mirror of
https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs.git
synced 2024-09-21 03:20:10 +00:00
301 lines
9.6 KiB
Rust
301 lines
9.6 KiB
Rust
// Copyright (C) 2021 Mathieu Duponchelle <mathieu@centricular.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License, v2.0.
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// If a copy of the MPL was not distributed with this file, You can obtain one at
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// <https://mozilla.org/MPL/2.0/>.
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//
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// SPDX-License-Identifier: MPL-2.0
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use gst::glib;
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use gst::prelude::*;
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use gst::subclass::prelude::*;
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use regex::Regex;
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use std::default::Default;
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use std::sync::Mutex;
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use once_cell::sync::Lazy;
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static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
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gst::DebugCategory::new(
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"regex",
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gst::DebugColorFlags::empty(),
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Some("Regular Expression element"),
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)
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});
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enum Operation {
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ReplaceAll(String),
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}
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struct Command {
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pattern: String,
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regex: Regex,
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operation: Operation,
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}
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#[derive(Default)]
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struct State {
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commands: Vec<Command>,
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}
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pub struct RegEx {
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srcpad: gst::Pad,
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sinkpad: gst::Pad,
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state: Mutex<State>,
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}
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impl RegEx {
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fn sink_chain(
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&self,
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_pad: &gst::Pad,
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buffer: gst::Buffer,
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) -> Result<gst::FlowSuccess, gst::FlowError> {
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let data = buffer.map_readable().map_err(|_| {
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gst::error!(CAT, imp: self, "Can't map buffer readable");
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gst::element_imp_error!(self, gst::CoreError::Failed, ["Failed to map buffer"]);
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gst::FlowError::Error
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})?;
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let mut data = std::str::from_utf8(&data)
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.map_err(|err| {
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gst::error!(CAT, imp: self, "Can't decode utf8: {}", err);
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gst::element_imp_error!(
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self,
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gst::StreamError::Decode,
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["Failed to decode utf8: {}", err]
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);
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gst::FlowError::Error
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})?
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.to_string();
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let state = self.state.lock().unwrap();
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for command in &state.commands {
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match &command.operation {
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Operation::ReplaceAll(replacement) => {
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data = command
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.regex
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.replace_all(&data, replacement.as_str())
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.to_string();
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}
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}
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}
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let mut outbuf = gst::Buffer::from_mut_slice(data.into_bytes());
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{
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let outbuf_mut = outbuf.get_mut().unwrap();
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let _ = buffer.copy_into(
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outbuf_mut,
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gst::BufferCopyFlags::FLAGS
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| gst::BufferCopyFlags::TIMESTAMPS
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| gst::BufferCopyFlags::META,
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0,
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None,
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);
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}
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drop(state);
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self.srcpad.push(outbuf)
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}
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}
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#[glib::object_subclass]
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impl ObjectSubclass for RegEx {
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const NAME: &'static str = "RsRegEx";
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type Type = super::RegEx;
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type ParentType = gst::Element;
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fn with_class(klass: &Self::Class) -> Self {
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let templ = klass.pad_template("sink").unwrap();
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let sinkpad = gst::Pad::builder_with_template(&templ, Some("sink"))
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.chain_function(|pad, parent, buffer| {
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RegEx::catch_panic_pad_function(
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parent,
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|| Err(gst::FlowError::Error),
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|regex| regex.sink_chain(pad, buffer),
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)
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})
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.flags(gst::PadFlags::PROXY_CAPS | gst::PadFlags::FIXED_CAPS)
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.build();
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let templ = klass.pad_template("src").unwrap();
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let srcpad = gst::Pad::builder_with_template(&templ, Some("src"))
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.flags(gst::PadFlags::PROXY_CAPS | gst::PadFlags::FIXED_CAPS)
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.build();
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let state = Mutex::new(State::default());
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Self {
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srcpad,
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sinkpad,
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state,
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}
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}
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}
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impl ObjectImpl for RegEx {
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fn properties() -> &'static [glib::ParamSpec] {
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static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
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vec![gst::ParamSpecArray::builder("commands")
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.nick("Commands")
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.blurb("A set of commands to apply on input text")
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.element_spec(
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&glib::ParamSpecBoxed::builder::<gst::Structure>("command")
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.nick("Command")
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.blurb("A command to apply on input text")
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.build(),
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)
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.mutable_playing()
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.build()]
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});
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PROPERTIES.as_ref()
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}
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fn constructed(&self) {
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self.parent_constructed();
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let obj = self.instance();
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obj.add_pad(&self.sinkpad).unwrap();
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obj.add_pad(&self.srcpad).unwrap();
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}
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fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
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match pspec.name() {
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"commands" => {
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let mut state = self.state.lock().unwrap();
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state.commands = vec![];
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let commands = value.get::<gst::ArrayRef>().expect("type checked upstream");
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for command in commands.as_slice() {
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let s = match command
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.get::<Option<gst::Structure>>()
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.expect("type checked upstream")
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{
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Some(s) => s,
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None => {
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continue;
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}
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};
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let operation = s.name();
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let pattern = match s.get::<Option<String>>("pattern") {
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Ok(Some(pattern)) => pattern,
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Ok(None) | Err(_) => {
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gst::error!(
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CAT,
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imp: self,
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"All commands require a pattern field as a string"
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);
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continue;
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}
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};
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let regex = match Regex::new(&pattern) {
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Ok(regex) => regex,
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Err(err) => {
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gst::error!(CAT, imp: self, "Failed to compile regex: {:?}", err);
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continue;
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}
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};
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match operation {
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"replace-all" | "replace_all" => {
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let replacement = match s.get::<Option<String>>("replacement") {
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Ok(Some(pattern)) => pattern,
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Ok(None) | Err(_) => {
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gst::error!(
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CAT,
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imp: self,
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"Replace operations require a replacement field as a string"
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);
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continue;
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}
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};
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state.commands.push(Command {
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pattern,
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regex,
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operation: Operation::ReplaceAll(replacement),
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});
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}
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val => {
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gst::error!(CAT, imp: self, "Unknown operation {}", val);
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}
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}
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}
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}
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_ => unimplemented!(),
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}
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}
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fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
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match pspec.name() {
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"commands" => {
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let state = self.state.lock().unwrap();
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let mut commands = vec![];
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for command in &state.commands {
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match command.operation {
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Operation::ReplaceAll(ref replacement) => {
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commands.push(
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gst::Structure::builder("replace-all")
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.field("pattern", &command.pattern)
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.field("replacement", replacement)
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.build()
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.to_send_value(),
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);
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}
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}
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}
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gst::Array::from(commands).to_value()
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}
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_ => unimplemented!(),
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}
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}
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}
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impl GstObjectImpl for RegEx {}
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impl ElementImpl for RegEx {
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fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
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static ELEMENT_METADATA: Lazy<gst::subclass::ElementMetadata> = Lazy::new(|| {
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gst::subclass::ElementMetadata::new(
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"Regular Expression processor",
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"Text/Filter",
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"Applies operations according to regular expressions",
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"Mathieu Duponchelle <mathieu@centricular.com>",
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)
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});
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Some(&*ELEMENT_METADATA)
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}
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fn pad_templates() -> &'static [gst::PadTemplate] {
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static PAD_TEMPLATES: Lazy<Vec<gst::PadTemplate>> = Lazy::new(|| {
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let caps = gst::Caps::builder("text/x-raw")
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.field("format", "utf8")
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.build();
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let src_pad_template = gst::PadTemplate::new(
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"src",
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gst::PadDirection::Src,
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gst::PadPresence::Always,
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&caps,
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)
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.unwrap();
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let sink_pad_template = gst::PadTemplate::new(
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"sink",
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gst::PadDirection::Sink,
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gst::PadPresence::Always,
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&caps,
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)
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.unwrap();
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vec![src_pad_template, sink_pad_template]
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});
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PAD_TEMPLATES.as_ref()
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}
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}
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