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// Copyright 2017 Lyndon Brown // // This file is part of the PulseAudio Rust language binding. // // This library is free software; you can redistribute it and/or modify it under the terms of the // GNU Lesser General Public License as published by the Free Software Foundation; either version // 2.1 of the License, or (at your option) any later version. // // This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without // even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License along with this library; // if not, see <http://www.gnu.org/licenses/>. //! Main loop abstraction layer API. use std; use capi; use std::os::raw::c_void; use std::rc::Rc; use libc::timeval; use super::events::io::{IoEvent, IoEventRef, IoEventInternal, IoEventFlagSet}; use super::events::timer::{TimeEvent, TimeEventRef, TimeEventInternal}; use super::events::deferred::{DeferEvent, DeferEventRef, DeferEventInternal}; use time::{UnixTs, MonotonicTs, Timeval, USEC_INVALID}; pub(crate) use capi::pa_mainloop_api as ApiInternal; /// This enables generic type enforcement with the opaque C objects. pub trait MainloopInternalType {} /// This enables generic type enforcement with MainloopInner objects, and describes mandatory /// accessors for the internal pointers, allowing access to these pointers across the generic /// implementations to work. pub trait MainloopInnerType { type I: MainloopInternalType; /// Return opaque main loop object pointer. fn get_ptr(&self) -> *mut Self::I; /// Return main loop API object pointer. fn get_api(&self) -> &MainloopApi; /// Returns `true` if the mainloop implementation supports monotonic based time events. fn supports_rtclock(&self) -> bool; } /// Mainloop inner wrapper. /// /// This contains the actual main loop object pointers, holding both the pointer to the actual /// opaque main loop C object, and the pointer to the associated API vtable. /// /// An instance of this type will be held, in an `Rc` ref counted wrapper both in an outer Mainloop /// wrapper, and by all event objects. With event objects holding a ref-counted copy, this both /// gives event objects access to the API pointer, which they need, and also it allows us to ensure /// that event objects do not outlive the main loop object (which internally owns the API object), /// and thus ensures correct destruction order of event and main loop objects. pub struct MainloopInner<T> where T: MainloopInternalType { /// An opaque main loop object. pub ptr: *mut T, /// The abstract main loop API vtable for the GLIB main loop object. No need to free this API as /// it is owned by the loop and is destroyed when the loop is freed. pub api: *const MainloopApi, /// All implementations must provide a drop method, to be called from an actual drop call. pub dropfn: fn(&mut MainloopInner<T>), /// Whether or not the implementation supports monotonic based time events. (`true` if so). pub supports_rtclock: bool, } impl<T> Drop for MainloopInner<T> where T: MainloopInternalType { fn drop(&mut self) { (self.dropfn)(self); } } /// This is the actual implementation of the ‘inner type’ trait. /// /// It is not possible to replace this with ‘default’ method implementations within the trait itself /// since the trait does not know about the existence of the struct attributes being accessed. impl<T> MainloopInnerType for MainloopInner<T> where T: MainloopInternalType { type I = T; /// Gets opaque main loop object pointer. fn get_ptr(&self) -> *mut T { self.ptr } /// Gets main loop API object pointer. fn get_api(&self) -> &MainloopApi { assert!(!self.api.is_null()); unsafe { &*self.api } } fn supports_rtclock(&self) -> bool { self.supports_rtclock } } pub trait Mainloop { type MI: MainloopInnerType; fn inner(&self) -> Rc<Self::MI>; /// Creates a new IO event. /// /// **Note**: You must ensure that the returned event object lives for as long as you want its /// event(s) to fire, as its `Drop` implementation destroys the event source. I.e. if you create /// a new event, but then immediately drop the object returned here, no event will fire! /// /// The given callback must accept three parameters, an [`IoEventRef`] object, a copy of the /// given file descriptor, and an event flag set, indicating the event(s) that occurred. The /// [`DeferEventRef`] object gives you some opportunity to manage the event source from within /// it’s callback execution. /// /// [`IoEventRef`]: ../events/io/struct.IoEventRef.html fn new_io_event(&mut self, fd: i32, events: IoEventFlagSet, mut callback: Box<dyn FnMut(IoEventRef<Self::MI>, i32, IoEventFlagSet) + 'static>) -> Option<IoEvent<Self::MI>> { let inner_for_wrapper = self.inner(); let wrapper_cb = Box::new(move |ptr, fd, flags| { let ref_obj = IoEventRef::<Self::MI>::from_raw(ptr, Rc::clone(&inner_for_wrapper)); callback(ref_obj, fd, flags); }); let to_save = super::events::io::EventCb::new(Some(wrapper_cb)); let (cb_fn, cb_data) = to_save.get_capi_params(super::events::io::event_cb_proxy); let inner = self.inner(); let api = inner.get_api(); let fn_ptr = api.io_new.unwrap(); let ptr = fn_ptr(api, fd, events, cb_fn, cb_data); match ptr.is_null() { false => Some(IoEvent::<Self::MI>::from_raw(ptr, Rc::clone(&inner), to_save)), true => None, } } /// Creates a new timer event. /// /// **Note**: You must ensure that the returned event object lives for as long as you want its /// event(s) to fire, as its `Drop` implementation destroys the event source. I.e. if you create /// a new event, but then immediately drop the object returned here, no event will fire! /// /// The callback must take a [`TimeEventRef`] object, which gives you some opportunity to /// manage the event source from within it’s callback execution. /// /// Example event set to fire in five seconds time: /// /// ```rust,ignore /// use pulse::time::{UnixTs, MicroSeconds, MICROS_PER_SEC}; /// let _t_event = mainloop.new_timer_event( /// &(UnixTs::now() + MicroSeconds(5 * MICROS_PER_SEC)), /// Box::new(|| { println!("Timer event fired!"); })); /// ``` /// /// [`TimeEventRef`]: ../events/timer/struct.TimeEventRef.html fn new_timer_event(&mut self, tv: &UnixTs, mut callback: Box<dyn FnMut(TimeEventRef<Self::MI>) + 'static>) -> Option<TimeEvent<Self::MI>> { let inner_for_wrapper = self.inner(); let wrapper_cb = Box::new(move |ptr| { let ref_obj = TimeEventRef::<Self::MI>::from_raw(ptr, Rc::clone(&inner_for_wrapper)); callback(ref_obj); }); let to_save = super::events::timer::EventCb::new(Some(wrapper_cb)); let (cb_fn, cb_data) = to_save.get_capi_params(super::events::timer::event_cb_proxy); let inner = self.inner(); let api = inner.get_api(); let fn_ptr = api.time_new.unwrap(); let ptr = fn_ptr(api, &(tv.0).0, cb_fn, cb_data); match ptr.is_null() { false => Some(TimeEvent::<Self::MI>::from_raw(ptr, Rc::clone(&inner), to_save)), true => None, } } /// Creates a new monotonic-based timer event. /// /// Asserts that `t` is not `USEC_INVALID`. /// /// This is an alternative to the `new_timer_event` method, taking a monotonic based time value. /// /// **Note**: You must ensure that the returned event object lives for as long as you want its /// event(s) to fire, as its `Drop` implementation destroys the event source. I.e. if you create /// a new event, but then immediately drop the object returned here, no event will fire! /// /// The callback must take a [`TimeEventRef`] object, which gives you some opportunity to /// manage the event source from within it’s callback execution. /// /// Example event set to fire in five seconds time: /// /// ```rust,ignore /// use pulse::time::{MonotonicTs, MicroSeconds, MICROS_PER_SEC}; /// let _t_event = mainloop.new_timer_event_rt( /// MonotonicTs::now() + MicroSeconds(5 * MICROS_PER_SEC), /// Box::new(|| { println!("Timer event fired!"); })); /// ``` /// /// [`TimeEventRef`]: ../events/timer/struct.TimeEventRef.html fn new_timer_event_rt(&mut self, t: MonotonicTs, mut callback: Box<dyn FnMut(TimeEventRef<Self::MI>) + 'static>) -> Option<TimeEvent<Self::MI>> { assert_ne!(t.0, USEC_INVALID); let inner_for_wrapper = self.inner(); let wrapper_cb = Box::new(move |ptr| { let ref_obj = TimeEventRef::<Self::MI>::from_raw(ptr, Rc::clone(&inner_for_wrapper)); callback(ref_obj); }); let to_save = super::events::timer::EventCb::new(Some(wrapper_cb)); let (cb_fn, cb_data) = to_save.get_capi_params(super::events::timer::event_cb_proxy); let inner = self.inner(); let mut tv = Timeval::new_zero(); tv.set_rt(t.0, inner.supports_rtclock()); let api = inner.get_api(); let fn_ptr = api.time_new.unwrap(); let ptr = fn_ptr(api, &tv.0, cb_fn, cb_data); match ptr.is_null() { false => Some(TimeEvent::<Self::MI>::from_raw(ptr, Rc::clone(&inner), to_save)), true => None, } } /// Creates a new deferred event. /// /// **Note**: You must ensure that the returned event object lives for as long as you want its /// event(s) to fire, as its `Drop` implementation destroys the event source. I.e. if you create /// a new event, but then immediately drop the object returned here, no event will fire! /// /// The callback must take a [`DeferEventRef`] object, which gives you some opportunity to /// manage the event source from within it’s callback execution. /// /// [`DeferEventRef`]: ../events/deferred/struct.DeferEventRef.html fn new_deferred_event(&mut self, mut callback: Box<dyn FnMut(DeferEventRef<Self::MI>) + 'static>) -> Option<DeferEvent<Self::MI>> { let inner_for_wrapper = self.inner(); let wrapper_cb = Box::new(move |ptr| { let ref_obj = DeferEventRef::<Self::MI>::from_raw(ptr, Rc::clone(&inner_for_wrapper)); callback(ref_obj); }); let to_save = super::events::deferred::EventCb::new(Some(wrapper_cb)); let (cb_fn, cb_data) = to_save.get_capi_params(super::events::deferred::event_cb_proxy); let inner = self.inner(); let api = inner.get_api(); let fn_ptr = api.defer_new.unwrap(); let ptr = fn_ptr(api, cb_fn, cb_data); match ptr.is_null() { false => Some(DeferEvent::<Self::MI>::from_raw(ptr, Rc::clone(&inner), to_save)), true => None, } } /// Runs the specified callback once from the main loop using an anonymous defer event. /// /// If the mainloop runs in a different thread, you need to follow the mainloop implementation’s /// rules regarding how to safely create defer events. In particular, if you’re using /// [`::mainloop::threaded`](../threaded/index.html), you must lock the mainloop before calling /// this function. fn once_event(&mut self, callback: Box<dyn FnMut() + 'static>) { let (cb_fn, cb_data): (Option<extern "C" fn(_, _)>, _) = ::callbacks::get_su_capi_params::<_, _>(Some(callback), once_cb_proxy); let inner = self.inner(); let api = inner.get_api(); unsafe { capi::pa_mainloop_api_once(api.as_ref(), cb_fn, cb_data) }; } /// Calls quit fn quit(&mut self, retval: ::def::Retval) { let inner = self.inner(); let api = inner.get_api(); let fn_ptr = api.quit.unwrap(); fn_ptr(api, retval.0); } } /// An IO event callback prototype. pub type IoEventCb = extern "C" fn(a: *const MainloopApi, e: *mut IoEventInternal, fd: i32, events: IoEventFlagSet, userdata: *mut c_void); /// A IO event destroy callback prototype. pub type IoEventDestroyCb = extern "C" fn(a: *const MainloopApi, e: *mut IoEventInternal, userdata: *mut c_void); /// A time event callback prototype. pub type TimeEventCb = extern "C" fn(a: *const MainloopApi, e: *mut TimeEventInternal, tv: *const timeval, userdata: *mut c_void); /// A time event destroy callback prototype. pub type TimeEventDestroyCb = extern "C" fn(a: *const MainloopApi, e: *mut TimeEventInternal, userdata: *mut c_void); /// A defer event callback prototype. pub type DeferEventCb = extern "C" fn(a: *const MainloopApi, e: *mut DeferEventInternal, userdata: *mut c_void); /// A defer event destroy callback prototype. pub type DeferEventDestroyCb = extern "C" fn(a: *const MainloopApi, e: *mut DeferEventInternal, userdata: *mut c_void); /// An abstract mainloop API vtable #[repr(C)] pub struct MainloopApi { /* NOTE: This struct must be directly usable by the C API, thus same attributes/layout/etc */ /// A pointer to some private, arbitrary data of the main loop implementation. pub userdata: *mut c_void, /// Creates a new IO event source object. pub io_new: Option<extern "C" fn(a: *const MainloopApi, fd: i32, events: IoEventFlagSet, cb: Option<IoEventCb>, userdata: *mut c_void) -> *mut IoEventInternal>, /// Enables or disables IO events on this object. pub io_enable: Option<extern "C" fn(e: *mut IoEventInternal, events: IoEventFlagSet)>, /// Frees a IO event source object. pub io_free: Option<extern "C" fn(e: *mut IoEventInternal)>, /// Sets a function that is called when the IO event source is destroyed. Use this to free the /// `userdata` argument if required. pub io_set_destroy: Option<extern "C" fn(e: *mut IoEventInternal, cb: Option<IoEventDestroyCb>)>, /// Creates a new timer event source object for the specified Unix time. pub time_new: Option<extern "C" fn(a: *const MainloopApi, tv: *const timeval, cb: Option<TimeEventCb>, userdata: *mut c_void) -> *mut TimeEventInternal>, /// Restarts a running or expired timer event source with a new Unix time. pub time_restart: Option<extern "C" fn(e: *mut TimeEventInternal, tv: *const timeval)>, /// Frees a deferred timer event source object. pub time_free: Option<extern "C" fn(e: *mut TimeEventInternal)>, /// Sets a function that is called when the timer event source is destroyed. Use this to free /// the `userdata` argument if required. pub time_set_destroy: Option<extern "C" fn(e: *mut TimeEventInternal, cb: Option<TimeEventDestroyCb>)>, /// Creates a new deferred event source object. pub defer_new: Option<extern "C" fn(a: *const MainloopApi, cb: Option<DeferEventCb>, userdata: *mut c_void) -> *mut DeferEventInternal>, /// Enables or disables a deferred event source temporarily. pub defer_enable: Option<extern "C" fn(e: *mut DeferEventInternal, b: i32)>, /// Frees a deferred event source object. pub defer_free: Option<extern "C" fn(e: *mut DeferEventInternal)>, /// Sets a function that is called when the deferred event source is /// destroyed. Use this to free the `userdata` argument if required. pub defer_set_destroy: Option<extern "C" fn(e: *mut DeferEventInternal, cb: Option<DeferEventDestroyCb>)>, /// Exits the main loop and return the specified retval. pub quit: Option<extern "C" fn(a: *const MainloopApi, retval: ::def::RetvalActual)>, } /// Test size is equal to `sys` equivalent (duplicated here for different documentation) #[test] fn api_compare_capi(){ assert_eq!(std::mem::size_of::<ApiInternal>(), std::mem::size_of::<capi::pa_mainloop_api>()); assert_eq!(std::mem::align_of::<ApiInternal>(), std::mem::align_of::<capi::pa_mainloop_api>()); } impl AsRef<capi::pa_mainloop_api> for MainloopApi { #[inline] fn as_ref(&self) -> &capi::pa_mainloop_api { unsafe { &*(self as *const Self as *const capi::pa_mainloop_api) } } } impl<'a> From<*const ApiInternal> for &'a MainloopApi { #[inline] fn from(a: *const ApiInternal) -> Self { unsafe { std::mem::transmute(a) } } } impl<'a> From<&'a MainloopApi> for *const ApiInternal { #[inline] fn from(a: &'a MainloopApi) -> Self { unsafe { std::mem::transmute(a) } } } /// Proxy for anonymous ‘once’ deferred event callbacks. /// /// Warning: This is for single-use cases only! It destroys the actual closure callback. extern "C" fn once_cb_proxy(_: *const ApiInternal, userdata: *mut c_void) { let _ = std::panic::catch_unwind(|| { // Note, destroys closure callback after use - restoring outer box means it gets dropped let mut callback = ::callbacks::get_su_callback::<dyn FnMut()>(userdata); (callback)(); }); }