components/font_service/public/cpp/font_service_thread.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_FONT_SERVICE_PUBLIC_CPP_FONT_SERVICE_THREAD_H_
   6 #define COMPONENTS_FONT_SERVICE_PUBLIC_CPP_FONT_SERVICE_THREAD_H_
   7
   8 #include "base/files/file.h"
   9 #include "base/threading/thread.h"
  10 #include "components/font_service/public/interfaces/font_service.mojom.h"
  11 #include "third_party/skia/include/core/SkStream.h"
  12 #include "third_party/skia/include/core/SkTypeface.h"
  13 #include "third_party/skia/include/ports/SkFontConfigInterface.h"
  14
  15 namespace font_service {
  16 namespace internal {
  17
  18 class MappedFontFile;
  19
  20 // The thread which services font requests.
  21 //
  22 // The SkFontConfigInterface is a global singleton which can be accessed from
  23 // multiple threads. However, mojo pipes are bound to a single thread. Because
  24 // of this mismatch, we create a thread which owns the mojo pipe, sends and
  25 // receives messages. The multiple threads which call through FontLoader class
  26 // do blocking message calls to this thread.
  27 class FontServiceThread : public base::Thread,
  28                           public base::RefCountedThreadSafe<FontServiceThread> {
  29  public:
  30   explicit FontServiceThread(FontServicePtr font_service);
  31
  32   // These methods are proxies which run on your thread, post a blocking task
  33   // to the FontServiceThread, and wait on an event signaled from the callback.
  34   bool MatchFamilyName(const char family_name[],
  35                        SkTypeface::Style requested_style,
  36                        SkFontConfigInterface::FontIdentity* out_font_identity,
  37                        SkString* out_family_name,
  38                        SkTypeface::Style* out_style);
  39   scoped_refptr<MappedFontFile> OpenStream(
  40       const SkFontConfigInterface::FontIdentity& identity);
  41
  42  private:
  43   friend class base::RefCountedThreadSafe<FontServiceThread>;
  44   ~FontServiceThread() override;
  45
  46   // Methods which run on the FontServiceThread. The public MatchFamilyName
  47   // calls this method, this method calls the mojo interface, and sets up the
  48   // callback to OnMatchFamilyNameComplete.
  49   void MatchFamilyNameImpl(
  50       base::WaitableEvent* done_event,
  51       const char family_name[],
  52       SkTypeface::Style requested_style,
  53       bool* out_valid,
  54       SkFontConfigInterface::FontIdentity* out_font_identity,
  55       SkString* out_family_name,
  56       SkTypeface::Style* out_style);
  57
  58   // Called on the FontServiceThread in response to receiving a message from
  59   // our MatchFamily mojo IPC. This writes the data returned by mojo, and then
  60   // signals |done_event| to wake up the other thread.
  61   void OnMatchFamilyNameComplete(
  62       base::WaitableEvent* done_event,
  63       bool* out_valid,
  64       SkFontConfigInterface::FontIdentity* out_font_identity,
  65       SkString* out_family_name,
  66       SkTypeface::Style* out_style,
  67       FontIdentityPtr font_identity,
  68       mojo::String family_name,
  69       TypefaceStyle style);
  70
  71   // Implementation of OpenStream; same threading restrictions as MatchFamily.
  72   void OpenStreamImpl(base::WaitableEvent* done_event,
  73                       base::File* output_file,
  74                       const uint32_t id_number);
  75   void OnOpenStreamComplete(base::WaitableEvent* done_event,
  76                             base::File* output_file,
  77                             mojo::ScopedHandle handle);
  78
  79   // base::Thread
  80   void Init() override;
  81   void CleanUp() override;
  82
  83   // This member is used to safely pass data from one thread to another. It is
  84   // set in the constructor and is consumed in Init().
  85   mojo::InterfacePtrInfo<FontService> font_service_info_;
  86
  87   // This member is set in Init(). It takes |font_service_info_|, which is
  88   // non-thread bound, and binds it to the newly created thread.
  89   mojo::InterfacePtr<FontService> font_service_;
  90
  91   DISALLOW_COPY_AND_ASSIGN(FontServiceThread);
  92 };
  93
  94 }  // namespace internal
  95 }  // namespace font_service
  96
  97 #endif  // COMPONENTS_FONT_SERVICE_PUBLIC_CPP_FONT_SERVICE_THREAD_H_