Offline Page download bridge

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageDownloadBridge.java

Index: chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageDownloadBridge.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageDownloadBridge.java b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageDownloadBridge.java
new file mode 100644
index 0000000000000000000000000000000000000000..428353e83d7a558081c4c6901eb47668b6b202bb
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageDownloadBridge.java
@@ -0,0 +1,166 @@
+// 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.
+
+package org.chromium.chrome.browser.offlinepages.downloads;
+
+import org.chromium.base.ObserverList;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.chrome.browser.profiles.Profile;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Serves as an interface between Download Home UI and offline page related items that are to be
+ * displayed in the downloads UI.
+ */
+@JNINamespace("offline_pages::android")
+public class OfflinePageDownloadBridge {
+    /**
+     * Base observer class for notifications on changes to the offline page related download items.
+     */
+    public abstract static class Observer {
+        /**
+         * Indicates that the bridge is loaded and consumers can call GetXXX methods on it.
+         * If the bridge is loaded at the time the observer is being added, the Loaded event will be
+         * dispatched immediately.
+         */
+        public void onItemsLoaded() {}
+
+        /**
+         * Event fired when an new item was added.
+         * @param item A newly added download item.
+         */
+        public void onItemAdded(OfflinePageDownloadItem item) {}
+
+        /**
+         * Event fired when an item was deleted
+         * @param guid A GUID of the deleted download item.
+         */
+        public void onItemDeleted(String guid) {}
+
+        /**
+         * Event fired when an new item was updated.
+         * @param item A newly updated download item.
+         */
+        public void onItemUpdated(OfflinePageDownloadItem item) {}
+    }
+
+    private static boolean sIsTesting = false;
+    private final ObserverList<Observer> mObservers = new ObserverList<Observer>();
+    private long mNativeOfflinePageDownloadBridge;
+    private boolean mIsLoaded;
+
+    public OfflinePageDownloadBridge(Profile profile) {
+        mNativeOfflinePageDownloadBridge = sIsTesting ? 0L : nativeInit(profile);
+    }
+
+    /** Destroys the native portion of the bridge. */
+    public void destroy() {
+        if (mNativeOfflinePageDownloadBridge != 0) {
+            nativeDestroy(mNativeOfflinePageDownloadBridge);
+            mNativeOfflinePageDownloadBridge = 0;
+            mIsLoaded = false;
+        }
+        mObservers.clear();
+    }
+
+    /**
+     * Add an observer of offline download items changes.
+     * @param observer The observer to be added.
+     */
+    public void addObserver(Observer observer) {
+        mObservers.addObserver(observer);
+        if (mIsLoaded) {
+            observer.onItemsLoaded();
+        }
+    }
+
+    /**
+     * Remove an observer of offline download items changes.
+     * @param observer The observer to be removed.
+     */
+    public void removeObserver(Observer observer) {
+        mObservers.removeObserver(observer);
+    }
+
+    /** @return all of the download items related to offline pages. */
+    public List<OfflinePageDownloadItem> getAllItems() {
+        List<OfflinePageDownloadItem> items = new ArrayList<>();
+        nativeGetAllItems(mNativeOfflinePageDownloadBridge, items);
+        return items;
+    }
+
+    /**
+     * Gets a download item related to the provided GUID.
+     * @param guid a GUID of the item to get.
+     * @return download item related to the offline page identified by GUID.
+     * */
+    public OfflinePageDownloadItem getItem(String guid) {
+        return nativeGetItemByGuid(mNativeOfflinePageDownloadBridge, guid);
+    }
+
+    /**
+     * Method to ensure that the bridge is created for tests without calling the native portion of
+     * initialization.
+     * @param isTesting flag indicating whether the constructor will initialize native code.
+     */
+    static void setIsTesting(boolean isTesting) {
+        sIsTesting = isTesting;
+    }
+
+    @CalledByNative
+    void downloadItemsLoaded() {
+        mIsLoaded = true;
+
+        for (Observer observer : mObservers) {
+            observer.onItemsLoaded();
+        }
+    }
+
+    @CalledByNative
+    void downloadItemAdded(OfflinePageDownloadItem item) {
+        assert item != null;
+
+        for (Observer observer : mObservers) {
+            observer.onItemAdded(item);
+        }
+    }
+
+    @CalledByNative
+    void downloadItemDeleted(String guid) {
+        for (Observer observer : mObservers) {
+            observer.onItemDeleted(guid);
+        }
+    }
+
+    @CalledByNative
+    void downloadItemUpdated(OfflinePageDownloadItem item) {
+        assert item != null;
+
+        for (Observer observer : mObservers) {
+            observer.onItemUpdated(item);
+        }
+    }
+
+    @CalledByNative
+    static void createDownloadItemAndAddToList(List<OfflinePageDownloadItem> list, String guid,
+            String url, String targetPath, long startTimeMs, long totalBytes) {
+        list.add(createDownloadItem(guid, url, targetPath, startTimeMs, totalBytes));
+    }
+
+    @CalledByNative
+    static OfflinePageDownloadItem createDownloadItem(
+            String guid, String url, String targetPath, long startTimeMs, long totalBytes) {
+        return new OfflinePageDownloadItem(guid, url, targetPath, startTimeMs, totalBytes);
+    }
+
+    private native long nativeInit(Profile profile);
+    private native void nativeDestroy(long nativeOfflinePageDownloadBridge);
+    native void nativeGetAllItems(
+            long nativeOfflinePageDownloadBridge, List<OfflinePageDownloadItem> items);
+    native OfflinePageDownloadItem nativeGetItemByGuid(
+            long nativeOfflinePageDownloadBridge, String guid);
+}