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// Copyright 2014 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 MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_
#define MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/process/launch.h"
#include "build/build_config.h"
#include "mojo/embedder/scoped_platform_handle.h"
#include "mojo/system/system_impl_export.h"
namespace base {
class CommandLine;
}
namespace mojo {
namespace embedder {
// It would be nice to refactor base/process/launch.h to have a more platform-
// independent way of representing handles that are passed to child processes.
#if defined(OS_WIN)
typedef base::HandlesToInheritVector HandlePassingInformation;
#elif defined(OS_POSIX)
typedef base::FileHandleMappingVector HandlePassingInformation;
#else
#error "Unsupported."
#endif
// This is used to create a pair of |PlatformHandle|s that are connected by a
// suitable (platform-specific) bidirectional "pipe" (e.g., socket on POSIX,
// named pipe on Windows). The resulting handles can then be used in the same
// process (e.g., in tests) or between processes. (The "server" handle is the
// one that will be used in the process that created the pair, whereas the
// "client" handle is the one that will be used in a different process.)
//
// This class provides facilities for passing the client handle to a child
// process. The parent should call |PrepareToPassClientHandlelToChildProcess()|
// to get the data needed to do this, spawn the child using that data, and then
// call |ChildProcessLaunched()|. Note that on Windows this facility (will) only
// work on Vista and later (TODO(vtl)).
//
// Note: |PlatformChannelPair()|, |PassClientHandleFromParentProcess()| and
// |PrepareToPassClientHandleToChildProcess()| have platform-specific
// implementations.
class MOJO_SYSTEM_IMPL_EXPORT PlatformChannelPair {
public:
PlatformChannelPair();
~PlatformChannelPair();
ScopedPlatformHandle PassServerHandle();
// For in-process use (e.g., in tests or to pass over another channel).
ScopedPlatformHandle PassClientHandle();
// To be called in the child process, after the parent process called
// |PrepareToPassClientHandleToChildProcess()| and launched the child (using
// the provided data), to create a client handle connected to the server
// handle (in the parent process).
static ScopedPlatformHandle PassClientHandleFromParentProcess(
const base::CommandLine& command_line);
// Prepares to pass the client channel to a new child process, to be launched
// using |LaunchProcess()| (from base/launch.h). Modifies |*command_line| and
// |*handle_passing_info| as needed.
// Note: For Windows, this method only works on Vista and later.
void PrepareToPassClientHandleToChildProcess(
base::CommandLine* command_line,
HandlePassingInformation* handle_passing_info) const;
// To be called once the child process has been successfully launched, to do
// any cleanup necessary.
void ChildProcessLaunched();
private:
static const char kMojoPlatformChannelHandleSwitch[];
ScopedPlatformHandle server_handle_;
ScopedPlatformHandle client_handle_;
DISALLOW_COPY_AND_ASSIGN(PlatformChannelPair);
};
} // namespace embedder
} // namespace mojo
#endif // MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_