| /* |
| * Copyright (C) 2006 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. |
| */ |
| |
| package android.webkit; |
| |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| |
| /** |
| * This class contains the back/forward list for a WebView. |
| * WebView.copyBackForwardList() will return a copy of this class used to |
| * inspect the entries in the list. |
| */ |
| public class WebBackForwardList implements Cloneable, Serializable { |
| // Current position in the list. |
| private int mCurrentIndex; |
| // ArrayList of WebHistoryItems for maintaining our copy. |
| private ArrayList<WebHistoryItem> mArray; |
| // Flag to indicate that the list is invalid |
| private boolean mClearPending; |
| // CallbackProxy to issue client callbacks. |
| private final CallbackProxy mCallbackProxy; |
| |
| /** |
| * Construct a back/forward list used by clients of WebView. |
| */ |
| /*package*/ WebBackForwardList(CallbackProxy proxy) { |
| mCurrentIndex = -1; |
| mArray = new ArrayList<WebHistoryItem>(); |
| mCallbackProxy = proxy; |
| } |
| |
| /** |
| * Return the current history item. This method returns null if the list is |
| * empty. |
| * @return The current history item. |
| */ |
| public synchronized WebHistoryItem getCurrentItem() { |
| return getItemAtIndex(mCurrentIndex); |
| } |
| |
| /** |
| * Get the index of the current history item. This index can be used to |
| * directly index into the array list. |
| * @return The current index from 0...n or -1 if the list is empty. |
| */ |
| public synchronized int getCurrentIndex() { |
| return mCurrentIndex; |
| } |
| |
| /** |
| * Get the history item at the given index. The index range is from 0...n |
| * where 0 is the first item and n is the last item. |
| * @param index The index to retrieve. |
| */ |
| public synchronized WebHistoryItem getItemAtIndex(int index) { |
| if (index < 0 || index >= getSize()) { |
| return null; |
| } |
| return mArray.get(index); |
| } |
| |
| /** |
| * Get the total size of the back/forward list. |
| * @return The size of the list. |
| */ |
| public synchronized int getSize() { |
| return mArray.size(); |
| } |
| |
| /** |
| * Mark the back/forward list as having a pending clear. This is used on the |
| * UI side to mark the list as being invalid during the clearHistory method. |
| */ |
| /*package*/ synchronized void setClearPending() { |
| mClearPending = true; |
| } |
| |
| /** |
| * Return the status of the clear flag. This is used on the UI side to |
| * determine if the list is valid for checking things like canGoBack. |
| */ |
| /*package*/ synchronized boolean getClearPending() { |
| return mClearPending; |
| } |
| |
| /** |
| * Add a new history item to the list. This will remove all items after the |
| * current item and append the new item to the end of the list. Called from |
| * the WebCore thread only. Synchronized because the UI thread may be |
| * reading the array or the current index. |
| * @param item A new history item. |
| */ |
| /*package*/ synchronized void addHistoryItem(WebHistoryItem item) { |
| // Update the current position because we are going to add the new item |
| // in that slot. |
| ++mCurrentIndex; |
| // If the current position is not at the end, remove all history items |
| // after the current item. |
| final int size = mArray.size(); |
| final int newPos = mCurrentIndex; |
| if (newPos != size) { |
| for (int i = size - 1; i >= newPos; i--) { |
| final WebHistoryItem h = mArray.remove(i); |
| } |
| } |
| // Add the item to the list. |
| mArray.add(item); |
| if (mCallbackProxy != null) { |
| mCallbackProxy.onNewHistoryItem(item); |
| } |
| } |
| |
| /** |
| * Clear the back/forward list. Called from the WebCore thread. |
| */ |
| /*package*/ synchronized void close(int nativeFrame) { |
| // Clear the array first because nativeClose will call addHistoryItem |
| // with the current item. |
| mArray.clear(); |
| mCurrentIndex = -1; |
| nativeClose(nativeFrame); |
| // Reset the clear flag |
| mClearPending = false; |
| } |
| |
| /* Remove the item at the given index. Called by JNI only. */ |
| private synchronized void removeHistoryItem(int index) { |
| // XXX: This is a special case. Since the callback is only triggered |
| // when removing the first item, we can assert that the index is 0. |
| // This lets us change the current index without having to query the |
| // native BackForwardList. |
| if (DebugFlags.WEB_BACK_FORWARD_LIST && (index != 0)) { |
| throw new AssertionError(); |
| } |
| final WebHistoryItem h = mArray.remove(index); |
| // XXX: If we ever add another callback for removing history items at |
| // any index, this will no longer be valid. |
| mCurrentIndex--; |
| } |
| |
| /** |
| * Clone the entire object to be used in the UI thread by clients of |
| * WebView. This creates a copy that should never be modified by any of the |
| * webkit package classes. |
| */ |
| protected synchronized WebBackForwardList clone() { |
| WebBackForwardList l = new WebBackForwardList(null); |
| if (mClearPending) { |
| // If a clear is pending, return a copy with only the current item. |
| l.addHistoryItem(getCurrentItem()); |
| return l; |
| } |
| l.mCurrentIndex = mCurrentIndex; |
| int size = getSize(); |
| l.mArray = new ArrayList<WebHistoryItem>(size); |
| for (int i = 0; i < size; i++) { |
| // Add a copy of each WebHistoryItem |
| l.mArray.add(mArray.get(i).clone()); |
| } |
| return l; |
| } |
| |
| /** |
| * Set the new history index. |
| * @param newIndex The new history index. |
| */ |
| /*package*/ synchronized void setCurrentIndex(int newIndex) { |
| mCurrentIndex = newIndex; |
| if (mCallbackProxy != null) { |
| mCallbackProxy.onIndexChanged(getItemAtIndex(newIndex), newIndex); |
| } |
| } |
| |
| /** |
| * Restore the history index. |
| */ |
| /*package*/ static native synchronized void restoreIndex(int nativeFrame, |
| int index); |
| |
| /* Close the native list. */ |
| private static native void nativeClose(int nativeFrame); |
| } |