108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
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#ifndef ANDROID_PDX_SERVICE_DISPATCHER_H_
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#define ANDROID_PDX_SERVICE_DISPATCHER_H_
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#include <memory>
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#include <mutex>
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#include <unordered_map>
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#include <vector>
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#include <pdx/file_handle.h>
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namespace android {
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namespace pdx {
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class Service;
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/*
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* ServiceDispatcher manages a list of Service instances and handles message
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* reception and dispatch to the services. This makes repetitive dispatch tasks
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* easier to implement.
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*/
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class ServiceDispatcher {
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public:
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// Get a new instance of ServiceDispatcher, or return nullptr if init failed.
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static std::unique_ptr<ServiceDispatcher> Create();
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~ServiceDispatcher();
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/*
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* Adds a service to the list of services handled by this dispatcher. This
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* will fail if any threads are blocked waiting for messages in this
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* dispatcher.
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*
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* Returns 0 on success; -EEXIST if the service was already added.
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*/
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int AddService(const std::shared_ptr<Service>& service);
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/*
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* Removes a service from this dispatcher. This will fail if any threads are
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* blocked waiting for messages in this dispatcher.
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*
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* Returns 0 on success; -ENOENT if the service was not previously added;
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* -EBUSY if there are threads in the dispatcher.
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*/
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int RemoveService(const std::shared_ptr<Service>& service);
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/*
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* Receive and dispatch one set of messages. Multiple threads may enter this
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* method to create an implicit thread pool, as described for
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* enterDispatchLoop() below, however this method exits after one dispatch
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* cycle, requiring an external loop. This is useful when other work needs
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* to be done in the service dispatch loop.
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*/
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int ReceiveAndDispatch();
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/*
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* Same as above with timeout in milliseconds. A negative value means
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* infinite timeout, while a value of 0 means return immediately if no
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* messages are available to receive.
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*/
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int ReceiveAndDispatch(int timeout);
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/*
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* Receive and dispatch messages until canceled. When more than one thread
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* enters this method it creates an implicit thread pool to dispatch messages.
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* Explicit thread pools may be created by using a single dispatch thread that
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* hands Message instances (via move assignment) over to a queue of threads
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* (or perhaps one of several) to handle.
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*/
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int EnterDispatchLoop();
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/*
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* Sets the canceled state of the dispatcher. When canceled is true, any
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* threads blocked waiting for messages will return. This method waits until
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* all dispatch threads have exited the dispatcher.
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*/
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void SetCanceled(bool cancel);
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/*
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* Gets the canceled state of the dispatcher.
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*/
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bool IsCanceled() const;
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private:
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ServiceDispatcher();
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// Internal thread accounting.
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int ThreadEnter();
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void ThreadExit();
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std::mutex mutex_;
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std::condition_variable condition_;
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std::atomic<bool> canceled_{false};
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std::vector<std::shared_ptr<Service>> services_;
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int thread_count_ = 0;
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LocalHandle event_fd_;
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LocalHandle epoll_fd_;
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ServiceDispatcher(const ServiceDispatcher&) = delete;
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void operator=(const ServiceDispatcher&) = delete;
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};
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} // namespace pdx
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} // namespace android
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#endif // ANDROID_PDX_SERVICE_DISPATCHER_H_
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