Make FileReader.abort() (synchronously) follow the spec.

third_party/WebKit/Source/core/fileapi/FileReader.cpp

 /*
  * Copyright (C) 2010 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 304 matching lines @@
   ASSERT(m_loadingState == LoadingStatePending);
   m_loadingState = LoadingStateLoading;
 
   m_loader = FileReaderLoader::create(m_readType, this);
   m_loader->setEncoding(m_encoding);
   m_loader->setDataType(m_blobType);
   m_loader->start(getExecutionContext(), m_blobDataHandle);
   m_blobDataHandle = nullptr;
 }
 
-static void delayedAbort(FileReader* reader) {
-  reader->doAbort();
-}
-
 void FileReader::abort() {
   DVLOG(1) << "aborting";
 
   if (m_loadingState != LoadingStateLoading &&
       m_loadingState != LoadingStatePending) {
     return;
   }
   m_loadingState = LoadingStateAborted;
 
-  // Schedule to have the abort done later since abort() might be called from
-  // the event handler and we do not want the resource loading code to be in the
-  // stack.
-  getExecutionContext()->postTask(
-      BLINK_FROM_HERE,
-      createSameThreadTask(&delayedAbort, wrapPersistent(this)));
-}
+  DCHECK_NE(kDone, m_state);
+  m_state = kDone;
 
-void FileReader::doAbort() {
-  DCHECK_NE(kDone, m_state);
   AutoReset<bool> firingEvents(&m_stillFiringEvents, true);
 
-  terminate();
-
+  // Setting error implicitly makes |result| return null.
   m_error = FileError::createDOMException(FileError::kAbortErr);
 
   // Unregister the reader.
   ThrottlingController::FinishReaderType finalStep =
       ThrottlingController::removeReader(getExecutionContext(), this);
 
   fireEvent(EventTypeNames::error);
   fireEvent(EventTypeNames::abort);
   fireEvent(EventTypeNames::loadend);
 
   // All possible events have fired and we're done, no more pending activity.
   ThrottlingController::finishReader(getExecutionContext(), this, finalStep);
+
+  // ..but perform the loader cancellation asynchronously as abort() could be
+  // called from the event handler and we do not want the resource loading code
+  // to be on the stack when doing so. The persistent reference keeps the
+  // reader alive until the task has completed.
+  getExecutionContext()->postTask(
+      BLINK_FROM_HERE,
+      createSameThreadTask(&FileReader::terminate, wrapPersistent(this)));
 }
 
 void FileReader::result(StringOrArrayBuffer& resultAttribute) const {
-  if (!m_loader || m_error)
+  if (m_error || !m_loader)
     return;
 
   if (m_readType == FileReaderLoader::ReadAsArrayBuffer)
     resultAttribute.setArrayBuffer(m_loader->arrayBufferResult());
   else
     resultAttribute.setString(m_loader->stringResult());
 }
 
 void FileReader::terminate() {
   if (m_loader) {
@@ skipping 60 matching lines @@
     return;
 
   AutoReset<bool> firingEvents(&m_stillFiringEvents, true);
 
   DCHECK_EQ(LoadingStateLoading, m_loadingState);
   m_loadingState = LoadingStateNone;
 
   DCHECK_NE(kDone, m_state);
   m_state = kDone;
 
-  m_error = FileError::createDOMException(
-      static_cast<FileError::ErrorCode>(errorCode));
+  m_error = FileError::createDOMException(errorCode);
 
   // Unregister the reader.
   ThrottlingController::FinishReaderType finalStep =
       ThrottlingController::removeReader(getExecutionContext(), this);
 
   fireEvent(EventTypeNames::error);
   fireEvent(EventTypeNames::loadend);
 
   // All possible events have fired and we're done, no more pending activity.
   ThrottlingController::finishReader(getExecutionContext(), this, finalStep);
@@ skipping 14 matching lines @@
         ProgressEvent::create(type, false, m_loader->bytesLoaded(), 0));
 }
 
 DEFINE_TRACE(FileReader) {
   visitor->trace(m_error);
   EventTargetWithInlineData::trace(visitor);
   ActiveDOMObject::trace(visitor);
 }
 
 }  // namespace blink