gstreamer/device: Add support for creating gst::Device subclasses

This commit is contained in:
Sebastian Dröge 2019-09-11 22:42:32 +03:00
parent 1528510c68
commit 161351e5c4
2 changed files with 145 additions and 0 deletions

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@ -0,0 +1,141 @@
// Copyright (C) 2019 Sebastian Dröge <sebastian@centricular.com>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use glib_sys;
use gst_sys;
use glib::translate::*;
use glib::subclass::prelude::*;
use Device;
use DeviceClass;
use Element;
use LoggableError;
use std::ptr;
pub trait DeviceImpl: DeviceImplExt + ObjectImpl + Send + Sync + 'static {
fn create_element(&self, device: &Device, name: Option<&str>) -> Option<Element> {
self.parent_create_element(device, name)
}
fn reconfigure_element(&self, device: &Device, element: &Element) -> Result<(), LoggableError> {
self.parent_reconfigure_element(device, element)
}
}
pub trait DeviceImplExt {
fn parent_create_element(&self, device: &Device, name: Option<&str>) -> Option<Element>;
fn parent_reconfigure_element(
&self,
device: &Device,
element: &Element,
) -> Result<(), LoggableError>;
}
impl<T: DeviceImpl + ObjectImpl> DeviceImplExt for T {
fn parent_create_element(&self, device: &Device, name: Option<&str>) -> Option<Element> {
unsafe {
let data = self.get_type_data();
let parent_class = data.as_ref().get_parent_class() as *mut gst_sys::GstDeviceClass;
if let Some(f) = (*parent_class).create_element {
from_glib_none(f(device.to_glib_none().0, name.to_glib_none().0))
} else {
None
}
}
}
fn parent_reconfigure_element(
&self,
device: &Device,
element: &Element,
) -> Result<(), LoggableError> {
unsafe {
let data = self.get_type_data();
let parent_class = data.as_ref().get_parent_class() as *mut gst_sys::GstDeviceClass;
let f = (*parent_class).reconfigure_element.ok_or_else(|| {
gst_loggable_error!(
::CAT_RUST,
"Parent function `reconfigure_element` is not defined"
)
})?;
gst_result_from_gboolean!(
f(device.to_glib_none().0, element.to_glib_none().0),
::CAT_RUST,
"Failed to reconfigure the element using the parent function"
)
}
}
}
unsafe impl<T: ObjectSubclass + DeviceImpl> IsSubclassable<T> for DeviceClass {
fn override_vfuncs(&mut self) {
<glib::ObjectClass as IsSubclassable<T>>::override_vfuncs(self);
unsafe {
let klass = &mut *(self as *mut Self as *mut gst_sys::GstDeviceClass);
klass.create_element = Some(device_create_element::<T>);
klass.reconfigure_element = Some(device_reconfigure_element::<T>);
}
}
}
unsafe extern "C" fn device_create_element<T: ObjectSubclass>(
ptr: *mut gst_sys::GstDevice,
name: *const libc::c_char,
) -> *mut gst_sys::GstElement
where
T: DeviceImpl,
{
glib_floating_reference_guard!(ptr);
let instance = &*(ptr as *mut T::Instance);
let imp = instance.get_impl();
let wrap: Device = from_glib_borrow(ptr);
match imp.create_element(
&wrap,
Option::<glib::GString>::from_glib_borrow(name)
.as_ref()
.map(|s| s.as_str()),
) {
Some(element) => {
// The reference we're going to return, the initial reference is going to
// be dropped here now
let element_ptr = element.to_glib_full();
drop(element);
// See https://gitlab.freedesktop.org/gstreamer/gstreamer/issues/444
gobject_sys::g_object_force_floating(element_ptr as *mut gobject_sys::GObject);
element_ptr
}
None => ptr::null_mut(),
}
}
unsafe extern "C" fn device_reconfigure_element<T: ObjectSubclass>(
ptr: *mut gst_sys::GstDevice,
element: *mut gst_sys::GstElement,
) -> glib_sys::gboolean
where
T: DeviceImpl,
{
glib_floating_reference_guard!(ptr);
let instance = &*(ptr as *mut T::Instance);
let imp = instance.get_impl();
let wrap: Device = from_glib_borrow(ptr);
match imp.reconfigure_element(&wrap, &from_glib_borrow(element)) {
Ok(()) => true,
Err(err) => {
err.log_with_object(&wrap);
false
}
}
.to_glib()
}

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@ -27,11 +27,15 @@ pub mod element;
pub mod ghost_pad;
pub mod pad;
pub mod pipeline;
pub mod device;
pub mod uri_handler;
pub mod prelude {
pub use super::bin::{BinImpl, BinImplExt};
pub use super::child_proxy::ChildProxyImpl;
pub use super::device::{DeviceImpl, DeviceImplExt};
pub use super::element::{ElementClassSubclassExt, ElementImpl, ElementImplExt};
pub use super::ghost_pad::GhostPadImpl;
pub use super::pad::{PadImpl, PadImplExt};