1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.documentsui;
18
19import android.content.AsyncTaskLoader;
20import android.content.Context;
21
22import com.android.documentsui.DocumentsActivity.State;
23import com.android.documentsui.model.RootInfo;
24
25import java.util.Collection;
26
27public class RootsLoader extends AsyncTaskLoader<Collection<RootInfo>> {
28    private final RootsCache mRoots;
29    private final State mState;
30
31    private Collection<RootInfo> mResult;
32
33    public RootsLoader(Context context, RootsCache roots, State state) {
34        super(context);
35        mRoots = roots;
36        mState = state;
37    }
38
39    @Override
40    public final Collection<RootInfo> loadInBackground() {
41        return mRoots.getMatchingRootsBlocking(mState);
42    }
43
44    @Override
45    public void deliverResult(Collection<RootInfo> result) {
46        if (isReset()) {
47            return;
48        }
49        Collection<RootInfo> oldResult = mResult;
50        mResult = result;
51
52        if (isStarted()) {
53            super.deliverResult(result);
54        }
55    }
56
57    @Override
58    protected void onStartLoading() {
59        if (mResult != null) {
60            deliverResult(mResult);
61        }
62        if (takeContentChanged() || mResult == null) {
63            forceLoad();
64        }
65    }
66
67    @Override
68    protected void onStopLoading() {
69        cancelLoad();
70    }
71
72    @Override
73    protected void onReset() {
74        super.onReset();
75
76        // Ensure the loader is stopped
77        onStopLoading();
78
79        mResult = null;
80    }
81}
82