Add gst::TagSetter example

examples/src/bin/tagsetter.rs

@@ -0,0 +1,99 @@
+extern crate gstreamer as gst;
+use gst::prelude::*;
+
+extern crate glib;
+
+use std::error::Error as StdError;
+
+extern crate failure;
+use failure::Error;
+
+#[macro_use]
+extern crate failure_derive;
+
+#[path = "../examples-common.rs"]
+mod examples_common;
+
+#[derive(Debug, Fail)]
+#[fail(display = "Missing element {}", _0)]
+struct MissingElement(String);
+
+#[derive(Debug, Fail)]
+#[fail(display = "Received error from {}: {} (debug: {:?})", src, error, debug)]
+struct ErrorMessage {
+    src: String,
+    error: String,
+    debug: Option<String>,
+    #[cause] cause: glib::Error,
+}
+
+fn example_main() -> Result<(), Error> {
+    gst::init()?;
+
+    let mut context = gst::ParseContext::new();
+    let pipeline = match gst::parse_launch_full(
+        "audiotestsrc wave=white-noise num-buffers=100 ! flacenc ! filesink location=test.flac",
+        Some(&mut context),
+        gst::ParseFlags::NONE,
+    ) {
+        Ok(pipeline) => pipeline,
+        Err(err) => {
+            if let Some(gst::ParseError::NoSuchElement) = err.kind::<gst::ParseError>() {
+                return Err(MissingElement(context.get_missing_elements().join(",")).into());
+            } else {
+                return Err(err.into());
+            }
+        }
+    };
+
+    let pipeline = pipeline
+        .downcast::<gst::Pipeline>()
+        .map_err(|_| failure::err_msg("Generated pipeline is no pipeline"))?;
+
+    let tagsetter = pipeline
+        .get_by_interface(gst::TagSetter::static_type())
+        .ok_or(failure::err_msg("No TagSetter found"))?;
+    let tagsetter = tagsetter
+        .dynamic_cast::<gst::TagSetter>()
+        .map_err(|_| failure::err_msg("No TagSetter found"))?;
+
+    tagsetter.set_tag_merge_mode(gst::TagMergeMode::KeepAll);
+    tagsetter.add::<gst::tags::Title>(&"Special randomized white-noise", gst::TagMergeMode::Append);
+
+    let bus = pipeline.get_bus().unwrap();
+
+    pipeline.set_state(gst::State::Playing).into_result()?;
+
+    while let Some(msg) = bus.timed_pop(gst::CLOCK_TIME_NONE) {
+        use gst::MessageView;
+
+        match msg.view() {
+            MessageView::Eos(..) => break,
+            MessageView::Error(err) => {
+                Err(ErrorMessage {
+                    src: msg.get_src()
+                        .map(|s| s.get_path_string())
+                        .unwrap_or_else(|| String::from("None")),
+                    error: err.get_error().description().into(),
+                    debug: err.get_debug(),
+                    cause: err.get_error(),
+                })?;
+                break;
+            }
+            _ => (),
+        }
+    }
+
+    pipeline.set_state(gst::State::Null).into_result()?;
+
+    Ok(())
+}
+
+fn main() {
+    // tutorials_common::run is only required to set up the application environent on macOS
+    // (but not necessary in normal Cocoa applications where this is set up autmatically)
+    match examples_common::run(example_main) {
+        Ok(r) => r,
+        Err(e) => eprintln!("Error! {}", e),
+    }
+}