Add a helper to verify that two paths are pointing to the same destin…

…ation (file or folder) (#97)

lib/util.js

@@ -2,6 +2,7 @@ import B from 'bluebird';
 import _ from 'lodash';
 import os from 'os';
 import path from 'path';
+import fs from './fs';
 
 const W3C_WEB_ELEMENT_IDENTIFIER = 'element-6066-11e4-a52e-4f735466cecf';
 
@@ -194,8 +195,31 @@ function isSubPath (originalPath, root, forcePosix = null) {
   return normalizedPath.startsWith(normalizedRoot);
 }
 
+/**
+ * Checks whether the given paths are pointing to the same file system
+ * destination.
+ *
+ * @param {string} path1 - Absolute or relative path to a file/folder
+ * @param {string} path2 - Absolute or relative path to a file/folder
+ * @param {...string} pathN - Zero or more absolute or relative paths to files/folders
+ * @returns {boolean} true if all paths are pointing to the same file system item
+ */
+async function isSameDestination (path1, path2, ...pathN) {
+  const allPaths = [path1, path2, ...pathN];
+  if (!await B.reduce(allPaths, async (a, b) => a && await fs.exists(b), true)) {
+    return false;
+  }
+
+  const areAllItemsEqual = (arr) => !!arr.reduce((a, b) => a === b ? a : NaN);
+  if (areAllItemsEqual(allPaths)) {
+    return true;
+  }
+  return areAllItemsEqual(await B.map(allPaths, async (x) => (await fs.stat(x)).ino));
+}
+
 export {
   hasValue, escapeSpace, escapeSpecialChars, localIp, cancellableDelay,
   multiResolve, safeJsonParse, unwrapElement, filterObject,
-  toReadableSizeString, isSubPath, W3C_WEB_ELEMENT_IDENTIFIER
+  toReadableSizeString, isSubPath, W3C_WEB_ELEMENT_IDENTIFIER,
+  isSameDestination,
 };

test/util-specs.js

@@ -1,10 +1,11 @@
 
-import { util } from '..';
+import { util, fs, tempDir } from '..';
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import B from 'bluebird';
 import sinon from 'sinon';
 import os from 'os';
+import path from 'path';
 
 const {W3C_WEB_ELEMENT_IDENTIFIER} = util;
 
@@ -334,4 +335,31 @@ describe('util', function () {
       should.throw(() => util.isSubPath('some/..', '/root'), /absolute/);
     });
   });
+
+  describe('isSameDestination', function () {
+    let path1;
+    let path2;
+    let tmpDir;
+    before(async function () {
+      tmpDir = await tempDir.openDir();
+      path1 = path.resolve(tmpDir, 'path1.txt');
+      path2 = path.resolve(tmpDir, 'path2.txt');
+      for (const p of [path1, path2]) {
+        await fs.writeFile(p, p, 'utf8');
+      }
+    });
+    after(async function () {
+      await fs.rimraf(tmpDir);
+    });
+    it('should match paths to the same file/folder', async function () {
+      (await util.isSameDestination(path1, path.resolve(tmpDir, '..', path.basename(tmpDir), path.basename(path1))))
+        .should.be.true;
+    });
+    it('should not match paths if they point to non existing items', async function () {
+      (await util.isSameDestination(path1, 'blabla')).should.be.false;
+    });
+    it('should not match paths to different files', async function () {
+      (await util.isSameDestination(path1, path2)).should.be.false;
+    });
+  });
 });