gecko-dev/gfx/2d/DrawEventRecorder.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_GFX_DRAWEVENTRECORDER_H_
#define MOZILLA_GFX_DRAWEVENTRECORDER_H_

#include "2D.h"
#include "RecordedEvent.h"
#include "RecordingTypes.h"
#include "mozilla/FStream.h"

#include <unordered_set>
#include <unordered_map>
#include <functional>

namespace mozilla {
namespace gfx {

class PathRecording;

class DrawEventRecorderPrivate : public DrawEventRecorder
{
public:
  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(DrawEventRecorderPrivate, override)

  DrawEventRecorderPrivate();
  virtual ~DrawEventRecorderPrivate() { }
  virtual void Finish() override { ClearResources(); }
  virtual void FlushItem(IntRect) { }
  void DetatchResources() {
    // The iteration is a bit awkward here because our iterator will
    // be invalidated by the removal
    for (auto font = mStoredFonts.begin(); font != mStoredFonts.end(); ) {
      auto oldFont = font++;
      (*oldFont)->RemoveUserData(reinterpret_cast<UserDataKey*>(this));
    }
    for (auto surface = mStoredSurfaces.begin(); surface != mStoredSurfaces.end(); ) {
      auto oldSurface = surface++;
      (*oldSurface)->RemoveUserData(reinterpret_cast<UserDataKey*>(this));
    }
    mStoredFonts.clear();
    mStoredSurfaces.clear();
  }

  void ClearResources() {
    mUnscaledFonts.clear();
    mStoredObjects.clear();
    mStoredFontData.clear();
    mUnscaledFontMap.clear();
  }

  template<class S>
  void WriteHeader(S& aStream) {
    WriteElement(aStream, kMagicInt);
    WriteElement(aStream, kMajorRevision);
    WriteElement(aStream, kMinorRevision);
  }

  virtual void RecordEvent(const RecordedEvent &aEvent) = 0;
  void WritePath(const PathRecording *aPath);

  void AddStoredObject(const ReferencePtr aObject) {
    mStoredObjects.insert(aObject);
  }

  void RemoveStoredObject(const ReferencePtr aObject) {
    mStoredObjects.erase(aObject);
  }

  void AddScaledFont(ScaledFont* aFont) {
    mStoredFonts.insert(aFont);
  }

  void RemoveScaledFont(ScaledFont* aFont) {
    mStoredFonts.erase(aFont);
  }

  void AddSourceSurface(SourceSurface* aSurface) {
    mStoredSurfaces.insert(aSurface);
  }

  void RemoveSourceSurface(SourceSurface* aSurface) {
    mStoredSurfaces.erase(aSurface);
  }

  bool HasStoredObject(const ReferencePtr aObject) {
    return mStoredObjects.find(aObject) != mStoredObjects.end();
  }

  void AddStoredFontData(const uint64_t aFontDataKey) {
    mStoredFontData.insert(aFontDataKey);
  }

  bool HasStoredFontData(const uint64_t aFontDataKey) {
    return mStoredFontData.find(aFontDataKey) != mStoredFontData.end();
  }

  // Returns the index of the UnscaledFont
  size_t GetUnscaledFontIndex(UnscaledFont *aFont) {
    auto i = mUnscaledFontMap.find(aFont);
    size_t index;
    if (i == mUnscaledFontMap.end()) {
      mUnscaledFonts.push_back(aFont);
      index = mUnscaledFonts.size() - 1;
      mUnscaledFontMap.insert({{aFont, index}});
    } else {
      index = i->second;
    }
    return index;
  }

  bool WantsExternalFonts() { return mExternalFonts; }

protected:
  virtual void Flush() = 0;

  std::unordered_set<const void*> mStoredObjects;
  std::unordered_set<uint64_t> mStoredFontData;
  std::unordered_set<ScaledFont*> mStoredFonts;
  std::unordered_set<SourceSurface*> mStoredSurfaces;
  std::vector<RefPtr<UnscaledFont>> mUnscaledFonts;
  std::unordered_map<UnscaledFont*, size_t> mUnscaledFontMap;
  bool mExternalFonts;
};

class DrawEventRecorderFile : public DrawEventRecorderPrivate
{
  using char_type = filesystem::Path::value_type;
public:
  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(DrawEventRecorderFile, override)
  explicit DrawEventRecorderFile(const char_type* aFilename);
  ~DrawEventRecorderFile();

  void RecordEvent(const RecordedEvent &aEvent) override;

  /**
   * Returns whether a recording file is currently open.
   */
  bool IsOpen();

  /**
   * Opens new file with the provided name. The recorder does NOT forget which
   * objects it has recorded. This can be used with Close, so that a recording
   * can be processed in chunks. The file must not already be open.
   */
  void OpenNew(const char_type* aFilename);

  /**
   * Closes the file so that it can be processed. The recorder does NOT forget
   * which objects it has recorded. This can be used with OpenNew, so that a
   * recording can be processed in chunks. The file must be open.
   */
  void Close();

private:
  void Flush() override;

  mozilla::OFStream mOutputStream;
};

typedef std::function<void(MemStream &aStream, std::vector<RefPtr<UnscaledFont>> &aUnscaledFonts)> SerializeResourcesFn;

// WARNING: This should not be used in its existing state because
// it is likely to OOM because of large continguous allocations.
class DrawEventRecorderMemory final : public DrawEventRecorderPrivate
{
public:
  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(DrawEventRecorderMemory, override)

  /**
   * Constructs a DrawEventRecorder that stores the recording in memory.
   */
  DrawEventRecorderMemory();
  explicit DrawEventRecorderMemory(const SerializeResourcesFn &aSerialize);

  void RecordEvent(const RecordedEvent &aEvent) override;

  /**
   * @return the current size of the recording (in chars).
   */
  size_t RecordingSize();

  /**
   * Wipes the internal recording buffer, but the recorder does NOT forget which
   * objects it has recorded. This can be used so that a recording can be copied
   * and processed in chunks, releasing memory as it goes.
   */
  void WipeRecording();
  void Finish() override;
  void FlushItem(IntRect) override;

  MemStream mOutputStream;
  /* The index stream is of the form:
   * ItemIndex { size_t dataEnd; size_t extraDataEnd; }
   * It gets concatenated to the end of mOutputStream in Finish()
   * The last size_t in the stream is offset of the begining of the
   * index.
   */
  MemStream mIndex;
private:
  SerializeResourcesFn mSerializeCallback;
  ~DrawEventRecorderMemory() {};

  void Flush() override;
};

} // namespace gfx
} // namespace mozilla

#endif /* MOZILLA_GFX_DRAWEVENTRECORDER_H_ */