFC: replay: Fix --loop to work when --singlethread is in effect

[Carl Worth]

The original implementation of --loop was made only to the code
implementing multi-threaded replay, (the RelayRunner class and
friends), so that when --singlethread is in effect, the --loop option
has no effect.

This commit fixes the bug by copying the --loop logic to the
single-threaded case as well.

Thanks to Peter Lohrmann for reporting the bug.
---

NOTE: This commit is ugly in that the implementation of --loop is
copied to two places in the code. I'd really rather eliminate that
copying, so this is sent out in some respect as a proof-of-concept,
(and as a way to help Peter get past the current bug).

One option to reduce code duplication would be to push the "if
(singleThread)" condition down into the lower loop. But my first looks
at doing that held little promise, (there are many places within the
"relay race" that would have to be touched up with "if
(singleThread)").

Another option would be to have some sort of getNextCall function that
both the single and multi-threaded code could use and then this
function could hold all of the logic needed for --loop.

I'm glad to do more of the legwork on the code here, but if someone
has a strong opinion on what direction to go, I'd be glad to hear it.

 retrace/retrace_main.cpp |   36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/retrace/retrace_main.cpp b/retrace/retrace_main.cpp
index 0c358e1..fd45e78 100644
--- a/retrace/retrace_main.cpp
+++ b/retrace/retrace_main.cpp
@@ -517,10 +517,42 @@ mainLoop() {
 
     if (singleThread) {
         trace::Call *call;
-        while ((call = parser.parse_call())) {
+
+        call = parser.parse_call();
+
+        /* If the user wants to loop we need to get a bookmark target. We
+         * usually get this after replaying a call that ends a frame, but
+         * for a trace that has only one frame we need to get it at the
+         * beginning. */
+        if (loopOnFinish) {
+            parser.getBookmark(lastFrameStart);
+        }
+
+        do {
+            bool callEndsFrame = false;
+            static trace::ParseBookmark frameStart;
+
+            if (loopOnFinish && call->flags & trace::CALL_FLAG_END_FRAME) {
+                callEndsFrame = true;
+                parser.getBookmark(frameStart);
+            }
+
             retraceCall(call);
             delete call;
-        };
+            call = parser.parse_call();
+
+            /* Restart last frame if looping is requested. */
+            if (loopOnFinish) {
+                if (!call) {
+                    parser.setBookmark(lastFrameStart);
+                    call = parser.parse_call();
+                } else if (callEndsFrame) {
+                    lastFrameStart = frameStart;
+                }
+            }
+
+        } while (call);
+
         flushRendering();
     } else {
         RelayRace race;
-- 
1.7.10.4