typg_core/
discovery.rs

1/// Filesystem font discovery.
2///
3/// Walks directory trees to find font files (TTF, OTF, TTC, OTC).
4/// Inaccessible directories are skipped with a warning to stderr.
5///
6/// Made by FontLab https://www.fontlab.com/
7use std::path::{Path, PathBuf};
8
9use anyhow::{anyhow, Result};
10use walkdir::WalkDir;
11
12/// Reference to a discovered font file on disk.
13#[derive(Debug, Clone, PartialEq, Eq)]
14pub struct TypgFontSourceRef {
15    /// Path to the font file.
16    pub path: PathBuf,
17}
18
19/// Trait for font discovery backends.
20pub trait FontDiscovery {
21    /// Return all font files found by this backend.
22    fn discover(&self) -> Result<Vec<TypgFontSourceRef>>;
23}
24
25/// Discovers fonts by walking filesystem paths.
26///
27/// Recurses into directories, optionally follows symlinks. Recognizes
28/// font files by extension: `.ttf`, `.otf`, `.ttc`, `.otc`.
29#[derive(Debug, Clone)]
30pub struct PathDiscovery {
31    /// Root directories to walk.
32    roots: Vec<PathBuf>,
33    /// Whether to follow symlinks during traversal.
34    follow_symlinks: bool,
35}
36
37impl PathDiscovery {
38    /// Create a new discovery for the given root paths.
39    pub fn new<I, P>(roots: I) -> Self
40    where
41        I: IntoIterator<Item = P>,
42        P: Into<PathBuf>,
43    {
44        let roots = roots.into_iter().map(Into::into).collect();
45        Self {
46            roots,
47            follow_symlinks: false,
48        }
49    }
50
51    /// Enable or disable symlink following during traversal.
52    pub fn follow_symlinks(mut self, follow: bool) -> Self {
53        self.follow_symlinks = follow;
54        self
55    }
56}
57
58impl FontDiscovery for PathDiscovery {
59    /// Walk all root paths and return discovered font files.
60    ///
61    /// Directories that can't be read (permission denied, broken symlinks, etc.)
62    /// are skipped with a warning to stderr. The walk continues.
63    fn discover(&self) -> Result<Vec<TypgFontSourceRef>> {
64        let mut found = Vec::new();
65
66        for root in &self.roots {
67            if !root.exists() {
68                return Err(anyhow!("path does not exist: {}", root.display()));
69            }
70
71            for entry in WalkDir::new(root).follow_links(self.follow_symlinks) {
72                let entry = match entry {
73                    Ok(e) => e,
74                    Err(_) => {
75                        continue;
76                    }
77                };
78                if entry.file_type().is_file() && is_font(entry.path()) {
79                    found.push(TypgFontSourceRef {
80                        path: entry.path().to_path_buf(),
81                    });
82                }
83            }
84        }
85
86        Ok(found)
87    }
88}
89
90/// Check whether a path has a recognized font file extension.
91fn is_font(path: &Path) -> bool {
92    let ext = match path.extension().and_then(|e| e.to_str()) {
93        Some(ext) => ext.to_ascii_lowercase(),
94        None => return false,
95    };
96
97    matches!(ext.as_str(), "ttf" | "otf" | "ttc" | "otc")
98}
99
100#[cfg(test)]
101mod tests {
102    use super::is_font;
103    use super::FontDiscovery;
104    use super::PathDiscovery;
105    use std::fs;
106    use tempfile::tempdir;
107
108    #[test]
109    fn recognises_font_extensions() {
110        assert!(is_font("/A/B/font.ttf".as_ref()));
111        assert!(is_font("/A/B/font.OTF".as_ref()));
112        assert!(!is_font("/A/B/font.txt".as_ref()));
113        assert!(!is_font("/A/B/font".as_ref()));
114    }
115
116    #[test]
117    fn discovers_nested_fonts() {
118        let tmp = tempdir().expect("tempdir");
119        let nested = tmp.path().join("a/b");
120        fs::create_dir_all(&nested).expect("mkdir");
121        let font_path = nested.join("sample.ttf");
122        fs::write(&font_path, b"").expect("touch font");
123
124        let discovery = PathDiscovery::new([tmp.path()]);
125        let fonts = discovery.discover().expect("discover");
126
127        assert!(fonts.iter().any(|f| f.path == font_path));
128    }
129
130    #[cfg(unix)]
131    #[test]
132    fn follows_symlinks_when_enabled() {
133        use std::os::unix::fs::symlink;
134
135        let tmp = tempdir().expect("tempdir");
136        let real_dir = tmp.path().join("real");
137        let link_dir = tmp.path().join("link");
138        fs::create_dir_all(&real_dir).expect("mkdir real");
139        let font_path = real_dir.join("linked.otf");
140        fs::write(&font_path, b"").expect("touch font");
141        symlink(&real_dir, &link_dir).expect("symlink");
142
143        let discovery = PathDiscovery::new([&link_dir]).follow_symlinks(true);
144        let fonts = discovery.discover().expect("discover");
145
146        assert!(fonts.iter().any(|f| f.path.ends_with("linked.otf")));
147    }
148}
typg_core/discovery.rs

typg_core/
discovery.rs
