Import in separate crate and change source ID calculation

import/src/error.rs

@@ -0,0 +1,96 @@
+use std::error;
+
+/// An error within an import session.
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+    /// A timeout was reached.
+    #[error("{0}")]
+    Timeout(String),
+
+    /// Some common error.
+    #[error("{msg}")]
+    Other {
+        /// The error message.
+        msg: String,
+
+        #[source]
+        source: Option<Box<dyn error::Error + Send + Sync>>,
+    },
+
+    /// Something unexpected happened.
+    #[error("{msg}")]
+    Unexpected {
+        /// The error message.
+        msg: String,
+
+        #[source]
+        source: Option<Box<dyn error::Error + Send + Sync>>,
+    },
+}
+
+impl Error {
+    /// Create a new error without an explicit source.
+    pub(super) fn o(msg: String) -> Self {
+        Self::Unexpected {
+            msg,
+            source: None,
+        }
+    }
+
+    /// Create a new error with an explicit source.
+    pub(super) fn os(source: impl error::Error + Send + Sync + 'static) -> Self {
+        Self::Unexpected {
+            msg: format!("An error has happened: {}", source),
+            source: Some(Box::new(source)),
+        }
+    }
+
+    /// Create a new unexpected error without an explicit source.
+    pub(super) fn u(msg: String) -> Self {
+        Self::Unexpected {
+            msg,
+            source: None,
+        }
+    }
+
+    /// Create a new unexpected error with an explicit source.
+    pub(super) fn us(source: impl error::Error + Send + Sync + 'static) -> Self {
+        Self::Unexpected {
+            msg: format!("An unexpected error has happened: {}", source),
+            source: Some(Box::new(source)),
+        }
+    }
+}
+
+impl From<futures_channel::oneshot::Canceled> for Error {
+    fn from(err: futures_channel::oneshot::Canceled) -> Self {
+        Self::us(err)
+    }
+}
+
+impl From<gstreamer::glib::Error> for Error {
+    fn from(err: gstreamer::glib::Error) -> Self {
+        Self::us(err)
+    }
+}
+
+impl From<gstreamer::glib::BoolError> for Error {
+    fn from(err: gstreamer::glib::BoolError) -> Self {
+        Self::us(err)
+    }
+}
+
+impl From<gstreamer::StateChangeError> for Error {
+    fn from(err: gstreamer::StateChangeError) -> Self {
+        Self::us(err)
+    }
+}
+
+impl From<std::io::Error> for Error {
+    fn from(err: std::io::Error) -> Self {
+        Self::us(err)
+    }
+}
+
+pub type Result<T> = std::result::Result<T, Error>;
+