third_party/WebKit/Source/core/dom/PendingScript.h

/*
 * 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef PendingScript_h
#define PendingScript_h

#include "bindings/core/v8/ScriptStreamer.h"
#include "core/CoreExport.h"
#include "core/dom/ScriptElementBase.h"
#include "core/loader/resource/ScriptResource.h"
#include "platform/MemoryCoordinator.h"
#include "platform/heap/Handle.h"
#include "platform/loader/fetch/ResourceOwner.h"
#include "wtf/Noncopyable.h"
#include "wtf/text/TextPosition.h"

namespace blink {

class PendingScript;
class ScriptSourceCode;

class CORE_EXPORT PendingScriptClient : public GarbageCollectedMixin {
 public:
  virtual ~PendingScriptClient() {}

  // Invoked when the pending script has finished loading. This could be during
  // |watchForLoad| (if the pending script was already ready), or when the
  // resource loads (if script streaming is not occurring), or when script
  // streaming finishes.
  virtual void pendingScriptFinished(PendingScript*) = 0;

  DEFINE_INLINE_VIRTUAL_TRACE() {}
};

// A container for an external script which may be loaded and executed.
//
// TODO(kochi): The comment below is from pre-oilpan age and may not be correct
// now.
// A RefPtr alone does not prevent the underlying Resource from purging its data
// buffer. This class holds a dummy client open for its lifetime in order to
// guarantee that the data buffer will not be purged.
class CORE_EXPORT PendingScript final
    : public GarbageCollectedFinalized<PendingScript>,
      public ResourceOwner<ScriptResource>,
      public MemoryCoordinatorClient {
  USING_GARBAGE_COLLECTED_MIXIN(PendingScript);
  USING_PRE_FINALIZER(PendingScript, dispose);
  WTF_MAKE_NONCOPYABLE(PendingScript);

 public:
  // For script from an external file.
  static PendingScript* create(ScriptElementBase*, ScriptResource*);
  // For inline script.
  static PendingScript* create(ScriptElementBase*, const TextPosition&);

  static PendingScript* createForTesting(ScriptResource*);

  ~PendingScript() override;

  TextPosition startingPosition() const { return m_startingPosition; }
  void markParserBlockingLoadStartTime();
  // Returns the time the load of this script started blocking the parser, or
  // zero if this script hasn't yet blocked the parser, in
  // monotonicallyIncreasingTime.
  double parserBlockingLoadStartTime() const {
    return m_parserBlockingLoadStartTime;
  }

  void watchForLoad(PendingScriptClient*);
  void stopWatchingForLoad();

  ScriptElementBase* element() const;

  DECLARE_TRACE();

  ScriptSourceCode getSource(const KURL& documentURL,
                             bool& errorOccurred) const;

  void setStreamer(ScriptStreamer*);
  void streamingFinished();

  bool isReady() const;
  bool errorOccurred() const;

  void startStreamingIfPossible(Document*, ScriptStreamer::Type);
  void dispose();

 private:
  PendingScript(ScriptElementBase*,
                ScriptResource*,
                const TextPosition&,
                bool isForTesting = false);
  PendingScript() = delete;

  void checkState() const;

  // ScriptResourceClient
  void notifyFinished(Resource*) override;
  String debugName() const override { return "PendingScript"; }
  void notifyAppendData(ScriptResource*) override;

  // MemoryCoordinatorClient
  void onPurgeMemory() override;

  bool m_watchingForLoad;

  // |m_element| must points to the corresponding ScriptLoader's
  // ScriptElementBase and thus must be non-null before dispose() is called
  // (except for unit tests).
  Member<ScriptElementBase> m_element;

  TextPosition m_startingPosition;  // Only used for inline script tags.
  bool m_integrityFailure;
  double m_parserBlockingLoadStartTime;

  Member<ScriptStreamer> m_streamer;
  Member<PendingScriptClient> m_client;

  // This flag is used to skip non-null checks of |m_element| in unit
  // tests, because |m_element| can be null in unit tests.
  const bool m_isForTesting;
};

}  // namespace blink

#endif  // PendingScript_h