utils/LocThread.h

/* Copyright (c) 2015, 2020 The Linux Foundation. All rights reserved.
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#ifndef __LOC_THREAD__
#define __LOC_THREAD__

#include <stddef.h>
#include <memory>

using std::shared_ptr;

namespace loc_util {

// abstract class to be implemented by client to provide a runnable class
// which gets scheduled by LocThread
class LocRunnable {
public:
    inline LocRunnable() = default;
    inline virtual ~LocRunnable() = default;

    // The method to be implemented by thread clients
    // and be scheduled by LocThread
    // This method will be repeated called until it returns false; or
    // until thread is stopped.
    virtual bool run() = 0;

    // The method to be run before thread loop (conditionally repeatedly)
    // calls run()
    inline virtual void prerun() {}

    // The method to be run after thread loop (conditionally repeatedly)
    // calls run()
    inline virtual void postrun() {}

    // The method to wake up the potential blocking thread
    // no op if not applicable
    inline virtual void interrupt() = 0;
};

// opaque class to provide service implementation.
class LocThreadDelegate;

// A utility class to create a thread and run LocRunnable
// caller passes in.
class LocThread {
    LocThreadDelegate* mThread;
public:
    inline LocThread() : mThread(NULL) {}
    inline virtual ~LocThread() { stop(); }

    // client starts thread with a runnable, which implements
    // the logics to fun in the created thread context.
    // The thread is always detached.
    // runnable is an obj managed by client. Client creates and
    //          frees it (but must be after stop() is called, or
    //          this LocThread obj is deleted).
    //          The obj will be deleted by LocThread if start()
    //          returns true. Else it is client's responsibility
    //          to delete the object
    // Returns 0 if success; false if failure.
    bool start(const char* threadName, shared_ptr<LocRunnable> runnable);

    void stop();

    // thread status check
    inline bool isRunning() { return NULL != mThread; }
};

} // loc_util
#endif //__LOC_THREAD__