Figure out the relative path from output to each crate

src/comp/back/rpath.rs

@@ -1,10 +1,13 @@
 import std::os;
 import std::fs;
+import std::os_fs;
 import std::vec;
+import std::map;
+import std::str;
+import std::uint;
 import metadata::cstore;
 import driver::session;
 import util::filesearch;
-import std::map;
 
 export get_rpath_flags, test;
 
@@ -70,18 +73,44 @@ fn get_rpaths_relative_to_output(cwd: fs::path,
     vec::map(bind get_rpath_relative_to_output(cwd, output, _), libs)
 }
 
-fn get_rpath_relative_to_output(_cwd: fs::path,
-                                _output: fs::path,
-                                _lib: fs::path) -> str {
-    fail;
-    /*get_relative_to(
+fn get_rpath_relative_to_output(cwd: fs::path,
+                                output: fs::path,
+                                lib: fs::path) -> str {
+    "$ORIGIN" + fs::path_sep() + get_relative_to(
         get_absolute(cwd, output),
-        get_absolute(cwd, lib))*/
+        get_absolute(cwd, lib))
 }
 
 // Find the relative path from one file to another
-fn get_relative_to(_abs1: fs::path, _abs2: fs::path) -> fs::path {
-    fail;
+fn get_relative_to(abs1: fs::path, abs2: fs::path) -> fs::path {
+    assert fs::path_is_absolute(abs1);
+    assert fs::path_is_absolute(abs2);
+    let normal1 = fs::normalize(abs1);
+    let normal2 = fs::normalize(abs2);
+    let split1 = str::split(normal1, os_fs::path_sep as u8);
+    let split2 = str::split(normal2, os_fs::path_sep as u8);
+    let len1 = vec::len(split1);
+    let len2 = vec::len(split2);
+    assert len1 > 0u;
+    assert len2 > 0u;
+
+    let max_common_path = uint::min(len1, len2) - 1u;
+    let start_idx = 0u;
+    while start_idx < max_common_path
+        && split1[start_idx] == split2[start_idx] {
+        start_idx += 1u;
+    }
+
+    let path = [];
+
+    for each _ in uint::range(start_idx, len1 - 1u) {
+        path += [".."];
+    }
+
+    path += vec::slice(split2, start_idx, len2 - 1u);
+
+    check vec::is_not_empty(path);
+    ret fs::connect_many(path);
 }
 
 fn get_absolute_rpaths(cwd: fs::path, libs: [fs::path]) -> [str] {
@@ -159,7 +188,6 @@ mod test {
     }
 
     #[test]
-    #[ignore]
     fn test_relative_to1() {
         let p1 = "/usr/bin/rustc";
         let p2 = "/usr/lib/mylib";
@@ -168,7 +196,6 @@ mod test {
     }
 
     #[test]
-    #[ignore]
     fn test_relative_to2() {
         let p1 = "/usr/bin/rustc";
         let p2 = "/usr/bin/../lib/mylib";
@@ -177,7 +204,6 @@ mod test {
     }
 
     #[test]
-    #[ignore]
     fn test_relative_to3() {
         let p1 = "/usr/bin/whatever/rustc";
         let p2 = "/usr/lib/whatever/mylib";
@@ -186,7 +212,6 @@ mod test {
     }
 
     #[test]
-    #[ignore]
     fn test_relative_to4() {
         let p1 = "/usr/bin/whatever/../rustc";
         let p2 = "/usr/lib/whatever/mylib";
@@ -195,11 +220,33 @@ mod test {
     }
 
     #[test]
-    #[ignore]
     fn test_relative_to5() {
         let p1 = "/usr/bin/whatever/../rustc";
         let p2 = "/usr/lib/whatever/../mylib";
         let res = get_relative_to(p1, p2);
-        assert res == "../lib/whatever";
+        assert res == "../lib";
+    }
+
+    #[test]
+    fn test_relative_to6() {
+        let p1 = "/1";
+        let p2 = "/2/3";
+        let res = get_relative_to(p1, p2);
+        assert res == "2";
+    }
+
+    #[test]
+    fn test_relative_to7() {
+        let p1 = "/1/2";
+        let p2 = "/3";
+        let res = get_relative_to(p1, p2);
+        assert res == "..";
+    }
+
+    #[test]
+    fn test_rpath_relative() {
+        let res = get_rpath_relative_to_output(
+            "/usr", "bin/rustc", "lib/libstd.so");
+        assert res == "$ORIGIN/../lib";
     }
 }