1 files changed, 70 insertions, 0 deletions
diff --git a/deps/npm/lib/utils/relativize.js b/deps/npm/lib/utils/relativize.js
new file mode 100644
index 0000000000..74c45c5d3e
--- /dev/null
+++ b/deps/npm/lib/utils/relativize.js
@@ -0,0 +1,70 @@
+
+module.exports = relativize
+
+// return the shortest path between two folders.
+// if the original path is shorter, then use that,
+// unless forceRelative is set to true.
+var path = require("path")
+function relativize (dest, src, forceRelative) {
+  var orig = dest
+  if (!isAbsolute(src)) forceRelative = true
+  else if (!isAbsolute(dest)) return false
+  src = path.resolve(src)
+  dest = path.resolve(dest)
+  if (src === dest) return "."
+  src = src.split(split)
+  dest = dest.split(split)
+  var i = 0
+  while (src[i] === dest[i]) i++
+  if (!forceRelative && i === 1) return orig // nothing in common
+  src.splice(0, i + 1)
+  var dots = [0, i, "."]
+  for (var i = 0, l = src.length; i < l; i ++) dots.push("..")
+  dest.splice.apply(dest, dots)
+  if (dest[0] === "." && dest[1] === "..") dest.shift()
+  dest = dest.join("/")
+  return !forceRelative && orig.length < dest.length ? orig : dest
+}
+
+var split = process.platform === "win32" ? /[\/\\]/ : "/"
+
+function isAbsolute (p) {
+  if (process.platform !== "win32") return p.charAt(0) === "/"
+  return path.resolve(p) === p
+}
+
+if (module === require.main) {
+  // from, to, result, relativeForced
+  var assert = require("assert")
+
+  ; [ ["/bar"        ,"/foo"           ,"/bar"          ,"./bar"         ]
+    , ["/foo/baz"    ,"/foo/bar/baz"   ,"../baz"        ,"../baz"        ]
+    , ["/a/d"        ,"/a/b/c/d/e/f"   ,"/a/d"          ,"../../../../d" ]
+    // trailing slashes are ignored.
+    , ["/a/d"        ,"/a/b/c/d/e/"    ,"/a/d"          ,"../../../d"    ]
+    , ["./foo/bar"   ,"./foo/baz"      ,"./bar"         ,"./bar"         ]
+    // force relative when the src is relative.
+    , ["./d"         ,"./a/b/c/d/e"    ,"../../../../d" ,"../../../../d" ]
+    // if src is abs and dest is relative, then fail
+    , ["./d"        ,"/a/b"            ,false           ,false           ]
+    ].forEach(function (test) {
+      var d = test[0]
+        , s = test[1]
+        , r = test[2]
+        , rr = test[3]
+        , ra = relativize(d, s)
+        , rra = relativize(d, s, true)
+      console.log([d, s, r, rr], [ra, rra], [r === ra, rr === rra])
+      assert.equal(r, ra)
+      assert.equal(rr, rra)
+      if (!r) return
+      // contract: this is the relative path from absolute A to absolute B
+      var ad = path.resolve(d)
+        , as = path.resolve(s)
+        , dir = path.dirname(as)
+      assert.equal(path.resolve(dir, rr), ad)
+      assert.equal(path.resolve(dir, r), ad)
+    })
+
+  console.log("ok")
+}