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// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MOJO_CORE_BROKER_H_
#define MOJO_CORE_BROKER_H_
#include "base/memory/writable_shared_memory_region.h"
#include "base/synchronization/lock.h"
#include "mojo/public/cpp/platform/platform_channel_endpoint.h"
#include "mojo/public/cpp/platform/platform_handle.h"
namespace mojo {
namespace core {
// The Broker is a channel to the broker process, which allows synchronous IPCs
// to fulfill shared memory allocation requests on some platforms.
class Broker {
public:
// Note: If |wait_for_channel_handle| is |true|, this constructor blocks the
// calling thread until it reads first message from |handle|, which must
// contain another PlatformHandle for a NodeChannel.
//
// Otherwise, no initialization message is expected and this will not wait for
// one.
Broker(PlatformHandle handle, bool wait_for_channel_handle);
Broker(const Broker&) = delete;
Broker& operator=(const Broker&) = delete;
~Broker();
// Returns the platform handle that should be used to establish a NodeChannel
// to the process which is inviting us to join its network. This is the first
// handle read off the Broker channel upon construction.
PlatformChannelEndpoint GetInviterEndpoint();
// Request a shared buffer from the broker process. Blocks the current thread.
base::WritableSharedMemoryRegion GetWritableSharedMemoryRegion(
size_t num_bytes);
private:
// Handle to the broker process, used for synchronous IPCs.
PlatformHandle sync_channel_;
// Channel endpoint connected to the inviter process. Received in the
// first message over |sync_channel_|.
PlatformChannelEndpoint inviter_endpoint_;
// Lock to only allow one sync message at a time. This avoids having to deal
// with message ordering since we can only have one request at a time
// in-flight.
base::Lock lock_;
};
} // namespace core
} // namespace mojo
#endif // MOJO_CORE_BROKER_H_
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