lex_syntax/
workspace.rs

1//! `lex.toml` manifest parsing and package resolution.
2//!
3//! A `lex.toml` file marks a project root and declares its package
4//! dependencies. Import paths of the form `"pkg-name/module"` are
5//! resolved against this file.
6//!
7//! ## File format
8//!
9//! ```toml
10//! [package]
11//! name = "lex-web"
12//! version = "0.1.0"
13//!
14//! [dependencies]
15//! lex-schema = { path = "../lex-schema" }
16//! # pin to a tag:
17//! lex-schema = { git = "https://github.com/alpibrusl/lex-schema", tag = "v1.2.0" }
18//! # pin to a commit:
19//! lex-schema = { git = "https://github.com/alpibrusl/lex-schema", rev = "abc1234" }
20//! # track a branch:
21//! lex-schema = { git = "https://github.com/alpibrusl/lex-schema", branch = "stable" }
22//! # or from a registry:
23//! lex-schema = { registry = "https://lexhub.alpibru.com", version = "0.9.2" }
24//! ```
25//!
26//! At most one of `tag`, `rev`, `branch` may be set; omitting all three
27//! clones the default branch at HEAD (not reproducible — pin for releases).
28//!
29//! ## Module resolution
30//!
31//! `import "lex-schema/validate" as v` splits into `pkg = "lex-schema"`,
32//! `module = "validate"`. The loader:
33//!
34//! 1. Walks up from the importing file to find the nearest `lex.toml`.
35//! 2. Looks up `lex-schema` in `[dependencies]`.
36//! 3. For `path =`: resolves `{dep_path}/src/validate.lex`; falls back to
37//!    `{dep_path}/validate.lex` if `src/` doesn't exist.
38//! 4. For `git =`: clones the repo into `~/.lex/packages/lex-schema-<ref>/`
39//!    (once; subsequent loads hit the cache), then resolves the same way.
40
41use serde::Deserialize;
42use std::collections::HashMap;
43use std::path::{Path, PathBuf};
44
45// ── Manifest types ────────────────────────────────────────────────────────────
46
47#[derive(Debug, Deserialize)]
48pub struct Manifest {
49    pub package: Option<PackageMeta>,
50    #[serde(default)]
51    pub dependencies: HashMap<String, Dependency>,
52}
53
54#[derive(Debug, Deserialize)]
55pub struct PackageMeta {
56    pub name: String,
57    #[serde(default)]
58    pub version: String,
59    #[serde(default)]
60    pub description: Option<String>,
61    /// Default registry URL for `lex pkg publish` when `--registry` is not supplied.
62    #[serde(default)]
63    pub registry: Option<String>,
64}
65
66#[derive(Debug, Deserialize)]
67#[serde(untagged)]
68pub enum Dependency {
69    Path     { path: String },
70    Git      {
71        git:    String,
72        #[serde(default)]
73        branch: Option<String>,
74        #[serde(default)]
75        tag:    Option<String>,
76        #[serde(default)]
77        rev:    Option<String>,
78    },
79    Registry { registry: String, version: String },
80}
81
82impl Dependency {
83    /// Return an error if more than one of branch/tag/rev is set.
84    pub fn validate(&self) -> Result<(), String> {
85        if let Dependency::Git { branch, tag, rev, .. } = self {
86            let count = [branch, tag, rev].iter().filter(|o| o.is_some()).count();
87            if count > 1 {
88                return Err("at most one of `branch`, `tag`, `rev` may be set on a git dependency".into());
89            }
90        }
91        Ok(())
92    }
93}
94
95impl Manifest {
96    pub fn load(toml_path: &Path) -> Result<Self, String> {
97        let src = std::fs::read_to_string(toml_path)
98            .map_err(|e| format!("reading {}: {e}", toml_path.display()))?;
99        toml::from_str(&src)
100            .map_err(|e| format!("parsing {}: {e}", toml_path.display()))
101    }
102}
103
104// ── Discovery ─────────────────────────────────────────────────────────────────
105
106/// Walk up from `start` (a file or directory) looking for `lex.toml`.
107/// Returns `(toml_path, toml_dir)` for the nearest ancestor that has one.
108pub fn find_manifest(start: &Path) -> Option<(PathBuf, PathBuf)> {
109    let mut dir = if start.is_dir() {
110        start.to_path_buf()
111    } else {
112        start.parent()?.to_path_buf()
113    };
114    loop {
115        let candidate = dir.join("lex.toml");
116        if candidate.exists() {
117            return Some((candidate, dir));
118        }
119        match dir.parent() {
120            Some(p) if p != dir => dir = p.to_path_buf(),
121            _ => return None,
122        }
123    }
124}
125
126// ── Resolution ────────────────────────────────────────────────────────────────
127
128/// Resolve `pkg_name/module_path` to a `.lex` file on disk.
129///
130/// `importer` is the file that contains the import statement; it's used
131/// to locate the nearest `lex.toml`.
132pub fn resolve_package_import(
133    importer: &Path,
134    pkg_name: &str,
135    module_path: &str,
136) -> Result<PathBuf, PackageError> {
137    let (toml_path, toml_dir) = find_manifest(importer).ok_or_else(|| {
138        PackageError::NoManifest {
139            reference: format!("{pkg_name}/{module_path}"),
140            searched_from: importer.display().to_string(),
141        }
142    })?;
143
144    let manifest = Manifest::load(&toml_path)
145        .map_err(|e| PackageError::ManifestParse { path: toml_path.display().to_string(), detail: e })?;
146
147    let dep = manifest.dependencies.get(pkg_name).ok_or_else(|| {
148        PackageError::UnknownPackage {
149            name: pkg_name.to_string(),
150            manifest: toml_path.display().to_string(),
151        }
152    })?;
153
154    let pkg_root = match dep {
155        Dependency::Path { path } => {
156            let raw = toml_dir.join(path);
157            raw.canonicalize().map_err(|e| PackageError::Io {
158                path: raw.display().to_string(),
159                detail: e.to_string(),
160            })?
161        }
162        Dependency::Git { git, branch, tag, rev } => {
163            dep.validate().map_err(|e| PackageError::ManifestParse {
164                path: toml_path.display().to_string(),
165                detail: e,
166            })?;
167            let git_ref = GitRef::from(branch.as_deref(), tag.as_deref(), rev.as_deref());
168            git_ensure_cached(pkg_name, git, &git_ref)?
169        }
170        Dependency::Registry { registry, version } => {
171            registry_ensure_cached(pkg_name, registry, version)?
172        }
173    };
174
175    find_module_file(&pkg_root, module_path).ok_or_else(|| PackageError::ModuleNotFound {
176        pkg: pkg_name.to_string(),
177        module: module_path.to_string(),
178        pkg_root: pkg_root.display().to_string(),
179    })
180}
181
182/// Look for `{module_path}.lex` inside a package root, checking `src/`
183/// first then the root itself.
184fn find_module_file(pkg_root: &Path, module_path: &str) -> Option<PathBuf> {
185    let rel = PathBuf::from(module_path).with_extension("lex");
186    let in_src = pkg_root.join("src").join(&rel);
187    if in_src.exists() {
188        return Some(in_src);
189    }
190    let at_root = pkg_root.join(&rel);
191    if at_root.exists() {
192        return Some(at_root);
193    }
194    None
195}
196
197// ── Git cache ─────────────────────────────────────────────────────────────────
198
199/// Parsed ref from a git dependency declaration.
200#[derive(Debug)]
201enum GitRef<'a> {
202    Branch(&'a str),
203    Tag(&'a str),
204    Rev(&'a str),
205    DefaultBranch,
206}
207
208impl<'a> GitRef<'a> {
209    fn from(branch: Option<&'a str>, tag: Option<&'a str>, rev: Option<&'a str>) -> Self {
210        if let Some(b) = branch { return GitRef::Branch(b); }
211        if let Some(t) = tag    { return GitRef::Tag(t); }
212        if let Some(r) = rev    { return GitRef::Rev(r); }
213        GitRef::DefaultBranch
214    }
215
216    /// Slug appended to the cache directory name to prevent collisions between
217    /// different refs of the same repo.
218    fn cache_slug(&self) -> String {
219        match self {
220            GitRef::Branch(b)    => format!("@branch-{}", sanitize_ref(b)),
221            GitRef::Tag(t)       => format!("@tag-{}", sanitize_ref(t)),
222            GitRef::Rev(r)       => format!("@rev-{}", &r[..r.len().min(12)]),
223            GitRef::DefaultBranch => String::new(),
224        }
225    }
226}
227
228/// Replace characters that are not safe in directory names.
229fn sanitize_ref(r: &str) -> String {
230    r.chars().map(|c| if c.is_alphanumeric() || c == '-' || c == '.' { c } else { '_' }).collect()
231}
232
233/// Return the local cache directory for `pkg_name`, cloning from `url`
234/// at the given ref if it isn't there yet.
235///
236/// Cache root: `$LEX_PACKAGES_DIR` if set, otherwise `~/.lex/packages/`.
237/// Cache key:  `{pkg_name}{ref_slug}` so different tags/revs don't collide.
238fn git_ensure_cached(pkg_name: &str, url: &str, git_ref: &GitRef<'_>) -> Result<PathBuf, PackageError> {
239    let cache_root = packages_cache_dir()?;
240    let dir_name = format!("{}{}", pkg_name, git_ref.cache_slug());
241    let pkg_dir = cache_root.join(&dir_name);
242    if pkg_dir.exists() {
243        return Ok(pkg_dir);
244    }
245    std::fs::create_dir_all(&cache_root).map_err(|e| PackageError::Io {
246        path: cache_root.display().to_string(),
247        detail: e.to_string(),
248    })?;
249
250    let dest = pkg_dir.to_str().unwrap_or(&dir_name);
251
252    let status = match git_ref {
253        GitRef::Rev(rev) => {
254            // Shallow clone is not possible for arbitrary commits; do a full
255            // clone then check out the specific revision.
256            let s = run_git(&["clone", "--quiet", url, dest], url)?;
257            if s {
258                run_git(&["-C", dest, "checkout", "--quiet", rev], url)?;
259                true
260            } else {
261                false
262            }
263        }
264        GitRef::Tag(tag) => run_git(&["clone", "--quiet", "--depth=1", "--branch", tag, url, dest], url)?,
265        GitRef::Branch(branch) => run_git(&["clone", "--quiet", "--depth=1", "--branch", branch, url, dest], url)?,
266        GitRef::DefaultBranch  => run_git(&["clone", "--quiet", "--depth=1", url, dest], url)?,
267    };
268
269    if !status {
270        // Clean up partial clone so a retry doesn't hit the cache check above.
271        let _ = std::fs::remove_dir_all(&pkg_dir);
272        return Err(PackageError::GitFailed {
273            url: url.to_string(),
274            detail: "`git` exited with non-zero status".into(),
275        });
276    }
277
278    pkg_dir.canonicalize().map_err(|e| PackageError::Io {
279        path: pkg_dir.display().to_string(),
280        detail: e.to_string(),
281    })
282}
283
284/// Run a git command and return `Ok(true)` on success, `Ok(false)` on non-zero
285/// exit, or `Err` if git could not be spawned.
286fn run_git(args: &[&str], url: &str) -> Result<bool, PackageError> {
287    let status = std::process::Command::new("git")
288        .args(args)
289        .status()
290        .map_err(|e| PackageError::GitFailed {
291            url: url.to_string(),
292            detail: format!("could not run `git`: {e}"),
293        })?;
294    Ok(status.success())
295}
296
297/// Download a registry package archive and extract it to the local cache.
298///
299/// Cache path: `$LEX_PACKAGES_DIR/{name}-{version}/` (versioned to avoid
300/// collisions with git-cached packages at `{name}/`).
301///
302/// Download URL: `{registry}/v1/pkg/{name}/{version}/archive`
303fn registry_ensure_cached(
304    pkg_name: &str,
305    registry: &str,
306    version: &str,
307) -> Result<PathBuf, PackageError> {
308    let cache_root = packages_cache_dir()?;
309    // Registry packages are cached under `{name}-{version}` to keep multiple
310    // versions side-by-side and separate from git-cached directories.
311    let pkg_dir = cache_root.join(format!("{pkg_name}-{version}"));
312    if pkg_dir.exists() {
313        return Ok(pkg_dir);
314    }
315    std::fs::create_dir_all(&cache_root).map_err(|e| PackageError::Io {
316        path: cache_root.display().to_string(),
317        detail: e.to_string(),
318    })?;
319
320    let url = format!(
321        "{}/v1/pkg/{}/{}/archive",
322        registry.trim_end_matches('/'),
323        pkg_name,
324        version,
325    );
326    let response = ureq::get(&url).call().map_err(|e| PackageError::RegistryFailed {
327        name: pkg_name.to_string(),
328        registry: registry.to_string(),
329        version: version.to_string(),
330        detail: format!("GET {url}: {e}"),
331    })?;
332    if response.status() != 200 {
333        return Err(PackageError::RegistryFailed {
334            name: pkg_name.to_string(),
335            registry: registry.to_string(),
336            version: version.to_string(),
337            detail: format!("GET {url} returned HTTP {}", response.status()),
338        });
339    }
340
341    let archive_bytes = response
342        .into_body()
343        .read_to_vec()
344        .map_err(|e| PackageError::RegistryFailed {
345            name: pkg_name.to_string(),
346            registry: registry.to_string(),
347            version: version.to_string(),
348            detail: format!("reading response body: {e}"),
349        })?;
350
351    let gz = flate2::read::GzDecoder::new(std::io::Cursor::new(&archive_bytes));
352    let mut ar = tar::Archive::new(gz);
353    ar.unpack(&pkg_dir).map_err(|e| PackageError::RegistryFailed {
354        name: pkg_name.to_string(),
355        registry: registry.to_string(),
356        version: version.to_string(),
357        detail: format!("extracting archive: {e}"),
358    })?;
359
360    pkg_dir.canonicalize().map_err(|e| PackageError::Io {
361        path: pkg_dir.display().to_string(),
362        detail: e.to_string(),
363    })
364}
365
366/// The flat package cache root used by the resolver — `$LEX_PACKAGES_DIR`
367/// if set, otherwise `~/.lex/packages/`. Returns `None` only when neither is
368/// available. Exposed so tooling can recognise dependencies whose path
369/// resolves *into* this cache (and are therefore aliases of an
370/// already-installed package rather than independent sources).
371pub fn packages_cache_root() -> Option<PathBuf> {
372    packages_cache_dir().ok()
373}
374
375fn packages_cache_dir() -> Result<PathBuf, PackageError> {
376    if let Ok(dir) = std::env::var("LEX_PACKAGES_DIR") {
377        return Ok(PathBuf::from(dir));
378    }
379    let home = std::env::var("HOME")
380        .or_else(|_| std::env::var("USERPROFILE"))
381        .map_err(|_| PackageError::Io {
382            path: "~/.lex/packages".into(),
383            detail: "could not determine home directory (set LEX_PACKAGES_DIR)".into(),
384        })?;
385    Ok(PathBuf::from(home).join(".lex").join("packages"))
386}
387
388// ── Errors ────────────────────────────────────────────────────────────────────
389
390#[derive(Debug, thiserror::Error)]
391pub enum PackageError {
392    #[error("no lex.toml found searching up from {searched_from} (needed to resolve \"{reference}\")")]
393    NoManifest { reference: String, searched_from: String },
394
395    #[error("failed to parse {path}: {detail}")]
396    ManifestParse { path: String, detail: String },
397
398    #[error("package \"{name}\" not found in {manifest}")]
399    UnknownPackage { name: String, manifest: String },
400
401    #[error("module \"{module}\" not found in package \"{pkg}\" (looked in {pkg_root}/src/ and {pkg_root}/)")]
402    ModuleNotFound { pkg: String, module: String, pkg_root: String },
403
404    #[error("git clone of {url} failed: {detail}")]
405    GitFailed { url: String, detail: String },
406
407    #[error("registry fetch of {name}@{version} from {registry} failed: {detail}")]
408    RegistryFailed { name: String, registry: String, version: String, detail: String },
409
410    #[error("I/O error at {path}: {detail}")]
411    Io { path: String, detail: String },
412}
lex_syntax/workspace.rs

lex_syntax/
workspace.rs
