Add ability for RepoInfo to iter configs

This will be necessary for building up a list of targets.

source_dir_test/Sources/README.md

@@ -0,0 +1,2 @@
+This directory exists to test that we correctly handle case on case-insensitive
+file systems.

src/lib.rs

@@ -7,7 +7,7 @@
 //! // get a list of repositories:
 //!
 //! let font_repo_cache = Path::new("~/where_i_want_to_checkout_fonts");
-//! let font_repos = google_fonts_sources::discover_sources(None, Some(font_repo_cache), false);
+//! let font_repos = google_fonts_sources::discover_sources(font_repo_cache).unwrap();
 //!
 //! // for each repo we find, do something with each source:
 //!
@@ -274,21 +274,18 @@ fn config_files_and_rev_for_repo(
     // - otherwise try naive http requests first,
     // - and then finally clone the repo and look
     let local_git_dir = local_repo_dir.join(".git");
-    if local_git_dir.exists() {
-        let rev = get_git_rev(&local_repo_dir).map_err(ConfigFetchIssue::GitFail)?;
-        let configs = get_config_paths(&local_repo_dir).ok_or(ConfigFetchIssue::NoConfigFound)?;
-        return Ok((configs, rev));
-    }
+    let skip_naive = local_git_dir.exists();
 
-    let naive = config_file_and_rev_from_remote_naive(repo_url).map(|(p, rev)| (vec![p], rev));
-    // if not found, try checking out and looking; otherwise return the result
-    if !matches!(naive, Err(ConfigFetchIssue::NoConfigFound)) {
-        naive
-    } else {
-        let configs = config_files_from_local_checkout(repo_url, &local_repo_dir)?;
-        let rev = get_git_rev(&local_repo_dir).map_err(ConfigFetchIssue::GitFail)?;
-        Ok((configs, rev))
+    if !skip_naive {
+        let naive = config_file_and_rev_from_remote_naive(repo_url).map(|(p, rev)| (vec![p], rev));
+        // if not found, try checking out and looking; otherwise return the result
+        if !matches!(naive, Err(ConfigFetchIssue::NoConfigFound)) {
+            return naive;
+        }
     }
+    let configs = config_files_from_local_checkout(repo_url, &local_repo_dir)?;
+    let rev = get_git_rev(&local_repo_dir).map_err(ConfigFetchIssue::GitFail)?;
+    Ok((configs, rev))
 }
 
 fn config_file_and_rev_from_remote_naive(
@@ -336,15 +333,20 @@ fn config_files_from_local_checkout(
         std::fs::create_dir_all(local_repo_dir).unwrap();
         clone_repo(repo_url, local_repo_dir).map_err(ConfigFetchIssue::GitFail)?;
     }
-    get_config_paths(local_repo_dir).ok_or(ConfigFetchIssue::NoConfigFound)
+    let configs: Vec<_> = iter_config_paths(local_repo_dir)?.collect();
+    if configs.is_empty() {
+        Err(ConfigFetchIssue::NoConfigFound)
+    } else {
+        Ok(configs)
+    }
 }
 
 /// Look for a file like 'config.yaml' in a google fonts font checkout.
 ///
 /// This will look for all files that begin with 'config' and have either the
 /// 'yaml' or 'yml' extension; if multiple files match this pattern it will
 /// return the one with the shortest name.
-fn get_config_paths(font_dir: &Path) -> Option<Vec<PathBuf>> {
+fn iter_config_paths(font_dir: &Path) -> Result<impl Iterator<Item = PathBuf>, ConfigFetchIssue> {
     #[allow(clippy::ptr_arg)] // we don't use &Path so we can pass this to a closure below
     fn looks_like_config_file(path: &PathBuf) -> bool {
         let (Some(stem), Some(extension)) =
@@ -355,19 +357,31 @@ fn get_config_paths(font_dir: &Path) -> Option<Vec<PathBuf>> {
         stem.starts_with("config") && (extension == "yaml" || extension == "yml")
     }
 
-    let sources_dir = font_dir.join("sources");
-    let contents = std::fs::read_dir(sources_dir).ok()?;
-    let mut config_files = contents
-        .filter_map(|entry| {
-            entry
-                .ok()
-                .and_then(|e| e.path().file_name().map(PathBuf::from))
-        })
-        .filter(looks_like_config_file)
-        .collect::<Vec<_>>();
-
-    config_files.sort_by_key(|p| p.to_str().map(|s| s.len()).unwrap_or(usize::MAX));
-    Some(config_files)
+    let sources_dir = find_sources_dir(font_dir).ok_or(ConfigFetchIssue::NoConfigFound)?;
+    let contents = std::fs::read_dir(sources_dir).map_err(|_| ConfigFetchIssue::NoConfigFound)?;
+    Ok(contents
+        .filter_map(|entry| entry.ok().map(|e| PathBuf::from(e.file_name())))
+        .filter(looks_like_config_file))
+}
+
+fn find_sources_dir(font_dir: &Path) -> Option<PathBuf> {
+    for case in ["sources", "Sources"] {
+        let path = font_dir.join(case);
+        if path.exists() {
+            // in order to handle case-insensitive file systems, we need to
+            // canonicalize this name, strip the canonical prefix, and glue
+            // it all back together
+            let canonical_font_dir = font_dir.canonicalize().ok()?;
+            let canonical_path = path.canonicalize().ok()?;
+            if let Ok(stripped) = canonical_path.strip_prefix(&canonical_font_dir) {
+                return Some(font_dir.join(stripped));
+            }
+            // if that fails for some reason just return the unnormalized path,
+            // we'll survive
+            return Some(path);
+        }
+    }
+    None
 }
 
 fn update_google_fonts_checkout(path: &Path) -> Result<(), Error> {
@@ -550,4 +564,12 @@ mod tests {
         assert!(rev.len() > 16);
         assert!(rev.chars().all(|c| c.is_ascii_hexdigit()));
     }
+
+    #[test]
+    fn source_dir_case() {
+        assert_eq!(
+            find_sources_dir(Path::new("./source_dir_test")),
+            Some(PathBuf::from("./source_dir_test/Sources"))
+        )
+    }
 }

src/repo_info.rs

@@ -5,7 +5,9 @@ use std::path::{Path, PathBuf};
 use crate::{error::LoadRepoError, Config};
 
 /// Information about a git repository containing font sources
-#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, serde::Serialize, serde::Deserialize)]
+#[derive(
+    Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, serde::Serialize, serde::Deserialize,
+)]
 #[non_exhaustive]
 pub struct RepoInfo {
     /// The repository's url
@@ -63,12 +65,17 @@ impl RepoInfo {
         repo_path_for_url(&self.repo_url, cache_dir).unwrap()
     }
 
-    /// Return the a `Vec` of source files in this respository.
+    /// Attempt to checkout/update this repo to the provided `cache_dir`.
     ///
-    /// If necessary, this will create a new checkout of this repo at
-    /// '{git_cache_dir}/{repo_org}/{repo_name}'.
-    pub fn get_sources(&self, git_cache_dir: &Path) -> Result<Vec<PathBuf>, LoadRepoError> {
-        let font_dir = self.repo_path(git_cache_dir);
+    /// The repo will be checked out to '{cache_dir}/{repo_org}/{repo_name}',
+    /// and HEAD will be set to the `self.git_rev()`.
+    ///
+    /// Returns the path to the checkout on success.
+    ///
+    /// Returns an error if the repo cannot be cloned, the git rev cannot be
+    /// found, or if there is an io error.
+    pub fn instantiate(&self, cache_dir: &Path) -> Result<PathBuf, LoadRepoError> {
+        let font_dir = self.repo_path(cache_dir);
         if !font_dir.exists() {
             std::fs::create_dir_all(&font_dir)?;
             super::clone_repo(&self.repo_url, &font_dir)?;
@@ -79,7 +86,33 @@ impl RepoInfo {
                 sha: self.rev.clone(),
             });
         }
+        Ok(font_dir)
+    }
 
+    /// Iterate paths to config files in this repo, checking it out if necessary
+    pub fn iter_configs(
+        &self,
+        cache_dir: &Path,
+    ) -> Result<impl Iterator<Item = PathBuf> + '_, LoadRepoError> {
+        let font_dir = self.instantiate(cache_dir)?;
+        let (left, right) = match super::iter_config_paths(&font_dir) {
+            Ok(iter) => (Some(iter), None),
+            Err(_) => (None, None),
+        };
+        let sources_dir = super::find_sources_dir(&font_dir).unwrap_or(font_dir);
+        Ok(left
+            .into_iter()
+            .flatten()
+            .chain(right)
+            .map(move |config| sources_dir.join(config)))
+    }
+
+    /// Return a `Vec` of source files in this respository.
+    ///
+    /// If necessary, this will create a new checkout of this repo at
+    /// '{git_cache_dir}/{repo_org}/{repo_name}'.
+    pub fn get_sources(&self, git_cache_dir: &Path) -> Result<Vec<PathBuf>, LoadRepoError> {
+        let font_dir = self.instantiate(git_cache_dir)?;
         let source_dir = font_dir.join("sources");
         let configs = self
             .config_files