introduce ra_vfs_glob crate

It manages exclusion rules for the vfs crate

crates/ra_vfs_glob/src/lib.rs

@@ -0,0 +1,93 @@
+//! `ra_vfs_glob` crate implements exclusion rules for vfs.
+//!
+//! By default, we include only `.rs` files, and skip some know offenders like
+//! `/target` or `/node_modules` altogether.
+//!
+//! It's also possible to add custom exclusion globs.
+
+use globset::{Glob, GlobSet, GlobSetBuilder};
+use ra_vfs::{Filter, RelativePath};
+
+const ALWAYS_IGNORED: &[&str] = &["target/**", "**/node_modules/**", "**/.git/**"];
+const IGNORED_FOR_NON_MEMBERS: &[&str] = &["examples/**", "tests/**", "benches/**"];
+
+pub struct RustPackageFilterBuilder {
+    is_member: bool,
+    exclude: GlobSetBuilder,
+}
+
+impl Default for RustPackageFilterBuilder {
+    fn default() -> RustPackageFilterBuilder {
+        RustPackageFilterBuilder { is_member: false, exclude: GlobSetBuilder::new() }
+    }
+}
+
+impl RustPackageFilterBuilder {
+    pub fn set_member(mut self, is_member: bool) -> RustPackageFilterBuilder {
+        self.is_member = is_member;
+        self
+    }
+    pub fn exclude(mut self, glob: &str) -> Result<RustPackageFilterBuilder, globset::Error> {
+        self.exclude.add(Glob::new(glob)?);
+        Ok(self)
+    }
+    pub fn into_vfs_filter(self) -> Box<dyn Filter> {
+        let RustPackageFilterBuilder { is_member, mut exclude } = self;
+        for &glob in ALWAYS_IGNORED {
+            exclude.add(Glob::new(glob).unwrap());
+        }
+        if !is_member {
+            for &glob in IGNORED_FOR_NON_MEMBERS {
+                exclude.add(Glob::new(glob).unwrap());
+            }
+        }
+        Box::new(RustPackageFilter { exclude: exclude.build().unwrap() })
+    }
+}
+
+struct RustPackageFilter {
+    exclude: GlobSet,
+}
+
+impl Filter for RustPackageFilter {
+    fn include_dir(&self, dir_path: &RelativePath) -> bool {
+        !self.exclude.is_match(dir_path.as_str())
+    }
+
+    fn include_file(&self, file_path: &RelativePath) -> bool {
+        file_path.extension() == Some("rs")
+    }
+}
+
+#[test]
+fn test_globs() {
+    let filter = RustPackageFilterBuilder::default().set_member(true).into_vfs_filter();
+
+    assert!(filter.include_dir(RelativePath::new("src/tests")));
+    assert!(filter.include_dir(RelativePath::new("src/target")));
+    assert!(filter.include_dir(RelativePath::new("tests")));
+    assert!(filter.include_dir(RelativePath::new("benches")));
+
+    assert!(!filter.include_dir(RelativePath::new("target")));
+    assert!(!filter.include_dir(RelativePath::new("src/foo/.git")));
+    assert!(!filter.include_dir(RelativePath::new("foo/node_modules")));
+
+    let filter = RustPackageFilterBuilder::default().set_member(false).into_vfs_filter();
+
+    assert!(filter.include_dir(RelativePath::new("src/tests")));
+    assert!(filter.include_dir(RelativePath::new("src/target")));
+
+    assert!(!filter.include_dir(RelativePath::new("target")));
+    assert!(!filter.include_dir(RelativePath::new("src/foo/.git")));
+    assert!(!filter.include_dir(RelativePath::new("foo/node_modules")));
+    assert!(!filter.include_dir(RelativePath::new("tests")));
+    assert!(!filter.include_dir(RelativePath::new("benches")));
+
+    let filter = RustPackageFilterBuilder::default()
+        .set_member(true)
+        .exclude("src/llvm-project/**")
+        .unwrap()
+        .into_vfs_filter();
+
+    assert!(!filter.include_dir(RelativePath::new("src/llvm-project/clang")));
+}