dart:io | Add FileSystemEntity.stat() and FileStat class.

sdk/lib/io/file_system_entity.dart

Index: sdk/lib/io/file_system_entity.dart
diff --git a/sdk/lib/io/file_system_entity.dart b/sdk/lib/io/file_system_entity.dart
index 847b7d12839eff0abbccca09027dbc5b8c2cf3a5..2ed7290ef6b8ce501d2d88ceb876f9e1f7c7439b 100644
--- a/sdk/lib/io/file_system_entity.dart
+++ b/sdk/lib/io/file_system_entity.dart
@@ -21,6 +21,90 @@ class FileSystemEntityType {
   final int _type;
 }
 
+
+class FileStat {
+  // These must agree with enum FileStat in file.h.
+  static const TYPE = 0;
+  static const CHANGED_TIME = 1;
+  static const MODIFIED_TIME = 2;
+  static const ACCESSED_TIME = 3;
+  static const MODE = 4;
+  static const SIZE = 5;
+
+  FileStat._internal(this.changed,
+                     this.modified,
+                     this.accessed,
+                     this.type,
+                     this.mode,
+                     this.size);
+
+  external static List<int> _statSync(String path);
+
+  static FileStat statSync(String path) {
+    var data = _statSync(path);
+    if (data is Error) throw data;
+    return new FileStat._internal(
+        new DateTime.fromMillisecondsSinceEpoch(data[CHANGED_TIME] * 1000),
+        new DateTime.fromMillisecondsSinceEpoch(data[MODIFIED_TIME] * 1000),
+        new DateTime.fromMillisecondsSinceEpoch(data[ACCESSED_TIME] * 1000),
+        FileSystemEntityType._lookup(data[TYPE]),
+        data[MODE],
+        data[SIZE]);
+  }
+
+  static Future<FileStat> stat(String path) {
+    // Get a new file service port for each request.  We could also cache one.
+    var service = _FileUtils._newServicePort();
+    List request = new List(2);
+    request[0] = _STAT_REQUEST;
+    request[1] = path;
+    return service.call(request).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response,
+                                     "Error getting stat of '$path'");
+      }
+      // Unwrap the real list from the "I'm not an error" wrapper.
+      List data = response[1];
+      return new FileStat._internal(
+          new DateTime.fromMillisecondsSinceEpoch(data[CHANGED_TIME] * 1000),
+          new DateTime.fromMillisecondsSinceEpoch(data[MODIFIED_TIME] * 1000),
+          new DateTime.fromMillisecondsSinceEpoch(data[ACCESSED_TIME] * 1000),
+          FileSystemEntityType._lookup(data[TYPE]),
+          data[MODE],
+          data[SIZE]);
+    });
+  }
+
+  String toString() => """
+FileStat: type $type
+          changed $changed
+          modified $modified
+          accessed $accessed
+          mode ${modeString()}
+          size $size""";
+
+  String modeString() {
+    var permissions = mode & 0xFFF;
+    var codes = const ['---', '--x', '-w-', '-wx', 'r--', 'r-x', 'rw-', 'rwx'];
+    var result = [];
+    if (permissions & 0x800) result.add("(suid) ");
+    if (permissions & 0x400) result.add("(guid) ");
+    if (permissions & 0x200) result.add("(sticky) ");
+    result.add(codes[(permissions >> 6) & 0x7]);
+    result.add(codes[(permissions >> 3) & 0x7]);
+    result.add(codes[permissions & 0x7]);
+    return result.join();
+  }
+
+  final DateTime changed;
+  final DateTime modified;
+  final DateTime accessed;
+  final FileSystemEntityType type;
+  final int mode;
+  final int size;
+}
+
+
 /**
  * A [FileSystemEntity] is a common super class for [File] and
  * [Directory] objects.