/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef INCLUDE_PERFETTO_EXT_TRACING_IPC_PRODUCER_IPC_CLIENT_H_
#define INCLUDE_PERFETTO_EXT_TRACING_IPC_PRODUCER_IPC_CLIENT_H_

#include <memory>
#include <string>

#include "perfetto/base/export.h"
#include "perfetto/ext/ipc/client.h"
#include "perfetto/ext/tracing/core/shared_memory.h"
#include "perfetto/ext/tracing/core/shared_memory_arbiter.h"
#include "perfetto/ext/tracing/core/tracing_service.h"

namespace perfetto {

class Producer;

// Allows to connect to a remote Service through a UNIX domain socket.
// Exposed to:
//   Producer(s) of the tracing library.
// Implemented in:
//   src/tracing/ipc/producer/producer_ipc_client_impl.cc
class PERFETTO_EXPORT_COMPONENT ProducerIPCClient {
 public:
  enum class ConnectionFlags {
    // Fails immediately with OnConnect(false) if the service connection cannot
    // be established.
    kDefault = 0,

    // Keeps retrying with exponential backoff indefinitely. The caller will
    // never see an OnConnect(false).
    kRetryIfUnreachable = 1,
  };

  // Connects to the producer port of the Service listening on the given
  // |service_sock_name|. If the connection is successful, the OnConnect()
  // method will be invoked asynchronously on the passed Producer interface. If
  // the connection fails, OnDisconnect() will be invoked instead. The returned
  // ProducerEndpoint serves also to delimit the scope of the callbacks invoked
  // on the Producer interface: no more Producer callbacks are invoked
  // immediately after its destruction and any pending callback will be dropped.
  // To provide a producer-allocated shared memory buffer, both |shm| and
  // |shm_arbiter| should be set. |shm_arbiter| should be an unbound
  // SharedMemoryArbiter instance. When |shm| and |shm_arbiter| are provided,
  // the service will attempt to adopt the provided SMB. If this fails, the
  // ProducerEndpoint will disconnect, but the SMB and arbiter will remain valid
  // until the client is destroyed.
  //
  // TODO(eseckler): Support adoption failure more gracefully.
  // TODO(primiano): move all the existing use cases to the Connect(ConnArgs)
  // below. Also move the functionality of ConnectionFlags into ConnArgs.
  static std::unique_ptr<TracingService::ProducerEndpoint> Connect(
      const char* service_sock_name,
      Producer*,
      const std::string& producer_name,
      base::TaskRunner*,
      TracingService::ProducerSMBScrapingMode smb_scraping_mode =
          TracingService::ProducerSMBScrapingMode::kDefault,
      size_t shared_memory_size_hint_bytes = 0,
      size_t shared_memory_page_size_hint_bytes = 0,
      std::unique_ptr<SharedMemory> shm = nullptr,
      std::unique_ptr<SharedMemoryArbiter> shm_arbiter = nullptr,
      ConnectionFlags = ConnectionFlags::kDefault);

  // Overload of Connect() to support adopting a connected socket using
  // ipc::Client::ConnArgs.
  static std::unique_ptr<TracingService::ProducerEndpoint> Connect(
      ipc::Client::ConnArgs,
      Producer*,
      const std::string& producer_name,
      base::TaskRunner*,
      TracingService::ProducerSMBScrapingMode smb_scraping_mode =
          TracingService::ProducerSMBScrapingMode::kDefault,
      size_t shared_memory_size_hint_bytes = 0,
      size_t shared_memory_page_size_hint_bytes = 0,
      std::unique_ptr<SharedMemory> shm = nullptr,
      std::unique_ptr<SharedMemoryArbiter> shm_arbiter = nullptr);

 protected:
  ProducerIPCClient() = delete;
};

}  // namespace perfetto

#endif  // INCLUDE_PERFETTO_EXT_TRACING_IPC_PRODUCER_IPC_CLIENT_H_