{- | Copyright : Will Thompson, Iñaki García Etxebarria and Jonas Platte License : LGPL-2.1 Maintainer : Iñaki García Etxebarria (garetxe@gmail.com) GCancellable is a thread-safe operation cancellation stack used throughout GIO to allow for cancellation of synchronous and asynchronous operations. -} #define ENABLE_OVERLOADING (MIN_VERSION_haskell_gi_overloading(1,0,0) \ && !defined(__HADDOCK_VERSION__)) module GI.Gio.Objects.Cancellable ( -- * Exported types Cancellable(..) , IsCancellable , toCancellable , noCancellable , -- * Methods -- ** cancel #method:cancel# #if ENABLE_OVERLOADING CancellableCancelMethodInfo , #endif cancellableCancel , -- ** connect #method:connect# #if ENABLE_OVERLOADING CancellableConnectMethodInfo , #endif cancellableConnect , -- ** disconnect #method:disconnect# #if ENABLE_OVERLOADING CancellableDisconnectMethodInfo , #endif cancellableDisconnect , -- ** getCurrent #method:getCurrent# cancellableGetCurrent , -- ** getFd #method:getFd# #if ENABLE_OVERLOADING CancellableGetFdMethodInfo , #endif cancellableGetFd , -- ** isCancelled #method:isCancelled# #if ENABLE_OVERLOADING CancellableIsCancelledMethodInfo , #endif cancellableIsCancelled , -- ** makePollfd #method:makePollfd# #if ENABLE_OVERLOADING CancellableMakePollfdMethodInfo , #endif cancellableMakePollfd , -- ** new #method:new# cancellableNew , -- ** popCurrent #method:popCurrent# #if ENABLE_OVERLOADING CancellablePopCurrentMethodInfo , #endif cancellablePopCurrent , -- ** pushCurrent #method:pushCurrent# #if ENABLE_OVERLOADING CancellablePushCurrentMethodInfo , #endif cancellablePushCurrent , -- ** releaseFd #method:releaseFd# #if ENABLE_OVERLOADING CancellableReleaseFdMethodInfo , #endif cancellableReleaseFd , -- ** reset #method:reset# #if ENABLE_OVERLOADING CancellableResetMethodInfo , #endif cancellableReset , -- ** setErrorIfCancelled #method:setErrorIfCancelled# #if ENABLE_OVERLOADING CancellableSetErrorIfCancelledMethodInfo, #endif cancellableSetErrorIfCancelled , -- * Signals -- ** cancelled #signal:cancelled# C_CancellableCancelledCallback , CancellableCancelledCallback , #if ENABLE_OVERLOADING CancellableCancelledSignalInfo , #endif afterCancellableCancelled , genClosure_CancellableCancelled , mk_CancellableCancelledCallback , noCancellableCancelledCallback , onCancellableCancelled , wrap_CancellableCancelledCallback , ) where import Data.GI.Base.ShortPrelude import qualified Data.GI.Base.ShortPrelude as SP import qualified Data.GI.Base.Overloading as O import qualified Prelude as P import qualified Data.GI.Base.Attributes as GI.Attributes import qualified Data.GI.Base.ManagedPtr as B.ManagedPtr import qualified Data.GI.Base.GError as B.GError import qualified Data.GI.Base.GVariant as B.GVariant import qualified Data.GI.Base.GValue as B.GValue import qualified Data.GI.Base.GParamSpec as B.GParamSpec import qualified Data.GI.Base.CallStack as B.CallStack import qualified Data.Text as T import qualified Data.ByteString.Char8 as B import qualified Data.Map as Map import qualified Foreign.Ptr as FP import qualified GI.GLib.Callbacks as GLib.Callbacks import qualified GI.GLib.Structs.PollFD as GLib.PollFD import qualified GI.GObject.Callbacks as GObject.Callbacks import qualified GI.GObject.Objects.Object as GObject.Object -- | Memory-managed wrapper type. newtype Cancellable = Cancellable (ManagedPtr Cancellable) foreign import ccall "g_cancellable_get_type" c_g_cancellable_get_type :: IO GType instance GObject Cancellable where gobjectType _ = c_g_cancellable_get_type -- | Type class for types which can be safely cast to `Cancellable`, for instance with `toCancellable`. class GObject o => IsCancellable o #if MIN_VERSION_base(4,9,0) instance {-# OVERLAPPABLE #-} (GObject a, O.UnknownAncestorError Cancellable a) => IsCancellable a #endif instance IsCancellable Cancellable instance GObject.Object.IsObject Cancellable -- | Cast to `Cancellable`, for types for which this is known to be safe. For general casts, use `Data.GI.Base.ManagedPtr.castTo`. toCancellable :: (MonadIO m, IsCancellable o) => o -> m Cancellable toCancellable = liftIO . unsafeCastTo Cancellable -- | A convenience alias for `Nothing` :: `Maybe` `Cancellable`. noCancellable :: Maybe Cancellable noCancellable = Nothing #if ENABLE_OVERLOADING type family ResolveCancellableMethod (t :: Symbol) (o :: *) :: * where ResolveCancellableMethod "bindProperty" o = GObject.Object.ObjectBindPropertyMethodInfo ResolveCancellableMethod "bindPropertyFull" o = GObject.Object.ObjectBindPropertyFullMethodInfo ResolveCancellableMethod "cancel" o = CancellableCancelMethodInfo ResolveCancellableMethod "connect" o = CancellableConnectMethodInfo ResolveCancellableMethod "disconnect" o = CancellableDisconnectMethodInfo ResolveCancellableMethod "forceFloating" o = GObject.Object.ObjectForceFloatingMethodInfo ResolveCancellableMethod "freezeNotify" o = GObject.Object.ObjectFreezeNotifyMethodInfo ResolveCancellableMethod "getv" o = GObject.Object.ObjectGetvMethodInfo ResolveCancellableMethod "isCancelled" o = CancellableIsCancelledMethodInfo ResolveCancellableMethod "isFloating" o = GObject.Object.ObjectIsFloatingMethodInfo ResolveCancellableMethod "makePollfd" o = CancellableMakePollfdMethodInfo ResolveCancellableMethod "notify" o = GObject.Object.ObjectNotifyMethodInfo ResolveCancellableMethod "notifyByPspec" o = GObject.Object.ObjectNotifyByPspecMethodInfo ResolveCancellableMethod "popCurrent" o = CancellablePopCurrentMethodInfo ResolveCancellableMethod "pushCurrent" o = CancellablePushCurrentMethodInfo ResolveCancellableMethod "ref" o = GObject.Object.ObjectRefMethodInfo ResolveCancellableMethod "refSink" o = GObject.Object.ObjectRefSinkMethodInfo ResolveCancellableMethod "releaseFd" o = CancellableReleaseFdMethodInfo ResolveCancellableMethod "reset" o = CancellableResetMethodInfo ResolveCancellableMethod "runDispose" o = GObject.Object.ObjectRunDisposeMethodInfo ResolveCancellableMethod "stealData" o = GObject.Object.ObjectStealDataMethodInfo ResolveCancellableMethod "stealQdata" o = GObject.Object.ObjectStealQdataMethodInfo ResolveCancellableMethod "thawNotify" o = GObject.Object.ObjectThawNotifyMethodInfo ResolveCancellableMethod "unref" o = GObject.Object.ObjectUnrefMethodInfo ResolveCancellableMethod "watchClosure" o = GObject.Object.ObjectWatchClosureMethodInfo ResolveCancellableMethod "getData" o = GObject.Object.ObjectGetDataMethodInfo ResolveCancellableMethod "getFd" o = CancellableGetFdMethodInfo ResolveCancellableMethod "getProperty" o = GObject.Object.ObjectGetPropertyMethodInfo ResolveCancellableMethod "getQdata" o = GObject.Object.ObjectGetQdataMethodInfo ResolveCancellableMethod "setData" o = GObject.Object.ObjectSetDataMethodInfo ResolveCancellableMethod "setErrorIfCancelled" o = CancellableSetErrorIfCancelledMethodInfo ResolveCancellableMethod "setProperty" o = GObject.Object.ObjectSetPropertyMethodInfo ResolveCancellableMethod l o = O.MethodResolutionFailed l o instance (info ~ ResolveCancellableMethod t Cancellable, O.MethodInfo info Cancellable p) => O.IsLabelProxy t (Cancellable -> p) where fromLabelProxy _ = O.overloadedMethod (O.MethodProxy :: O.MethodProxy info) #if MIN_VERSION_base(4,9,0) instance (info ~ ResolveCancellableMethod t Cancellable, O.MethodInfo info Cancellable p) => O.IsLabel t (Cancellable -> p) where #if MIN_VERSION_base(4,10,0) fromLabel = O.overloadedMethod (O.MethodProxy :: O.MethodProxy info) #else fromLabel _ = O.overloadedMethod (O.MethodProxy :: O.MethodProxy info) #endif #endif #endif -- signal Cancellable::cancelled {- | Emitted when the operation has been cancelled. Can be used by implementations of cancellable operations. If the operation is cancelled from another thread, the signal will be emitted in the thread that cancelled the operation, not the thread that is running the operation. Note that disconnecting from this signal (or any signal) in a multi-threaded program is prone to race conditions. For instance it is possible that a signal handler may be invoked even after a call to 'GI.GObject.Functions.signalHandlerDisconnect' for that handler has already returned. There is also a problem when cancellation happens right before connecting to the signal. If this happens the signal will unexpectedly not be emitted, and checking before connecting to the signal leaves a race condition where this is still happening. In order to make it safe and easy to connect handlers there are two helper functions: 'GI.Gio.Objects.Cancellable.cancellableConnect' and 'GI.Gio.Objects.Cancellable.cancellableDisconnect' which protect against problems like this. An example of how to us this: === /C code/ > > // Make sure we don't do unnecessary work if already cancelled > if (g_cancellable_set_error_if_cancelled (cancellable, error)) > return; > > // Set up all the data needed to be able to handle cancellation > // of the operation > my_data = my_data_new (...); > > id = 0; > if (cancellable) > id = g_cancellable_connect (cancellable, > G_CALLBACK (cancelled_handler) > data, NULL); > > // cancellable operation here... > > g_cancellable_disconnect (cancellable, id); > > // cancelled_handler is never called after this, it is now safe > // to free the data > my_data_free (my_data); Note that the cancelled signal is emitted in the thread that the user cancelled from, which may be the main thread. So, the cancellable signal should not do something that can block. -} type CancellableCancelledCallback = IO () -- | A convenience synonym for @`Nothing` :: `Maybe` `CancellableCancelledCallback`@. noCancellableCancelledCallback :: Maybe CancellableCancelledCallback noCancellableCancelledCallback = Nothing -- | Type for the callback on the (unwrapped) C side. type C_CancellableCancelledCallback = Ptr () -> -- object Ptr () -> -- user_data IO () -- | Generate a function pointer callable from C code, from a `C_CancellableCancelledCallback`. foreign import ccall "wrapper" mk_CancellableCancelledCallback :: C_CancellableCancelledCallback -> IO (FunPtr C_CancellableCancelledCallback) -- | Wrap the callback into a `Closure`. genClosure_CancellableCancelled :: CancellableCancelledCallback -> IO Closure genClosure_CancellableCancelled cb = do let cb' = wrap_CancellableCancelledCallback cb mk_CancellableCancelledCallback cb' >>= newCClosure -- | Wrap a `CancellableCancelledCallback` into a `C_CancellableCancelledCallback`. wrap_CancellableCancelledCallback :: CancellableCancelledCallback -> C_CancellableCancelledCallback wrap_CancellableCancelledCallback _cb _ _ = do _cb {- | Connect a signal handler for the “@cancelled@” signal, to be run before the default handler. When <https://github.com/haskell-gi/haskell-gi/wiki/Overloading overloading> is enabled, this is equivalent to @ 'Data.GI.Base.Signals.on' cancellable #cancelled callback @ -} onCancellableCancelled :: (IsCancellable a, MonadIO m) => a -> CancellableCancelledCallback -> m SignalHandlerId onCancellableCancelled obj cb = liftIO $ do let cb' = wrap_CancellableCancelledCallback cb cb'' <- mk_CancellableCancelledCallback cb' connectSignalFunPtr obj "cancelled" cb'' SignalConnectBefore {- | Connect a signal handler for the “@cancelled@” signal, to be run after the default handler. When <https://github.com/haskell-gi/haskell-gi/wiki/Overloading overloading> is enabled, this is equivalent to @ 'Data.GI.Base.Signals.after' cancellable #cancelled callback @ -} afterCancellableCancelled :: (IsCancellable a, MonadIO m) => a -> CancellableCancelledCallback -> m SignalHandlerId afterCancellableCancelled obj cb = liftIO $ do let cb' = wrap_CancellableCancelledCallback cb cb'' <- mk_CancellableCancelledCallback cb' connectSignalFunPtr obj "cancelled" cb'' SignalConnectAfter #if ENABLE_OVERLOADING instance O.HasAttributeList Cancellable type instance O.AttributeList Cancellable = CancellableAttributeList type CancellableAttributeList = ('[ ] :: [(Symbol, *)]) #endif #if ENABLE_OVERLOADING #endif #if ENABLE_OVERLOADING data CancellableCancelledSignalInfo instance SignalInfo CancellableCancelledSignalInfo where type HaskellCallbackType CancellableCancelledSignalInfo = CancellableCancelledCallback connectSignal _ obj cb connectMode = do let cb' = wrap_CancellableCancelledCallback cb cb'' <- mk_CancellableCancelledCallback cb' connectSignalFunPtr obj "cancelled" cb'' connectMode type instance O.SignalList Cancellable = CancellableSignalList type CancellableSignalList = ('[ '("cancelled", CancellableCancelledSignalInfo), '("notify", GObject.Object.ObjectNotifySignalInfo)] :: [(Symbol, *)]) #endif -- method Cancellable::new -- method type : Constructor -- Args : [] -- Lengths : [] -- returnType : Just (TInterface (Name {namespace = "Gio", name = "Cancellable"})) -- throws : False -- Skip return : False foreign import ccall "g_cancellable_new" g_cancellable_new :: IO (Ptr Cancellable) {- | Creates a new 'GI.Gio.Objects.Cancellable.Cancellable' object. Applications that want to start one or more operations that should be cancellable should create a 'GI.Gio.Objects.Cancellable.Cancellable' and pass it to the operations. One 'GI.Gio.Objects.Cancellable.Cancellable' can be used in multiple consecutive operations or in multiple concurrent operations. -} cancellableNew :: (B.CallStack.HasCallStack, MonadIO m) => m Cancellable {- ^ __Returns:__ a 'GI.Gio.Objects.Cancellable.Cancellable'. -} cancellableNew = liftIO $ do result <- g_cancellable_new checkUnexpectedReturnNULL "cancellableNew" result result' <- (wrapObject Cancellable) result return result' #if ENABLE_OVERLOADING #endif -- method Cancellable::cancel -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable object.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Nothing -- throws : False -- Skip return : False foreign import ccall "g_cancellable_cancel" g_cancellable_cancel :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO () {- | Will set /@cancellable@/ to cancelled, and will emit the 'GI.Gio.Objects.Cancellable.Cancellable'::@/cancelled/@ signal. (However, see the warning about race conditions in the documentation for that signal if you are planning to connect to it.) This function is thread-safe. In other words, you can safely call it from a thread other than the one running the operation that was passed the /@cancellable@/. If /@cancellable@/ is 'Nothing', this function returns immediately for convenience. The convention within GIO is that cancelling an asynchronous operation causes it to complete asynchronously. That is, if you cancel the operation from the same thread in which it is running, then the operation\'s 'GI.Gio.Callbacks.AsyncReadyCallback' will not be invoked until the application returns to the main loop. -} cancellableCancel :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' object. -} -> m () cancellableCancel cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable g_cancellable_cancel cancellable' touchManagedPtr cancellable return () #if ENABLE_OVERLOADING data CancellableCancelMethodInfo instance (signature ~ (m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellableCancelMethodInfo a signature where overloadedMethod _ = cancellableCancel #endif -- method Cancellable::connect -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "A #GCancellable.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing},Arg {argCName = "callback", argType = TInterface (Name {namespace = "GObject", name = "Callback"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "The #GCallback to connect.", sinceVersion = Nothing}, argScope = ScopeTypeNotified, argClosure = 2, argDestroy = 3, argCallerAllocates = False, transfer = TransferNothing},Arg {argCName = "data", argType = TBasicType TPtr, direction = DirectionIn, mayBeNull = True, argDoc = Documentation {rawDocText = Just "Data to pass to @callback.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing},Arg {argCName = "data_destroy_func", argType = TInterface (Name {namespace = "GLib", name = "DestroyNotify"}), direction = DirectionIn, mayBeNull = True, argDoc = Documentation {rawDocText = Just "Free function for @data or %NULL.", sinceVersion = Nothing}, argScope = ScopeTypeAsync, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Just (TBasicType TULong) -- throws : False -- Skip return : False foreign import ccall "g_cancellable_connect" g_cancellable_connect :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) FunPtr GObject.Callbacks.C_Callback -> -- callback : TInterface (Name {namespace = "GObject", name = "Callback"}) Ptr () -> -- data : TBasicType TPtr FunPtr GLib.Callbacks.C_DestroyNotify -> -- data_destroy_func : TInterface (Name {namespace = "GLib", name = "DestroyNotify"}) IO CULong {- | Convenience function to connect to the 'GI.Gio.Objects.Cancellable.Cancellable'::@/cancelled/@ signal. Also handles the race condition that may happen if the cancellable is cancelled right before connecting. /@callback@/ is called at most once, either directly at the time of the connect if /@cancellable@/ is already cancelled, or when /@cancellable@/ is cancelled in some thread. /@dataDestroyFunc@/ will be called when the handler is disconnected, or immediately if the cancellable is already cancelled. See 'GI.Gio.Objects.Cancellable.Cancellable'::@/cancelled/@ for details on how to use this. Since GLib 2.40, the lock protecting /@cancellable@/ is not held when /@callback@/ is invoked. This lifts a restriction in place for earlier GLib versions which now makes it easier to write cleanup code that unconditionally invokes e.g. 'GI.Gio.Objects.Cancellable.cancellableCancel'. /Since: 2.22/ -} cancellableConnect :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: A 'GI.Gio.Objects.Cancellable.Cancellable'. -} -> GObject.Callbacks.Callback {- ^ /@callback@/: The 'GI.GObject.Callbacks.Callback' to connect. -} -> m CULong {- ^ __Returns:__ The id of the signal handler or 0 if /@cancellable@/ has already been cancelled. -} cancellableConnect cancellable callback = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable callback' <- GObject.Callbacks.mk_Callback (GObject.Callbacks.wrap_Callback Nothing callback) let data_ = castFunPtrToPtr callback' let dataDestroyFunc = safeFreeFunPtrPtr result <- g_cancellable_connect cancellable' callback' data_ dataDestroyFunc touchManagedPtr cancellable return result #if ENABLE_OVERLOADING data CancellableConnectMethodInfo instance (signature ~ (GObject.Callbacks.Callback -> m CULong), MonadIO m, IsCancellable a) => O.MethodInfo CancellableConnectMethodInfo a signature where overloadedMethod _ = cancellableConnect #endif -- method Cancellable::disconnect -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "A #GCancellable or %NULL.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing},Arg {argCName = "handler_id", argType = TBasicType TULong, direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "Handler id of the handler to be disconnected, or `0`.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Nothing -- throws : False -- Skip return : False foreign import ccall "g_cancellable_disconnect" g_cancellable_disconnect :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) CULong -> -- handler_id : TBasicType TULong IO () {- | Disconnects a handler from a cancellable instance similar to 'GI.GObject.Functions.signalHandlerDisconnect'. Additionally, in the event that a signal handler is currently running, this call will block until the handler has finished. Calling this function from a 'GI.Gio.Objects.Cancellable.Cancellable'::@/cancelled/@ signal handler will therefore result in a deadlock. This avoids a race condition where a thread cancels at the same time as the cancellable operation is finished and the signal handler is removed. See 'GI.Gio.Objects.Cancellable.Cancellable'::@/cancelled/@ for details on how to use this. If /@cancellable@/ is 'Nothing' or /@handlerId@/ is @0@ this function does nothing. /Since: 2.22/ -} cancellableDisconnect :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: A 'GI.Gio.Objects.Cancellable.Cancellable' or 'Nothing'. -} -> CULong {- ^ /@handlerId@/: Handler id of the handler to be disconnected, or @0@. -} -> m () cancellableDisconnect cancellable handlerId = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable g_cancellable_disconnect cancellable' handlerId touchManagedPtr cancellable return () #if ENABLE_OVERLOADING data CancellableDisconnectMethodInfo instance (signature ~ (CULong -> m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellableDisconnectMethodInfo a signature where overloadedMethod _ = cancellableDisconnect #endif -- method Cancellable::get_fd -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Just (TBasicType TInt) -- throws : False -- Skip return : False foreign import ccall "g_cancellable_get_fd" g_cancellable_get_fd :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO Int32 {- | Gets the file descriptor for a cancellable job. This can be used to implement cancellable operations on Unix systems. The returned fd will turn readable when /@cancellable@/ is cancelled. You are not supposed to read from the fd yourself, just check for readable status. Reading to unset the readable status is done with 'GI.Gio.Objects.Cancellable.cancellableReset'. After a successful return from this function, you should use 'GI.Gio.Objects.Cancellable.cancellableReleaseFd' to free up resources allocated for the returned file descriptor. See also 'GI.Gio.Objects.Cancellable.cancellableMakePollfd'. -} cancellableGetFd :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable'. -} -> m Int32 {- ^ __Returns:__ A valid file descriptor. %-1 if the file descriptor is not supported, or on errors. -} cancellableGetFd cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable result <- g_cancellable_get_fd cancellable' touchManagedPtr cancellable return result #if ENABLE_OVERLOADING data CancellableGetFdMethodInfo instance (signature ~ (m Int32), MonadIO m, IsCancellable a) => O.MethodInfo CancellableGetFdMethodInfo a signature where overloadedMethod _ = cancellableGetFd #endif -- method Cancellable::is_cancelled -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable or %NULL", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Just (TBasicType TBoolean) -- throws : False -- Skip return : False foreign import ccall "g_cancellable_is_cancelled" g_cancellable_is_cancelled :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO CInt {- | Checks if a cancellable job has been cancelled. -} cancellableIsCancelled :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' or 'Nothing' -} -> m Bool {- ^ __Returns:__ 'True' if /@cancellable@/ is cancelled, FALSE if called with 'Nothing' or if item is not cancelled. -} cancellableIsCancelled cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable result <- g_cancellable_is_cancelled cancellable' let result' = (/= 0) result touchManagedPtr cancellable return result' #if ENABLE_OVERLOADING data CancellableIsCancelledMethodInfo instance (signature ~ (m Bool), MonadIO m, IsCancellable a) => O.MethodInfo CancellableIsCancelledMethodInfo a signature where overloadedMethod _ = cancellableIsCancelled #endif -- method Cancellable::make_pollfd -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable or %NULL", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing},Arg {argCName = "pollfd", argType = TInterface (Name {namespace = "GLib", name = "PollFD"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a pointer to a #GPollFD", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Just (TBasicType TBoolean) -- throws : False -- Skip return : False foreign import ccall "g_cancellable_make_pollfd" g_cancellable_make_pollfd :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) Ptr GLib.PollFD.PollFD -> -- pollfd : TInterface (Name {namespace = "GLib", name = "PollFD"}) IO CInt {- | Creates a 'GI.GLib.Structs.PollFD.PollFD' corresponding to /@cancellable@/; this can be passed to 'GI.GLib.Functions.poll' and used to poll for cancellation. This is useful both for unix systems without a native poll and for portability to windows. When this function returns 'True', you should use 'GI.Gio.Objects.Cancellable.cancellableReleaseFd' to free up resources allocated for the /@pollfd@/. After a 'False' return, do not call 'GI.Gio.Objects.Cancellable.cancellableReleaseFd'. If this function returns 'False', either no /@cancellable@/ was given or resource limits prevent this function from allocating the necessary structures for polling. (On Linux, you will likely have reached the maximum number of file descriptors.) The suggested way to handle these cases is to ignore the /@cancellable@/. You are not supposed to read from the fd yourself, just check for readable status. Reading to unset the readable status is done with 'GI.Gio.Objects.Cancellable.cancellableReset'. /Since: 2.22/ -} cancellableMakePollfd :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' or 'Nothing' -} -> GLib.PollFD.PollFD {- ^ /@pollfd@/: a pointer to a 'GI.GLib.Structs.PollFD.PollFD' -} -> m Bool {- ^ __Returns:__ 'True' if /@pollfd@/ was successfully initialized, 'False' on failure to prepare the cancellable. -} cancellableMakePollfd cancellable pollfd = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable pollfd' <- unsafeManagedPtrGetPtr pollfd result <- g_cancellable_make_pollfd cancellable' pollfd' let result' = (/= 0) result touchManagedPtr cancellable touchManagedPtr pollfd return result' #if ENABLE_OVERLOADING data CancellableMakePollfdMethodInfo instance (signature ~ (GLib.PollFD.PollFD -> m Bool), MonadIO m, IsCancellable a) => O.MethodInfo CancellableMakePollfdMethodInfo a signature where overloadedMethod _ = cancellableMakePollfd #endif -- method Cancellable::pop_current -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable object", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Nothing -- throws : False -- Skip return : False foreign import ccall "g_cancellable_pop_current" g_cancellable_pop_current :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO () {- | Pops /@cancellable@/ off the cancellable stack (verifying that /@cancellable@/ is on the top of the stack). -} cancellablePopCurrent :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' object -} -> m () cancellablePopCurrent cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable g_cancellable_pop_current cancellable' touchManagedPtr cancellable return () #if ENABLE_OVERLOADING data CancellablePopCurrentMethodInfo instance (signature ~ (m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellablePopCurrentMethodInfo a signature where overloadedMethod _ = cancellablePopCurrent #endif -- method Cancellable::push_current -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable object", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Nothing -- throws : False -- Skip return : False foreign import ccall "g_cancellable_push_current" g_cancellable_push_current :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO () {- | Pushes /@cancellable@/ onto the cancellable stack. The current cancellable can then be received using 'GI.Gio.Objects.Cancellable.cancellableGetCurrent'. This is useful when implementing cancellable operations in code that does not allow you to pass down the cancellable object. This is typically called automatically by e.g. 'GI.Gio.Interfaces.File.File' operations, so you rarely have to call this yourself. -} cancellablePushCurrent :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' object -} -> m () cancellablePushCurrent cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable g_cancellable_push_current cancellable' touchManagedPtr cancellable return () #if ENABLE_OVERLOADING data CancellablePushCurrentMethodInfo instance (signature ~ (m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellablePushCurrentMethodInfo a signature where overloadedMethod _ = cancellablePushCurrent #endif -- method Cancellable::release_fd -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Nothing -- throws : False -- Skip return : False foreign import ccall "g_cancellable_release_fd" g_cancellable_release_fd :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO () {- | Releases a resources previously allocated by 'GI.Gio.Objects.Cancellable.cancellableGetFd' or 'GI.Gio.Objects.Cancellable.cancellableMakePollfd'. For compatibility reasons with older releases, calling this function is not strictly required, the resources will be automatically freed when the /@cancellable@/ is finalized. However, the /@cancellable@/ will block scarce file descriptors until it is finalized if this function is not called. This can cause the application to run out of file descriptors when many @/GCancellables/@ are used at the same time. /Since: 2.22/ -} cancellableReleaseFd :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' -} -> m () cancellableReleaseFd cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable g_cancellable_release_fd cancellable' touchManagedPtr cancellable return () #if ENABLE_OVERLOADING data CancellableReleaseFdMethodInfo instance (signature ~ (m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellableReleaseFdMethodInfo a signature where overloadedMethod _ = cancellableReleaseFd #endif -- method Cancellable::reset -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable object.", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Nothing -- throws : False -- Skip return : False foreign import ccall "g_cancellable_reset" g_cancellable_reset :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) IO () {- | Resets /@cancellable@/ to its uncancelled state. If cancellable is currently in use by any cancellable operation then the behavior of this function is undefined. Note that it is generally not a good idea to reuse an existing cancellable for more operations after it has been cancelled once, as this function might tempt you to do. The recommended practice is to drop the reference to a cancellable after cancelling it, and let it die with the outstanding async operations. You should create a fresh cancellable for further async operations. -} cancellableReset :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' object. -} -> m () cancellableReset cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable g_cancellable_reset cancellable' touchManagedPtr cancellable return () #if ENABLE_OVERLOADING data CancellableResetMethodInfo instance (signature ~ (m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellableResetMethodInfo a signature where overloadedMethod _ = cancellableReset #endif -- method Cancellable::set_error_if_cancelled -- method type : OrdinaryMethod -- Args : [Arg {argCName = "cancellable", argType = TInterface (Name {namespace = "Gio", name = "Cancellable"}), direction = DirectionIn, mayBeNull = False, argDoc = Documentation {rawDocText = Just "a #GCancellable or %NULL", sinceVersion = Nothing}, argScope = ScopeTypeInvalid, argClosure = -1, argDestroy = -1, argCallerAllocates = False, transfer = TransferNothing}] -- Lengths : [] -- returnType : Just (TBasicType TBoolean) -- throws : True -- Skip return : False foreign import ccall "g_cancellable_set_error_if_cancelled" g_cancellable_set_error_if_cancelled :: Ptr Cancellable -> -- cancellable : TInterface (Name {namespace = "Gio", name = "Cancellable"}) Ptr (Ptr GError) -> -- error IO CInt {- | If the /@cancellable@/ is cancelled, sets the error to notify that the operation was cancelled. -} cancellableSetErrorIfCancelled :: (B.CallStack.HasCallStack, MonadIO m, IsCancellable a) => a {- ^ /@cancellable@/: a 'GI.Gio.Objects.Cancellable.Cancellable' or 'Nothing' -} -> m () {- ^ /(Can throw 'Data.GI.Base.GError.GError')/ -} cancellableSetErrorIfCancelled cancellable = liftIO $ do cancellable' <- unsafeManagedPtrCastPtr cancellable onException (do _ <- propagateGError $ g_cancellable_set_error_if_cancelled cancellable' touchManagedPtr cancellable return () ) (do return () ) #if ENABLE_OVERLOADING data CancellableSetErrorIfCancelledMethodInfo instance (signature ~ (m ()), MonadIO m, IsCancellable a) => O.MethodInfo CancellableSetErrorIfCancelledMethodInfo a signature where overloadedMethod _ = cancellableSetErrorIfCancelled #endif -- method Cancellable::get_current -- method type : MemberFunction -- Args : [] -- Lengths : [] -- returnType : Just (TInterface (Name {namespace = "Gio", name = "Cancellable"})) -- throws : False -- Skip return : False foreign import ccall "g_cancellable_get_current" g_cancellable_get_current :: IO (Ptr Cancellable) {- | Gets the top cancellable from the stack. -} cancellableGetCurrent :: (B.CallStack.HasCallStack, MonadIO m) => m (Maybe Cancellable) {- ^ __Returns:__ a 'GI.Gio.Objects.Cancellable.Cancellable' from the top of the stack, or 'Nothing' if the stack is empty. -} cancellableGetCurrent = liftIO $ do result <- g_cancellable_get_current maybeResult <- convertIfNonNull result $ \result' -> do result'' <- (newObject Cancellable) result' return result'' return maybeResult #if ENABLE_OVERLOADING #endif