From 1032db93b15f0a5fd38d6cfe0aacf021102c0ee0 Mon Sep 17 00:00:00 2001
From: Charles Otto <ottochar@gmail.com>
Date: Tue, 17 Jun 2014 17:10:14 -0400
Subject: [PATCH] Per @jklontz's suggestion, replace the look-ahead scheme with a sentinel

---
 openbr/plugins/stream.cpp | 41 +++++------------------------------------
 1 file changed, 5 insertions(+), 36 deletions(-)

diff --git a/openbr/plugins/stream.cpp b/openbr/plugins/stream.cpp
index 6220a05..6693ed5 100644
--- a/openbr/plugins/stream.cpp
+++ b/openbr/plugins/stream.cpp
@@ -647,28 +647,6 @@ public:
             return false;
         }
 
-        // Try to get a frame from the global pool
-        FrameData * firstFrame = allFrames.tryGetItem();
-
-        // If this fails, things have gone pretty badly.
-        if (firstFrame == NULL) {
-            is_broken = true;
-            return false;
-        }
-
-        // Read a frame from the video source
-        bool res = getNextFrame(*firstFrame);
-
-        // the data source broke already, we couldn't even get one frame
-        // from it even though it claimed to have opened successfully.
-        if (!res) {
-            is_broken = true;
-            return false;
-        }
-
-        // We read one frame ahead of the last one returned, this allows
-        // us to know which frame is the final frame when we return it.
-        lookAhead.append(firstFrame);
         return true;
     }
 
@@ -698,26 +676,17 @@ public:
         if (!res)
         {
             QMutexLocker lock(&last_frame_update);
-            final_frame = lookAhead.back()->sequenceNumber;
-            allFrames.addItem(aFrame);
+            final_frame = aFrame->sequenceNumber;
+            aFrame->data().clear();
         }
-        else {
-            lookAhead.push_back(aFrame);
-        }
-
-        // we will return the first frame on the lookAhead buffer
-        FrameData * rVal = lookAhead.first();
-        lookAhead.pop_front();
-        if (rVal->data.empty())
-            qDebug("returning empty frame from look ahead!");
 
         // If this is the last frame, say so
-        if (rVal->sequenceNumber == final_frame) {
+        if (aFrame->sequenceNumber == final_frame) {
             last_frame = true;
             is_broken = true;
         }
 
-        return rVal;
+        return aFrame;
     }
 
     // Return a frame to the pool, returns true if the frame returned was the last
@@ -845,6 +814,7 @@ protected:
             // couldn't get the next template? nothing to do, otherwise we try to read
             // a frame at the top of this loop.
             if (!open_res) {
+                output.sequenceNumber = next_sequence_number;
                 return false;
             }
         }
@@ -870,7 +840,6 @@ protected:
     bool allReturned;
 
     DoubleBuffer allFrames;
-    QList<FrameData *> lookAhead;
 
     QWaitCondition lastReturned;
     QMutex last_frame_update;
--
libgit2 0.21.4