Introduce a list to cache freed input packet entries for reuse

src/InputStream.c

@@ -6,11 +6,14 @@ static bool initialized;
 static PPLT_CRYPTO_CONTEXT cryptoContext;
 
 static LINKED_BLOCKING_QUEUE packetQueue;
+static LINKED_BLOCKING_QUEUE packetHolderFreeList;
 static PLT_THREAD inputSendThread;
 
 #define MAX_INPUT_PACKET_SIZE 128
 #define INPUT_STREAM_TIMEOUT_SEC 10
 
+#define MAX_QUEUED_INPUT_PACKETS 150
+
 // Contains input stream packets
 typedef struct _PACKET_HOLDER {
     int packetLength;
@@ -33,7 +36,8 @@ int initializeInputStream(void) {
     
     // Set a high maximum queue size limit to ensure input isn't dropped
     // while the input send thread is blocked for short periods.
-    LbqInitializeLinkedBlockingQueue(&packetQueue, 150);
+    LbqInitializeLinkedBlockingQueue(&packetQueue, MAX_QUEUED_INPUT_PACKETS);
+    LbqInitializeLinkedBlockingQueue(&packetHolderFreeList, MAX_QUEUED_INPUT_PACKETS);
 
     cryptoContext = PltCreateCryptoContext();
     return 0;
@@ -55,6 +59,17 @@ void destroyInputStream(void) {
 
         entry = nextEntry;
     }
+
+    entry = LbqDestroyLinkedBlockingQueue(&packetHolderFreeList);
+
+    while (entry != NULL) {
+        nextEntry = entry->flink;
+
+        // The entry is stored in the data buffer
+        free(entry->data);
+
+        entry = nextEntry;
+    }
 }
 
 static int encryptData(unsigned char* plaintext, int plaintextLen,
@@ -92,6 +107,34 @@ static int encryptData(unsigned char* plaintext, int plaintextLen,
     }
 }
 
+static void freePacketHolder(PPACKET_HOLDER holder) {
+    // Place the packet holder back into the free list
+    if (LbqOfferQueueItem(&packetHolderFreeList, holder, &holder->entry) != LBQ_SUCCESS) {
+        free(holder);
+    }
+}
+
+static PPACKET_HOLDER allocatePacketHolder(void) {
+    PPACKET_HOLDER holder;
+    int err;
+
+    // Grab an entry from the free list (if available)
+    err = LbqPollQueueElement(&packetHolderFreeList, (void**)&holder);
+    if (err == LBQ_SUCCESS) {
+        return holder;
+    }
+    else if (err == LBQ_INTERRUPTED) {
+        // We're shutting down. Don't bother allocating.
+        return NULL;
+    }
+    else {
+        LC_ASSERT(err == LBQ_NO_ELEMENT);
+
+        // Otherwise we'll have to allocate
+        return malloc(sizeof(*holder));
+    }
+}
+
 // Input thread proc
 static void inputSendThreadProc(void* context) {
     SOCK_RET err;
@@ -154,7 +197,7 @@ static void inputSendThreadProc(void* context) {
                 origPkt->rightStickY = newPkt->rightStickY;
 
                 // Free the batched packet holder
-                free(controllerBatchHolder);
+                freePacketHolder(controllerBatchHolder);
             }
         }
         // If it's a relative mouse move packet, we can also do batching
@@ -198,7 +241,7 @@ static void inputSendThreadProc(void* context) {
                 totalDeltaY += partialDeltaY;
 
                 // Free the batched packet holder
-                free(mouseBatchHolder);
+                freePacketHolder(mouseBatchHolder);
             }
 
             // Update the original packet
@@ -226,7 +269,7 @@ static void inputSendThreadProc(void* context) {
                 }
 
                 // Replace the current packet with the new one
-                free(holder);
+                freePacketHolder(holder);
                 holder = mouseBatchHolder;
             }
         }
@@ -236,7 +279,7 @@ static void inputSendThreadProc(void* context) {
         // the encryption.
         if (encryptedControlStream) {
             err = (SOCK_RET)sendInputPacketOnControlStream((unsigned char*)&holder->packet, holder->packetLength);
-            free(holder);
+            freePacketHolder(holder);
             if (err < 0) {
                 Limelog("Input: sendInputPacketOnControlStream() failed: %d\n", (int) err);
                 ListenerCallbacks.connectionTerminated(err);
@@ -248,7 +291,7 @@ static void inputSendThreadProc(void* context) {
             encryptedSize = sizeof(encryptedBuffer) - 4;
             err = encryptData((unsigned char*)&holder->packet, holder->packetLength,
                 (unsigned char*)&encryptedBuffer[4], (int*)&encryptedSize);
-            free(holder);
+            freePacketHolder(holder);
             if (err != 0) {
                 Limelog("Input: Encryption failed: %d\n", (int)err);
                 ListenerCallbacks.connectionTerminated(err);
@@ -303,7 +346,7 @@ static int sendEnableHaptics(void) {
         return 0;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -317,7 +360,7 @@ static int sendEnableHaptics(void) {
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;
@@ -360,6 +403,7 @@ int startInputStream(void) {
 int stopInputStream(void) {
     // No more packets should be queued now
     initialized = false;
+    LbqSignalQueueShutdown(&packetHolderFreeList);
 
     // Signal the input send thread to drain all pending
     // input packets before shutting down.
@@ -392,7 +436,7 @@ int LiSendMouseMoveEvent(short deltaX, short deltaY) {
         return 0;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -412,7 +456,7 @@ int LiSendMouseMoveEvent(short deltaX, short deltaY) {
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;
@@ -427,7 +471,7 @@ int LiSendMousePositionEvent(short x, short y, short referenceWidth, short refer
         return -2;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -451,7 +495,7 @@ int LiSendMousePositionEvent(short x, short y, short referenceWidth, short refer
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;
@@ -466,7 +510,7 @@ int LiSendMouseButtonEvent(char action, int button) {
         return -2;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -483,7 +527,7 @@ int LiSendMouseButtonEvent(char action, int button) {
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;
@@ -498,7 +542,7 @@ int LiSendKeyboardEvent(short keyCode, char keyAction, char modifiers) {
         return -2;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -557,7 +601,7 @@ int LiSendKeyboardEvent(short keyCode, char keyAction, char modifiers) {
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;
@@ -574,7 +618,7 @@ static int sendControllerEventInternal(short controllerNumber, short activeGamep
         return -2;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -625,7 +669,7 @@ static int sendControllerEventInternal(short controllerNumber, short activeGamep
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;
@@ -662,7 +706,7 @@ int LiSendHighResScrollEvent(short scrollAmount) {
         return 0;
     }
 
-    holder = malloc(sizeof(*holder));
+    holder = allocatePacketHolder();
     if (holder == NULL) {
         return -1;
     }
@@ -684,7 +728,7 @@ int LiSendHighResScrollEvent(short scrollAmount) {
     if (err != LBQ_SUCCESS) {
         LC_ASSERT(err == LBQ_BOUND_EXCEEDED);
         Limelog("Input queue reached maximum size limit\n");
-        free(holder);
+        freePacketHolder(holder);
     }
 
     return err;