dropCwd option, fixes #15

Gruntfile.js

@@ -45,6 +45,15 @@ module.exports = function (grunt) {
         src: ['*'],
         dest: 'test/tmp/expand'
       },
+      withDropCwd: {
+        options: {
+          dropCwd: true
+        },
+        expand: true,
+        cwd: 'test/fixtures',
+        src: ['file.png'],
+        dest: 'test/tmp/withDropCwd'
+      },
       withSummaryAttributeName: {
         options: {
           summary: 'foo'
@@ -89,5 +98,8 @@ module.exports = function (grunt) {
     var src = path.normalize('test/fixtures/file.png');
     var expected = path.normalize('test/tmp/file.26365248.png');
     assert.equal(grunt.filerev.summary[src], expected);
+    src = path.normalize('file.png');
+    expected = path.normalize('tmp/withDropCwd/file.26365248.png');
+    assert.equal(grunt.filerev.summary[src], expected);
   });
 };

tasks/filerev.js

@@ -9,10 +9,12 @@ module.exports = function (grunt) {
   grunt.registerMultiTask('filerev', 'File revisioning based on content hashing', function () {
     var options = this.options({
       algorithm: 'md5',
-      length: 8
+      length: 8,
+      dropCwd: false
     });
     var target = this.target;
     var filerev = grunt.filerev || {summary: {}};
+    var cwd = this.data.cwd || '';
 
     eachAsync(this.files, function (el, i, next) {
       var move = true;
@@ -74,10 +76,10 @@ module.exports = function (grunt) {
            }
         }
 
-        filerev.summary[path.normalize(file)] = path.join(dirname, newName);
+        filerev.summary[dropCwd(path.normalize(file))] = dropCwd(path.join(dirname, newName));
         grunt.verbose.writeln(chalk.green('✔ ') + file + chalk.gray(' changed to ') + newName);
         if (sourceMap) {
-            filerev.summary[path.normalize(file + '.map')] = path.join(dirname, newName + '.map');
+            filerev.summary[dropCwd(path.normalize(file + '.map'))] = dropCwd(path.join(dirname, newName + '.map'));
             grunt.verbose.writeln(chalk.green('✔ ') + file + '.map' + chalk.gray(' changed to ') + newName + '.map');
         }
 
@@ -90,6 +92,22 @@ module.exports = function (grunt) {
       next();
     }, this.async());
 
+    // Drop cwd from path if relative option is set to true
+    function dropCwd (file) {
+        if (options.dropCwd === true && cwd) {
+            var filePath = file.split(path.sep),
+                cwdPath = path.normalize(cwd).split(path.sep),
+                pos = 0;
+            for (var i = 0; i < cwdPath.length; i++) {
+                if (filePath[i] === cwdPath[i]) {
+                    pos = i + 1;
+                }
+            }
+            file = filePath.slice(pos).join(path.sep);
+        }
+        return file;
+    }
+
     grunt.filerev = filerev;
   });
 };