shaka-packager/packager/app/job_manager.h

131 lines
4.2 KiB
C++

// Copyright 2017 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#ifndef PACKAGER_APP_JOB_MANAGER_H_
#define PACKAGER_APP_JOB_MANAGER_H_
#include <functional>
#include <map>
#include <memory>
#include <thread>
#include <vector>
#include <absl/synchronization/mutex.h>
#include <packager/status.h>
namespace shaka {
namespace media {
class OriginHandler;
class SyncPointQueue;
// A job is a single line of work that is expected to run in parallel with
// other jobs.
class Job {
public:
typedef std::function<void(Job*)> OnCompleteFunction;
Job(const std::string& name,
std::shared_ptr<OriginHandler> work,
OnCompleteFunction on_complete);
// Initialize the work object. Call before Start() or Run(). Updates status()
// and returns it for convenience.
const Status& Initialize();
// Begin the job in a new thread. This is only a request and will not block.
// If you want to wait for the job to complete, use |complete|.
// Use either Start() for threaded operation or Run() for non-threaded
// operation. DO NOT USE BOTH!
void Start();
// Run the job's work synchronously, blocking until complete. Updates status()
// and returns it for convenience.
// Use either Start() for threaded operation or Run() for non-threaded
// operation. DO NOT USE BOTH!
const Status& Run();
// Request that the job stops executing. This is only a request and will not
// block. If you want to wait for the job to complete, use |complete|.
void Cancel();
// Join the thread, if any was started. Blocks until the thread has stopped.
void Join();
// Get the current status of the job. If the job failed to initialize or
// encountered an error during execution this will return the error.
const Status& status() const { return status_; }
// The name given to this job in the constructor.
const std::string& name() const { return name_; }
private:
Job(const Job&) = delete;
Job& operator=(const Job&) = delete;
std::string name_;
std::shared_ptr<OriginHandler> work_;
OnCompleteFunction on_complete_;
std::unique_ptr<std::thread> thread_;
Status status_;
};
// Similar to a thread pool, JobManager manages multiple jobs that are expected
// to run in parallel. It can be used to register, run, and stop a batch of
// jobs.
class JobManager {
public:
// @param sync_points is an optional SyncPointQueue used to synchronize and
// align cue points. JobManager cancels @a sync_points when any job
// fails or is cancelled. It can be NULL.
explicit JobManager(std::unique_ptr<SyncPointQueue> sync_points);
virtual ~JobManager() = default;
// Create a new job entry by specifying the origin handler at the top of the
// chain and a name for the thread. This will only register the job. To start
// the job, you need to call |RunJobs|.
void Add(const std::string& name, std::shared_ptr<OriginHandler> handler);
// Initialize all registered jobs. If any job fails to initialize, this will
// return the error and it will not be safe to call |RunJobs| as not all jobs
// will be properly initialized.
Status InitializeJobs();
// Run all registered jobs. Before calling this make sure that
// |InitializedJobs| returned |Status::OK|. This call is blocking and will
// block until all jobs exit.
virtual Status RunJobs();
// Ask all jobs to stop running. This call is non-blocking and can be used to
// unblock a call to |RunJobs|.
void CancelJobs();
SyncPointQueue* sync_points() { return sync_points_.get(); }
protected:
JobManager(const JobManager&) = delete;
JobManager& operator=(const JobManager&) = delete;
void OnJobComplete(Job* job);
// Stored in JobManager so JobManager can cancel |sync_points| when any job
// fails or is cancelled.
std::unique_ptr<SyncPointQueue> sync_points_;
std::vector<std::unique_ptr<Job>> jobs_;
absl::Mutex mutex_;
std::map<Job*, bool> complete_ ABSL_GUARDED_BY(mutex_);
absl::CondVar any_job_complete_ ABSL_GUARDED_BY(mutex_);
};
} // namespace media
} // namespace shaka
#endif // PACKAGER_APP_JOB_MANAGER_H_