latest SDK

foobar2000/SDK/abort_callback.h

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+#ifndef _foobar2000_sdk_abort_callback_h_
+#define _foobar2000_sdk_abort_callback_h_
+
+namespace foobar2000_io {
+
+PFC_DECLARE_EXCEPTION(exception_aborted,pfc::exception,"User abort");
+
+typedef pfc::eventHandle_t abort_callback_event;
+
+#ifdef check
+#undef check
+#endif
+//! This class is used to signal underlying worker code whether user has decided to abort a potentially time-consuming operation. \n
+//! It is commonly required by all filesystem related or decoding-related operations. \n
+//! Code that receives an abort_callback object should periodically check it and abort any operations being performed if it is signaled, typically throwing exception_aborted. \n
+//! See abort_callback_impl for an implementation.
+class NOVTABLE abort_callback
+{
+public:
+	//! Returns whether user has requested the operation to be aborted.
+	virtual bool is_aborting() const = 0;
+
+	inline bool is_set() const {return is_aborting();}
+
+	//! Retrieves event object that can be used with some OS calls. The even object becomes signaled when abort is triggered. On win32, this is equivalent to win32 event handle (see: CreateEvent). \n
+	//! You must not close this handle or call any methods that change this handle's state (SetEvent() or ResetEvent()), you can only wait for it.
+	virtual abort_callback_event get_abort_event() const = 0;
+
+	inline abort_callback_event get_handle() const {return get_abort_event();}
+	
+	//! Checks if user has requested the operation to be aborted, and throws exception_aborted if so.
+	void check() const;
+
+	//! For compatibility with old code. Do not call.
+	inline void check_e() const {check();}
+
+	
+	//! Sleeps p_timeout_seconds or less when aborted, throws exception_aborted on abort.
+	void sleep(double p_timeout_seconds) const;
+	//! Sleeps p_timeout_seconds or less when aborted, returns true when execution should continue, false when not.
+	bool sleep_ex(double p_timeout_seconds) const;
+    
+	//! Waits for an event. Returns true if event is now signaled, false if the specified period has elapsed and the event did not become signaled. \n
+	//! Throws exception_aborted if aborted.
+	bool waitForEvent( pfc::eventHandle_t evtHandle, double timeOut );
+	//! Waits for an event. Returns true if event is now signaled, false if the specified period has elapsed and the event did not become signaled. \n
+	//! Throws exception_aborted if aborted.
+	bool waitForEvent(pfc::event& evt, double timeOut);
+
+	//! Waits for an event. Returns once the event became signaled; throw exception_aborted if abort occurred first.
+	void waitForEvent(pfc::eventHandle_t evtHandle);
+	//! Waits for an event. Returns once the event became signaled; throw exception_aborted if abort occurred first.
+	void waitForEvent(pfc::event& evt);
+protected:
+	abort_callback() {}
+	~abort_callback() {}
+};
+
+
+
+//! Implementation of abort_callback interface.
+class abort_callback_impl : public abort_callback {
+public:
+	abort_callback_impl() : m_aborting(false) {}
+	inline void abort() {set_state(true);}
+	inline void set() {set_state(true);}
+	inline void reset() {set_state(false);}
+
+	void set_state(bool p_state) {m_aborting = p_state; m_event.set_state(p_state);}
+
+	bool is_aborting() const {return m_aborting;}
+
+	abort_callback_event get_abort_event() const {return m_event.get_handle();}
+
+private:
+	abort_callback_impl(const abort_callback_impl &) = delete;
+	const abort_callback_impl & operator=(const abort_callback_impl&) = delete;
+	
+	volatile bool m_aborting;
+	pfc::event m_event;
+};
+
+#ifdef _WIN32
+//! Dummy abort_callback that never gets aborted. \n
+//! Slightly more efficient than the regular one especially when you need to regularly create temporary instances of it.
+class abort_callback_dummy : public abort_callback {
+public:
+	bool is_aborting() const { return false; }
+
+	abort_callback_event get_abort_event() const { return GetInfiniteWaitEvent();}
+};
+#else
+
+// FIX ME come up with a scheme to produce a persistent infinite wait filedescriptor on non Windows
+// Could use /dev/null but still need to open it on upon object creation which defeats the purpose
+typedef abort_callback_impl abort_callback_dummy;
+
+#endif
+
+}
+typedef foobar2000_io::abort_callback_event fb2k_event_handle;
+typedef foobar2000_io::abort_callback fb2k_event;
+typedef foobar2000_io::abort_callback_impl fb2k_event_impl;
+
+using namespace foobar2000_io;
+
+#define FB2K_PFCv2_ABORTER_SCOPE( abortObj ) \
+    (abortObj).check(); \
+    PP::waitableReadRef_t aborterRef = {(abortObj).get_abort_event()}; \
+    PP::aborter aborter_pfcv2( aborterRef );    \
+    PP::aborterScope l_aborterScope( aborter_pfcv2 );
+
+
+namespace fb2k {
+	// A shared abort_callback_dummy instance
+	extern abort_callback_dummy noAbort;
+}
+
+#endif //_foobar2000_sdk_abort_callback_h_