Commit e218f7a9 authored by Philippe Normand's avatar Philippe Normand 🥑 Committed by Sebastian Dröge
Browse files

examples: appsink: improved error handling

The program should now exit gracefully with human readable messages.
parent 50e6e2e1
......@@ -3,21 +3,63 @@ use gst::*;
extern crate gstreamer_app as gst_app;
use gst_app::*;
extern crate glib;
use std::fmt;
use std::u64;
use std::i16;
use std::i32;
fn main() {
gst::init().unwrap();
#[derive(Debug)]
enum AppSinkExError {
InitFailed(glib::Error),
ElementNotFound(&'static str),
ElementLinkFailed(&'static str, &'static str),
SetStateError(&'static str),
ElementError(std::string::String, glib::Error, std::string::String),
}
impl fmt::Display for AppSinkExError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
AppSinkExError::InitFailed(ref e) => {
write!(f, "GStreamer initialization failed: {:?}", e)
}
AppSinkExError::ElementNotFound(ref e) => write!(f, "Element {} not found", e),
AppSinkExError::ElementLinkFailed(ref e1, ref e2) => {
write!(f, "Link failed between {} and {}", e1, e2)
}
AppSinkExError::SetStateError(ref state) => {
write!(f, "Pipeline failed to switch to state {}", state)
}
AppSinkExError::ElementError(ref element, ref err, ref debug) => {
write!(f, "Error from {}: {} ({:?})", element, err, debug)
}
}
}
}
fn create_pipeline() -> Result<Pipeline, AppSinkExError> {
gst::init().map_err(|e| AppSinkExError::InitFailed(e))?;
let pipeline = gst::Pipeline::new(None);
let src = gst::ElementFactory::make("audiotestsrc", None).unwrap();
let sink = gst::ElementFactory::make("appsink", None).unwrap();
let src = gst::ElementFactory::make("audiotestsrc", None)
.ok_or(AppSinkExError::ElementNotFound("audiotestsrc"))?;
let sink = gst::ElementFactory::make("appsink", None)
.ok_or(AppSinkExError::ElementNotFound("appsink"))?;
pipeline
.add_many(&[&src, &sink])
.expect("Unable to add elements in the pipeline");
pipeline.add_many(&[&src, &sink]).unwrap();
gst::Element::link_many(&[&src, &sink]).unwrap();
gst::Element::link(&src, &sink)
.map_err(|_| {
AppSinkExError::ElementLinkFailed("audiotestsrc", "appsink")
})?;
let appsink = sink.clone()
.dynamic_cast::<AppSink>()
.expect("Sink element is expected to be an appsink!");
let appsink = sink.clone().dynamic_cast::<AppSink>().unwrap();
appsink.set_caps(&Caps::new_simple(
"audio/x-raw",
&[
......@@ -40,9 +82,11 @@ fn main() {
Some(sample) => sample,
};
let buffer = sample.get_buffer().unwrap();
let buffer = sample
.get_buffer()
.expect("Unable to extract buffer from the sample");
assert_eq!(buffer.get_size() % 2, 0);
let map = buffer.map_read().unwrap();
let map = buffer.map_read().expect("Unable to map buffer for reading");
let data = map.as_slice();
let sum: f64 = data.chunks(2)
.map(|sample| {
......@@ -58,12 +102,19 @@ fn main() {
},
));
assert_ne!(
pipeline.set_state(gst::State::Playing),
gst::StateChangeReturn::Failure
);
Ok(pipeline)
}
fn main_loop() -> Result<(), AppSinkExError> {
let pipeline = create_pipeline()?;
let bus = pipeline.get_bus().unwrap();
if let gst::StateChangeReturn::Failure = pipeline.set_state(gst::State::Playing) {
return Err(AppSinkExError::SetStateError("playing"));
}
let bus = pipeline
.get_bus()
.expect("Pipeline without bus. Shouldn't happen!");
loop {
let msg = match bus.timed_pop(u64::MAX) {
......@@ -74,20 +125,29 @@ fn main() {
match msg.view() {
MessageView::Eos(..) => break,
MessageView::Error(err) => {
println!(
"Error from {}: {} ({:?})",
if let gst::StateChangeReturn::Failure = pipeline.set_state(gst::State::Null) {
return Err(AppSinkExError::SetStateError("null"));
}
return Err(AppSinkExError::ElementError(
msg.get_src().get_path_string(),
err.get_error(),
err.get_debug()
);
break;
err.get_debug().unwrap(),
));
}
_ => (),
}
}
assert_ne!(
pipeline.set_state(gst::State::Null),
gst::StateChangeReturn::Failure
);
if let gst::StateChangeReturn::Failure = pipeline.set_state(gst::State::Null) {
return Err(AppSinkExError::SetStateError("null"));
}
Ok(())
}
fn main() {
match main_loop() {
Ok(r) => r,
Err(e) => eprintln!("Error! {}", e),
}
}
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