forked from mirrors/gstreamer-rs
948fb2ae4b
... in function signatures. These breaking changes aim at improving usability by allowing users to take advantage of Rust error management features sur as `ok_or`, `map_err`, `expect` and the `?` operator. See the `examples` and `tutorials` to get an idea of the impacts.
78 lines
2.8 KiB
Rust
78 lines
2.8 KiB
Rust
// This example demonstrates how to use the gstreamer crate in conjunction
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// with the future trait. The example waits for either an error to occur,
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// or for an EOS message. When a message notifying about either of both
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// is received, the future is resolved.
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extern crate gstreamer as gst;
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use gst::prelude::*;
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extern crate futures;
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use futures::executor::block_on;
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use futures::prelude::*;
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use std::env;
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#[path = "../examples-common.rs"]
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mod examples_common;
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fn example_main() {
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// Read the pipeline to launch from the commandline, using the launch syntax.
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let pipeline_str = env::args().collect::<Vec<String>>()[1..].join(" ");
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gst::init().unwrap();
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// Create a pipeline from the launch-syntax given on the cli.
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let pipeline = gst::parse_launch(&pipeline_str).unwrap();
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let bus = pipeline.get_bus().unwrap();
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pipeline
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.set_state(gst::State::Playing)
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.expect("Unable to set the pipeline to the `Playing` state");
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// BusStream implements the Stream trait, but Stream::for_each is
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// calling a closure for each item and returns a Future that resolves
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// when the stream is done or an error has happened
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let messages = gst::BusStream::new(&bus)
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.for_each(|msg| {
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use gst::MessageView;
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// Determine whether we want to resolve the future, or we still have
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// to wait. The future is resolved when either an error occurs, or the
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// pipeline succeeded execution (got an EOS event).
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let quit = match msg.view() {
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MessageView::Eos(..) => true,
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MessageView::Error(err) => {
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println!(
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"Error from {:?}: {} ({:?})",
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err.get_src().map(|s| s.get_path_string()),
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err.get_error(),
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err.get_debug()
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);
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true
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}
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_ => false,
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};
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if quit {
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Err(()) // This resolves the future that is returned by for_each
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// FIXME: At the moment, EOS messages also result in the future to be resolved
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// by an error. This should probably be changed in the future.
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} else {
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Ok(()) // Continue - do not resolve the future yet.
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}
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})
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.and_then(|_| Ok(()));
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// Synchronously wait on the future we created above.
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let _ = block_on(messages);
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pipeline
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.set_state(gst::State::Null)
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.expect("Unable to set the pipeline to the `Null` state");
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}
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fn main() {
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// tutorials_common::run is only required to set up the application environent on macOS
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// (but not necessary in normal Cocoa applications where this is set up autmatically)
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examples_common::run(example_main);
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}
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