third_party/WebKit/Source/core/loader/resource/FontResource.h

/*
 * Copyright (C) 2007, 2008 Apple 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 COMPUTER, 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 COMPUTER, 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef FontResource_h
#define FontResource_h

#include "base/gtest_prod_util.h"
#include "core/CoreExport.h"
#include "core/fetch/Resource.h"
#include "core/fetch/ResourceClient.h"
#include "platform/Timer.h"
#include "platform/fonts/FontOrientation.h"
#include "platform/heap/Handle.h"
#include <memory>

namespace blink {

class FetchRequest;
class ResourceFetcher;
class FontPlatformData;
class FontCustomPlatformData;
class FontResourceClient;
class FontVariationSettings;

class CORE_EXPORT FontResource final : public Resource {
 public:
  using ClientType = FontResourceClient;

  static FontResource* fetch(FetchRequest&, ResourceFetcher*);
  ~FontResource() override;

  void didAddClient(ResourceClient*) override;

  void setRevalidatingRequest(const ResourceRequest&) override;

  void allClientsAndObserversRemoved() override;
  void startLoadLimitTimers();

  void setCORSFailed() override { m_corsFailed = true; }
  bool isCORSFailed() const { return m_corsFailed; }
  String otsParsingMessage() const { return m_otsParsingMessage; }

  bool ensureCustomFontData();
  FontPlatformData platformDataFromCustomData(
      float size,
      bool bold,
      bool italic,
      FontOrientation = FontOrientation::Horizontal,
      FontVariationSettings* = nullptr);

  // Returns true if the loading priority of the remote font resource can be
  // lowered. The loading priority of the font can be lowered only if the
  // font is not needed for painting the text.
  bool isLowPriorityLoadingAllowedForRemoteFont() const;

  void willReloadAfterDiskCacheMiss() override;

  void onMemoryDump(WebMemoryDumpLevelOfDetail,
                    WebProcessMemoryDump*) const override;

 private:
  class FontResourceFactory : public ResourceFactory {
   public:
    FontResourceFactory() : ResourceFactory(Resource::Font) {}

    Resource* create(const ResourceRequest& request,
                     const ResourceLoaderOptions& options,
                     const String& charset) const override {
      return new FontResource(request, options);
    }
  };
  FontResource(const ResourceRequest&, const ResourceLoaderOptions&);

  void checkNotify() override;
  void fontLoadShortLimitCallback(TimerBase*);
  void fontLoadLongLimitCallback(TimerBase*);
  void notifyClientsShortLimitExceeded();
  void notifyClientsLongLimitExceeded();

  // This is used in UMA histograms, should not change order.
  enum LoadLimitState {
    LoadNotStarted,
    UnderLimit,
    ShortLimitExceeded,
    LongLimitExceeded,
    LoadLimitStateEnumMax
  };

  std::unique_ptr<FontCustomPlatformData> m_fontData;
  String m_otsParsingMessage;
  LoadLimitState m_loadLimitState;
  bool m_corsFailed;
  Timer<FontResource> m_fontLoadShortLimitTimer;
  Timer<FontResource> m_fontLoadLongLimitTimer;

  friend class MemoryCache;
  FRIEND_TEST_ALL_PREFIXES(FontResourceTest, CacheAwareFontLoading);
};

DEFINE_RESOURCE_TYPE_CASTS(Font);

class FontResourceClient : public ResourceClient {
 public:
  ~FontResourceClient() override {}
  static bool isExpectedType(ResourceClient* client) {
    return client->getResourceClientType() == FontType;
  }
  ResourceClientType getResourceClientType() const final { return FontType; }

  // If cache-aware loading is activated, both callbacks will be blocked until
  // disk cache miss. Calls to addClient() and removeClient() in both callbacks
  // are prohibited to prevent race issues regarding current loading state.
  virtual void fontLoadShortLimitExceeded(FontResource*) {}
  virtual void fontLoadLongLimitExceeded(FontResource*) {}

  // Returns true if loading priority of remote font resources can be lowered.
  virtual bool isLowPriorityLoadingAllowedForRemoteFont() const {
    // Only the RemoteFontFaceSources clients can prevent lowering of loading
    // priority of the remote fonts.  Set the default to true to prevent
    // other clients from incorrectly returning false.
    return true;
  }
};

}  // namespace blink

#endif