Make ChildProcessHost be used through an interface in content/public, instead of by inheritence.

BUG=98716
Review URL: http://codereview.chromium.org/8787004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112878 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 93 insertions, 0 deletions

diff --git a/content/common/child_process_host_impl.h b/content/common/child_process_host_impl.h
new file mode 100644
index 0000000..32736f3
--- /dev/null
+++ b/content/common/child_process_host_impl.h
@@ -0,0 +1,93 @@
+// 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_IMPL_H_
+#define CONTENT_COMMON_CHILD_PROCESS_HOST_IMPL_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "build/build_config.h"
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "base/shared_memory.h"
+#include "base/string16.h"
+#include "content/public/common/child_process_host.h"
+
+class FilePath;
+
+namespace content {
+class ChildProcessHostDelegate;
+
+// Provides common functionality for hosting a child process and processing IPC
+// messages between the host and the child process. Users are responsible
+// for the actual launching and terminating of the child processes.
+class CONTENT_EXPORT ChildProcessHostImpl : public ChildProcessHost,
+                                            public IPC::Channel::Listener {
+ public:
+  virtual ~ChildProcessHostImpl();
+
+  // Public and static for reuse by RenderMessageFilter.
+  static void AllocateSharedMemory(
+      uint32 buffer_size, base::ProcessHandle child_process,
+      base::SharedMemoryHandle* handle);
+
+  // Generates a unique channel name for a child process.
+  // The "instance" pointer value is baked into the channel id.
+  static std::string GenerateRandomChannelID(void* instance);
+
+  // Returns a unique ID to identify a child process. On construction, this
+  // function will be used to generate the id_, but it is also used to generate
+  // IDs for the RenderProcessHost, which doesn't inherit from us, and whose IDs
+  // must be unique for all child processes.
+  //
+  // This function is threadsafe since RenderProcessHost is on the UI thread,
+  // but normally this will be used on the IO thread.
+  static int GenerateChildProcessUniqueId();
+
+  // ChildProcessHost implementation
+  virtual bool Send(IPC::Message* message) OVERRIDE;
+  virtual void ForceShutdown() OVERRIDE;
+  virtual std::string CreateChannel() OVERRIDE;
+  virtual bool IsChannelOpening() OVERRIDE;
+  virtual void AddFilter(IPC::ChannelProxy::MessageFilter* filter) OVERRIDE;
+#if defined(OS_POSIX)
+  virtual int TakeClientFileDescriptor() OVERRIDE;
+#endif
+
+ private:
+  friend class ChildProcessHost;
+
+  explicit ChildProcessHostImpl(ChildProcessHostDelegate* delegate);
+
+  // IPC::Channel::Listener methods:
+  virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
+  virtual void OnChannelConnected(int32 peer_pid) OVERRIDE;
+  virtual void OnChannelError() OVERRIDE;
+
+  // Message handlers:
+  void OnShutdownRequest();
+  void OnAllocateSharedMemory(uint32 buffer_size,
+                              base::SharedMemoryHandle* handle);
+
+  ChildProcessHostDelegate* delegate_;
+  base::ProcessHandle peer_handle_;
+  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(ChildProcessHostImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_CHILD_PROCESS_HOST_IMPL_H_