Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/matcher/mirror_matchers.dart

Index: observatory_pub_packages/matcher/mirror_matchers.dart
===================================================================
--- observatory_pub_packages/matcher/mirror_matchers.dart	(revision 0)
+++ observatory_pub_packages/matcher/mirror_matchers.dart	(working copy)
@@ -0,0 +1,76 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// The mirror matchers library provides some additional matchers that
+/// make use of `dart:mirrors`.
+library matcher.mirror_matchers;
+
+import 'dart:mirrors';
+
+import 'matcher.dart';
+
+/// Returns a matcher that checks if a class instance has a property
+/// with name [name], and optionally, if that property in turn satisfies
+/// a [matcher].
+Matcher hasProperty(String name, [matcher]) =>
+  new _HasProperty(name, matcher == null ? null : wrapMatcher(matcher));
+
+class _HasProperty extends Matcher {
+  final String _name;
+  final Matcher _matcher;
+
+  const _HasProperty(this._name, [this._matcher]);
+
+  bool matches(item, Map matchState) {
+    var mirror = reflect(item);
+    var classMirror = mirror.type;
+    var symbol = new Symbol(_name);
+    var candidate = classMirror.declarations[symbol];
+    if (candidate == null) {
+      addStateInfo(matchState, {'reason': 'has no property named "$_name"'});
+      return false;
+    }
+    bool isInstanceField = candidate is VariableMirror && !candidate.isStatic;
+    bool isInstanceGetter =
+        candidate is MethodMirror && candidate.isGetter && !candidate.isStatic;
+    if (!(isInstanceField || isInstanceGetter)) {
+      addStateInfo(matchState, {'reason':
+          'has a member named "$_name", but it is not an instance property'});
+      return false;
+    }
+    if (_matcher == null) return true;
+    var result = mirror.getField(symbol);
+    var resultMatches = _matcher.matches(result.reflectee, matchState);
+    if (!resultMatches) {
+      addStateInfo(matchState, {'value': result.reflectee});
+    }
+    return resultMatches;
+  }
+
+  Description describe(Description description) {
+    description.add('has property "$_name"');
+    if (_matcher != null) {
+      description.add(' which matches ').addDescriptionOf(_matcher);
+    }
+    return description;
+  }
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    var reason = matchState == null ? null : matchState['reason'];
+    if (reason != null) {
+      mismatchDescription.add(reason);
+    } else {
+      mismatchDescription.add('has property "$_name" with value ').
+        addDescriptionOf(matchState['value']);
+      var innerDescription = new StringDescription();
+      _matcher.describeMismatch(matchState['value'], innerDescription,
+          matchState['state'], verbose);
+      if (innerDescription.length > 0) {
+        mismatchDescription.add(' which ').add(innerDescription.toString());
+      }
+    }
+    return mismatchDescription;
+  }
+}