Allow references to be returned from lines

codespan-reporting/src/files.rs

@@ -79,22 +79,26 @@ where
 }
 
 /// Files that can be used for pretty printing.
-pub trait Files {
-    type FileId: Copy + PartialEq + PartialOrd + Eq + Ord + std::hash::Hash;
-    type Origin: std::fmt::Display;
-    type LineSource: AsRef<str>;
+///
+/// A lifetime parameter `'a` is provided to allow any of the returned values to returned by reference.
+/// This is to workaround the lack of higher kinded lifetime parameters.
+/// This can be ignored if this is not needed, however.
+pub trait Files<'a> {
+    type FileId: 'a + Copy + PartialEq + PartialOrd + Eq + Ord + std::hash::Hash;
+    type Origin: 'a + std::fmt::Display;
+    type LineSource: 'a + AsRef<str>;
 
     /// The origin of a file.
-    fn origin(&self, id: Self::FileId) -> Option<Self::Origin>;
+    fn origin(&'a self, id: Self::FileId) -> Option<Self::Origin>;
 
     /// The line at the given index.
-    fn line(&self, id: Self::FileId, line_index: usize) -> Option<Line<Self::LineSource>>;
+    fn line(&'a self, id: Self::FileId, line_index: usize) -> Option<Line<Self::LineSource>>;
 
     /// The index of the line at the given byte index.
-    fn line_index(&self, id: Self::FileId, byte_index: usize) -> Option<usize>;
+    fn line_index(&'a self, id: Self::FileId, byte_index: usize) -> Option<usize>;
 
     /// The location of the given byte index.
-    fn location(&self, id: Self::FileId, byte_index: usize) -> Option<Location> {
+    fn location(&'a self, id: Self::FileId, byte_index: usize) -> Option<Location> {
         let line_index = self.line_index(id, byte_index)?;
         let line = self.line(id, line_index)?;
 
@@ -165,10 +169,10 @@ where
     }
 }
 
-impl<Origin, Source> Files for SimpleFile<Origin, Source>
+impl<'a, Origin, Source> Files<'a> for SimpleFile<Origin, Source>
 where
-    Origin: std::fmt::Display + Clone,
-    Source: AsRef<str>,
+    Origin: 'a + std::fmt::Display + Clone,
+    Source: 'a + AsRef<str>,
 {
     type FileId = ();
     type Origin = Origin;
@@ -229,10 +233,10 @@ where
     }
 }
 
-impl<Origin, Source> Files for SimpleFiles<Origin, Source>
+impl<'a, Origin, Source> Files<'a> for SimpleFiles<Origin, Source>
 where
-    Origin: std::fmt::Display + Clone,
-    Source: AsRef<str>,
+    Origin: 'a + std::fmt::Display + Clone,
+    Source: 'a + AsRef<str>,
 {
     type FileId = usize;
     type Origin = Origin;

codespan-reporting/src/term.rs

@@ -15,10 +15,10 @@ pub use termcolor;
 pub use self::config::{Chars, Config, DisplayStyle, Styles};
 
 /// Emit a diagnostic using the given writer, context, config, and files.
-pub fn emit<F: Files>(
+pub fn emit<'files, F: Files<'files>>(
     writer: &mut (impl WriteColor + ?Sized),
     config: &Config,
-    files: &F,
+    files: &'files F,
     diagnostic: &Diagnostic<F::FileId>,
 ) -> io::Result<()> {
     use self::views::{RichDiagnostic, ShortDiagnostic};

codespan-reporting/src/term/views/diagnostic.rs

@@ -20,12 +20,15 @@ where
         RichDiagnostic { diagnostic }
     }
 
-    pub fn emit(
+    pub fn emit<'files>(
         &self,
-        files: &impl Files<FileId = FileId>,
+        files: &'files impl Files<'files, FileId = FileId>,
         writer: &mut (impl WriteColor + ?Sized),
         config: &Config,
-    ) -> io::Result<()> {
+    ) -> io::Result<()>
+    where
+        FileId: 'files,
+    {
         use std::collections::BTreeMap;
 
         use super::MarkStyle;
@@ -82,12 +85,15 @@ where
         ShortDiagnostic { diagnostic }
     }
 
-    pub fn emit(
+    pub fn emit<'files>(
         &self,
-        files: &impl Files<FileId = FileId>,
+        files: &'files impl Files<'files, FileId = FileId>,
         writer: &mut (impl WriteColor + ?Sized),
         config: &Config,
-    ) -> io::Result<()> {
+    ) -> io::Result<()>
+    where
+        FileId: 'files,
+    {
         let label = &self.diagnostic.primary_label;
         let origin = files
             .origin(self.diagnostic.primary_label.file_id)

codespan-reporting/src/term/views/source_snippet.rs

@@ -41,18 +41,18 @@ fn count_digits(mut n: usize) -> usize {
 ///   = expected type `Int`
 ///        found type `String`
 /// ```
-pub struct SourceSnippet<'a, F: Files> {
+pub struct SourceSnippet<'a, 'files, F: Files<'files>> {
     file_id: F::FileId,
     ranges: Vec<(&'a Label<F::FileId>, MarkStyle)>,
     notes: &'a [String],
 }
 
-impl<'a, F: Files> SourceSnippet<'a, F> {
+impl<'a, 'files: 'a, F: Files<'files>> SourceSnippet<'a, 'files, F> {
     pub fn new(
         file_id: F::FileId,
         ranges: Vec<(&'a Label<F::FileId>, MarkStyle)>,
         notes: &'a [String],
-    ) -> SourceSnippet<'a, F> {
+    ) -> SourceSnippet<'a, 'files, F> {
         SourceSnippet {
             file_id,
             ranges,
@@ -89,7 +89,7 @@ impl<'a, F: Files> SourceSnippet<'a, F> {
 
     pub fn emit(
         &self,
-        files: &F,
+        files: &'files F,
         writer: &mut (impl WriteColor + ?Sized),
         config: &Config,
     ) -> io::Result<()> {

codespan-reporting/tests/support/mod.rs

@@ -7,24 +7,24 @@ mod color_buffer;
 
 use self::color_buffer::ColorBuffer;
 
-pub struct TestData<F: Files> {
+pub struct TestData<'files, F: Files<'files>> {
     pub files: F,
     pub diagnostics: Vec<Diagnostic<F::FileId>>,
 }
 
-impl<F: Files> TestData<F> {
-    fn emit<W: WriteColor>(&self, mut writer: W, config: &Config) -> W {
+impl<'files, F: Files<'files>> TestData<'files, F> {
+    fn emit<W: WriteColor>(&'files self, mut writer: W, config: &Config) -> W {
         for diagnostic in &self.diagnostics {
             emit(&mut writer, config, &self.files, &diagnostic).unwrap();
         }
         writer
     }
 
-    pub fn emit_color(&self, config: &Config) -> String {
+    pub fn emit_color(&'files self, config: &Config) -> String {
         self.emit(ColorBuffer::new(), &config).into_string()
     }
 
-    pub fn emit_no_color(&self, config: &Config) -> String {
+    pub fn emit_no_color(&'files self, config: &Config) -> String {
         let buffer = self.emit(Buffer::no_color(), &config);
         String::from_utf8_lossy(buffer.as_slice()).into_owned()
     }

codespan-reporting/tests/term.rs

@@ -18,7 +18,7 @@ mod empty_spans {
     use super::*;
 
     lazy_static::lazy_static! {
-        static ref TEST_DATA: TestData<SimpleFile<&'static str, &'static str>> = {
+        static ref TEST_DATA: TestData<'static, SimpleFile<&'static str, &'static str>> = {
             let file = SimpleFile::new("hello", "Hello world!\nBye world!");
             let eof = file.source().len();
 
@@ -57,7 +57,7 @@ mod multifile {
     use super::*;
 
     lazy_static::lazy_static! {
-        static ref TEST_DATA: TestData<SimpleFiles<&'static str, String>> = {
+        static ref TEST_DATA: TestData<'static, SimpleFiles<&'static str, String>> = {
             let mut files = SimpleFiles::new();
 
             let file_id1 = files.add(
@@ -175,7 +175,7 @@ mod fizz_buzz {
     use super::*;
 
     lazy_static::lazy_static! {
-        static ref TEST_DATA: TestData<SimpleFiles<&'static str, String>> = {
+        static ref TEST_DATA: TestData<'static, SimpleFiles<&'static str, String>> = {
             let mut files = SimpleFiles::new();
 
             let file_id = files.add(
@@ -287,7 +287,7 @@ mod tabbed {
     use super::*;
 
     lazy_static::lazy_static! {
-        static ref TEST_DATA: TestData<SimpleFiles<&'static str, String>> = {
+        static ref TEST_DATA: TestData<'static, SimpleFiles<&'static str, String>> = {
             let mut files = SimpleFiles::new();
 
             let file_id = files.add(

codespan/src/file.rs

@@ -295,13 +295,13 @@ where
 }
 
 #[cfg(feature = "reporting")]
-impl<Source> codespan_reporting::files::Files for Files<Source>
+impl<'a, Source> codespan_reporting::files::Files<'a> for Files<Source>
 where
     Source: AsRef<str>,
 {
     type FileId = FileId;
     type Origin = String;
-    type LineSource = String;
+    type LineSource = &'a str;
 
     fn origin(&self, id: FileId) -> Option<String> {
         use std::path::PathBuf;
@@ -314,17 +314,17 @@ where
     }
 
     fn line(
-        &self,
+        &'a self,
         id: FileId,
         line_index: usize,
-    ) -> Option<codespan_reporting::files::Line<String>> {
+    ) -> Option<codespan_reporting::files::Line<&'a str>> {
         let span = self.line_span(id, line_index as u32).ok()?;
         let source = self.source_slice(id, span).ok()?;
 
         Some(codespan_reporting::files::Line {
             start: span.start().to_usize(),
             number: line_index + 1,
-            source: source.to_owned(),
+            source,
         })
     }
 }