feat(shell): add plugin (#327)

plugins/shell/src/error.rs

@@ -0,0 +1,32 @@
+use std::path::PathBuf;
+
+use serde::{Serialize, Serializer};
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error(transparent)]
+    Io(#[from] std::io::Error),
+    #[error("current executable path has no parent")]
+    CurrentExeHasNoParent,
+    #[error("unknown program {0}")]
+    UnknownProgramName(String),
+    #[error(transparent)]
+    Scope(#[from] crate::scope::Error),
+    /// Sidecar not allowed by the configuration.
+    #[error("sidecar not configured under `tauri.conf.json > tauri > bundle > externalBin`: {0}")]
+    SidecarNotAllowed(PathBuf),
+    /// Program not allowed by the scope.
+    #[error("program not allowed on the configured shell scope: {0}")]
+    ProgramNotAllowed(PathBuf),
+    #[error("unknown encoding {0}")]
+    UnknownEncoding(String),
+}
+
+impl Serialize for Error {
+    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(self.to_string().as_ref())
+    }
+}