1 files changed, 95 insertions, 0 deletions
diff --git a/third_party/rust/askama_shared/src/error.rs b/third_party/rust/askama_shared/src/error.rs
new file mode 100644
index 0000000000..98f2703323
--- /dev/null
+++ b/third_party/rust/askama_shared/src/error.rs
@@ -0,0 +1,95 @@
+use std::fmt::{self, Display};
+
+pub type Result<I, E = Error> = ::std::result::Result<I, E>;
+
+/// askama error type
+///
+/// # Feature Interaction
+///
+/// If the feature `serde_json` is enabled an
+/// additional error variant `Json` is added.
+///
+/// # Why not `failure`/`error-chain`?
+///
+/// Error from `error-chain` are not `Sync` which
+/// can lead to problems e.g. when this is used
+/// by a crate which use `failure`. Implementing
+/// `Fail` on the other hand prevents the implementation
+/// of `std::error::Error` until specialization lands
+/// on stable. While errors impl. `Fail` can be
+/// converted to a type impl. `std::error::Error`
+/// using a adapter the benefits `failure` would
+/// bring to this crate are small, which is why
+/// `std::error::Error` was used.
+///
+#[non_exhaustive]
+#[derive(Debug)]
+pub enum Error {
+    /// formatting error
+    Fmt(fmt::Error),
+
+    /// an error raised by using `?` in a template
+    Custom(Box<dyn std::error::Error + Send + Sync>),
+
+    /// json conversion error
+    #[cfg(feature = "serde_json")]
+    Json(::serde_json::Error),
+
+    /// yaml conversion error
+    #[cfg(feature = "serde_yaml")]
+    Yaml(::serde_yaml::Error),
+}
+
+impl std::error::Error for Error {
+    fn cause(&self) -> Option<&dyn std::error::Error> {
+        match *self {
+            Error::Fmt(ref err) => err.source(),
+            Error::Custom(ref err) => Some(err.as_ref()),
+            #[cfg(feature = "serde_json")]
+            Error::Json(ref err) => err.source(),
+            #[cfg(feature = "serde_yaml")]
+            Error::Yaml(ref err) => err.source(),
+        }
+    }
+}
+
+impl Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Error::Fmt(err) => write!(formatter, "formatting error: {}", err),
+            Error::Custom(err) => write!(formatter, "{}", err),
+            #[cfg(feature = "serde_json")]
+            Error::Json(err) => write!(formatter, "json conversion error: {}", err),
+            #[cfg(feature = "serde_yaml")]
+            Error::Yaml(err) => write!(formatter, "yaml conversion error: {}", err),
+        }
+    }
+}
+
+impl From<fmt::Error> for Error {
+    fn from(err: fmt::Error) -> Self {
+        Error::Fmt(err)
+    }
+}
+
+#[cfg(feature = "serde_json")]
+impl From<::serde_json::Error> for Error {
+    fn from(err: ::serde_json::Error) -> Self {
+        Error::Json(err)
+    }
+}
+
+#[cfg(feature = "serde_yaml")]
+impl From<::serde_yaml::Error> for Error {
+    fn from(err: ::serde_yaml::Error) -> Self {
+        Error::Yaml(err)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Error;
+
+    trait AssertSendSyncStatic: Send + Sync + 'static {}
+    impl AssertSendSyncStatic for Error {}
+}