From a960136802834bd3741ef637d91f73287870b1ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kat=20March=C3=A1n?= <kzm@zkat.tech>
Date: Sat, 14 Aug 2021 13:32:22 -0700
Subject: [PATCH] feat(utils): various convenience utilities for creating and
 working with Diagnostics

---
 src/lib.rs   |  2 ++
 src/utils.rs | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 src/utils.rs

diff --git a/src/lib.rs b/src/lib.rs
index 4c1ca43..2e9ef49 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,9 +3,11 @@
 pub use error::*;
 pub use protocol::*;
 pub use reporter::*;
+pub use utils::*;
 
 mod chain;
 mod error;
 mod protocol;
 mod reporter;
 mod source_impls;
+mod utils;
diff --git a/src/utils.rs b/src/utils.rs
new file mode 100644
index 0000000..8320eb7
--- /dev/null
+++ b/src/utils.rs
@@ -0,0 +1,39 @@
+use std::fmt;
+
+use thiserror::Error;
+
+use crate::Diagnostic;
+
+/// Convenience [Diagnostic] that can be used as an "anonymous" wrapper for
+/// Errors. This is intended to be paired with [IntoDiagnostic].
+#[derive(Debug, Error)]
+#[error("{}", self.error)]
+pub struct DiagnosticError {
+    #[source]
+    pub error: Box<dyn std::error::Error + Send + Sync + 'static>,
+    pub code: String,
+}
+
+impl Diagnostic for DiagnosticError {
+    fn code<'a>(&'a self) -> Box<dyn std::fmt::Display + 'a> {
+        Box::new(&self.code)
+    }
+}
+
+/// Utility Result type for functions that return boxed [Diagnostic]s.
+pub type DiagnosticResult<T> = Result<T, Box<dyn Diagnostic + Send + Sync + 'static>>;
+
+pub trait IntoDiagnostic<T, E> {
+    /// Converts [Result]-like types that return regular errors into a
+    /// `Result` that returns a [Diagnostic].
+    fn into_diagnostic(self, code: &(dyn fmt::Display)) -> Result<T, DiagnosticError>;
+}
+
+impl<T, E: std::error::Error + Send + Sync + 'static> IntoDiagnostic<T, E> for Result<T, E> {
+    fn into_diagnostic(self, code: &(dyn fmt::Display)) -> Result<T, DiagnosticError> {
+        self.map_err(|e| DiagnosticError {
+            error: Box::new(e),
+            code: format!("{}", code),
+        })
+    }
+}