gst-plugins-rs/generic/threadshare/tests/pad.rs

// Copyright (C) 2019-2020 François Laignel <fengalin@free.fr>
// Copyright (C) 2020 Sebastian Dröge <sebastian@centricular.com>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the
// Free Software Foundation, Inc., 51 Franklin Street, Suite 500,
// Boston, MA 02110-1335, USA.
//
// SPDX-License-Identifier: LGPL-2.1-or-later
#![allow(clippy::non_send_fields_in_send_ty, unused_doc_comments)]

use futures::channel::mpsc;
use futures::future::BoxFuture;
use futures::prelude::*;

use gst::glib;

use gst::prelude::*;
use gst::subclass::prelude::*;
use gst::EventView;

use std::sync::LazyLock;

use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Mutex;
use std::time::Duration;

use gstthreadshare::runtime::prelude::*;
use gstthreadshare::runtime::{Context, PadSink, PadSrc, Task, TaskState};

const DEFAULT_CONTEXT: &str = "";
const THROTTLING_DURATION: Duration = Duration::from_millis(2);

fn init() {
    use std::sync::Once;
    static INIT: Once = Once::new();

    INIT.call_once(|| {
        gst::init().unwrap();
        gstthreadshare::plugin_register_static().expect("gstthreadshare pad test");
    });
}

#[derive(Debug)]
pub enum Item {
    Buffer(gst::Buffer),
    BufferList(gst::BufferList),
    Event(gst::Event),
}

#[derive(Clone, Debug, glib::Boxed)]
#[boxed_type(name = "TsTestItemSender")]
struct ItemSender {
    sender: mpsc::Sender<Item>,
}

// Src
mod imp_src {
    use super::*;

    #[derive(Clone, Debug, Default)]
    struct Settings {
        context: String,
    }

    pub static SRC_CAT: LazyLock<gst::DebugCategory> = LazyLock::new(|| {
        gst::DebugCategory::new(
            "ts-element-src-test",
            gst::DebugColorFlags::empty(),
            Some("Thread-sharing Test Src Element"),
        )
    });

    #[derive(Clone, Debug)]
    struct PadSrcTestHandler;

    impl PadSrcHandler for PadSrcTestHandler {
        type ElementImpl = ElementSrcTest;

        fn src_event(self, pad: &gst::Pad, imp: &ElementSrcTest, event: gst::Event) -> bool {
            gst::log!(SRC_CAT, obj = pad, "Handling {:?}", event);

            let ret = match event.view() {
                EventView::FlushStart(..) => {
                    imp.task.flush_start().await_maybe_on_context().is_ok()
                }
                EventView::Qos(..) | EventView::Reconfigure(..) | EventView::Latency(..) => true,
                EventView::FlushStop(..) => imp.task.flush_stop().await_maybe_on_context().is_ok(),
                _ => false,
            };

            if ret {
                gst::log!(SRC_CAT, obj = pad, "Handled {:?}", event);
            } else {
                gst::log!(SRC_CAT, obj = pad, "Didn't handle {:?}", event);
            }

            ret
        }
    }

    #[derive(Debug)]
    struct ElementSrcTestTask {
        element: super::ElementSrcTest,
        receiver: mpsc::Receiver<Item>,
    }

    impl ElementSrcTestTask {
        fn new(element: super::ElementSrcTest, receiver: mpsc::Receiver<Item>) -> Self {
            ElementSrcTestTask { element, receiver }
        }
    }

    impl ElementSrcTestTask {
        fn flush(&mut self) {
            // Purge the channel
            while let Ok(Some(_item)) = self.receiver.try_next() {}
        }
        async fn push_item(&self, item: Item) -> Result<gst::FlowSuccess, gst::FlowError> {
            gst::debug!(SRC_CAT, obj = self.element, "Handling {:?}", item);

            let elementsrctest = self.element.imp();
            match item {
                Item::Event(event) => {
                    elementsrctest.src_pad.push_event(event).await;

                    Ok(gst::FlowSuccess::Ok)
                }
                Item::Buffer(buffer) => elementsrctest.src_pad.push(buffer).await,
                Item::BufferList(list) => elementsrctest.src_pad.push_list(list).await,
            }
        }
    }

    impl TaskImpl for ElementSrcTestTask {
        type Item = Item;

        fn try_next(&mut self) -> BoxFuture<'_, Result<Item, gst::FlowError>> {
            async move {
                self.receiver.next().await.ok_or_else(|| {
                    gst::log!(SRC_CAT, obj = self.element, "SrcPad channel aborted");
                    gst::FlowError::Eos
                })
            }
            .boxed()
        }

        fn handle_item(&mut self, item: Item) -> BoxFuture<'_, Result<(), gst::FlowError>> {
            async move {
                let res = self.push_item(item).await.map(drop);
                match res {
                    Ok(_) => gst::log!(SRC_CAT, obj = self.element, "Successfully pushed item"),
                    Err(gst::FlowError::Flushing) => {
                        gst::debug!(SRC_CAT, obj = self.element, "Flushing")
                    }
                    Err(err) => panic!("Got error {err}"),
                }

                res
            }
            .boxed()
        }

        fn stop(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
            async move {
                gst::log!(SRC_CAT, obj = self.element, "Stopping task");
                self.flush();
                gst::log!(SRC_CAT, obj = self.element, "Task stopped");
                Ok(())
            }
            .boxed()
        }

        fn flush_start(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
            async move {
                gst::log!(SRC_CAT, obj = self.element, "Starting task flush");
                self.flush();
                gst::log!(SRC_CAT, obj = self.element, "Task flush started");
                Ok(())
            }
            .boxed()
        }
    }

    #[derive(Debug)]
    pub struct ElementSrcTest {
        src_pad: PadSrc,
        task: Task,
        sender: Mutex<Option<mpsc::Sender<Item>>>,
        settings: Mutex<Settings>,
    }

    impl ElementSrcTest {
        pub fn try_push(&self, item: Item) -> Result<(), Item> {
            let state = self.task.lock_state();
            if *state != TaskState::Started && *state != TaskState::Paused {
                gst::debug!(SRC_CAT, "ElementSrcTest rejecting item due to pad state");

                return Err(item);
            }

            let mut sender = self.sender.lock().unwrap();
            match sender.as_mut() {
                Some(sender) => sender
                    .try_send(item)
                    .map_err(mpsc::TrySendError::into_inner),
                None => Err(item),
            }
        }

        fn prepare(&self) -> Result<(), gst::ErrorMessage> {
            gst::debug!(SRC_CAT, imp = self, "Preparing");

            let settings = self.settings.lock().unwrap().clone();
            let context =
                Context::acquire(&settings.context, THROTTLING_DURATION).map_err(|err| {
                    gst::error_msg!(
                        gst::ResourceError::OpenRead,
                        ["Failed to acquire Context: {}", err]
                    )
                })?;

            let (sender, receiver) = mpsc::channel(1);
            *self.sender.lock().unwrap() = Some(sender);

            self.task
                .prepare(
                    ElementSrcTestTask::new(self.obj().clone(), receiver),
                    context,
                )
                .block_on()?;

            gst::debug!(SRC_CAT, imp = self, "Prepared");

            Ok(())
        }

        fn unprepare(&self) {
            gst::debug!(SRC_CAT, imp = self, "Unpreparing");

            *self.sender.lock().unwrap() = None;
            self.task.unprepare().block_on().unwrap();

            gst::debug!(SRC_CAT, imp = self, "Unprepared");
        }

        fn stop(&self) {
            gst::debug!(SRC_CAT, imp = self, "Stopping");
            self.task.stop().await_maybe_on_context().unwrap();
            gst::debug!(SRC_CAT, imp = self, "Stopped");
        }

        fn start(&self) {
            gst::debug!(SRC_CAT, imp = self, "Starting");
            self.task.start().await_maybe_on_context().unwrap();
            gst::debug!(SRC_CAT, imp = self, "Started");
        }

        fn pause(&self) {
            gst::debug!(SRC_CAT, imp = self, "Pausing");
            self.task.pause().block_on().unwrap();
            gst::debug!(SRC_CAT, imp = self, "Paused");
        }
    }

    #[glib::object_subclass]
    impl ObjectSubclass for ElementSrcTest {
        const NAME: &'static str = "TsElementSrcTest";
        type Type = super::ElementSrcTest;
        type ParentType = gst::Element;

        fn with_class(klass: &Self::Class) -> Self {
            ElementSrcTest {
                src_pad: PadSrc::new(
                    gst::Pad::from_template(&klass.pad_template("src").unwrap()),
                    PadSrcTestHandler,
                ),
                task: Task::default(),
                sender: Mutex::new(None),
                settings: Mutex::new(Settings::default()),
            }
        }
    }

    impl ObjectImpl for ElementSrcTest {
        fn properties() -> &'static [glib::ParamSpec] {
            static PROPERTIES: LazyLock<Vec<glib::ParamSpec>> = LazyLock::new(|| {
                vec![glib::ParamSpecString::builder("context")
                    .nick("Context")
                    .blurb("Context name to share threads with")
                    .default_value(Some(DEFAULT_CONTEXT))
                    .write_only()
                    .build()]
            });

            PROPERTIES.as_ref()
        }

        fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
            match pspec.name() {
                "context" => {
                    let context = value
                        .get::<Option<String>>()
                        .expect("type checked upstream")
                        .unwrap_or_else(|| "".into());

                    self.settings.lock().unwrap().context = context;
                }
                _ => unimplemented!(),
            }
        }

        fn constructed(&self) {
            self.parent_constructed();

            let obj = self.obj();
            obj.add_pad(self.src_pad.gst_pad()).unwrap();
            obj.set_element_flags(gst::ElementFlags::SOURCE);
        }
    }

    impl GstObjectImpl for ElementSrcTest {}

    impl ElementImpl for ElementSrcTest {
        fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
            static ELEMENT_METADATA: LazyLock<gst::subclass::ElementMetadata> =
                LazyLock::new(|| {
                    gst::subclass::ElementMetadata::new(
                        "Thread-sharing Test Src Element",
                        "Generic",
                        "Src Element for Pad Src Test",
                        "François Laignel <fengalin@free.fr>",
                    )
                });

            Some(&*ELEMENT_METADATA)
        }

        fn pad_templates() -> &'static [gst::PadTemplate] {
            static PAD_TEMPLATES: LazyLock<Vec<gst::PadTemplate>> = LazyLock::new(|| {
                let caps = gst::Caps::new_any();
                let src_pad_template = gst::PadTemplate::new(
                    "src",
                    gst::PadDirection::Src,
                    gst::PadPresence::Always,
                    &caps,
                )
                .unwrap();

                vec![src_pad_template]
            });

            PAD_TEMPLATES.as_ref()
        }

        fn change_state(
            &self,
            transition: gst::StateChange,
        ) -> Result<gst::StateChangeSuccess, gst::StateChangeError> {
            gst::log!(SRC_CAT, imp = self, "Changing state {:?}", transition);

            match transition {
                gst::StateChange::NullToReady => {
                    self.prepare().map_err(|err| {
                        self.post_error_message(err);
                        gst::StateChangeError
                    })?;
                }
                gst::StateChange::PlayingToPaused => {
                    self.pause();
                }
                gst::StateChange::ReadyToNull => {
                    self.unprepare();
                }
                _ => (),
            }

            let mut success = self.parent_change_state(transition)?;

            match transition {
                gst::StateChange::PausedToReady => {
                    self.stop();
                }
                gst::StateChange::PausedToPlaying => {
                    self.start();
                }
                gst::StateChange::ReadyToPaused | gst::StateChange::PlayingToPaused => {
                    success = gst::StateChangeSuccess::NoPreroll;
                }
                _ => (),
            }

            Ok(success)
        }

        fn send_event(&self, event: gst::Event) -> bool {
            match event.view() {
                EventView::FlushStart(..) => {
                    self.task.flush_start().await_maybe_on_context().unwrap();
                }
                EventView::FlushStop(..) => {
                    self.task.flush_stop().await_maybe_on_context().unwrap();
                }
                _ => (),
            }

            if !event.is_serialized() {
                self.src_pad.gst_pad().push_event(event)
            } else {
                self.try_push(Item::Event(event)).is_ok()
            }
        }
    }
}

glib::wrapper! {
    pub struct ElementSrcTest(ObjectSubclass<imp_src::ElementSrcTest>) @extends gst::Element, gst::Object;
}

// Sink

mod imp_sink {
    use super::*;

    #[derive(Clone, Debug, Default)]
    struct PadSinkTestHandler;

    impl PadSinkHandler for PadSinkTestHandler {
        type ElementImpl = ElementSinkTest;

        fn sink_chain(
            self,
            _pad: gst::Pad,
            elem: super::ElementSinkTest,
            buffer: gst::Buffer,
        ) -> BoxFuture<'static, Result<gst::FlowSuccess, gst::FlowError>> {
            async move {
                let imp = elem.imp();
                imp.forward_item(Item::Buffer(buffer)).await
            }
            .boxed()
        }

        fn sink_chain_list(
            self,
            _pad: gst::Pad,
            elem: super::ElementSinkTest,
            list: gst::BufferList,
        ) -> BoxFuture<'static, Result<gst::FlowSuccess, gst::FlowError>> {
            async move {
                let imp = elem.imp();
                imp.forward_item(Item::BufferList(list)).await
            }
            .boxed()
        }

        fn sink_event(self, pad: &gst::Pad, imp: &ElementSinkTest, event: gst::Event) -> bool {
            gst::debug!(SINK_CAT, obj = pad, "Handling non-serialized {:?}", event);

            match event.view() {
                EventView::FlushStart(..) => {
                    imp.stop();
                    true
                }
                _ => false,
            }
        }

        fn sink_event_serialized(
            self,
            pad: gst::Pad,
            elem: super::ElementSinkTest,
            event: gst::Event,
        ) -> BoxFuture<'static, bool> {
            async move {
                gst::log!(SINK_CAT, obj = pad, "Handling serialized {:?}", event);

                let imp = elem.imp();
                if let EventView::FlushStop(..) = event.view() {
                    imp.start();
                }

                imp.forward_item(Item::Event(event)).await.is_ok()
            }
            .boxed()
        }
    }

    #[derive(Debug)]
    pub struct ElementSinkTest {
        sink_pad: PadSink,
        flushing: AtomicBool,
        sender: Mutex<Option<mpsc::Sender<Item>>>,
    }

    impl ElementSinkTest {
        async fn forward_item(&self, item: Item) -> Result<gst::FlowSuccess, gst::FlowError> {
            if !self.flushing.load(Ordering::SeqCst) {
                gst::debug!(SINK_CAT, imp = self, "Forwarding {:?}", item);
                let mut sender = self
                    .sender
                    .lock()
                    .unwrap()
                    .as_mut()
                    .expect("Item Sender not set")
                    .clone();
                sender
                    .send(item)
                    .await
                    .map(|_| gst::FlowSuccess::Ok)
                    .map_err(|_| gst::FlowError::Error)
            } else {
                gst::debug!(
                    SINK_CAT,
                    imp = self,
                    "Not forwarding {:?} due to flushing",
                    item
                );
                Err(gst::FlowError::Flushing)
            }
        }

        fn start(&self) {
            gst::debug!(SINK_CAT, imp = self, "Starting");
            self.flushing.store(false, Ordering::SeqCst);
            gst::debug!(SINK_CAT, imp = self, "Started");
        }

        fn stop(&self) {
            gst::debug!(SINK_CAT, imp = self, "Stopping");
            self.flushing.store(true, Ordering::SeqCst);
            gst::debug!(SINK_CAT, imp = self, "Stopped");
        }

        pub fn push_flush_start(&self) {
            gst::debug!(SINK_CAT, imp = self, "Pushing FlushStart");
            self.sink_pad
                .gst_pad()
                .push_event(gst::event::FlushStart::new());
            gst::debug!(SINK_CAT, imp = self, "FlushStart pushed");
        }

        pub fn push_flush_stop(&self) {
            gst::debug!(SINK_CAT, imp = self, "Pushing FlushStop");
            self.sink_pad
                .gst_pad()
                .push_event(gst::event::FlushStop::new(true));
            gst::debug!(SINK_CAT, imp = self, "FlushStop pushed");
        }
    }

    static SINK_CAT: LazyLock<gst::DebugCategory> = LazyLock::new(|| {
        gst::DebugCategory::new(
            "ts-element-sink-test",
            gst::DebugColorFlags::empty(),
            Some("Thread-sharing Test Sink Element"),
        )
    });

    #[glib::object_subclass]
    impl ObjectSubclass for ElementSinkTest {
        const NAME: &'static str = "TsElementSinkTest";
        type Type = super::ElementSinkTest;
        type ParentType = gst::Element;

        fn with_class(klass: &Self::Class) -> Self {
            ElementSinkTest {
                sink_pad: PadSink::new(
                    gst::Pad::from_template(&klass.pad_template("sink").unwrap()),
                    PadSinkTestHandler,
                ),
                flushing: AtomicBool::new(true),
                sender: Mutex::new(None),
            }
        }
    }

    impl ObjectImpl for ElementSinkTest {
        fn properties() -> &'static [glib::ParamSpec] {
            static PROPERTIES: LazyLock<Vec<glib::ParamSpec>> = LazyLock::new(|| {
                vec![glib::ParamSpecBoxed::builder::<ItemSender>("sender")
                    .nick("Sender")
                    .blurb("Channel sender to forward the incoming items to")
                    .write_only()
                    .construct_only()
                    .build()]
            });

            PROPERTIES.as_ref()
        }

        fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
            match pspec.name() {
                "sender" => {
                    let ItemSender { sender } = value
                        .get::<&ItemSender>()
                        .expect("type checked upstream")
                        .clone();
                    *self.sender.lock().unwrap() = Some(sender);
                }
                _ => unimplemented!(),
            }
        }

        fn constructed(&self) {
            self.parent_constructed();

            let obj = self.obj();
            obj.add_pad(self.sink_pad.gst_pad()).unwrap();
            obj.set_element_flags(gst::ElementFlags::SINK);
        }
    }

    impl GstObjectImpl for ElementSinkTest {}

    impl ElementImpl for ElementSinkTest {
        fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
            static ELEMENT_METADATA: LazyLock<gst::subclass::ElementMetadata> =
                LazyLock::new(|| {
                    gst::subclass::ElementMetadata::new(
                        "Thread-sharing Test Sink Element",
                        "Generic",
                        "Sink Element for Pad Test",
                        "François Laignel <fengalin@free.fr>",
                    )
                });

            Some(&*ELEMENT_METADATA)
        }

        fn pad_templates() -> &'static [gst::PadTemplate] {
            static PAD_TEMPLATES: LazyLock<Vec<gst::PadTemplate>> = LazyLock::new(|| {
                let caps = gst::Caps::new_any();
                let sink_pad_template = gst::PadTemplate::new(
                    "sink",
                    gst::PadDirection::Sink,
                    gst::PadPresence::Always,
                    &caps,
                )
                .unwrap();

                vec![sink_pad_template]
            });

            PAD_TEMPLATES.as_ref()
        }

        fn change_state(
            &self,
            transition: gst::StateChange,
        ) -> Result<gst::StateChangeSuccess, gst::StateChangeError> {
            gst::log!(SINK_CAT, imp = self, "Changing state {:?}", transition);

            if let gst::StateChange::PausedToReady = transition {
                self.stop();
            }

            let success = self.parent_change_state(transition)?;

            if let gst::StateChange::ReadyToPaused = transition {
                self.start();
            }

            Ok(success)
        }
    }
}

glib::wrapper! {
    pub struct ElementSinkTest(ObjectSubclass<imp_sink::ElementSinkTest>) @extends gst::Element, gst::Object;
}

fn setup(
    context_name: &str,
    mut middle_element_1: Option<gst::Element>,
    mut middle_element_2: Option<gst::Element>,
) -> (
    gst::Pipeline,
    ElementSrcTest,
    ElementSinkTest,
    mpsc::Receiver<Item>,
) {
    init();

    let pipeline = gst::Pipeline::default();

    // Src
    let src_element = glib::Object::new::<ElementSrcTest>();
    src_element.set_property("context", context_name);
    pipeline.add(&src_element).unwrap();

    let mut last_element = src_element.clone().upcast::<gst::Element>();

    if let Some(middle_element) = middle_element_1.take() {
        pipeline.add(&middle_element).unwrap();
        last_element.link(&middle_element).unwrap();
        last_element = middle_element;
    }

    if let Some(middle_element) = middle_element_2.take() {
        // Don't link the 2 middle elements: this is used for ts-proxy
        pipeline.add(&middle_element).unwrap();
        last_element = middle_element;
    }

    // Sink
    let (sender, receiver) = mpsc::channel::<Item>(10);
    let sink_element = glib::Object::builder::<ElementSinkTest>()
        .property("sender", ItemSender { sender })
        .build();
    pipeline.add(&sink_element).unwrap();
    last_element.link(&sink_element).unwrap();

    (pipeline, src_element, sink_element, receiver)
}

fn nominal_scenario(
    scenario_name: &str,
    pipeline: gst::Pipeline,
    src_element: ElementSrcTest,
    mut receiver: mpsc::Receiver<Item>,
) {
    let elem_src_test = src_element.imp();

    pipeline.set_state(gst::State::Playing).unwrap();

    // Initial events
    elem_src_test
        .try_push(Item::Event(
            gst::event::StreamStart::builder(scenario_name)
                .group_id(gst::GroupId::next())
                .build(),
        ))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::StreamStart(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    // Buffer
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![1, 2, 3, 4])))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![1, 2, 3, 4].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    // BufferList
    let mut list = gst::BufferList::new();
    list.get_mut()
        .unwrap()
        .add(gst::Buffer::from_slice(vec![1, 2, 3, 4]));
    elem_src_test.try_push(Item::BufferList(list)).unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::BufferList(_) => (),
        other => panic!("Unexpected item {other:?}"),
    }

    // Pause the Pad task
    pipeline.set_state(gst::State::Paused).unwrap();

    // Item accepted, but not processed before switching to Playing again
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![5, 6, 7])))
        .unwrap();

    // Nothing forwarded
    receiver.try_next().unwrap_err();

    // Switch back the Pad task to Started
    pipeline.set_state(gst::State::Playing).unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![5, 6, 7].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    // Flush
    src_element.send_event(gst::event::FlushStart::new());
    src_element.send_event(gst::event::FlushStop::new(true));

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::FlushStop(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    // Buffer
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![8, 9])))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![8, 9].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    // EOS
    elem_src_test
        .try_push(Item::Event(gst::event::Eos::new()))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Eos(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    pipeline.set_state(gst::State::Ready).unwrap();

    // Receiver was dropped when stopping => can't send anymore
    elem_src_test
        .try_push(Item::Event(
            gst::event::StreamStart::builder(&format!("{scenario_name}_past_stop"))
                .group_id(gst::GroupId::next())
                .build(),
        ))
        .unwrap_err();

    pipeline.set_state(gst::State::Null).unwrap();
}

#[test]
fn src_sink_nominal() {
    let name = "src_sink_nominal";

    let (pipeline, src_element, _sink_element, receiver) = setup(name, None, None);

    nominal_scenario(name, pipeline, src_element, receiver);
}

#[test]
fn src_tsqueue_sink_nominal() {
    init();

    let name = "src_tsqueue_sink";

    let ts_queue = gst::ElementFactory::make("ts-queue")
        .name("ts-queue")
        .property("context", format!("{name}_queue"))
        .property("context-wait", THROTTLING_DURATION.as_millis() as u32)
        .build()
        .unwrap();

    let (pipeline, src_element, _sink_element, receiver) = setup(name, Some(ts_queue), None);

    nominal_scenario(name, pipeline, src_element, receiver);
}

#[test]
fn src_queue_sink_nominal() {
    init();

    let name = "src_queue_sink";

    let queue = gst::ElementFactory::make("queue")
        .name("queue")
        .build()
        .unwrap();
    let (pipeline, src_element, _sink_element, receiver) = setup(name, Some(queue), None);

    nominal_scenario(name, pipeline, src_element, receiver);
}

#[test]
fn src_tsproxy_sink_nominal() {
    init();

    let name = "src_tsproxy_sink";

    let ts_proxy_sink = gst::ElementFactory::make("ts-proxysink")
        .name("ts-proxysink")
        .property("proxy-context", format!("{name}_proxy_context"))
        .build()
        .unwrap();

    let ts_proxy_src = gst::ElementFactory::make("ts-proxysrc")
        .name("ts-proxysrc")
        .property("proxy-context", format!("{name}_proxy_context"))
        .property("context", format!("{name}_context"))
        .property("context-wait", THROTTLING_DURATION.as_millis() as u32)
        .build()
        .unwrap();

    let (pipeline, src_element, _sink_element, receiver) =
        setup(name, Some(ts_proxy_sink), Some(ts_proxy_src));

    nominal_scenario(name, pipeline, src_element, receiver);
}

#[test]
fn start_pause_start() {
    init();

    let scenario_name = "start_pause_start";

    let (pipeline, src_element, _sink_element, mut receiver) = setup(scenario_name, None, None);

    let elem_src_test = src_element.imp();

    pipeline.set_state(gst::State::Playing).unwrap();

    // Initial events
    elem_src_test
        .try_push(Item::Event(
            gst::event::StreamStart::builder(scenario_name)
                .group_id(gst::GroupId::next())
                .build(),
        ))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::StreamStart(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    // Buffer
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![1, 2, 3, 4])))
        .unwrap();

    pipeline.set_state(gst::State::Paused).unwrap();

    pipeline.set_state(gst::State::Playing).unwrap();

    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![5, 6, 7])))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![1, 2, 3, 4].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![5, 6, 7].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    // Nothing else forwarded
    receiver.try_next().unwrap_err();

    pipeline.set_state(gst::State::Null).unwrap();
}

#[test]
fn start_stop_start() {
    init();

    let scenario_name = "start_stop_start";

    let (pipeline, src_element, _sink_element, mut receiver) = setup(scenario_name, None, None);

    let elem_src_test = src_element.imp();

    pipeline.set_state(gst::State::Playing).unwrap();

    // Initial events
    elem_src_test
        .try_push(Item::Event(
            gst::event::StreamStart::builder(&format!("{scenario_name}-after_stop"))
                .group_id(gst::GroupId::next())
                .build(),
        ))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::StreamStart(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    // Buffer
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![1, 2, 3, 4])))
        .unwrap();

    pipeline.set_state(gst::State::Ready).unwrap();

    pipeline.set_state(gst::State::Playing).unwrap();

    // Initial events again
    elem_src_test
        .try_push(Item::Event(
            gst::event::StreamStart::builder(scenario_name)
                .group_id(gst::GroupId::next())
                .build(),
        ))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(_buffer) => {
            gst::info!(
                imp_src::SRC_CAT,
                "{}: initial buffer went through, don't expect any pending item to be dropped",
                scenario_name
            );

            match futures::executor::block_on(receiver.next()).unwrap() {
                Item::Event(event) => match event.view() {
                    EventView::StreamStart(_) => (),
                    other => panic!("Unexpected event {other:?}"),
                },
                other => panic!("Unexpected item {other:?}"),
            }
        }
        Item::Event(event) => match event.view() {
            EventView::StreamStart(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![5, 6, 7])))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![5, 6, 7].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    pipeline.set_state(gst::State::Null).unwrap();
}

#[test]
fn start_flush() {
    init();

    let scenario_name = "start_flush";

    let (pipeline, src_element, sink_element, mut receiver) = setup(scenario_name, None, None);

    let elem_src_test = src_element.imp();

    pipeline.set_state(gst::State::Playing).unwrap();

    // Initial events
    elem_src_test
        .try_push(Item::Event(
            gst::event::StreamStart::builder(&format!("{scenario_name}-after_stop"))
                .group_id(gst::GroupId::next())
                .build(),
        ))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::StreamStart(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        other => panic!("Unexpected item {other:?}"),
    }

    // Buffer
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![1, 2, 3, 4])))
        .unwrap();

    let elem_sink_test = sink_element.imp();

    elem_sink_test.push_flush_start();

    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![5, 6, 7])))
        .unwrap_err();

    elem_sink_test.push_flush_stop();

    elem_src_test
        .try_push(Item::Event(gst::event::Segment::new(
            &gst::FormattedSegment::<gst::format::Time>::new(),
        )))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Event(event) => match event.view() {
            EventView::Segment(_) => (),
            other => panic!("Unexpected event {other:?}"),
        },
        Item::Buffer(buffer) => {
            // In some cases, the first Buffer might be processed before FlushStart
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![1, 2, 3, 4].as_slice());

            match futures::executor::block_on(receiver.next()).unwrap() {
                Item::Event(event) => match event.view() {
                    EventView::Segment(_) => (),
                    other => panic!("Unexpected event {other:?}"),
                },
                other => panic!("Unexpected item {other:?}"),
            }
        }
        other => panic!("Unexpected item {other:?}"),
    }

    // Post flush buffer
    elem_src_test
        .try_push(Item::Buffer(gst::Buffer::from_slice(vec![8, 9])))
        .unwrap();

    match futures::executor::block_on(receiver.next()).unwrap() {
        Item::Buffer(buffer) => {
            let data = buffer.map_readable().unwrap();
            assert_eq!(data.as_slice(), vec![8, 9].as_slice());
        }
        other => panic!("Unexpected item {other:?}"),
    }

    pipeline.set_state(gst::State::Null).unwrap();
}