1 // Copyright 2016 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MOJO_CORE_BROKER_H_ 6 #define MOJO_CORE_BROKER_H_ 7 8 #include "base/macros.h" 9 #include "base/memory/ref_counted.h" 10 #include "base/memory/writable_shared_memory_region.h" 11 #include "base/synchronization/lock.h" 12 #include "mojo/public/cpp/platform/platform_channel_endpoint.h" 13 #include "mojo/public/cpp/platform/platform_handle.h" 14 15 namespace mojo { 16 namespace core { 17 18 // The Broker is a channel to the broker process, which allows synchronous IPCs 19 // to fulfill shared memory allocation requests on some platforms. 20 class Broker { 21 public: 22 // Note: This is blocking, and will wait for the first message over 23 // the endpoint handle in |handle|. 24 explicit Broker(PlatformHandle handle); 25 ~Broker(); 26 27 // Returns the platform handle that should be used to establish a NodeChannel 28 // to the process which is inviting us to join its network. This is the first 29 // handle read off the Broker channel upon construction. 30 PlatformChannelEndpoint GetInviterEndpoint(); 31 32 // Request a shared buffer from the broker process. Blocks the current thread. 33 base::WritableSharedMemoryRegion GetWritableSharedMemoryRegion( 34 size_t num_bytes); 35 36 private: 37 // Handle to the broker process, used for synchronous IPCs. 38 PlatformHandle sync_channel_; 39 40 // Channel endpoint connected to the inviter process. Recieved in the first 41 // first message over |sync_channel_|. 42 PlatformChannelEndpoint inviter_endpoint_; 43 44 // Lock to only allow one sync message at a time. This avoids having to deal 45 // with message ordering since we can only have one request at a time 46 // in-flight. 47 base::Lock lock_; 48 49 DISALLOW_COPY_AND_ASSIGN(Broker); 50 }; 51 52 } // namespace core 53 } // namespace mojo 54 55 #endif // MOJO_CORE_BROKER_H_ 56