stream-buffer: always pass null buffer for buffer initialization.

Author: Christian Hergert

src/mongoc/mongoc-buffer.c

@@ -54,19 +54,22 @@ _mongoc_buffer_init (mongoc_buffer_t   *buffer,
                      size_t             buflen,
                      bson_realloc_func  realloc_func)
 {
-   bson_return_if_fail(buffer);
-   bson_return_if_fail(buf || !buflen);
+   bson_return_if_fail (buffer);
+   bson_return_if_fail (buflen || !buf);
 
    if (!realloc_func) {
       realloc_func = bson_realloc_ctx;
    }
 
-   if (!buf || !buflen) {
-      buf = realloc_func (NULL, MONGOC_BUFFER_DEFAULT_SIZE, NULL);
+   if (!buflen) {
       buflen = MONGOC_BUFFER_DEFAULT_SIZE;
    }
 
-   memset(buffer, 0, sizeof *buffer);
+   if (!buf) {
+      buf = realloc_func (NULL, buflen, NULL);
+   }
+
+   memset (buffer, 0, sizeof *buffer);
 
    buffer->data = buf;
    buffer->datalen = buflen;

src/mongoc/mongoc-stream-buffered.c

@@ -322,7 +322,6 @@ mongoc_stream_buffered_new (mongoc_stream_t *base_stream, /* IN */
                             size_t           buffer_size) /* IN */
 {
    mongoc_stream_buffered_t *stream;
-   void *buffer;
 
    bson_return_val_if_fail(base_stream, NULL);
 
@@ -339,8 +338,7 @@ mongoc_stream_buffered_new (mongoc_stream_t *base_stream, /* IN */
 
    stream->base_stream = base_stream;
 
-   buffer = bson_malloc0(buffer_size);
-   _mongoc_buffer_init (&stream->buffer, buffer, buffer_size, bson_realloc_ctx);
+   _mongoc_buffer_init (&stream->buffer, NULL, buffer_size, bson_realloc_ctx);
 
    mongoc_counter_streams_active_inc();