auto merge of #9498 : catamorphism/rust/rust-path-hack-fix, r=cmr,metajack

r? @metajack

1 files changed, 54 insertions, 0 deletions

diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 336284963a2..af2565ec67a 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -233,6 +233,21 @@ pub trait GenericPath : Clone + Eq + ToStr {
         result
     }
 
+
+    /// Returns `true` iff `child` is a suffix of `parent`. See the test
+    /// case for examples.
+    fn is_parent_of(&self, child: &Self) -> bool {
+        if !self.is_absolute() || child.is_absolute()
+            || self.components().len() < child.components().len()
+            || self.components().is_empty() {
+            return false;
+        }
+        let child_components = child.components().len();
+        let parent_components = self.components().len();
+        let to_drop = self.components().len() - child_components;
+        self.components().slice(to_drop, parent_components) == child.components()
+    }
+
     fn components<'a>(&'a self) -> &'a [~str];
 }
 
@@ -1450,4 +1465,43 @@ mod tests {
 
     }
 
+
+    #[test]
+    fn test_is_parent_of() {
+        fn is_parent_of_pp(p: &PosixPath, q: &PosixPath) -> bool {
+            p.is_parent_of(q)
+        }
+
+        assert!(is_parent_of_pp(&PosixPath("/a/b/c/d/e"), &PosixPath("c/d/e")));
+        assert!(!is_parent_of_pp(&PosixPath("a/b/c/d/e"), &PosixPath("c/d/e")));
+        assert!(!is_parent_of_pp(&PosixPath("/a/b/c/d/e"), &PosixPath("/c/d/e")));
+        assert!(!is_parent_of_pp(&PosixPath(""), &PosixPath("")));
+        assert!(!is_parent_of_pp(&PosixPath(""), &PosixPath("a/b/c")));
+        assert!(is_parent_of_pp(&PosixPath("/a/b/c"), &PosixPath("")));
+        assert!(is_parent_of_pp(&PosixPath("/a/b/c"), &PosixPath("a/b/c")));
+        assert!(!is_parent_of_pp(&PosixPath("/a/b/c"), &PosixPath("d/e/f")));
+
+        fn is_parent_of_wp(p: &WindowsPath, q: &WindowsPath) -> bool {
+            p.is_parent_of(q)
+        }
+
+        let abcde = WindowsPath("C:\\a\\b\\c\\d\\e");
+        let rel_abcde = WindowsPath("a\\b\\c\\d\\e");
+        let cde   = WindowsPath("c\\d\\e");
+        let slashcde = WindowsPath("C:\\c\\d\\e");
+        let empty = WindowsPath("");
+        let abc = WindowsPath("C:\\a\\b\\c");
+        let rel_abc = WindowsPath("a\\b\\c");
+        let def = WindowsPath("d\\e\\f");
+
+        assert!(is_parent_of_wp(&abcde, &cde));
+        assert!(!is_parent_of_wp(&rel_abcde, &cde));
+        assert!(!is_parent_of_wp(&abcde, &slashcde));
+        assert!(!is_parent_of_wp(&empty, &empty));
+        assert!(!is_parent_of_wp(&empty, &rel_abc));
+        assert!(is_parent_of_wp(&abc, &empty));
+        assert!(is_parent_of_wp(&abc, &rel_abc));
+        assert!(!is_parent_of_wp(&abc, &def));
+    }
+
 }