uriplaylistbin: use thiserror

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1234>

utils/uriplaylistbin/Cargo.toml

@@ -13,6 +13,7 @@ gst = { package = "gstreamer", git = "https://gitlab.freedesktop.org/gstreamer/g
 once_cell = "1.0"
 anyhow = "1"
 clap = { version = "4", optional = true, features = ["derive"] }
+thiserror = "1"
 
 [dev-dependencies]
 gst-app = { package = "gstreamer-app", git = "https://gitlab.freedesktop.org/gstreamer/gstreamer-rs", branch = "0.19", version = "0.19" }

utils/uriplaylistbin/src/uriplaylistbin/imp.rs

@@ -26,35 +26,14 @@ static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
 /// how many items are allowed to be prepared and waiting in the pipeline
 const MAX_STREAMING_ITEMS: usize = 2;
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 enum PlaylistError {
+    #[error("plugin missing: {error}")]
     PluginMissing { error: anyhow::Error },
+    #[error("{item:?} failed: {error}")]
     ItemFailed { error: anyhow::Error, item: Item },
 }
 
-impl std::fmt::Display for PlaylistError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            PlaylistError::PluginMissing { error } => {
-                write!(f, "{}", error)
-            }
-            PlaylistError::ItemFailed { error, item } => {
-                write!(f, "{} (URI: {})", error, item.uri())
-            }
-        }
-    }
-}
-
-impl std::error::Error for PlaylistError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-        match self {
-            PlaylistError::PluginMissing { error } | PlaylistError::ItemFailed { error, .. } => {
-                Some(error.as_ref())
-            }
-        }
-    }
-}
-
 /// Number of different streams currently handled by the element
 #[derive(Debug, Default, Clone, PartialEq)]
 struct StreamsTopology {