Merge pull request #50 from humphd/expose-path

Expose path on IDBFS, add missing node.js bits of path module

README.md

@@ -95,7 +95,7 @@ fs = new IDBFS.FileSystem({
 }, fsReady);
 ```
 
-###IDBFS.FileSystem.providers - Storage Providers
+####IDBFS.FileSystem.providers - Storage Providers
 
 IDBFS can be configured to use a number of different storage providers. The provider object encapsulates all aspects
 of data access, making it possible to swap in different backend storage options.  There are currently 4 different
@@ -131,6 +131,39 @@ if( IDBFS.FileSystem.providers.WebSQL.isSupported() ) {
 
 You can also write your own provider if you need a different backend. See the code in `src/providers` for details.
 
+####IDBFS.Path
+
+The node.js [path module](http://nodejs.org/api/path.html) is available via the `IDBFS.Path` object. It is
+identical to the node.js version with the following differences:
+* No support for `exits()` or `existsSync()`. Use `fs.stat()` instead.
+* No notion of a current working directory in `resolve` (the root dir is used instead)
+
+```javascript
+var path = IDBFS.Path;
+var dir = path.dirname('/foo/bar/baz/asdf/quux');
+// dir is now '/foo/bar/baz/asdf'
+
+var base = path.basename('/foo/bar/baz/asdf/quux.html');
+// base is now 'quux.html'
+
+var ext = path.extname('index.html');
+// ext is now '.html'
+
+var newpath = path.join('/foo', 'bar', 'baz/asdf', 'quux', '..');
+// new path is now '/foo/bar/baz/asdf'
+```
+
+For more info see the docs in the [path module](http://nodejs.org/api/path.html) for a particular method:
+* `path.normalize(p)`
+* `path.join([path1], [path2], [...])`
+* `path.resolve([from ...], to)`
+* `path.relative(from, to)`
+* `path.dirname(p)`
+* `path.basename(p, [ext])`
+* `path.extname(p)`
+* `path.sep`
+* `path.delimiter`
+
 #### fs.stat(path, callback)
 
 Asynchronous stat(2). Callback gets `(error, stats)`, where `stats` is an object like

src/fs.js

@@ -1721,7 +1721,8 @@ define(function(require) {
   };
 
   return {
-    FileSystem: FileSystem
+    FileSystem: FileSystem,
+    Path: require('src/path')
   };
 
 });

src/path.js

@@ -19,18 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-// https://github.com/joyent/node/blob/41e53e557992a7d552a8e23de035f9463da25c99/lib/path.js
-
-define(function(require) {
-
-  // Split a filename into [root, dir, basename, ext], unix version
-  // 'root' is just a slash, or nothing.
-  var splitPathRe =
-      /^(\/?)([\s\S]+\/(?!$)|\/)?((?:\.{1,2}$|[\s\S]+?)?(\.[^.\/]*)?)$/;
-  var splitPath = function(filename) {
-    var result = splitPathRe.exec(filename);
-    return [result[1] || '', result[2] || '', result[3] || '', result[4] || ''];
-  };
+// Based on https://github.com/joyent/node/blob/41e53e557992a7d552a8e23de035f9463da25c99/lib/path.js
+define(function() {
 
   // resolves . and .. elements in a path array with directory names there
   // must be no slashes, empty elements, or device names (c:\) in the array
@@ -62,11 +52,48 @@ define(function(require) {
     return parts;
   }
 
+  // Split a filename into [root, dir, basename, ext], unix version
+  // 'root' is just a slash, or nothing.
+  var splitPathRe =
+        /^(\/?)([\s\S]+\/(?!$)|\/)?((?:\.{1,2}$|[\s\S]+?)?(\.[^.\/]*)?)$/;
+  var splitPath = function(filename) {
+    var result = splitPathRe.exec(filename);
+    return [result[1] || '', result[2] || '', result[3] || '', result[4] || ''];
+  };
+
+  // path.resolve([from ...], to)
+  function resolve() {
+    var resolvedPath = '',
+        resolvedAbsolute = false;
+
+    for (var i = arguments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
+      // XXXidbfs: we don't have process.cwd() so we use '/' as a fallback
+      var path = (i >= 0) ? arguments[i] : '/';
+
+      // Skip empty and invalid entries
+      if (typeof path !== 'string' || !path) {
+        continue;
+      }
+
+      resolvedPath = path + '/' + resolvedPath;
+      resolvedAbsolute = path.charAt(0) === '/';
+    }
+
+    // At this point the path should be resolved to a full absolute path, but
+    // handle relative paths to be safe (might happen when process.cwd() fails)
+
+    // Normalize the path
+    resolvedPath = normalizeArray(resolvedPath.split('/').filter(function(p) {
+      return !!p;
+    }), !resolvedAbsolute).join('/');
+
+    return ((resolvedAbsolute ? '/' : '') + resolvedPath) || '.';
+  }
+
   // path.normalize(path)
-  // posix version
   function normalize(path) {
-    var isAbsolute = path.charAt(0) === '/';
-    // var trailingSlash = path.substr(-1) === '/';
+    var isAbsolute = path.charAt(0) === '/',
+        trailingSlash = path.substr(-1) === '/';
 
     // Normalize the path
     path = normalizeArray(path.split('/').filter(function(p) {
@@ -76,14 +103,61 @@ define(function(require) {
     if (!path && !isAbsolute) {
       path = '.';
     }
-    /*
     if (path && trailingSlash) {
       path += '/';
     }
-    */
 
     return (isAbsolute ? '/' : '') + path;
-  };
+  }
+
+  function join() {
+    var paths = Array.prototype.slice.call(arguments, 0);
+    return normalize(paths.filter(function(p, index) {
+      return p && typeof p === 'string';
+    }).join('/'));
+  }
+
+  // path.relative(from, to)
+  function relative(from, to) {
+    from = exports.resolve(from).substr(1);
+    to = exports.resolve(to).substr(1);
+
+    function trim(arr) {
+      var start = 0;
+      for (; start < arr.length; start++) {
+        if (arr[start] !== '') break;
+      }
+
+      var end = arr.length - 1;
+      for (; end >= 0; end--) {
+        if (arr[end] !== '') break;
+      }
+
+      if (start > end) return [];
+      return arr.slice(start, end - start + 1);
+    }
+
+    var fromParts = trim(from.split('/'));
+    var toParts = trim(to.split('/'));
+
+    var length = Math.min(fromParts.length, toParts.length);
+    var samePartsLength = length;
+    for (var i = 0; i < length; i++) {
+      if (fromParts[i] !== toParts[i]) {
+        samePartsLength = i;
+        break;
+      }
+    }
+
+    var outputParts = [];
+    for (var i = samePartsLength; i < fromParts.length; i++) {
+      outputParts.push('..');
+    }
+
+    outputParts = outputParts.concat(toParts.slice(samePartsLength));
+
+    return outputParts.join('/');
+  }
 
   function dirname(path) {
     var result = splitPath(path),
@@ -101,8 +175,7 @@ define(function(require) {
     }
 
     return root + dir;
-  };
-
+  }
 
   function basename(path, ext) {
     var f = splitPath(path)[2];
@@ -110,18 +183,27 @@ define(function(require) {
     if (ext && f.substr(-1 * ext.length) === ext) {
       f = f.substr(0, f.length - ext.length);
     }
+    // XXXidbfs: node.js just does `return f`
     return f === "" ? "/" : f;
-  };
-
-  function isAbsolute(path) {
-    return path.charAt(0) === '/';
   }
 
+  function extname(path) {
+    return splitPath(path)[3];
+  }
+
+  // XXXidbfs: we don't support path.exists() or path.existsSync(), which
+  // are deprecated, and need a FileSystem instance to work. Use fs.stat().
+
   return {
     normalize: normalize,
+    resolve: resolve,
+    join: join,
+    relative: relative,
+    sep: '/',
+    delimiter: ':',
     dirname: dirname,
     basename: basename,
-    isAbsolute: isAbsolute
-  }
+    extname: extname
+  };
 
 });