Moved common parts of ChildProcessHost into chrome/common and created a BrowserChildProcessHost with browser-specific implementation. This is in preparation of creating a ServiceChildProcessHost.

BUG=None
TEST=Test for regressions .

Review URL: http://codereview.chromium.org/2885017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@51593 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 111 insertions, 0 deletions

diff --git a/chrome/common/child_process_host.h b/chrome/common/child_process_host.h
new file mode 100644
index 0000000..980ad7d
--- /dev/null
+++ b/chrome/common/child_process_host.h
@@ -0,0 +1,111 @@
+// Copyright (c) 2010 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 CHROME_COMMON_CHILD_PROCESS_HOST_H_
+#define CHROME_COMMON_CHILD_PROCESS_HOST_H_
+
+#include <list>
+#include <string>
+
+// Must be included early (e.g. before chrome/common/plugin_messages.h)
+#include "ipc/ipc_logging.h"
+
+#include "base/basictypes.h"
+#include "base/file_path.h"
+#include "base/scoped_ptr.h"
+#include "chrome/common/notification_type.h"
+#include "ipc/ipc_channel.h"
+
+class CommandLine;
+
+// 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:
+  virtual ~ChildProcessHost();
+
+  // Returns the pathname to be used for a child process.  If a subprocess
+  // pathname was specified on the command line, that will be used.  Otherwise,
+  // the default child process pathname will be returned.  On most platforms,
+  // this will be the same as the currently-executing process.
+  //
+  // The argument allow_self is used on Linux to indicate that we allow us to
+  // fork from /proc/self/exe rather than using the "real" app path. This
+  // prevents autoupdate from confusing us if it changes the file out from
+  // under us. You will generally want to set this to true, except when there
+  // is an override to the command line (for example, we're forking a renderer
+  // in gdb). In this case, you'd use GetChildPath to get the real executable
+  // file name, and then prepend the GDB command to the command line.
+  //
+  // On failure, returns an empty FilePath.
+  static FilePath GetChildPath(bool allow_self);
+
+ protected:
+  ChildProcessHost();
+
+  // A helper method to send an IPC message to the child on the channel.
+  // It behavies just like IPC::Message::Sender::Send. The implementor takes
+  // ownership of the given Message regardless of whether or not this method
+  // succeeds. This class does not implement IPC::Message::Sender to prevent
+  // conflicts with subclasses which indirectly could inherit from
+  // IPC::Message::Sender.
+  bool SendOnChannel(IPC::Message* msg);
+
+  // Derived classes return true if it's ok to shut down the child process.
+  virtual bool CanShutdown() = 0;
+
+  // Send the shutdown message to the child process.
+  // Does not check if CanShutdown is true.
+  virtual void ForceShutdown();
+
+  // Creates the IPC channel.  Returns true iff it succeeded.
+  virtual bool CreateChannel();
+
+  // Notifies us that an instance has been created on this child process.
+  virtual void InstanceCreated();
+
+  // IPC::Channel::Listener implementation:
+  virtual void OnMessageReceived(const IPC::Message& msg) { }
+  virtual void OnChannelConnected(int32 peer_pid) { }
+  virtual void OnChannelError() { }
+
+  bool opening_channel() { return opening_channel_; }
+  const std::string& channel_id() { return channel_id_; }
+  IPC::Channel* channel() { return channel_.get(); }
+
+  // Called when the child process goes away.
+  virtual void OnChildDied();
+  // Allows the derived implementation to intercept a message before it is
+  // handed to the IPC::Channel::Listener::OnMessageReceived implementation.
+  virtual bool InterceptMessageFromChild(const IPC::Message& msg) {
+    return false;
+  }
+  // Subclasses can implement specific notification methods.
+  virtual void Notify(NotificationType type) { }
+
+ private:
+  // By using an internal class as the IPC::Channel::Listener, we can intercept
+  // OnMessageReceived/OnChannelConnected and do our own processing before
+  // calling the subclass' implementation.
+  class ListenerHook : public IPC::Channel::Listener {
+   public:
+    explicit ListenerHook(ChildProcessHost* host);
+    virtual void OnMessageReceived(const IPC::Message& msg);
+    virtual void OnChannelConnected(int32 peer_pid);
+    virtual void OnChannelError();
+   private:
+    ChildProcessHost* host_;
+  };
+
+  ListenerHook listener_;
+
+  bool opening_channel_;  // True while we're waiting the channel to be opened.
+  scoped_ptr<IPC::Channel> channel_;
+  std::string channel_id_;
+};
+
+#endif  // CHROME_COMMON_CHILD_PROCESS_HOST_H_
+