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      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_UNIX_TASK_RUNNER_H_
     18 #define INCLUDE_PERFETTO_BASE_UNIX_TASK_RUNNER_H_
     19 
     20 #include "perfetto/base/scoped_file.h"
     21 #include "perfetto/base/task_runner.h"
     22 #include "perfetto/base/thread_checker.h"
     23 #include "perfetto/base/time.h"
     24 
     25 #include <poll.h>
     26 #include <chrono>
     27 #include <deque>
     28 #include <map>
     29 #include <mutex>
     30 #include <vector>
     31 
     32 namespace perfetto {
     33 namespace base {
     34 
     35 // Runs a task runner on the current thread.
     36 class UnixTaskRunner : public TaskRunner {
     37  public:
     38   UnixTaskRunner();
     39   ~UnixTaskRunner() override;
     40 
     41   // Start executing tasks. Doesn't return until Quit() is called. Run() may be
     42   // called multiple times on the same task runner.
     43   void Run();
     44   void Quit();
     45 
     46   // Checks whether there are any pending immediate tasks to run. Note that
     47   // delayed tasks don't count even if they are due to run.
     48   bool IsIdleForTesting();
     49 
     50   // TaskRunner implementation:
     51   void PostTask(std::function<void()>) override;
     52   void PostDelayedTask(std::function<void()>, uint32_t delay_ms) override;
     53   void AddFileDescriptorWatch(int fd, std::function<void()>) override;
     54   void RemoveFileDescriptorWatch(int fd) override;
     55 
     56  private:
     57   void WakeUp();
     58 
     59   void UpdateWatchTasksLocked();
     60 
     61   int GetDelayMsToNextTaskLocked() const;
     62   void RunImmediateAndDelayedTask();
     63   void PostFileDescriptorWatches();
     64   void RunFileDescriptorWatch(int fd);
     65 
     66   ThreadChecker thread_checker_;
     67 
     68   ScopedFile control_read_;
     69   ScopedFile control_write_;
     70 
     71   std::vector<struct pollfd> poll_fds_;
     72 
     73   // --- Begin lock-protected members ---
     74 
     75   std::mutex lock_;
     76 
     77   std::deque<std::function<void()>> immediate_tasks_;
     78   std::multimap<TimeMillis, std::function<void()>> delayed_tasks_;
     79   bool quit_ = false;
     80 
     81   struct WatchTask {
     82     std::function<void()> callback;
     83     size_t poll_fd_index;  // Index into |poll_fds_|.
     84   };
     85 
     86   std::map<int, WatchTask> watch_tasks_;
     87   bool watch_tasks_changed_ = false;
     88 
     89   // --- End lock-protected members ---
     90 };
     91 
     92 }  // namespace base
     93 }  // namespace perfetto
     94 
     95 #endif  // INCLUDE_PERFETTO_BASE_UNIX_TASK_RUNNER_H_
     96