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// This file was generated by gir (https://github.com/gtk-rs/gir)
// from gir-files (https://github.com/gtk-rs/gir-files)
// from gst-gir-files (https://gitlab.freedesktop.org/gstreamer/gir-files-rs.git)
// DO NOT EDIT

use crate::Caps;
use crate::Element;
use crate::Event;
use crate::FlowError;
use crate::FlowSuccess;
use crate::Object;
use crate::PadDirection;
use crate::PadLinkCheck;
use crate::PadLinkError;
use crate::PadLinkSuccess;
use crate::PadMode;
use crate::PadTemplate;
use crate::Stream;
use crate::TaskState;
use glib::object::Cast;
use glib::object::IsA;
use glib::signal::connect_raw;
use glib::signal::SignalHandlerId;
use glib::translate::*;
use glib::StaticType;
use std::boxed::Box as Box_;
use std::mem::transmute;

glib::wrapper! {
    /// A [`Element`][crate::Element] is linked to other elements via "pads", which are extremely
    /// light-weight generic link points.
    ///
    /// Pads have a [`PadDirection`][crate::PadDirection], source pads produce data, sink pads consume
    /// data.
    ///
    /// Pads are typically created from a [`PadTemplate`][crate::PadTemplate] with
    /// [`from_template()`][Self::from_template()] and are then added to a [`Element`][crate::Element]. This usually
    /// happens when the element is created but it can also happen dynamically based
    /// on the data that the element is processing or based on the pads that the
    /// application requests.
    ///
    /// Pads without pad templates can be created with [`new()`][Self::new()],
    /// which takes a direction and a name as an argument. If the name is [`None`],
    /// then a guaranteed unique name will be assigned to it.
    ///
    /// A [`Element`][crate::Element] creating a pad will typically use the various
    /// gst_pad_set_*_function\() calls to register callbacks for events, queries or
    /// dataflow on the pads.
    ///
    /// `gst_pad_get_parent()` will retrieve the [`Element`][crate::Element] that owns the pad.
    ///
    /// After two pads are retrieved from an element by [`ElementExt::static_pad()`][crate::prelude::ElementExt::static_pad()],
    /// the pads can be linked with [`PadExt::link()`][crate::prelude::PadExt::link()]. (For quick links,
    /// you can also use [`ElementExtManual::link()`][crate::prelude::ElementExtManual::link()], which will make the obvious
    /// link for you if it's straightforward.). Pads can be unlinked again with
    /// [`PadExt::unlink()`][crate::prelude::PadExt::unlink()]. [`PadExt::peer()`][crate::prelude::PadExt::peer()] can be used to check what the pad is
    /// linked to.
    ///
    /// Before dataflow is possible on the pads, they need to be activated with
    /// [`PadExt::set_active()`][crate::prelude::PadExt::set_active()].
    ///
    /// [`PadExtManual::query()`][crate::prelude::PadExtManual::query()] and [`PadExtManual::peer_query()`][crate::prelude::PadExtManual::peer_query()] can be used to query various
    /// properties of the pad and the stream.
    ///
    /// To send a [`Event`][crate::Event] on a pad, use [`PadExtManual::send_event()`][crate::prelude::PadExtManual::send_event()] and
    /// [`PadExtManual::push_event()`][crate::prelude::PadExtManual::push_event()]. Some events will be sticky on the pad, meaning that
    /// after they pass on the pad they can be queried later with
    /// [`PadExtManual::sticky_event()`][crate::prelude::PadExtManual::sticky_event()] and [`PadExtManual::sticky_events_foreach()`][crate::prelude::PadExtManual::sticky_events_foreach()].
    /// [`PadExt::current_caps()`][crate::prelude::PadExt::current_caps()] and [`PadExt::has_current_caps()`][crate::prelude::PadExt::has_current_caps()] are convenience
    /// functions to query the current sticky CAPS event on a pad.
    ///
    /// GstElements will use [`PadExtManual::push()`][crate::prelude::PadExtManual::push()] and [`PadExtManual::pull_range()`][crate::prelude::PadExtManual::pull_range()] to push out
    /// or pull in a buffer.
    ///
    /// The dataflow, events and queries that happen on a pad can be monitored with
    /// probes that can be installed with [`PadExtManual::add_probe()`][crate::prelude::PadExtManual::add_probe()]. [`PadExt::is_blocked()`][crate::prelude::PadExt::is_blocked()]
    /// can be used to check if a block probe is installed on the pad.
    /// [`PadExt::is_blocking()`][crate::prelude::PadExt::is_blocking()] checks if the blocking probe is currently blocking the
    /// pad. [`PadExtManual::remove_probe()`][crate::prelude::PadExtManual::remove_probe()] is used to remove a previously installed probe
    /// and unblock blocking probes if any.
    ///
    /// Pad have an offset that can be retrieved with [`PadExt::offset()`][crate::prelude::PadExt::offset()]. This
    /// offset will be applied to the running_time of all data passing over the pad.
    /// [`PadExt::set_offset()`][crate::prelude::PadExt::set_offset()] can be used to change the offset.
    ///
    /// Convenience functions exist to start, pause and stop the task on a pad with
    /// [`PadExtManual::start_task()`][crate::prelude::PadExtManual::start_task()], [`PadExt::pause_task()`][crate::prelude::PadExt::pause_task()] and [`PadExt::stop_task()`][crate::prelude::PadExt::stop_task()]
    /// respectively.
    ///
    /// # Implements
    ///
    /// [`PadExt`][trait@crate::prelude::PadExt], [`GstObjectExt`][trait@crate::prelude::GstObjectExt], [`trait@glib::ObjectExt`], [`PadExtManual`][trait@crate::prelude::PadExtManual]
    #[doc(alias = "GstPad")]
    pub struct Pad(Object<ffi::GstPad, ffi::GstPadClass>) @extends Object;

    match fn {
        type_ => || ffi::gst_pad_get_type(),
    }
}

impl Pad {
    pub const NONE: Option<&'static Pad> = None;
}

unsafe impl Send for Pad {}
unsafe impl Sync for Pad {}

/// Trait containing all [`struct@Pad`] methods.
///
/// # Implementors
///
/// [`Pad`][struct@crate::Pad], [`ProxyPad`][struct@crate::ProxyPad]
pub trait PadExt: 'static {
    /// Activates or deactivates the given pad in `mode` via dispatching to the
    /// pad's activatemodefunc. For use from within pad activation functions only.
    ///
    /// If you don't know what this is, you probably don't want to call it.
    /// ## `mode`
    /// the requested activation mode
    /// ## `active`
    /// whether or not the pad should be active.
    ///
    /// # Returns
    ///
    /// [`true`] if the operation was successful.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_activate_mode")]
    fn activate_mode(&self, mode: PadMode, active: bool) -> Result<(), glib::error::BoolError>;

    /// Checks if the source pad and the sink pad are compatible so they can be
    /// linked.
    /// ## `sinkpad`
    /// the sink [`Pad`][crate::Pad].
    ///
    /// # Returns
    ///
    /// [`true`] if the pads can be linked.
    #[doc(alias = "gst_pad_can_link")]
    fn can_link(&self, sinkpad: &impl IsA<Pad>) -> bool;

    /// Check and clear the [`PadFlags::NEED_RECONFIGURE`][crate::PadFlags::NEED_RECONFIGURE] flag on `self` and return [`true`]
    /// if the flag was set.
    ///
    /// # Returns
    ///
    /// [`true`] is the GST_PAD_FLAG_NEED_RECONFIGURE flag was set on `self`.
    #[doc(alias = "gst_pad_check_reconfigure")]
    fn check_reconfigure(&self) -> bool;

    /// Creates a stream-id for the source [`Pad`][crate::Pad] `self` by combining the
    /// upstream information with the optional `stream_id` of the stream
    /// of `self`. `self` must have a parent [`Element`][crate::Element] and which must have zero
    /// or one sinkpad. `stream_id` can only be [`None`] if the parent element
    /// of `self` has only a single source pad.
    ///
    /// This function generates an unique stream-id by getting the upstream
    /// stream-start event stream ID and appending `stream_id` to it. If the
    /// element has no sinkpad it will generate an upstream stream-id by
    /// doing an URI query on the element and in the worst case just uses
    /// a random number. Source elements that don't implement the URI
    /// handler interface should ideally generate a unique, deterministic
    /// stream-id manually instead.
    ///
    /// Since stream IDs are sorted alphabetically, any numbers in the
    /// stream ID should be printed with a fixed number of characters,
    /// preceded by 0's, such as by using the format \`03u` instead of \`u`.
    /// ## `parent`
    /// Parent [`Element`][crate::Element] of `self`
    /// ## `stream_id`
    /// The stream-id
    ///
    /// # Returns
    ///
    /// A stream-id for `self`. `g_free()` after usage.
    #[doc(alias = "gst_pad_create_stream_id")]
    fn create_stream_id(
        &self,
        parent: &impl IsA<Element>,
        stream_id: Option<&str>,
    ) -> glib::GString;

    //#[doc(alias = "gst_pad_create_stream_id_printf")]
    //fn create_stream_id_printf(&self, parent: &impl IsA<Element>, stream_id: Option<&str>, : /*Unknown conversion*//*Unimplemented*/Basic: VarArgs) -> glib::GString;

    //#[doc(alias = "gst_pad_create_stream_id_printf_valist")]
    //fn create_stream_id_printf_valist(&self, parent: &impl IsA<Element>, stream_id: Option<&str>, var_args: /*Unknown conversion*//*Unimplemented*/Unsupported) -> glib::GString;

    /// Calls `forward` for all internally linked pads of `self`. This function deals with
    /// dynamically changing internal pads and will make sure that the `forward`
    /// function is only called once for each pad.
    ///
    /// When `forward` returns [`true`], no further pads will be processed.
    /// ## `forward`
    /// a `GstPadForwardFunction`
    ///
    /// # Returns
    ///
    /// [`true`] if one of the dispatcher functions returned [`true`].
    #[doc(alias = "gst_pad_forward")]
    fn forward<P: FnMut(&Pad) -> bool>(&self, forward: P) -> bool;

    /// Gets the capabilities of the allowed media types that can flow through
    /// `self` and its peer.
    ///
    /// The allowed capabilities is calculated as the intersection of the results of
    /// calling [`query_caps()`][Self::query_caps()] on `self` and its peer. The caller owns a reference
    /// on the resulting caps.
    ///
    /// # Returns
    ///
    /// the allowed [`Caps`][crate::Caps] of the
    ///  pad link. Unref the caps when you no longer need it. This
    ///  function returns [`None`] when `self` has no peer.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_get_allowed_caps")]
    #[doc(alias = "get_allowed_caps")]
    fn allowed_caps(&self) -> Option<Caps>;

    /// Gets the capabilities currently configured on `self` with the last
    /// [`EventType::Caps`][crate::EventType::Caps] event.
    ///
    /// # Returns
    ///
    /// the current caps of the pad with
    /// incremented ref-count or [`None`] when pad has no caps. Unref after usage.
    #[doc(alias = "gst_pad_get_current_caps")]
    #[doc(alias = "get_current_caps")]
    fn current_caps(&self) -> Option<Caps>;

    /// Gets the direction of the pad. The direction of the pad is
    /// decided at construction time so this function does not take
    /// the LOCK.
    ///
    /// # Returns
    ///
    /// the [`PadDirection`][crate::PadDirection] of the pad.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_get_direction")]
    #[doc(alias = "get_direction")]
    fn direction(&self) -> PadDirection;

    //#[doc(alias = "gst_pad_get_element_private")]
    //#[doc(alias = "get_element_private")]
    //fn element_private(&self) -> /*Unimplemented*/Option<Basic: Pointer>;

    /// Gets the [`FlowReturn`][crate::FlowReturn] return from the last data passed by this pad.
    #[doc(alias = "gst_pad_get_last_flow_return")]
    #[doc(alias = "get_last_flow_return")]
    fn last_flow_result(&self) -> Result<FlowSuccess, FlowError>;

    /// Get the offset applied to the running time of `self`. `self` has to be a source
    /// pad.
    ///
    /// # Returns
    ///
    /// the offset.
    #[doc(alias = "gst_pad_get_offset")]
    #[doc(alias = "get_offset")]
    fn offset(&self) -> i64;

    /// Gets the template for `self`.
    ///
    /// # Returns
    ///
    /// the [`PadTemplate`][crate::PadTemplate] from which
    ///  this pad was instantiated, or [`None`] if this pad has no
    ///  template. Unref after usage.
    #[doc(alias = "gst_pad_get_pad_template")]
    #[doc(alias = "get_pad_template")]
    fn pad_template(&self) -> Option<PadTemplate>;

    /// Gets the capabilities for `self`'s template.
    ///
    /// # Returns
    ///
    /// the [`Caps`][crate::Caps] of this pad template.
    /// Unref after usage.
    #[doc(alias = "gst_pad_get_pad_template_caps")]
    #[doc(alias = "get_pad_template_caps")]
    fn pad_template_caps(&self) -> Caps;

    /// Gets the parent of `self`, cast to a [`Element`][crate::Element]. If a `self` has no parent or
    /// its parent is not an element, return [`None`].
    ///
    /// # Returns
    ///
    /// the parent of the pad. The
    /// caller has a reference on the parent, so unref when you're finished
    /// with it.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_get_parent_element")]
    #[doc(alias = "get_parent_element")]
    fn parent_element(&self) -> Option<Element>;

    /// Gets the peer of `self`. This function refs the peer pad so
    /// you need to unref it after use.
    ///
    /// # Returns
    ///
    /// the peer [`Pad`][crate::Pad]. Unref after usage.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_get_peer")]
    #[doc(alias = "get_peer")]
    #[must_use]
    fn peer(&self) -> Option<Pad>;

    /// If there is a single internal link of the given pad, this function will
    /// return it. Otherwise, it will return NULL.
    ///
    /// # Returns
    ///
    /// a [`Pad`][crate::Pad], or [`None`] if `self` has none
    /// or more than one internal links. Unref returned pad with
    /// `gst_object_unref()`.
    #[cfg(any(feature = "v1_18", feature = "dox"))]
    #[cfg_attr(feature = "dox", doc(cfg(feature = "v1_18")))]
    #[doc(alias = "gst_pad_get_single_internal_link")]
    #[doc(alias = "get_single_internal_link")]
    #[must_use]
    fn single_internal_link(&self) -> Option<Pad>;

    /// Returns the current [`Stream`][crate::Stream] for the `self`, or [`None`] if none has been
    /// set yet, i.e. the pad has not received a stream-start event yet.
    ///
    /// This is a convenience wrapper around [`PadExtManual::sticky_event()`][crate::prelude::PadExtManual::sticky_event()] and
    /// `gst_event_parse_stream()`.
    ///
    /// # Returns
    ///
    /// the current [`Stream`][crate::Stream] for `self`, or [`None`].
    ///  unref the returned stream when no longer needed.
    #[doc(alias = "gst_pad_get_stream")]
    #[doc(alias = "get_stream")]
    fn stream(&self) -> Option<Stream>;

    /// Returns the current stream-id for the `self`, or [`None`] if none has been
    /// set yet, i.e. the pad has not received a stream-start event yet.
    ///
    /// This is a convenience wrapper around [`PadExtManual::sticky_event()`][crate::prelude::PadExtManual::sticky_event()] and
    /// `gst_event_parse_stream_start()`.
    ///
    /// The returned stream-id string should be treated as an opaque string, its
    /// contents should not be interpreted.
    ///
    /// # Returns
    ///
    /// a newly-allocated copy of the stream-id for
    ///  `self`, or [`None`]. `g_free()` the returned string when no longer
    ///  needed.
    #[doc(alias = "gst_pad_get_stream_id")]
    #[doc(alias = "get_stream_id")]
    fn stream_id(&self) -> Option<glib::GString>;

    /// Get `self` task state. If no task is currently
    /// set, [`TaskState::Stopped`][crate::TaskState::Stopped] is returned.
    ///
    /// # Returns
    ///
    /// The current state of `self`'s task.
    #[doc(alias = "gst_pad_get_task_state")]
    #[doc(alias = "get_task_state")]
    fn task_state(&self) -> TaskState;

    /// Check if `self` has caps set on it with a [`EventType::Caps`][crate::EventType::Caps] event.
    ///
    /// # Returns
    ///
    /// [`true`] when `self` has caps associated with it.
    #[doc(alias = "gst_pad_has_current_caps")]
    fn has_current_caps(&self) -> bool;

    /// Query if a pad is active
    ///
    /// # Returns
    ///
    /// [`true`] if the pad is active.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_is_active")]
    fn is_active(&self) -> bool;

    /// Checks if the pad is blocked or not. This function returns the
    /// last requested state of the pad. It is not certain that the pad
    /// is actually blocking at this point (see [`is_blocking()`][Self::is_blocking()]).
    ///
    /// # Returns
    ///
    /// [`true`] if the pad is blocked.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_is_blocked")]
    fn is_blocked(&self) -> bool;

    /// Checks if the pad is blocking or not. This is a guaranteed state
    /// of whether the pad is actually blocking on a [`Buffer`][crate::Buffer] or a [`Event`][crate::Event].
    ///
    /// # Returns
    ///
    /// [`true`] if the pad is blocking.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_is_blocking")]
    fn is_blocking(&self) -> bool;

    /// Checks if a `self` is linked to another pad or not.
    ///
    /// # Returns
    ///
    /// [`true`] if the pad is linked, [`false`] otherwise.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_is_linked")]
    fn is_linked(&self) -> bool;

    //#[doc(alias = "gst_pad_iterate_internal_links")]
    //fn iterate_internal_links(&self) -> /*Ignored*/Option<Iterator>;

    //#[doc(alias = "gst_pad_iterate_internal_links_default")]
    //fn iterate_internal_links_default(&self, parent: Option<&impl IsA<Object>>) -> /*Ignored*/Option<Iterator>;

    /// Links the source pad and the sink pad.
    /// ## `sinkpad`
    /// the sink [`Pad`][crate::Pad] to link.
    ///
    /// # Returns
    ///
    /// A result code indicating if the connection worked or
    ///  what went wrong.
    ///
    /// MT Safe.
    #[doc(alias = "gst_pad_link")]
    fn link(&self, sinkpad: &impl IsA<Pad>) -> Result<PadLinkSuccess, PadLinkError>;

    /// Links the source pad and the sink pad.
    ///
    /// This variant of `gst_pad_link` provides a more granular control on the
    /// checks being done when linking. While providing some considerable speedups
    /// the caller of this method must be aware that wrong usage of those flags
    /// can cause severe issues. Refer to the documentation of [`PadLinkCheck`][crate::PadLinkCheck]
    /// for more information.
    ///
    /// MT Safe.
    /// ## `sinkpad`
    /// the sink [`Pad`][crate::Pad] to link.
    /// ## `flags`
    /// the checks to validate when linking
    ///
    /// # Returns
    ///
    /// A result code indicating if the connection worked or
    ///  what went wrong.
    #[doc(alias = "gst_pad_link_full")]
    fn link_full(
        &self,
        sinkpad: &impl IsA<Pad>,
        flags: PadLinkCheck,
    ) -> Result<PadLinkSuccess, PadLinkError>;

    /// Links `self` to `sink`, creating any [`GhostPad`][crate::GhostPad]'s in between as necessary.
    ///
    /// This is a convenience function to save having to create and add intermediate
    /// [`GhostPad`][crate::GhostPad]'s as required for linking across [`Bin`][crate::Bin] boundaries.
    ///
    /// If `self` or `sink` pads don't have parent elements or do not share a common
    /// ancestor, the link will fail.
    /// ## `sink`
    /// a [`Pad`][crate::Pad]
    ///
    /// # Returns
    ///
    /// whether the link succeeded.
    #[doc(alias = "gst_pad_link_maybe_ghosting")]
    fn link_maybe_ghosting(&self, sink: &impl IsA<Pad>) -> Result<(), glib::error::BoolError>;

    /// Links `self` to `sink`, creating any [`GhostPad`][crate::GhostPad]'s in between as necessary.
    ///
    /// This is a convenience function to save having to create and add intermediate
    /// [`GhostPad`][crate::GhostPad]'s as required for linking across [`Bin`][crate::Bin] boundaries.
    ///
    /// If `self` or `sink` pads don't have parent elements or do not share a common
    /// ancestor, the link will fail.
    ///
    /// Calling [`link_maybe_ghosting_full()`][Self::link_maybe_ghosting_full()] with
    /// `flags` == [`PadLinkCheck::DEFAULT`][crate::PadLinkCheck::DEFAULT] is the recommended way of linking
    /// pads with safety checks applied.
    /// ## `sink`
    /// a [`Pad`][crate::Pad]
    /// ## `flags`
    /// some [`PadLinkCheck`][crate::PadLinkCheck] flags
    ///
    /// # Returns
    ///
    /// whether the link succeeded.
    #[doc(alias = "gst_pad_link_maybe_ghosting_full")]
    fn link_maybe_ghosting_full(
        &self,
        sink: &impl IsA<Pad>,
        flags: PadLinkCheck,
    ) -> Result<(), glib::error::BoolError>;

    /// Mark a pad for needing reconfiguration. The next call to
    /// [`check_reconfigure()`][Self::check_reconfigure()] will return [`true`] after this call.
    #[doc(alias = "gst_pad_mark_reconfigure")]
    fn mark_reconfigure(&self);

    /// Check the [`PadFlags::NEED_RECONFIGURE`][crate::PadFlags::NEED_RECONFIGURE] flag on `self` and return [`true`]
    /// if the flag was set.
    ///
    /// # Returns
    ///
    /// [`true`] is the GST_PAD_FLAG_NEED_RECONFIGURE flag is set on `self`.
    #[doc(alias = "gst_pad_needs_reconfigure")]
    fn needs_reconfigure(&self) -> bool;

    /// Pause the task of `self`. This function will also wait until the
    /// function executed by the task is finished if this function is not
    /// called from the task function.
    ///
    /// # Returns
    ///
    /// a [`true`] if the task could be paused or [`false`] when the pad
    /// has no task.
    #[doc(alias = "gst_pad_pause_task")]
    fn pause_task(&self) -> Result<(), glib::error::BoolError>;

    /// Check if the peer of `self` accepts `caps`. If `self` has no peer, this function
    /// returns [`true`].
    /// ## `caps`
    /// a [`Caps`][crate::Caps] to check on the pad
    ///
    /// # Returns
    ///
    /// [`true`] if the peer of `self` can accept the caps or `self` has no peer.
    #[doc(alias = "gst_pad_peer_query_accept_caps")]
    fn peer_query_accept_caps(&self, caps: &Caps) -> bool;

    /// Gets the capabilities of the peer connected to this pad. Similar to
    /// [`query_caps()`][Self::query_caps()].
    ///
    /// When called on srcpads `filter` contains the caps that
    /// upstream could produce in the order preferred by upstream. When
    /// called on sinkpads `filter` contains the caps accepted by
    /// downstream in the preferred order. `filter` might be [`None`] but
    /// if it is not [`None`] the returned caps will be a subset of `filter`.
    /// ## `filter`
    /// a [`Caps`][crate::Caps] filter, or [`None`].
    ///
    /// # Returns
    ///
    /// the caps of the peer pad with incremented
    /// ref-count. When there is no peer pad, this function returns `filter` or,
    /// when `filter` is [`None`], ANY caps.
    #[doc(alias = "gst_pad_peer_query_caps")]
    fn peer_query_caps(&self, filter: Option<&Caps>) -> Caps;

    /// Check if the given pad accepts the caps.
    /// ## `caps`
    /// a [`Caps`][crate::Caps] to check on the pad
    ///
    /// # Returns
    ///
    /// [`true`] if the pad can accept the caps.
    #[doc(alias = "gst_pad_query_accept_caps")]
    fn query_accept_caps(&self, caps: &Caps) -> bool;

    /// Gets the capabilities this pad can produce or consume.
    /// Note that this method doesn't necessarily return the caps set by sending a
    /// `gst_event_new_caps()` - use [`current_caps()`][Self::current_caps()] for that instead.
    /// gst_pad_query_caps returns all possible caps a pad can operate with, using
    /// the pad's CAPS query function, If the query fails, this function will return
    /// `filter`, if not [`None`], otherwise ANY.
    ///
    /// When called on sinkpads `filter` contains the caps that
    /// upstream could produce in the order preferred by upstream. When
    /// called on srcpads `filter` contains the caps accepted by
    /// downstream in the preferred order. `filter` might be [`None`] but
    /// if it is not [`None`] the returned caps will be a subset of `filter`.
    ///
    /// Note that this function does not return writable [`Caps`][crate::Caps], use
    /// `gst_caps_make_writable()` before modifying the caps.
    /// ## `filter`
    /// suggested [`Caps`][crate::Caps], or [`None`]
    ///
    /// # Returns
    ///
    /// the caps of the pad with incremented ref-count.
    #[doc(alias = "gst_pad_query_caps")]
    fn query_caps(&self, filter: Option<&Caps>) -> Caps;

    /// Activates or deactivates the given pad.
    /// Normally called from within core state change functions.
    ///
    /// If `active`, makes sure the pad is active. If it is already active, either in
    /// push or pull mode, just return. Otherwise dispatches to the pad's activate
    /// function to perform the actual activation.
    ///
    /// If not `active`, calls [`activate_mode()`][Self::activate_mode()] with the pad's current mode
    /// and a [`false`] argument.
    /// ## `active`
    /// whether or not the pad should be active.
    ///
    /// # Returns
    ///
    /// [`true`] if the operation was successful.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_set_active")]
    fn set_active(&self, active: bool) -> Result<(), glib::error::BoolError>;

    //#[doc(alias = "gst_pad_set_element_private")]
    //fn set_element_private(&self, priv_: /*Unimplemented*/Option<Basic: Pointer>);

    /// Set the offset that will be applied to the running time of `self`.
    /// ## `offset`
    /// the offset
    #[doc(alias = "gst_pad_set_offset")]
    fn set_offset(&self, offset: i64);

    /// Stop the task of `self`. This function will also make sure that the
    /// function executed by the task will effectively stop if not called
    /// from the GstTaskFunction.
    ///
    /// This function will deadlock if called from the GstTaskFunction of
    /// the task. Use [`TaskExt::pause()`][crate::prelude::TaskExt::pause()] instead.
    ///
    /// Regardless of whether the pad has a task, the stream lock is acquired and
    /// released so as to ensure that streaming through this pad has finished.
    ///
    /// # Returns
    ///
    /// a [`true`] if the task could be stopped or [`false`] on error.
    #[doc(alias = "gst_pad_stop_task")]
    fn stop_task(&self) -> Result<(), glib::error::BoolError>;

    /// Store the sticky `event` on `self`
    /// ## `event`
    /// a [`Event`][crate::Event]
    ///
    /// # Returns
    ///
    /// [`FlowReturn::Ok`][crate::FlowReturn::Ok] on success, [`FlowReturn::Flushing`][crate::FlowReturn::Flushing] when the pad
    /// was flushing or [`FlowReturn::Eos`][crate::FlowReturn::Eos] when the pad was EOS.
    #[doc(alias = "gst_pad_store_sticky_event")]
    fn store_sticky_event(&self, event: &Event) -> Result<FlowSuccess, FlowError>;

    /// Unlinks the source pad from the sink pad. Will emit the `signal::Pad::unlinked`
    /// signal on both pads.
    /// ## `sinkpad`
    /// the sink [`Pad`][crate::Pad] to unlink.
    ///
    /// # Returns
    ///
    /// [`true`] if the pads were unlinked. This function returns [`false`] if
    /// the pads were not linked together.
    ///
    /// MT safe.
    #[doc(alias = "gst_pad_unlink")]
    fn unlink(&self, sinkpad: &impl IsA<Pad>) -> Result<(), glib::error::BoolError>;

    /// A helper function you can use that sets the FIXED_CAPS flag
    /// This way the default CAPS query will always return the negotiated caps
    /// or in case the pad is not negotiated, the padtemplate caps.
    ///
    /// The negotiated caps are the caps of the last CAPS event that passed on the
    /// pad. Use this function on a pad that, once it negotiated to a CAPS, cannot
    /// be renegotiated to something else.
    #[doc(alias = "gst_pad_use_fixed_caps")]
    fn use_fixed_caps(&self);

    fn caps(&self) -> Option<Caps>;

    /// Signals that a pad has been linked to the peer pad.
    /// ## `peer`
    /// the peer pad that has been connected
    #[doc(alias = "linked")]
    fn connect_linked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId;

    /// Signals that a pad has been unlinked from the peer pad.
    /// ## `peer`
    /// the peer pad that has been disconnected
    #[doc(alias = "unlinked")]
    fn connect_unlinked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F)
        -> SignalHandlerId;

    #[doc(alias = "caps")]
    fn connect_caps_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId;

    #[doc(alias = "offset")]
    fn connect_offset_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId;
}

impl<O: IsA<Pad>> PadExt for O {
    fn activate_mode(&self, mode: PadMode, active: bool) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_activate_mode(
                    self.as_ref().to_glib_none().0,
                    mode.into_glib(),
                    active.into_glib()
                ),
                "Failed to activate mode pad"
            )
        }
    }

    fn can_link(&self, sinkpad: &impl IsA<Pad>) -> bool {
        unsafe {
            from_glib(ffi::gst_pad_can_link(
                self.as_ref().to_glib_none().0,
                sinkpad.as_ref().to_glib_none().0,
            ))
        }
    }

    fn check_reconfigure(&self) -> bool {
        unsafe {
            from_glib(ffi::gst_pad_check_reconfigure(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn create_stream_id(
        &self,
        parent: &impl IsA<Element>,
        stream_id: Option<&str>,
    ) -> glib::GString {
        unsafe {
            from_glib_full(ffi::gst_pad_create_stream_id(
                self.as_ref().to_glib_none().0,
                parent.as_ref().to_glib_none().0,
                stream_id.to_glib_none().0,
            ))
        }
    }

    //fn create_stream_id_printf(&self, parent: &impl IsA<Element>, stream_id: Option<&str>, : /*Unknown conversion*//*Unimplemented*/Basic: VarArgs) -> glib::GString {
    //    unsafe { TODO: call ffi:gst_pad_create_stream_id_printf() }
    //}

    //fn create_stream_id_printf_valist(&self, parent: &impl IsA<Element>, stream_id: Option<&str>, var_args: /*Unknown conversion*//*Unimplemented*/Unsupported) -> glib::GString {
    //    unsafe { TODO: call ffi:gst_pad_create_stream_id_printf_valist() }
    //}

    fn forward<P: FnMut(&Pad) -> bool>(&self, forward: P) -> bool {
        let forward_data: P = forward;
        unsafe extern "C" fn forward_func<P: FnMut(&Pad) -> bool>(
            pad: *mut ffi::GstPad,
            user_data: glib::ffi::gpointer,
        ) -> glib::ffi::gboolean {
            let pad = from_glib_borrow(pad);
            let callback: *mut P = user_data as *const _ as usize as *mut P;
            let res = (*callback)(&pad);
            res.into_glib()
        }
        let forward = Some(forward_func::<P> as _);
        let super_callback0: &P = &forward_data;
        unsafe {
            from_glib(ffi::gst_pad_forward(
                self.as_ref().to_glib_none().0,
                forward,
                super_callback0 as *const _ as usize as *mut _,
            ))
        }
    }

    fn allowed_caps(&self) -> Option<Caps> {
        unsafe {
            from_glib_full(ffi::gst_pad_get_allowed_caps(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn current_caps(&self) -> Option<Caps> {
        unsafe {
            from_glib_full(ffi::gst_pad_get_current_caps(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn direction(&self) -> PadDirection {
        unsafe { from_glib(ffi::gst_pad_get_direction(self.as_ref().to_glib_none().0)) }
    }

    //fn element_private(&self) -> /*Unimplemented*/Option<Basic: Pointer> {
    //    unsafe { TODO: call ffi:gst_pad_get_element_private() }
    //}

    fn last_flow_result(&self) -> Result<FlowSuccess, FlowError> {
        unsafe {
            try_from_glib(ffi::gst_pad_get_last_flow_return(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn offset(&self) -> i64 {
        unsafe { ffi::gst_pad_get_offset(self.as_ref().to_glib_none().0) }
    }

    fn pad_template(&self) -> Option<PadTemplate> {
        unsafe {
            from_glib_full(ffi::gst_pad_get_pad_template(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn pad_template_caps(&self) -> Caps {
        unsafe {
            from_glib_full(ffi::gst_pad_get_pad_template_caps(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn parent_element(&self) -> Option<Element> {
        unsafe {
            from_glib_full(ffi::gst_pad_get_parent_element(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn peer(&self) -> Option<Pad> {
        unsafe { from_glib_full(ffi::gst_pad_get_peer(self.as_ref().to_glib_none().0)) }
    }

    #[cfg(any(feature = "v1_18", feature = "dox"))]
    #[cfg_attr(feature = "dox", doc(cfg(feature = "v1_18")))]
    fn single_internal_link(&self) -> Option<Pad> {
        unsafe {
            from_glib_full(ffi::gst_pad_get_single_internal_link(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn stream(&self) -> Option<Stream> {
        unsafe { from_glib_full(ffi::gst_pad_get_stream(self.as_ref().to_glib_none().0)) }
    }

    fn stream_id(&self) -> Option<glib::GString> {
        unsafe { from_glib_full(ffi::gst_pad_get_stream_id(self.as_ref().to_glib_none().0)) }
    }

    fn task_state(&self) -> TaskState {
        unsafe { from_glib(ffi::gst_pad_get_task_state(self.as_ref().to_glib_none().0)) }
    }

    fn has_current_caps(&self) -> bool {
        unsafe {
            from_glib(ffi::gst_pad_has_current_caps(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn is_active(&self) -> bool {
        unsafe { from_glib(ffi::gst_pad_is_active(self.as_ref().to_glib_none().0)) }
    }

    fn is_blocked(&self) -> bool {
        unsafe { from_glib(ffi::gst_pad_is_blocked(self.as_ref().to_glib_none().0)) }
    }

    fn is_blocking(&self) -> bool {
        unsafe { from_glib(ffi::gst_pad_is_blocking(self.as_ref().to_glib_none().0)) }
    }

    fn is_linked(&self) -> bool {
        unsafe { from_glib(ffi::gst_pad_is_linked(self.as_ref().to_glib_none().0)) }
    }

    //fn iterate_internal_links(&self) -> /*Ignored*/Option<Iterator> {
    //    unsafe { TODO: call ffi:gst_pad_iterate_internal_links() }
    //}

    //fn iterate_internal_links_default(&self, parent: Option<&impl IsA<Object>>) -> /*Ignored*/Option<Iterator> {
    //    unsafe { TODO: call ffi:gst_pad_iterate_internal_links_default() }
    //}

    fn link(&self, sinkpad: &impl IsA<Pad>) -> Result<PadLinkSuccess, PadLinkError> {
        unsafe {
            try_from_glib(ffi::gst_pad_link(
                self.as_ref().to_glib_none().0,
                sinkpad.as_ref().to_glib_none().0,
            ))
        }
    }

    fn link_full(
        &self,
        sinkpad: &impl IsA<Pad>,
        flags: PadLinkCheck,
    ) -> Result<PadLinkSuccess, PadLinkError> {
        unsafe {
            try_from_glib(ffi::gst_pad_link_full(
                self.as_ref().to_glib_none().0,
                sinkpad.as_ref().to_glib_none().0,
                flags.into_glib(),
            ))
        }
    }

    fn link_maybe_ghosting(&self, sink: &impl IsA<Pad>) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_link_maybe_ghosting(
                    self.as_ref().to_glib_none().0,
                    sink.as_ref().to_glib_none().0
                ),
                "Failed to link pads, possibly ghosting"
            )
        }
    }

    fn link_maybe_ghosting_full(
        &self,
        sink: &impl IsA<Pad>,
        flags: PadLinkCheck,
    ) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_link_maybe_ghosting_full(
                    self.as_ref().to_glib_none().0,
                    sink.as_ref().to_glib_none().0,
                    flags.into_glib()
                ),
                "Failed to link pads, possibly ghosting"
            )
        }
    }

    fn mark_reconfigure(&self) {
        unsafe {
            ffi::gst_pad_mark_reconfigure(self.as_ref().to_glib_none().0);
        }
    }

    fn needs_reconfigure(&self) -> bool {
        unsafe {
            from_glib(ffi::gst_pad_needs_reconfigure(
                self.as_ref().to_glib_none().0,
            ))
        }
    }

    fn pause_task(&self) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_pause_task(self.as_ref().to_glib_none().0),
                "Failed to pause pad task"
            )
        }
    }

    fn peer_query_accept_caps(&self, caps: &Caps) -> bool {
        unsafe {
            from_glib(ffi::gst_pad_peer_query_accept_caps(
                self.as_ref().to_glib_none().0,
                caps.to_glib_none().0,
            ))
        }
    }

    fn peer_query_caps(&self, filter: Option<&Caps>) -> Caps {
        unsafe {
            from_glib_full(ffi::gst_pad_peer_query_caps(
                self.as_ref().to_glib_none().0,
                filter.to_glib_none().0,
            ))
        }
    }

    fn query_accept_caps(&self, caps: &Caps) -> bool {
        unsafe {
            from_glib(ffi::gst_pad_query_accept_caps(
                self.as_ref().to_glib_none().0,
                caps.to_glib_none().0,
            ))
        }
    }

    fn query_caps(&self, filter: Option<&Caps>) -> Caps {
        unsafe {
            from_glib_full(ffi::gst_pad_query_caps(
                self.as_ref().to_glib_none().0,
                filter.to_glib_none().0,
            ))
        }
    }

    fn set_active(&self, active: bool) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_set_active(self.as_ref().to_glib_none().0, active.into_glib()),
                "Failed to activate pad"
            )
        }
    }

    //fn set_element_private(&self, priv_: /*Unimplemented*/Option<Basic: Pointer>) {
    //    unsafe { TODO: call ffi:gst_pad_set_element_private() }
    //}

    fn set_offset(&self, offset: i64) {
        unsafe {
            ffi::gst_pad_set_offset(self.as_ref().to_glib_none().0, offset);
        }
    }

    fn stop_task(&self) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_stop_task(self.as_ref().to_glib_none().0),
                "Failed to stop pad task"
            )
        }
    }

    fn store_sticky_event(&self, event: &Event) -> Result<FlowSuccess, FlowError> {
        unsafe {
            try_from_glib(ffi::gst_pad_store_sticky_event(
                self.as_ref().to_glib_none().0,
                event.to_glib_none().0,
            ))
        }
    }

    fn unlink(&self, sinkpad: &impl IsA<Pad>) -> Result<(), glib::error::BoolError> {
        unsafe {
            glib::result_from_gboolean!(
                ffi::gst_pad_unlink(
                    self.as_ref().to_glib_none().0,
                    sinkpad.as_ref().to_glib_none().0
                ),
                "Failed to unlink pad"
            )
        }
    }

    fn use_fixed_caps(&self) {
        unsafe {
            ffi::gst_pad_use_fixed_caps(self.as_ref().to_glib_none().0);
        }
    }

    fn caps(&self) -> Option<Caps> {
        glib::ObjectExt::property(self.as_ref(), "caps")
    }

    fn connect_linked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
        unsafe extern "C" fn linked_trampoline<
            P: IsA<Pad>,
            F: Fn(&P, &Pad) + Send + Sync + 'static,
        >(
            this: *mut ffi::GstPad,
            peer: *mut ffi::GstPad,
            f: glib::ffi::gpointer,
        ) {
            let f: &F = &*(f as *const F);
            f(
                Pad::from_glib_borrow(this).unsafe_cast_ref(),
                &from_glib_borrow(peer),
            )
        }
        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"linked\0".as_ptr() as *const _,
                Some(transmute::<_, unsafe extern "C" fn()>(
                    linked_trampoline::<Self, F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }

    fn connect_unlinked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(
        &self,
        f: F,
    ) -> SignalHandlerId {
        unsafe extern "C" fn unlinked_trampoline<
            P: IsA<Pad>,
            F: Fn(&P, &Pad) + Send + Sync + 'static,
        >(
            this: *mut ffi::GstPad,
            peer: *mut ffi::GstPad,
            f: glib::ffi::gpointer,
        ) {
            let f: &F = &*(f as *const F);
            f(
                Pad::from_glib_borrow(this).unsafe_cast_ref(),
                &from_glib_borrow(peer),
            )
        }
        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"unlinked\0".as_ptr() as *const _,
                Some(transmute::<_, unsafe extern "C" fn()>(
                    unlinked_trampoline::<Self, F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }

    fn connect_caps_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
        unsafe extern "C" fn notify_caps_trampoline<
            P: IsA<Pad>,
            F: Fn(&P) + Send + Sync + 'static,
        >(
            this: *mut ffi::GstPad,
            _param_spec: glib::ffi::gpointer,
            f: glib::ffi::gpointer,
        ) {
            let f: &F = &*(f as *const F);
            f(Pad::from_glib_borrow(this).unsafe_cast_ref())
        }
        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"notify::caps\0".as_ptr() as *const _,
                Some(transmute::<_, unsafe extern "C" fn()>(
                    notify_caps_trampoline::<Self, F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }

    fn connect_offset_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
        unsafe extern "C" fn notify_offset_trampoline<
            P: IsA<Pad>,
            F: Fn(&P) + Send + Sync + 'static,
        >(
            this: *mut ffi::GstPad,
            _param_spec: glib::ffi::gpointer,
            f: glib::ffi::gpointer,
        ) {
            let f: &F = &*(f as *const F);
            f(Pad::from_glib_borrow(this).unsafe_cast_ref())
        }
        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"notify::offset\0".as_ptr() as *const _,
                Some(transmute::<_, unsafe extern "C" fn()>(
                    notify_offset_trampoline::<Self, F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }
}