Improve Platform MessagePool support. (#1171)

include/platform/messagepool.h

@@ -63,14 +63,13 @@ extern "C" {
 #endif
 
 /**
- * Initialize the platform implemented message pool with the provided buffer list.
+ * Initialize the platform implemented message pool.
  *
- * @param[in] aFreeBufferList   A linked list of free buffers.
- * @param[in] aNumFreeBuffers   A pointer to an int containing the number of free buffers in aFreeBufferList.
- * @param[in] aBufferSize       The size in bytes of a Buffer object.
+ * @param[in] aMinNumFreeBuffers   An int containing the minimum number of free buffers desired by OpenThread.
+ * @param[in] aBufferSize          The size in bytes of a Buffer object.
  *
  */
-void otPlatMessagePoolInit(struct BufferHeader *aFreeBufferList, int *aNumFreeBuffers, size_t aBufferSize);
+void otPlatMessagePoolInit(int aMinNumFreeBuffers, size_t aBufferSize);
 
 /**
  * Allocate a buffer from the platform managed buffer pool.
@@ -88,6 +87,14 @@ struct BufferHeader *otPlatMessagePoolNew(void);
  */
 void otPlatMessagePoolFree(struct BufferHeader *aBuffer);
 
+/**
+ * Get the number of free buffers.
+ *
+ * @returns The number of buffers currently free and available to OpenThread.
+ *
+ */
+int otPlatMessagePoolNumFreeBuffers(void);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif

src/core/common/message.cpp

@@ -44,6 +44,10 @@ namespace Thread {
 MessagePool::MessagePool(void) :
     mAllQueue()
 {
+#if OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
+    // Initialize Platform buffer pool management.
+    otPlatMessagePoolInit(kNumBuffers, sizeof(Buffer));
+#else
     memset(mBuffers, 0, sizeof(mBuffers));
 
     mFreeBuffers = mBuffers;
@@ -55,11 +59,6 @@ MessagePool::MessagePool(void) :
 
     mBuffers[kNumBuffers - 1].SetNextBuffer(NULL);
     mNumFreeBuffers = kNumBuffers;
-
-#if OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
-    // Pass the list of free buffers and a pointer to the count of free buffers
-    // to the platform for management.
-    otPlatMessagePoolInit(static_cast<BufferHeader *>(mFreeBuffers), &mNumFreeBuffers, sizeof(Buffer));
 #endif
 }
 
@@ -109,7 +108,7 @@ Buffer *MessagePool::NewBuffer(void)
         otLogInfoMac("No available message buffer\n");
     }
 
-#else // OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
+#else
 
     if (mFreeBuffers == NULL)
     {
@@ -121,7 +120,7 @@ Buffer *MessagePool::NewBuffer(void)
     mFreeBuffers = mFreeBuffers->GetNextBuffer();
     buffer->SetNextBuffer(NULL);
     mNumFreeBuffers--;
-#endif // OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
+#endif
 
 exit:
     return buffer;
@@ -149,7 +148,15 @@ ThreadError MessagePool::FreeBuffers(Buffer *aBuffer)
 
 ThreadError MessagePool::ReclaimBuffers(int aNumBuffers)
 {
-    return (aNumBuffers <= mNumFreeBuffers) ? kThreadError_None : kThreadError_NoBufs;
+    int numFreeBuffers;
+
+#if OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
+    numFreeBuffers = otPlatMessagePoolNumFreeBuffers();
+#else
+    numFreeBuffers = mNumFreeBuffers;
+#endif
+
+    return (aNumBuffers <= numFreeBuffers) ? kThreadError_None : kThreadError_NoBufs;
 }
 
 Message *MessagePool::Iterator::Next(void) const

src/core/common/message.hpp

@@ -1091,7 +1091,11 @@ public:
      * @returns The number of free buffers.
      *
      */
+#if OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
+    uint16_t GetFreeBufferCount(void) const { return static_cast<uint16_t>(otPlatMessagePoolNumFreeBuffers()); }
+#else
     uint16_t GetFreeBufferCount(void) const { return static_cast<uint16_t>(mNumFreeBuffers); }
+#endif
 
 private:
     enum
@@ -1104,9 +1108,11 @@ private:
     ThreadError ReclaimBuffers(int aNumBuffers);
     PriorityQueue *GetAllMessagesQueue(void) { return &mAllQueue; }
 
+#if OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT == 0
     int mNumFreeBuffers;
     Buffer mBuffers[kNumBuffers];
     Buffer *mFreeBuffers;
+#endif
     PriorityQueue mAllQueue;
 };