Fix bug looping non-blocking fifos.

Change-Id: I33dcf575466bfef672af4e113ad692397b5213e9

3 files changed, 28 insertions, 2 deletions

diff --git a/rsContext.cpp b/rsContext.cpp
index 1a7c5ad6..08dd57bf 100644
--- a/rsContext.cpp
+++ b/rsContext.cpp
@@ -744,7 +744,7 @@ bool Context::sendMessageToClient(void *data, uint32_t cmdID, size_t len, bool w
         return false;
     }
     if (!waitForSpace) {
-        if (mIO.mToClient.getFreeSpace() <= (len + 8)) {
+        if (!mIO.mToClient.makeSpaceNonBlocking(len + 8)) {
             // Not enough room, and not waiting.
             return false;
         }
diff --git a/rsLocklessFifo.cpp b/rsLocklessFifo.cpp
index 76ca32e9..019ea72b 100644
--- a/rsLocklessFifo.cpp
+++ b/rsLocklessFifo.cpp
@@ -169,6 +169,30 @@ void LocklessCommandFifo::next()
     //dumpState("next");
 }
 
+bool LocklessCommandFifo::makeSpaceNonBlocking(uint32_t bytes)
+{
+    //dumpState("make space non-blocking");
+    if ((mPut+bytes) > mEnd) {
+        // Need to loop regardless of where get is.
+        if((mGet > mPut) && (mBuffer+4 >= mGet)) {
+            return false;
+        }
+
+        // Toss in a reset then the normal wait for space will do the rest.
+        reinterpret_cast<uint16_t *>(mPut)[0] = 0;
+        reinterpret_cast<uint16_t *>(mPut)[1] = 0;
+        mPut = mBuffer;
+        mSignalToWorker.set();
+    }
+
+    // it will fit here so we just need to wait for space.
+    if(getFreeSpace() < bytes) {
+        return false;
+    }
+
+    return true;
+}
+
 void LocklessCommandFifo::makeSpace(uint32_t bytes)
 {
     //dumpState("make space");
@@ -182,6 +206,7 @@ void LocklessCommandFifo::makeSpace(uint32_t bytes)
         reinterpret_cast<uint16_t *>(mPut)[0] = 0;
         reinterpret_cast<uint16_t *>(mPut)[1] = 0;
         mPut = mBuffer;
+        mSignalToWorker.set();
     }
 
     // it will fit here so we just need to wait for space.
@@ -193,6 +218,6 @@ void LocklessCommandFifo::makeSpace(uint32_t bytes)
 
 void LocklessCommandFifo::dumpState(const char *s) const
 {
-    LOGV("%s  put %p, get %p,  buf %p,  end %p", s, mPut, mGet, mBuffer, mEnd);
+    LOGV("%s %p  put %p, get %p,  buf %p,  end %p", s, this, mPut, mGet, mBuffer, mEnd);
 }
 
diff --git a/rsLocklessFifo.h b/rsLocklessFifo.h
index ae906ca6..b8ceeed3 100644
--- a/rsLocklessFifo.h
+++ b/rsLocklessFifo.h
@@ -62,6 +62,7 @@ public:
     void next();
 
     void makeSpace(uint32_t bytes);
+    bool makeSpaceNonBlocking(uint32_t bytes);
 
     bool isEmpty() const;
     uint32_t getFreeSpace() const;