reduce 3 times memcpy of message to 1 time only.

src/php/ext/grpc/byte_buffer.c

@@ -31,6 +31,8 @@ grpc_byte_buffer *string_to_byte_buffer(char *string, size_t length) {
   return buffer;
 }
 
+#if PHP_MAJOR_VERSION < 7
+
 void byte_buffer_to_string(grpc_byte_buffer *buffer, char **out_string,
                            size_t *out_length) {
   grpc_byte_buffer_reader reader;
@@ -50,3 +52,31 @@ void byte_buffer_to_string(grpc_byte_buffer *buffer, char **out_string,
   *out_string = string;
   *out_length = length;
 }
+
+#else
+
+zend_string* byte_buffer_to_zend_string(grpc_byte_buffer *buffer) {
+  grpc_byte_buffer_reader reader;
+  if (buffer == NULL || !grpc_byte_buffer_reader_init(&reader, buffer)) {
+    /* TODO(dgq): distinguish between the error cases. */
+    return NULL;
+  }
+
+  const size_t length = grpc_byte_buffer_length(reader.buffer_out);
+  zend_string* zstr = zend_string_alloc(length, 0);
+
+  char* buf = ZSTR_VAL(zstr);
+  grpc_slice next;
+  while (grpc_byte_buffer_reader_next(&reader, &next) != 0) {
+    const size_t next_len = GRPC_SLICE_LENGTH(next);
+    memcpy(buf, GRPC_SLICE_START_PTR(next), next_len);
+    buf += next_len;
+    grpc_slice_unref(next);
+  }
+
+  *buf = '\0';
+  
+  return zstr;
+}
+
+#endif // PHP_MAJOR_VERSION < 7

src/php/ext/grpc/byte_buffer.h

@@ -23,7 +23,11 @@
 
 grpc_byte_buffer *string_to_byte_buffer(char *string, size_t length);
 
+#if PHP_MAJOR_VERSION < 7
 void byte_buffer_to_string(grpc_byte_buffer *buffer, char **out_string,
                            size_t *out_length);
+#else
+zend_string* byte_buffer_to_zend_string(grpc_byte_buffer *buffer);
+#endif // PHP_MAJOR_VERSION < 7
 
 #endif /* NET_GRPC_PHP_GRPC_BYTE_BUFFER_H_ */

src/php/ext/grpc/call.c

@@ -294,8 +294,13 @@ PHP_METHOD(Call, startBatch) {
   grpc_byte_buffer *message;
   int cancelled;
   grpc_call_error error;
+
+  #if PHP_MAJOR_VERSION < 7
   char *message_str;
   size_t message_len;
+  #else
+  zend_string* zmessage = NULL;
+  #endif // PHP_MAJOR_VERSION < 7
 
   grpc_metadata_array_init(&metadata);
   grpc_metadata_array_init(&trailing_metadata);
@@ -483,12 +488,28 @@ PHP_METHOD(Call, startBatch) {
       PHP_GRPC_DELREF(array);
       break;
     case GRPC_OP_RECV_MESSAGE:
+#if PHP_MAJOR_VERSION < 7
       byte_buffer_to_string(message, &message_str, &message_len);
+#else
+      zmessage = byte_buffer_to_zend_string(message);
+#endif // PHP_MAJOR_VERSION < 7
+
+#if PHP_MAJOR_VERSION < 7
       if (message_str == NULL) {
+#else
+      if (zmessage == NULL) {
+#endif // PHP_MAJOR_VERSION < 7
         add_property_null(result, "message");
       } else {
+#if PHP_MAJOR_VERSION < 7
         php_grpc_add_property_stringl(result, "message", message_str,
                                       message_len, false);
+#else
+        zval zmessage_val;
+        ZVAL_NEW_STR(&zmessage_val, zmessage);
+        add_property_zval(result, "message", &zmessage_val);
+        zval_ptr_dtor(&zmessage_val);
+#endif // PHP_MAJOR_VERSION < 7
       }
       break;
     case GRPC_OP_RECV_STATUS_ON_CLIENT:
@@ -537,7 +558,9 @@ cleanup:
     }
     if (ops[i].op == GRPC_OP_RECV_MESSAGE) {
       grpc_byte_buffer_destroy(message);
+      #if PHP_MAJOR_VERSION < 7
       PHP_GRPC_FREE_STD_ZVAL(message_str);
+      #endif // PHP_MAJOR_VERSION < 7
     }
   }
   RETURN_DESTROY_ZVAL(result);