[cli] enhance buffer info (#5831)

This commit enhances buffer info when using heap for message buffers.

src/core/api/message_api.cpp

@@ -174,7 +174,7 @@ void otMessageGetBufferInfo(otInstance *aInstance, otBufferInfo *aBufferInfo)
     uint16_t  messages, buffers;
     Instance &instance = *static_cast<Instance *>(aInstance);
 
-    aBufferInfo->mTotalBuffers = OPENTHREAD_CONFIG_NUM_MESSAGE_BUFFERS;
+    aBufferInfo->mTotalBuffers = instance.Get<MessagePool>().GetTotalBufferCount();
 
     aBufferInfo->mFreeBuffers = instance.Get<MessagePool>().GetFreeBufferCount();
 

src/core/common/message.cpp

@@ -42,6 +42,11 @@
 #include "net/ip6.hpp"
 
 #if OPENTHREAD_MTD || OPENTHREAD_FTD
+
+#if OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE && !OPENTHREAD_CONFIG_DTLS_ENABLE
+#error "OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE is strongly discouraged when OPENTHREAD_CONFIG_DTLS_ENABLE is off."
+#endif
+
 namespace ot {
 
 MessagePool::MessagePool(Instance &aInstance)
@@ -169,6 +174,15 @@ uint16_t MessagePool::GetFreeBufferCount(void) const
     return rval;
 }
 
+uint16_t MessagePool::GetTotalBufferCount(void) const
+{
+#if OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE
+    return static_cast<uint16_t>(GetInstance().GetHeap().GetCapacity() / sizeof(Buffer));
+#else
+    return OPENTHREAD_CONFIG_NUM_MESSAGE_BUFFERS;
+#endif
+}
+
 const Message::Settings Message::Settings::kDefault(Message::kWithLinkSecurity, Message::kPriorityNormal);
 
 Message::Settings::Settings(LinkSecurityMode aSecurityMode, Priority aPriority)

src/core/common/message.hpp

@@ -1468,6 +1468,14 @@ public:
      */
     uint16_t GetFreeBufferCount(void) const;
 
+    /**
+     * This method returns the total number of buffers.
+     *
+     * @returns The total number of buffers.
+     *
+     */
+    uint16_t GetTotalBufferCount(void) const;
+
 private:
     Buffer *NewBuffer(Message::Priority aPriority);
     void    FreeBuffers(Buffer *aBuffer);

src/core/config/openthread-core-config-check.h

@@ -546,13 +546,8 @@
        "(and OPENTHREAD_CONFIG_LOG_DEFINE_AS_MACRO_ONLY)"
 #endif
 
-#if OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE
-#if !OPENTHREAD_CONFIG_DTLS_ENABLE
-#error "OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE is strongly discouraged when OPENTHREAD_CONFIG_DTLS_ENABLE is off."
-#endif
-#if OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
+#if OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE && OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT
 #error "OPENTHREAD_CONFIG_MESSAGE_USE_HEAP_ENABLE conflicts with OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT."
 #endif
-#endif
 
 #endif // OPENTHREAD_CORE_CONFIG_CHECK_H_