[Android] Expose foreign session sync related funtionalities through JNI.

chrome/android/java/src/org/chromium/chrome/browser/ForeignSessionHelper.java

+// Copyright 2013 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;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.chrome.browser.profiles.Profile;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * This class exposes to Java information about sessions, windows, and tabs on the user's synced
+ * devices.
+ */
+public class ForeignSessionHelper {
+    private int mNativeForeignSessionHelper;
+
+    /**
+     * Callback interface for getting notified when foreign session sync is updated.
+     */
+    public interface ForeignSessionCallback {
+        /**
+         * This method will be called every time foreign session sync is updated.
+         *
+         * It's a good place to call {@link ForeignSessionHelper#getForeignSessions()} to get the
+         * updated information.
+         */
+        @CalledByNative("ForeignSessionCallback")
+        public void onUpdated();
+    }
+
+    /**
+     * Represents synced foreign session.
+     */
+    public static class ForeignSession {
+        public final String tag;
+        public final String name;
+        public final String deviceType;
+        public final long modifiedTime;
+        public final List<ForeignSessionWindow> windows = new ArrayList<ForeignSessionWindow>();
+
+        private ForeignSession(String tag, String name, String deviceType, long modifiedTime) {
+            this.tag = tag;
+            this.name = name;
+            this.deviceType = deviceType;
+            this.modifiedTime = modifiedTime;
+        }
+    }
+
+    /**
+     * Represents synced foreign window. Note that desktop Chrome can have multiple windows in a
+     * session.
+     */
+    public static class ForeignSessionWindow {
+        public final long timestamp;
+        public final int sessionId;
+        public final List<ForeignSessionTab> tabs = new ArrayList<ForeignSessionTab>();
+
+        private ForeignSessionWindow(long timestamp, int sessionId) {
+            this.timestamp = timestamp;
+            this.sessionId = sessionId;
+        }
+    }
+
+    /**
+     * Represents synced foreign tab.
+     */
+    public static class ForeignSessionTab {
+        public final String url;
+        public final String title;
+        public final long timestamp;
+        public final int id;
+
+        private ForeignSessionTab(String url, String title, long timestamp, int id) {
+            this.url = url;
+            this.title = title;
+            this.timestamp = timestamp;
+            this.id = id;
+        }
+    }
+
+    @CalledByNative
+    private static ForeignSession pushSession(
+            List<ForeignSession> sessions, String tag, String name, String deviceType,
+            long modifiedTime) {
+        ForeignSession session = new ForeignSession(tag, name, deviceType, modifiedTime);
+        sessions.add(session);
+        return session;
+    }
+
+    @CalledByNative
+    private static ForeignSessionWindow pushWindow(
+            ForeignSession session, long timestamp, int sessionId) {
+        ForeignSessionWindow window = new ForeignSessionWindow(timestamp, sessionId);
+        session.windows.add(window);
+        return window;
+    }
+
+    @CalledByNative
+    private static void pushTab(
+            ForeignSessionWindow window, String url, String title, long timestamp, int sessionId) {
+        ForeignSessionTab tab = new ForeignSessionTab(url, title, timestamp, sessionId);
+        window.tabs.add(tab);
+    }
+
+    /**
+     * Initialize this class with the given profile.
+     * @param profile Profile that will be used for syncing.
+     */
+    public ForeignSessionHelper(Profile profile) {
+        mNativeForeignSessionHelper = nativeInit(profile);
+    }
+
+    /**
+     * Clean up the C++ side of this class. After the call, this class instance shouldn't be used.
+     */
+    public void destroy() {
+        assert mNativeForeignSessionHelper != 0;
+        nativeDestroy(mNativeForeignSessionHelper);
+    }
+
+    @Override
+    protected void finalize() {
+        // Just to make sure that we called destroy() before the java garbage collection picks up.
+        assert mNativeForeignSessionHelper == 0;
+    }
+
+    /**
+     * @return {@code True} iff Tab sync is enabled.
+     */
+    public boolean isTabSyncEnabled() {
+        return nativeIsTabSyncEnabled(mNativeForeignSessionHelper);
+    }
+
+    /**
+     * Sets callback instance that will be called on every foreign session sync update.
+     */
+    public void setOnForeignSessionCallback(ForeignSessionCallback callback) {
+        nativeSetOnForeignSessionCallback(mNativeForeignSessionHelper, callback);
+    }
+
+    /**
+     * @return The list of synced foreign sessions. {@code null} iff it fails to get them for some
+     *         reason.
+     */
+    public List<ForeignSession> getForeignSessions() {
+        List<ForeignSession> result = new ArrayList<ForeignSession>();
+        boolean received = nativeGetForeignSessions(mNativeForeignSessionHelper, result);
+        if (received) {
+            // Sort sessions from most recent to least recent.
+            Collections.sort(result, new Comparator<ForeignSession>() {
+                @Override
+                public int compare(ForeignSession lhs, ForeignSession rhs) {
+                    return lhs.modifiedTime < rhs.modifiedTime ? 1 :
+                        (lhs.modifiedTime == rhs.modifiedTime ? 0: -1);
+                }
+            });
+        } else {
+            result = null;
+        }
+
+        return result;
+    }
+
+    /**
+     * Opens the given foreign tab in a new tab.
+     * @param session Session that the target tab belongs to.
+     * @param tab     Target tab to open.
+     * @return        {@code True} iff the tab is successfully opened.
+     */
+    public boolean openForeignSessionTab(ForeignSession session, ForeignSessionTab tab) {
+        return nativeOpenForeignSessionTab(mNativeForeignSessionHelper, session.tag, tab.id);
+    }
+
+    /**
+     * Set the given session collapsed or uncollapsed in preferences.
+     * @param session     Session to set collapsed or uncollapsed.
+     * @param isCollapsed {@code True} iff we want the session to be collapsed.
+     */
+    public void setForeignSessionCollapsed(ForeignSession session, boolean isCollapsed) {
+        nativeSetForeignSessionCollapsed(mNativeForeignSessionHelper, session.tag, isCollapsed);
+    }
+
+    /**
+     * Remove Foreign session to display. Note that it will be reappear on the next sync.
+     *
+     * This is mainly for when user wants to delete very old session that won't be used or syned in
+     * the future.
+     * @param session Session to be deleted.
+     */
+    public void deleteForeignSession(ForeignSession session) {
+        nativeDeleteForeignSession(mNativeForeignSessionHelper, session.tag);
+    }
+
+    private static native int nativeInit(Profile profile);
+    private static native void nativeDestroy(int nativeForeignSessionHelper);
+    private static native boolean nativeIsTabSyncEnabled(int nativeForeignSessionHelper);
+    private static native void nativeSetOnForeignSessionCallback(
+            int nativeForeignSessionHelper, ForeignSessionCallback callback);
+    private static native boolean nativeGetForeignSessions(int nativeForeignSessionHelper,
+            List<ForeignSession> resultSessions);
+    private static native boolean nativeOpenForeignSessionTab(
+            int nativeForeignSessionHelper, String sessionTag, int tabId);
+    private static native void nativeSetForeignSessionCollapsed(
+            int nativeForeignSessionHelper, String sessionTag, boolean isCollapsed);
+    private static native void nativeDeleteForeignSession(
+            int nativeForeignSessionHelper, String sessionTag);
+}