Unified file loading errors

6 files changed, 49 insertions, 42 deletions

diff --git a/src/diag.rs b/src/diag.rs
index 76cad792..c4438307 100644
--- a/src/diag.rs
+++ b/src/diag.rs
@@ -1,6 +1,8 @@
 //! Diagnostics.
 
 use std::fmt::{self, Display, Formatter};
+use std::io;
+use std::path::Path;
 
 use crate::syntax::{Span, Spanned};
 use crate::Context;
@@ -134,3 +136,13 @@ pub fn with_alternative(msg: String, alt: &str) -> String {
         msg
     }
 }
+
+/// Format a file loading failure.
+pub fn failed_to_load(target: &str, path: &Path, error: io::Error) -> String {
+    match error.kind() {
+        io::ErrorKind::NotFound => {
+            format!("file not found (searched at {})", path.display())
+        }
+        _ => format!("failed to load {target} ({error})"),
+    }
+}
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index b1cf9e0b..e2090cd2 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -967,12 +967,7 @@ impl Eval for IncludeExpr {
 fn import(vm: &mut Machine, path: &str, span: Span) -> TypResult<Module> {
     // Load the source file.
     let full = vm.locate(&path).at(span)?;
-    let id = vm.ctx.sources.load(&full).map_err(|err| match err.kind() {
-        std::io::ErrorKind::NotFound => {
-            error!(span, "file not found (searched at {})", full.display())
-        }
-        _ => error!(span, "failed to load source file ({})", err),
-    })?;
+    let id = vm.ctx.sources.load(&full).at(span)?;
 
     // Prevent cyclic importing.
     if vm.route.contains(&id) {
diff --git a/src/image.rs b/src/image.rs
index 6b21bdd9..8ef404fe 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -10,6 +10,7 @@ use std::sync::Arc;
 use image::io::Reader as ImageReader;
 use image::{DynamicImage, ImageFormat};
 
+use crate::diag::{failed_to_load, StrResult};
 use crate::loading::{FileHash, Loader};
 
 /// A unique identifier for a loaded image.
@@ -60,19 +61,24 @@ impl ImageStore {
 
     /// Load and decode an image file from a path relative to the compilation
     /// environment's root.
-    pub fn load(&mut self, path: &Path) -> io::Result<ImageId> {
-        let hash = self.loader.resolve(path)?;
-        Ok(*match self.files.entry(hash) {
-            Entry::Occupied(entry) => entry.into_mut(),
-            Entry::Vacant(entry) => {
-                let buffer = self.loader.load(path)?;
-                let ext = path.extension().and_then(OsStr::to_str).unwrap_or_default();
-                let image = Image::parse(&buffer, ext)?;
-                let id = ImageId(self.images.len() as u32);
-                self.images.push(image);
-                entry.insert(id)
-            }
-        })
+    pub fn load(&mut self, path: &Path) -> StrResult<ImageId> {
+        let mut try_load = || -> io::Result<ImageId> {
+            let hash = self.loader.resolve(path)?;
+            Ok(*match self.files.entry(hash) {
+                Entry::Occupied(entry) => entry.into_mut(),
+                Entry::Vacant(entry) => {
+                    let buffer = self.loader.load(path)?;
+                    let ext =
+                        path.extension().and_then(OsStr::to_str).unwrap_or_default();
+                    let image = Image::parse(&buffer, ext)?;
+                    let id = ImageId(self.images.len() as u32);
+                    self.images.push(image);
+                    entry.insert(id)
+                }
+            })
+        };
+
+        try_load().map_err(|err| failed_to_load("image", path, err))
     }
 }
 
diff --git a/src/library/graphics/image.rs b/src/library/graphics/image.rs
index 1781eb8a..feb37ae6 100644
--- a/src/library/graphics/image.rs
+++ b/src/library/graphics/image.rs
@@ -16,13 +16,7 @@ impl ImageNode {
             args.expect::<Spanned<EcoString>>("path to image file")?;
 
         let full = vm.locate(&path).at(span)?;
-        let id = vm.ctx.images.load(&full).map_err(|err| match err.kind() {
-            std::io::ErrorKind::NotFound => {
-                error!(span, "file not found (searched at {})", full.display())
-            }
-            _ => error!(span, "failed to load image ({})", err),
-        })?;
-
+        let id = vm.ctx.images.load(&full).at(span)?;
         let width = args.named("width")?;
         let height = args.named("height")?;
 
diff --git a/src/main.rs b/src/main.rs
index 2f31d135..784dbc2d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -206,10 +206,7 @@ fn typeset(command: TypesetCommand) -> StrResult<()> {
     let mut ctx = Context::new(Arc::new(loader), config.build());
 
     // Load the source file.
-    let id = ctx
-        .sources
-        .load(&command.input)
-        .map_err(|_| "failed to load source file")?;
+    let id = ctx.sources.load(&command.input)?;
 
     // Typeset.
     match typst::typeset(&mut ctx, id) {
diff --git a/src/source.rs b/src/source.rs
index ce837f9e..c299da4f 100644
--- a/src/source.rs
+++ b/src/source.rs
@@ -8,7 +8,7 @@ use std::sync::Arc;
 
 use unscanny::Scanner;
 
-use crate::diag::TypResult;
+use crate::diag::{failed_to_load, StrResult, TypResult};
 use crate::loading::{FileHash, Loader};
 use crate::parse::{is_newline, parse, reparse};
 use crate::syntax::ast::Markup;
@@ -74,19 +74,22 @@ impl SourceStore {
     ///
     /// If there already exists a source file for this path, it is
     /// [replaced](SourceFile::replace).
-    pub fn load(&mut self, path: impl AsRef<Path>) -> io::Result<SourceId> {
-        let path = path.as_ref();
-        let hash = self.loader.resolve(path)?;
-        if let Some(&id) = self.files.get(&hash) {
-            return Ok(id);
-        }
+    pub fn load(&mut self, path: &Path) -> StrResult<SourceId> {
+        let mut try_load = || -> io::Result<SourceId> {
+            let hash = self.loader.resolve(path)?;
+            if let Some(&id) = self.files.get(&hash) {
+                return Ok(id);
+            }
+
+            let data = self.loader.load(path)?;
+            let src = String::from_utf8(data).map_err(|_| {
+                io::Error::new(io::ErrorKind::InvalidData, "file is not valid utf-8")
+            })?;
 
-        let data = self.loader.load(path)?;
-        let src = String::from_utf8(data).map_err(|_| {
-            io::Error::new(io::ErrorKind::InvalidData, "file is not valid utf-8")
-        })?;
+            Ok(self.provide(path, src))
+        };
 
-        Ok(self.provide(path, src))
+        try_load().map_err(|err| failed_to_load("source file", path, err))
     }
 
     /// Directly provide a source file.