Add appengine/gcloud/mustache dependencies.

pkg/gcloud/lib/src/db/models.dart

+// 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.
+
+part of gcloud.db;
+
+/**
+ * Represents a unique identifier for a [Model] stored in a datastore.
+ *
+ * The [Key] can be incomplete if it's id is `null`. In this case the id will
+ * be automatically allocated and set at commit time.
+ */
+class Key {
+  // Either KeyImpl or PartitionImpl
+  final Object _parent;
+
+  final Type type;
+  final Object id;
+
+  Key(Key parent, this.type, this.id) : _parent = parent {
+    if (type == null) {
+      throw new ArgumentError('The type argument must not be null.');
+    }
+    if (id != null && id is! String && id is! int) {
+      throw new ArgumentError(
+          'The id argument must be an integer or a String.');
+    }
+  }
+
+  Key.emptyKey(Partition partition)
+      : _parent = partition, type = null, id = null;
+
+  /**
+   * Parent of this [Key].
+   */
+  Key get parent {
+    if (_parent is Key) {
+      return _parent;
+    }
+    return null;
+  }
+
+  /**
+   * The partition of this [Key].
+   */
+  Partition get partition {
+    var obj = _parent;
+    while (obj is! Partition) {
+      obj = obj._parent;
+    }
+    return obj;
+  }
+
+  Key append(Type modelType, {Object id}) {
+    return new Key(this, modelType, id);
+  }
+
+  bool get isEmpty => _parent is Partition;
+
+  operator==(Object other) {
+    return
+        other is Key &&
+        _parent == other._parent &&
+        type == other.type &&
+        id == other.id;
+  }
+
+  int get hashCode => _parent.hashCode ^ type.hashCode ^ id.hashCode;
+}
+
+/**
+ * Represents a datastore partition.
+ *
+ * A datastore is partitioned into namespaces. The default namespace is
+ * `null`.
+ */
+class Partition {
+  final String namespace;
+
+  Partition(this.namespace) {
+    if (namespace == '') {
+      throw new ArgumentError(
+          'The namespace must not be an empty string');
+    }
+  }
+
+  /**
+   * Returns an empty [Key].
+   *
+   * Entities where the parent [Key] is empty will create their own entity
+   * group.
+   */
+  Key get emptyKey => new Key.emptyKey(this);
+
+  operator==(Object other) {
+    return other is Partition && namespace == other.namespace;
+  }
+
+  int get hashCode => namespace.hashCode;
+}
+
+/**
+ * Superclass for all model classes.
+ *
+ * Every model class has a [id] -- which must be an integer or a string, and
+ * a [parentKey]. The [key] getter is returning the key for the model object.
+ */
+abstract class Model {
+  Object id;
+  Key parentKey;
+
+  Key get key => parentKey.append(this.runtimeType, id: id);
+}
+
+/**
+ * Superclass for all expanded model classes.
+ *
+ * The [ExpandoModel] class adds support for having dynamic properties. You can
+ * set arbitrary fields on these models. The expanded values must be values
+ * accepted by the [RawDatastore] implementation.
+ */
+@proxy
+abstract class ExpandoModel extends Model {
+  final Map<String, Object> additionalProperties = {};
+
+  Object noSuchMethod(Invocation invocation) {
+    var name = mirrors.MirrorSystem.getName(invocation.memberName);
+    if (name.endsWith('=')) name = name.substring(0, name.length - 1);
+    if (invocation.isGetter) {
+      return additionalProperties[name];
+    } else if (invocation.isSetter) {
+      var value = invocation.positionalArguments[0];
+      additionalProperties[name] = value;
+      return value;
+    } else {
+      throw new ArgumentError('Unsupported noSuchMethod call on ExpandoModel');
+    }
+  }
+}