Refactor

Author: tverghis

src/cargo/util/toml/mod.rs

@@ -1199,19 +1199,11 @@ impl TomlManifest {
             project.namespaced_features.unwrap_or(false),
         )?;
 
-        let readme = match &project.readme {
-            None => default_readme_from_package_root(package_root),
-            Some(value) => match value.as_str() {
-                "false" => None,
-                _ => Some(value.clone())
-            }
-        };
-
         let metadata = ManifestMetadata {
             description: project.description.clone(),
             homepage: project.homepage.clone(),
             documentation: project.documentation.clone(),
-            readme,
+            readme: readme_for_project(package_root, project),
             authors: project.authors.clone().unwrap_or_default(),
             license: project.license.clone(),
             license_file: project.license_file.clone(),
@@ -1522,17 +1514,37 @@ impl TomlManifest {
     }
 }
 
+/// Returns the name of the README file for a `TomlProject`.
+fn readme_for_project(package_root: &Path, project: &Box<TomlProject>) -> Option<String> {
+    match &project.readme {
+        None => default_readme_from_package_root(package_root),
+        Some(value) => match value.as_str() {
+            "false" => None,
+            _ => Some(value.clone())
+        }
+    }
+}
+
 const DEFAULT_README_FILES: [&str; 3] = ["README.md", "README.txt", "README"];
 
 /// Checks if a file with any of the default README file names exists in the package root.
-/// If so, returns a String representing that name.
+/// If so, returns a `String` representing that name.
 fn default_readme_from_package_root(package_root: &Path) -> Option<String> {
-    DEFAULT_README_FILES
-        .iter()
-        .map(|&fname| package_root.join(Path::new(fname)))
-        .filter(|path| path.is_file())
-        .flat_map(|path| path.file_name().map(|fname| fname.to_string_lossy().into_owned()))
-        .next()
+    _default_readme_from_package_root(package_root).ok()
+}
+
+fn _default_readme_from_package_root(package_root: &Path) -> CargoResult<String> {
+    for entry in package_root.read_dir()? {
+        let entry = entry?;
+
+        let fname = entry.file_name();
+
+        if entry.metadata()?.is_file() && DEFAULT_README_FILES.contains(&fname.to_str().unwrap()) {
+            return Ok(fname.into_string().map_err(|_| anyhow!("Could not convert the README's file name into a String"))?);
+        }
+    }
+
+    Err(anyhow!("No files with the default README file names found in the package root."))
 }
 
 /// Checks a list of build targets, and ensures the target names are unique within a vector.