1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef INCLUDE_PERFETTO_BASE_TASK_RUNNER_H_ 18 #define INCLUDE_PERFETTO_BASE_TASK_RUNNER_H_ 19 20 #include <functional> 21 22 #include "perfetto/base/build_config.h" 23 #include "perfetto/base/utils.h" 24 #include "perfetto/base/watchdog.h" 25 26 namespace perfetto { 27 namespace base { 28 29 // Maximum time a single task can take in a TaskRunner before the 30 // program suicides. 31 constexpr int64_t kWatchdogMillis = 30000; // 30s 32 33 // A generic interface to allow the library clients to interleave the execution 34 // of the tracing internals in their runtime environment. 35 // The expectation is that all tasks, which are queued either via PostTask() or 36 // AddFileDescriptorWatch(), are executed on the same sequence (either on the 37 // same thread, or on a thread pool that gives sequencing guarantees). 38 // 39 // Tasks are never executed synchronously inside PostTask and there is a full 40 // memory barrier between tasks. 41 // 42 // All methods of this interface can be called from any thread. 43 class TaskRunner { 44 public: 45 virtual ~TaskRunner(); 46 47 // Schedule a task for immediate execution. Immediate tasks are always 48 // executed in the order they are posted. Can be called from any thread. 49 virtual void PostTask(std::function<void()>) = 0; 50 51 // Schedule a task for execution after |delay_ms|. Note that there is no 52 // strict ordering guarantee between immediate and delayed tasks. Can be 53 // called from any thread. 54 virtual void PostDelayedTask(std::function<void()>, uint32_t delay_ms) = 0; 55 56 // Schedule a task to run when |fd| becomes readable. The same |fd| can only 57 // be monitored by one function. Note that this function only needs to be 58 // implemented on platforms where the built-in ipc framework is used. Can be 59 // called from any thread. 60 // TODO(skyostil): Refactor this out of the shared interface. 61 virtual void AddFileDescriptorWatch(int fd, std::function<void()>) = 0; 62 63 // Remove a previously scheduled watch for |fd|. If this is run on the target 64 // thread of this TaskRunner, guarantees that the task registered to this fd 65 // will not be executed after this function call. Can be called from any 66 // thread. 67 virtual void RemoveFileDescriptorWatch(int fd) = 0; 68 69 protected: 70 static void RunTask(const std::function<void()>& task) { 71 Watchdog::Timer handle = 72 base::Watchdog::GetInstance()->CreateFatalTimer(kWatchdogMillis); 73 task(); 74 } 75 }; 76 77 } // namespace base 78 } // namespace perfetto 79 80 #endif // INCLUDE_PERFETTO_BASE_TASK_RUNNER_H_ 81
