refs #1670: support decode the metadata response.

@@ -273,6 +273,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define ERROR_KAFKA_CODEC_REQUEST           4032
 #define ERROR_KAFKA_CODEC_RESPONSE          4033
 #define ERROR_KAFKA_CODEC_ARRAY             4034
+#define ERROR_KAFKA_CODEC_METADATA          4035
 
 ///////////////////////////////////////////////////////
 // HTTP API error.

@@ -601,6 +601,200 @@ int SrsKafkaTopicMetadataRequest::decode(SrsBuffer* buf)
     return ret;
 }
 
+SrsKafkaBroker::SrsKafkaBroker()
+{
+    node_id = port = 0;
+}
+
+SrsKafkaBroker::~SrsKafkaBroker()
+{
+}
+
+int SrsKafkaBroker::size()
+{
+    return 4 + host.size() + 4;
+}
+
+int SrsKafkaBroker::encode(SrsBuffer* buf)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (!buf->require(4)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka encode broker node_id failed. ret=%d", ret);
+        return ret;
+    }
+    buf->write_4bytes(node_id);
+    
+    if ((ret = host.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode broker host failed. ret=%d", ret);
+        return ret;
+    }
+    
+    if (!buf->require(4)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka encode broker port failed. ret=%d", ret);
+        return ret;
+    }
+    buf->write_4bytes(port);
+
+    return ret;
+}
+
+int SrsKafkaBroker::decode(SrsBuffer* buf)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (!buf->require(4)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka decode broker node_id failed. ret=%d", ret);
+        return ret;
+    }
+    node_id = buf->read_4bytes();
+    
+    if ((ret = host.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode broker host failed. ret=%d", ret);
+        return ret;
+    }
+    
+    if (!buf->require(4)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka decode broker port failed. ret=%d", ret);
+        return ret;
+    }
+    port = buf->read_4bytes();
+    
+    return ret;
+}
+
+SrsKafkaPartitionMetadata::SrsKafkaPartitionMetadata()
+{
+    error_code = 0;
+    partition_id = 0;
+    leader = 0;
+}
+
+SrsKafkaPartitionMetadata::~SrsKafkaPartitionMetadata()
+{
+}
+
+int SrsKafkaPartitionMetadata::size()
+{
+    return 2 + 4 + 4 + replicas.size() + isr.size();
+}
+
+int SrsKafkaPartitionMetadata::encode(SrsBuffer* buf)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (!buf->require(2 + 4 + 4)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka encode partition metadata failed. ret=%d", ret);
+        return ret;
+    }
+    buf->write_2bytes(error_code);
+    buf->write_4bytes(partition_id);
+    buf->write_4bytes(leader);
+    
+    if ((ret = replicas.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode partition metadata replicas failed. ret=%d", ret);
+        return ret;
+    }
+    if ((ret = isr.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode partition metadata isr failed. ret=%d", ret);
+        return ret;
+    }
+    
+    return ret;
+}
+
+int SrsKafkaPartitionMetadata::decode(SrsBuffer* buf)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (!buf->require(2 + 4 + 4)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka decode partition metadata failed. ret=%d", ret);
+        return ret;
+    }
+    error_code = buf->read_2bytes();
+    partition_id = buf->read_4bytes();
+    leader = buf->read_4bytes();
+    
+    if ((ret = replicas.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode partition metadata replicas failed. ret=%d", ret);
+        return ret;
+    }
+    if ((ret = isr.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode partition metadata isr failed. ret=%d", ret);
+        return ret;
+    }
+    
+    return ret;
+}
+
+SrsKafkaTopicMetadata::SrsKafkaTopicMetadata()
+{
+    error_code = 0;
+}
+
+SrsKafkaTopicMetadata::~SrsKafkaTopicMetadata()
+{
+}
+
+int SrsKafkaTopicMetadata::size()
+{
+    return 2 + name.size() + metadatas.size();
+}
+
+int SrsKafkaTopicMetadata::encode(SrsBuffer* buf)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (!buf->require(2)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka encode topic metadata failed. ret=%d", ret);
+        return ret;
+    }
+    buf->write_2bytes(error_code);
+    
+    if ((ret = name.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode topic name failed. ret=%d", ret);
+        return ret;
+    }
+    
+    if ((ret = metadatas.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode topic metadatas failed. ret=%d", ret);
+        return ret;
+    }
+    
+    return ret;
+}
+
+int SrsKafkaTopicMetadata::decode(SrsBuffer* buf)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (!buf->require(2)) {
+        ret = ERROR_KAFKA_CODEC_METADATA;
+        srs_error("kafka decode topic metadata failed. ret=%d", ret);
+        return ret;
+    }
+    error_code = buf->read_2bytes();
+    
+    if ((ret = name.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode topic name failed. ret=%d", ret);
+        return ret;
+    }
+    
+    if ((ret = metadatas.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode topic metadatas failed. ret=%d", ret);
+        return ret;
+    }
+    
+    return ret;
+}
+
 SrsKafkaTopicMetadataResponse::SrsKafkaTopicMetadataResponse()
 {
 }
@@ -611,8 +805,7 @@ SrsKafkaTopicMetadataResponse::~SrsKafkaTopicMetadataResponse()
 
 int SrsKafkaTopicMetadataResponse::size()
 {
-    // TODO: FIXME: implements it.
-    return SrsKafkaResponse::size();
+    return SrsKafkaResponse::size() + brokers.size() + metadatas.size();
 }
 
 int SrsKafkaTopicMetadataResponse::encode(SrsBuffer* buf)
@@ -624,7 +817,16 @@ int SrsKafkaTopicMetadataResponse::encode(SrsBuffer* buf)
         return ret;
     }
     
-    // TODO: FIXME: implements it.
+    if ((ret = brokers.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode metadata brokers failed. ret=%d", ret);
+        return ret;
+    }
+    
+    if ((ret = metadatas.encode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka encode metadatas failed. ret=%d", ret);
+        return ret;
+    }
+    
     return ret;
 }
 
@@ -637,7 +839,16 @@ int SrsKafkaTopicMetadataResponse::decode(SrsBuffer* buf)
         return ret;
     }
     
-    // TODO: FIXME: implements it.
+    if ((ret = brokers.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode metadata brokers failed. ret=%d", ret);
+        return ret;
+    }
+    
+    if ((ret = metadatas.decode(buf)) != ERROR_SUCCESS) {
+        srs_error("kafka decode metadatas failed. ret=%d", ret);
+        return ret;
+    }
+    
     return ret;
 }
 

@@ -190,7 +190,7 @@ public:
             srs_error("kafka decode array failed. ret=%d", ret);
             return ret;
         }
-        length = buf->read_2bytes();
+        length = buf->read_4bytes();
         
         for (int i = 0; i < length; i++) {
             T* elem = new T();
@@ -206,6 +206,78 @@ public:
         return ret;
     }
 };
+template<>
+class SrsKafkaArray<int32_t> : public ISrsCodec
+{
+private:
+    int32_t length;
+    std::vector<int32_t> elems;
+    typedef std::vector<int32_t>::iterator SrsIterator;
+public:
+    SrsKafkaArray()
+    {
+        length = 0;
+    }
+    virtual ~SrsKafkaArray()
+    {
+        elems.clear();
+    }
+public:
+    virtual void append(int32_t elem)
+    {
+        length++;
+        elems.push_back(elem);
+    }
+    // interface ISrsCodec
+public:
+    virtual int size()
+    {
+        return 4 + sizeof(int32_t) * (int)elems.size();
+    }
+    virtual int encode(SrsBuffer* buf)
+    {
+        int ret = ERROR_SUCCESS;
+        
+        if (!buf->require(4 + sizeof(int32_t) * (int)elems.size())) {
+            ret = ERROR_KAFKA_CODEC_ARRAY;
+            srs_error("kafka encode array failed. ret=%d", ret);
+            return ret;
+        }
+        buf->write_4bytes(length);
+        
+        for (SrsIterator it = elems.begin(); it != elems.end(); ++it) {
+            int32_t elem = *it;
+            buf->write_4bytes(elem);
+        }
+        
+        return ret;
+    }
+    virtual int decode(SrsBuffer* buf)
+    {
+        int ret = ERROR_SUCCESS;
+        
+        if (!buf->require(4)) {
+            ret = ERROR_KAFKA_CODEC_ARRAY;
+            srs_error("kafka decode array failed. ret=%d", ret);
+            return ret;
+        }
+        length = buf->read_4bytes();
+        
+        for (int i = 0; i < length; i++) {
+            if (!buf->require(sizeof(int32_t))) {
+                ret = ERROR_KAFKA_CODEC_ARRAY;
+                srs_error("kafka decode array elem failed. ret=%d", ret);
+                return ret;
+                
+            }
+            
+            int32_t elem = buf->read_4bytes();
+            elems.push_back(elem);
+        }
+        
+        return ret;
+    }
+};
 
 /**
  * the header of request, includes the size of request.
@@ -533,6 +605,58 @@ public:
 };
 
 /**
+ * the metadata response data.
+ * @see https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-MetadataResponse
+ */
+struct SrsKafkaBroker : public ISrsCodec
+{
+public:
+    int32_t node_id;
+    SrsKafkaString host;
+    int32_t port;
+public:
+    SrsKafkaBroker();
+    virtual ~SrsKafkaBroker();
+// interface ISrsCodec
+public:
+    virtual int size();
+    virtual int encode(SrsBuffer* buf);
+    virtual int decode(SrsBuffer* buf);
+};
+struct SrsKafkaPartitionMetadata : public ISrsCodec
+{
+public:
+    int16_t error_code;
+    int32_t partition_id;
+    int32_t leader;
+    SrsKafkaArray<int32_t> replicas;
+    SrsKafkaArray<int32_t> isr;
+public:
+    SrsKafkaPartitionMetadata();
+    virtual ~SrsKafkaPartitionMetadata();
+// interface ISrsCodec
+public:
+    virtual int size();
+    virtual int encode(SrsBuffer* buf);
+    virtual int decode(SrsBuffer* buf);
+};
+struct SrsKafkaTopicMetadata : public ISrsCodec
+{
+public:
+    int16_t error_code;
+    SrsKafkaString name;
+    SrsKafkaArray<SrsKafkaPartitionMetadata> metadatas;
+public:
+    SrsKafkaTopicMetadata();
+    virtual ~SrsKafkaTopicMetadata();
+// interface ISrsCodec
+public:
+    virtual int size();
+    virtual int encode(SrsBuffer* buf);
+    virtual int decode(SrsBuffer* buf);
+};
+
+/**
  * response for the metadata request from broker.
  * The response contains metadata for each partition, 
  * with partitions grouped together by topic. This 
@@ -542,6 +666,9 @@ public:
  */
 class SrsKafkaTopicMetadataResponse : public SrsKafkaResponse
 {
+private:
+    SrsKafkaArray<SrsKafkaBroker> brokers;
+    SrsKafkaArray<SrsKafkaTopicMetadata> metadatas;
 public:
     SrsKafkaTopicMetadataResponse();
     virtual ~SrsKafkaTopicMetadataResponse();