Expose Physical Web metadata to native clients over JNI

chrome/browser/android/physical_web/physical_web_data_source_android.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_ANDROID_PHYSICAL_WEB_PHYSICAL_WEB_DATA_SOURCE_ANDROID_H_
 #define CHROME_BROWSER_ANDROID_PHYSICAL_WEB_PHYSICAL_WEB_DATA_SOURCE_ANDROID_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/macros.h"
 #include "components/physical_web/data_source/physical_web_data_source_impl.h"
 
 namespace base {
 class ListValue;
 }
 
+// A container for Physical Web metadata. This is primarily a wrapper for a
+// ListValue so we can append to it over JNI.
+class PhysicalWebCollection {
+ public:
+  PhysicalWebCollection();
+  ~PhysicalWebCollection();
+
+  void AppendMetadataItem(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& j_request_url,
+      jdouble distance_estimate,
+      jint scan_timestamp,
+      const base::android::JavaParamRef<jstring>& j_site_url,
+      const base::android::JavaParamRef<jstring>& j_icon_url,
+      const base::android::JavaParamRef<jstring>& j_title,
+      const base::android::JavaParamRef<jstring>& j_description,
+      const base::android::JavaParamRef<jstring>& j_group_id);
+
+  // Returns the metadata list and transfers ownership of the list to the
+  // caller. Call only once.
+  std::unique_ptr<base::ListValue> GetMetadataList();
+
+ private:
+  std::unique_ptr<base::ListValue> metadata_list_;
+  bool accessed_once_;
+
+  DISALLOW_COPY_AND_ASSIGN(PhysicalWebCollection);
+};
+
 class PhysicalWebDataSourceAndroid : public PhysicalWebDataSourceImpl {
  public:
   PhysicalWebDataSourceAndroid();
   ~PhysicalWebDataSourceAndroid() override;
 
   static bool RegisterPhysicalWebDataSource(JNIEnv* env);
 
   void Initialize();
 
   void StartDiscovery(bool network_request_enabled) override;
   void StopDiscovery() override;
 
   std::unique_ptr<base::ListValue> GetMetadata() override;
   bool HasUnresolvedDiscoveries() override;
 
  private:
   // A reference to the Java UrlManager singleton.
   base::android::ScopedJavaGlobalRef<jobject> url_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(PhysicalWebDataSourceAndroid);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_PHYSICAL_WEB_PHYSICAL_WEB_DATA_SOURCE_ANDROID_H_