src: add method to compute storage in WriteWrap

addaleax · MylesBorins · commit 8ffb24bcf9d4 · 2017-12-07T16:34:58.000-05:00
`WriteWrap` instances may contain extra storage space. `self_size()` returns the size of the *entire* struct, member fields as well as storage space, so it is not an accurate measure for the storage space available. Add a method `ExtraSize()` (like the existing `Extra()` for accessing the storage memory) that yields the wanted value, and use it in the HTTP2 impl to fix a crash. PR-URL: #16727 Refs: #16669 Reviewed-By: Anatoli Papirovski <apapirovski@mac.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/src/node_http2_core-inl.h b/src/node_http2_core-inl.h
@@ -501,7 +501,7 @@ inline void Nghttp2Session::SendPendingData() {
   while ((srcLength = nghttp2_session_mem_send(session_, &src)) > 0) {
     if (req == nullptr) {
       req = AllocateSend();
-      destRemaining = req->self_size();
+      destRemaining = req->ExtraSize();
       dest = req->Extra();
     }
     DEBUG_HTTP2("Nghttp2Session %s: nghttp2 has %d bytes to send\n",
@@ -523,7 +523,7 @@ inline void Nghttp2Session::SendPendingData() {
       srcRemaining -= destRemaining;
       srcOffset += destRemaining;
       req = AllocateSend();
-      destRemaining = req->self_size();
+      destRemaining = req->ExtraSize();
       dest = req->Extra();
     }
 
diff --git a/src/stream_base-inl.h b/src/stream_base-inl.h
@@ -167,6 +167,10 @@ char* WriteWrap::Extra(size_t offset) {
          offset;
 }
 
+size_t WriteWrap::ExtraSize() const {
+  return storage_size_ - ROUND_UP(sizeof(*this), kAlignSize);
+}
+
 }  // namespace node
 
 #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
diff --git a/src/stream_base.h b/src/stream_base.h
@@ -77,6 +77,7 @@ class WriteWrap: public ReqWrap<uv_write_t>,
                                size_t extra = 0);
   inline void Dispose();
   inline char* Extra(size_t offset = 0);
+  inline size_t ExtraSize() const;
 
   inline StreamBase* wrap() const { return wrap_; }
 

Original file line number	Diff line number	Diff line change
`@@ -167,6 +167,10 @@ char* WriteWrap::Extra(size_t offset) {`
`167`	`167`	`offset;`
`168`	`168`	`}`
`169`	`169`
	`170`	`+size_t WriteWrap::ExtraSize() const {`
	`171`	`+ return storage_size_ - ROUND_UP(sizeof(*this), kAlignSize);`
	`172`	`+}`
	`173`	`+`
`170`	`174`	`} // namespace node`
`171`	`175`
`172`	`176`	`#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS`