src/com/android/gallery3d/data/FilterDeleteSet.java - platform/packages/apps/Gallery2 - Git at Google

 /*
  * Copyright (C) 2012 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 com.android.gallery3d.data;

 import java.util.ArrayList;

 // FilterDeleteSet filters a base MediaSet to remove some deletion items (we
 // expect the number to be small). The user can use the following methods to
 // add/remove deletion items:
 //
 // void addDeletion(Path path, int index);
 // void removeDelection(Path path);
 // void clearDeletion();
 // int getNumberOfDeletions();
 //
 public class FilterDeleteSet extends MediaSet implements ContentListener {
     @SuppressWarnings("unused")
     private static final String TAG = "FilterDeleteSet";

     private static final int REQUEST_ADD = 1;
     private static final int REQUEST_REMOVE = 2;
     private static final int REQUEST_CLEAR = 3;

     private static class Request {
         int type;  // one of the REQUEST_* constants
         Path path;
         int indexHint;
         public Request(int type, Path path, int indexHint) {
             this.type = type;
             this.path = path;
             this.indexHint = indexHint;
         }
     }

     private static class Deletion {
         Path path;
         int index;
         public Deletion(Path path, int index) {
             this.path = path;
             this.index = index;
         }
     }

     // The underlying MediaSet
     private final MediaSet mBaseSet;

     // Pending Requests
     private ArrayList<Request> mRequests = new ArrayList<Request>();

     // Deletions currently in effect, ordered by index
     private ArrayList<Deletion> mCurrent = new ArrayList<Deletion>();

     public FilterDeleteSet(Path path, MediaSet baseSet) {
         super(path, INVALID_DATA_VERSION);
         mBaseSet = baseSet;
         mBaseSet.addContentListener(this);
     }

     @Override
     public boolean isCameraRoll() {
         return mBaseSet.isCameraRoll();
     }

     @Override
     public String getName() {
         return mBaseSet.getName();
     }

     @Override
     public int getMediaItemCount() {
         return mBaseSet.getMediaItemCount() - mCurrent.size();
     }

     // Gets the MediaItems whose (post-deletion) index are in the range [start,
     // start + count). Because we remove some of the MediaItems, the index need
     // to be adjusted.
     //
     // For example, if there are 12 items in total. The deleted items are 3, 5,
     // 10, and the the requested range is [3, 7]:
     //
     // The original index:   0 1 2 3 4 5 6 7 8 9 A B C
     // The deleted items:          X   X         X
     // The new index:        0 1 2   3   4 5 6 7   8 9
     // Requested:                    *   * * * *
     //
     // We need to figure out the [3, 7] actually maps to the original index 4,
     // 6, 7, 8, 9.
     //
     // We can break the MediaItems into segments, each segment other than the
     // last one ends in a deleted item. The difference between the new index and
     // the original index increases with each segment:
     //
     // 0 1 2 X     (new index = old index)
     // 4 X         (new index = old index - 1)
     // 6 7 8 9 X   (new index = old index - 2)
     // B C         (new index = old index - 3)
     //
     @Override
     public ArrayList<MediaItem> getMediaItem(int start, int count) {
         if (count <= 0) return new ArrayList<MediaItem>();

         int end = start + count - 1;
         int n = mCurrent.size();
         // Find the segment that "start" falls into. Count the number of items
         // not yet deleted until it reaches "start".
         int i = 0;
         for (i = 0; i < n; i++) {
             Deletion d = mCurrent.get(i);
             if (d.index - i > start) break;
         }
         // Find the segment that "end" falls into.
         int j = i;
         for (; j < n; j++) {
             Deletion d = mCurrent.get(j);
             if (d.index - j > end) break;
         }

         // Now get enough to cover deleted items in [start, end]
         ArrayList<MediaItem> base = mBaseSet.getMediaItem(start + i, count + (j - i));

         // Remove the deleted items.
         for (int m = j - 1; m >= i; m--) {
             Deletion d = mCurrent.get(m);
             int k = d.index - (start + i);
             base.remove(k);
         }
         return base;
     }

     // We apply the pending requests in the mRequests to construct mCurrent in reload().
     @Override
     public long reload() {
         boolean newData = mBaseSet.reload() > mDataVersion;
         synchronized (mRequests) {
             if (!newData && mRequests.isEmpty()) {
                 return mDataVersion;
             }
             for (int i = 0; i < mRequests.size(); i++) {
                 Request r = mRequests.get(i);
                 switch (r.type) {
                     case REQUEST_ADD: {
                         // Add the path into mCurrent if there is no duplicate.
                         int n = mCurrent.size();
                         int j;
                         for (j = 0; j < n; j++) {
                             if (mCurrent.get(j).path == r.path) break;
                         }
                         if (j == n) {
                             mCurrent.add(new Deletion(r.path, r.indexHint));
                         }
                         break;
                     }
                     case REQUEST_REMOVE: {
                         // Remove the path from mCurrent.
                         int n = mCurrent.size();
                         for (int j = 0; j < n; j++) {
                             if (mCurrent.get(j).path == r.path) {
                                 mCurrent.remove(j);
                                 break;
                             }
                         }
                         break;
                     }
                     case REQUEST_CLEAR: {
                         mCurrent.clear();
                         break;
                     }
                 }
             }
             mRequests.clear();
         }

         if (!mCurrent.isEmpty()) {
             // See if the elements in mCurrent can be found in the MediaSet. We
             // don't want to search the whole mBaseSet, so we just search a
             // small window that contains the index hints (plus some margin).
             int minIndex = mCurrent.get(0).index;
             int maxIndex = minIndex;
             for (int i = 1; i < mCurrent.size(); i++) {
                 Deletion d = mCurrent.get(i);
                 minIndex = Math.min(d.index, minIndex);
                 maxIndex = Math.max(d.index, maxIndex);
             }

             int n = mBaseSet.getMediaItemCount();
             int from = Math.max(minIndex - 5, 0);
             int to = Math.min(maxIndex + 5, n);
             ArrayList<MediaItem> items = mBaseSet.getMediaItem(from, to - from);
             ArrayList<Deletion> result = new ArrayList<Deletion>();
             for (int i = 0; i < items.size(); i++) {
                 MediaItem item = items.get(i);
                 if (item == null) continue;
                 Path p = item.getPath();
                 // Find the matching path in mCurrent, if found move it to result
                 for (int j = 0; j < mCurrent.size(); j++) {
                     Deletion d = mCurrent.get(j);
                     if (d.path == p) {
                         d.index = from + i;
                         result.add(d);
                         mCurrent.remove(j);
                         break;
                     }
                 }
             }
             mCurrent = result;
         }

         mDataVersion = nextVersionNumber();
         return mDataVersion;
     }

     private void sendRequest(int type, Path path, int indexHint) {
         Request r = new Request(type, path, indexHint);
         synchronized (mRequests) {
             mRequests.add(r);
         }
         notifyContentChanged();
     }

     @Override
     public void onContentDirty() {
         notifyContentChanged();
     }

     public void addDeletion(Path path, int indexHint) {
         sendRequest(REQUEST_ADD, path, indexHint);
     }

     public void removeDeletion(Path path) {
         sendRequest(REQUEST_REMOVE, path, 0 /* unused */);
     }

     public void clearDeletion() {
         sendRequest(REQUEST_CLEAR, null /* unused */ , 0 /* unused */);
     }

     // Returns number of deletions _in effect_ (the number will only gets
     // updated after a reload()).
     public int getNumberOfDeletions() {
         return mCurrent.size();
     }
 }
	/*
	* Copyright (C) 2012 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 com.android.gallery3d.data;

	import java.util.ArrayList;

	// FilterDeleteSet filters a base MediaSet to remove some deletion items (we
	// expect the number to be small). The user can use the following methods to
	// add/remove deletion items:
	//
	// void addDeletion(Path path, int index);
	// void removeDelection(Path path);
	// void clearDeletion();
	// int getNumberOfDeletions();
	//
	public class FilterDeleteSet extends MediaSet implements ContentListener {
	@SuppressWarnings("unused")
	private static final String TAG = "FilterDeleteSet";

	private static final int REQUEST_ADD = 1;
	private static final int REQUEST_REMOVE = 2;
	private static final int REQUEST_CLEAR = 3;

	private static class Request {
	int type; // one of the REQUEST_* constants
	Path path;
	int indexHint;
	public Request(int type, Path path, int indexHint) {
	this.type = type;
	this.path = path;
	this.indexHint = indexHint;
	}
	}

	private static class Deletion {
	Path path;
	int index;
	public Deletion(Path path, int index) {
	this.path = path;
	this.index = index;
	}
	}

	// The underlying MediaSet
	private final MediaSet mBaseSet;

	// Pending Requests
	private ArrayList<Request> mRequests = new ArrayList<Request>();

	// Deletions currently in effect, ordered by index
	private ArrayList<Deletion> mCurrent = new ArrayList<Deletion>();

	public FilterDeleteSet(Path path, MediaSet baseSet) {
	super(path, INVALID_DATA_VERSION);
	mBaseSet = baseSet;
	mBaseSet.addContentListener(this);
	}

	@Override
	public boolean isCameraRoll() {
	return mBaseSet.isCameraRoll();
	}

	@Override
	public String getName() {
	return mBaseSet.getName();
	}

	@Override
	public int getMediaItemCount() {
	return mBaseSet.getMediaItemCount() - mCurrent.size();
	}

	// Gets the MediaItems whose (post-deletion) index are in the range [start,
	// start + count). Because we remove some of the MediaItems, the index need
	// to be adjusted.
	//
	// For example, if there are 12 items in total. The deleted items are 3, 5,
	// 10, and the the requested range is [3, 7]:
	//
	// The original index: 0 1 2 3 4 5 6 7 8 9 A B C
	// The deleted items: X X X
	// The new index: 0 1 2 3 4 5 6 7 8 9
	// Requested: * * * * *
	//
	// We need to figure out the [3, 7] actually maps to the original index 4,
	// 6, 7, 8, 9.
	//
	// We can break the MediaItems into segments, each segment other than the
	// last one ends in a deleted item. The difference between the new index and
	// the original index increases with each segment:
	//
	// 0 1 2 X (new index = old index)
	// 4 X (new index = old index - 1)
	// 6 7 8 9 X (new index = old index - 2)
	// B C (new index = old index - 3)
	//
	@Override
	public ArrayList<MediaItem> getMediaItem(int start, int count) {
	if (count <= 0) return new ArrayList<MediaItem>();

	int end = start + count - 1;
	int n = mCurrent.size();
	// Find the segment that "start" falls into. Count the number of items
	// not yet deleted until it reaches "start".
	int i = 0;
	for (i = 0; i < n; i++) {
	Deletion d = mCurrent.get(i);
	if (d.index - i > start) break;
	}
	// Find the segment that "end" falls into.
	int j = i;
	for (; j < n; j++) {
	Deletion d = mCurrent.get(j);
	if (d.index - j > end) break;
	}

	// Now get enough to cover deleted items in [start, end]
	ArrayList<MediaItem> base = mBaseSet.getMediaItem(start + i, count + (j - i));

	// Remove the deleted items.
	for (int m = j - 1; m >= i; m--) {
	Deletion d = mCurrent.get(m);
	int k = d.index - (start + i);
	base.remove(k);
	}
	return base;
	}

	// We apply the pending requests in the mRequests to construct mCurrent in reload().
	@Override
	public long reload() {
	boolean newData = mBaseSet.reload() > mDataVersion;
	synchronized (mRequests) {
	if (!newData && mRequests.isEmpty()) {
	return mDataVersion;
	}
	for (int i = 0; i < mRequests.size(); i++) {
	Request r = mRequests.get(i);
	switch (r.type) {
	case REQUEST_ADD: {
	// Add the path into mCurrent if there is no duplicate.
	int n = mCurrent.size();
	int j;
	for (j = 0; j < n; j++) {
	if (mCurrent.get(j).path == r.path) break;
	}
	if (j == n) {
	mCurrent.add(new Deletion(r.path, r.indexHint));
	}
	break;
	}
	case REQUEST_REMOVE: {
	// Remove the path from mCurrent.
	int n = mCurrent.size();
	for (int j = 0; j < n; j++) {
	if (mCurrent.get(j).path == r.path) {
	mCurrent.remove(j);
	break;
	}
	}
	break;
	}
	case REQUEST_CLEAR: {
	mCurrent.clear();
	break;
	}
	}
	}
	mRequests.clear();
	}

	if (!mCurrent.isEmpty()) {
	// See if the elements in mCurrent can be found in the MediaSet. We
	// don't want to search the whole mBaseSet, so we just search a
	// small window that contains the index hints (plus some margin).
	int minIndex = mCurrent.get(0).index;
	int maxIndex = minIndex;
	for (int i = 1; i < mCurrent.size(); i++) {
	Deletion d = mCurrent.get(i);
	minIndex = Math.min(d.index, minIndex);
	maxIndex = Math.max(d.index, maxIndex);
	}

	int n = mBaseSet.getMediaItemCount();
	int from = Math.max(minIndex - 5, 0);
	int to = Math.min(maxIndex + 5, n);
	ArrayList<MediaItem> items = mBaseSet.getMediaItem(from, to - from);
	ArrayList<Deletion> result = new ArrayList<Deletion>();
	for (int i = 0; i < items.size(); i++) {
	MediaItem item = items.get(i);
	if (item == null) continue;
	Path p = item.getPath();
	// Find the matching path in mCurrent, if found move it to result
	for (int j = 0; j < mCurrent.size(); j++) {
	Deletion d = mCurrent.get(j);
	if (d.path == p) {
	d.index = from + i;
	result.add(d);
	mCurrent.remove(j);
	break;
	}
	}
	}
	mCurrent = result;
	}

	mDataVersion = nextVersionNumber();
	return mDataVersion;
	}

	private void sendRequest(int type, Path path, int indexHint) {
	Request r = new Request(type, path, indexHint);
	synchronized (mRequests) {
	mRequests.add(r);
	}
	notifyContentChanged();
	}

	@Override
	public void onContentDirty() {
	notifyContentChanged();
	}

	public void addDeletion(Path path, int indexHint) {
	sendRequest(REQUEST_ADD, path, indexHint);
	}

	public void removeDeletion(Path path) {
	sendRequest(REQUEST_REMOVE, path, 0 /* unused */);
	}

	public void clearDeletion() {
	sendRequest(REQUEST_CLEAR, null /* unused / , 0 / unused */);
	}

	// Returns number of deletions _in effect_ (the number will only gets
	// updated after a reload()).
	public int getNumberOfDeletions() {
	return mCurrent.size();
	}
	}