upload android base code part6

android/system/libvintf/include/vintf/XmlFileGroup.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_VINTF_XML_FILE_GROUP_H
+#define ANDROID_VINTF_XML_FILE_GROUP_H
+
+#include <map>
+#include <type_traits>
+
+#include "MapValueIterator.h"
+#include "XmlFile.h"
+
+namespace android {
+namespace vintf {
+
+// A XmlFileGroup is a wrapped multimap from name to T, where T
+// must be a subclass of XmlFile.
+template <typename T>
+struct XmlFileGroup {
+    static_assert(std::is_base_of<XmlFile, T>::value, "T must be a subclass of XmlFile");
+
+   private:
+    using map = std::multimap<std::string, T>;
+    using const_range = std::pair<typename map::const_iterator, typename map::const_iterator>;
+
+   public:
+    virtual ~XmlFileGroup() {}
+
+    bool addXmlFile(T&& t) {
+        if (!shouldAddXmlFile(t)) {
+            return false;
+        }
+        std::string name = t.name();
+        mXmlFiles.emplace(std::move(name), std::move(t));
+        return true;
+    }
+
+    virtual bool shouldAddXmlFile(const T&) const { return true; }
+
+    const_range getXmlFiles(const std::string& key) const { return mXmlFiles.equal_range(key); }
+
+    // Return an iterable to all T objects. Call it as follows:
+    // for (const auto& e : vm.getXmlFiles()) { }
+    ConstMultiMapValueIterable<std::string, T> getXmlFiles() const {
+        return ConstMultiMapValueIterable<std::string, T>(mXmlFiles);
+    }
+
+   protected:
+    map mXmlFiles;
+};
+
+}  // namespace vintf
+}  // namespace android
+
+#endif  // ANDROID_VINTF_XML_FILE_GROUP_H