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