New implementation of font precache on Windows.

content/common/child_process_host.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_COMMON_CHILD_PROCESS_HOST_H_
 #define CONTENT_COMMON_CHILD_PROCESS_HOST_H_
 #pragma once
 
 #include <string>
 #include <vector>
+#include <map>
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif  // defined(OS_WIN)
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_notification_types.h"
 #include "ipc/ipc_channel_proxy.h"
 
 class CommandLine;
 class FilePath;
 
 namespace IPC {
 class Message;
 }
 
+#if defined(OS_WIN)
+// Types used in PreCacheFont

[rvargas (doing something else), 2011/09/13 23:40:30]

Comments should end with period.

These are fairly specific, so should not be global.

[arthurhsu, 2011/09/14 02:06:56]

Done.

+typedef std::vector<std::wstring> FontNameVector;
+typedef std::map<int, FontNameVector> PidToFontNames;
+#endif  // defined(OS_WIN)
+
 // Provides common functionality for hosting a child process and processing IPC
 // messages between the host and the child process. Subclasses are responsible
 // for the actual launching and terminating of the child processes.
 class ChildProcessHost : public IPC::Channel::Listener,
                          public IPC::Message::Sender {
  public:
 
   // These flags may be passed to GetChildPath in order to alter its behavior,
   // causing it to return a child path more suited to a specific task.
   enum {
@@ skipping 39 matching lines @@
   // The |flags| argument accepts one or more flags such as CHILD_ALLOW_SELF
   // and CHILD_ALLOW_HEAP_EXECUTION as defined above. Pass only CHILD_NORMAL
   // if none of these special behaviors are required.
   //
   // On failure, returns an empty FilePath.
   static FilePath GetChildPath(int flags);
 
 #if defined(OS_WIN)
   // See comments in the cc file. This is a common hack needed for a process
   // hosting a sandboxed child process. Hence it lives in this file.
-  static void PreCacheFont(LOGFONT font);
+  static void PreCacheFont(LOGFONT font, int pid);
+  static void ReleaseCachedFont(int pid);

[rvargas (doing something else), 2011/09/13 23:40:30]

This doesn't release a font... releases all fonts for the given PID so font
should be plural... if we keep this method :)

[arthurhsu, 2011/09/14 02:06:56]

Done.

 #endif  // defined(OS_WIN)
 
   // IPC::Message::Sender implementation.
   virtual bool Send(IPC::Message* message);
 
   // Adds an IPC message filter.  A reference will be kept to the filter.
   void AddFilter(IPC::ChannelProxy::MessageFilter* filter);
 
  protected:
   ChildProcessHost();
@@ skipping 41 matching lines @@
     virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
     virtual void OnChannelConnected(int32 peer_pid) OVERRIDE;
     virtual void OnChannelError() OVERRIDE;
    private:
     ChildProcessHost* host_;
     DISALLOW_COPY_AND_ASSIGN(ListenerHook);
   };
 
   ListenerHook listener_;
 
+#if defined (OS_WIN)
+  class FontCache {
+   public:
+    FontCache() {}  // Make Singleton<> happy.

[rvargas (doing something else), 2011/09/13 23:40:30]

friend struct DefaultSingletonTraits<FontCache>;

Constructors and destructors should not be inlined.

[arthurhsu, 2011/09/14 02:06:56]

Done.

+    ~FontCache() {}
+
+    static FontCache* GetInstance();
+    void PreCacheFont(LOGFONT font, int pid);
+    void ReleaseCachedFont(int pid);
+
+   private:
+    struct CacheElement {
+      CacheElement();
+      ~CacheElement();
+
+      HFONT font_;
+      HDC dc_;
+      int ref_count_;
+    };
+    std::map<std::wstring, CacheElement> cache_;
+    PidToFontNames pid_font_map_;
+    base::Lock mutex_;
+
+    DISALLOW_COPY_AND_ASSIGN(FontCache);
+  };
+#endif
+
   bool opening_channel_;  // True while we're waiting the channel to be opened.
   scoped_ptr<IPC::Channel> channel_;
   std::string channel_id_;
 
   // Holds all the IPC message filters.  Since this object lives on the IO
   // thread, we don't have a IPC::ChannelProxy and so we manage filters
   // manually.
   std::vector<scoped_refptr<IPC::ChannelProxy::MessageFilter> > filters_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildProcessHost);
 };
 
 #endif  // CONTENT_COMMON_CHILD_PROCESS_HOST_H_