QuickViewIntentBuilder.java revision 32a34d337977618d95ab183f65627a4ff4b9a390 
1/*
2 * Copyright (C) 2015 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 static com.android.documentsui.Shared.DEBUG;
20import static com.android.documentsui.Shared.TAG;
21import static com.android.documentsui.model.DocumentInfo.getCursorString;
22
23import android.content.ClipData;
24import android.content.ClipDescription;
25import android.content.ComponentName;
26import android.content.Intent;
27import android.content.pm.PackageManager;
28import android.content.res.Resources;
29import android.database.Cursor;
30import android.net.Uri;
31import android.provider.DocumentsContract;
32import android.provider.DocumentsContract.Document;
33import android.support.annotation.Nullable;
34import android.text.TextUtils;
35import android.util.Log;
36import android.util.Range;
37
38import com.android.documentsui.dirlist.Model;
39import com.android.documentsui.model.DocumentInfo;
40
41import java.util.ArrayList;
42import java.util.List;
43
44/**
45 * Provides support for gather a list of quick-viewable files into a quick view intent.
46 */
47final class QuickViewIntentBuilder {
48    private static final int MAX_CLIP_ITEMS = 1000;
49
50    private final DocumentInfo mDocument;
51    private final Model mModel;
52
53    private final PackageManager mPkgManager;
54    private final Resources mResources;
55
56    public QuickViewIntentBuilder(
57            PackageManager pkgManager,
58            Resources resources,
59            DocumentInfo doc,
60            Model model) {
61
62        mPkgManager = pkgManager;
63        mResources = resources;
64        mDocument = doc;
65        mModel = model;
66    }
67
68    /**
69     * Builds the intent for quick viewing. Short circuits building if a handler cannot
70     * be resolved; in this case {@code null} is returned.
71     */
72    @Nullable Intent build() {
73        if (DEBUG) Log.d(TAG, "Preparing intent for doc:" + mDocument.documentId);
74
75        String trustedPkg = mResources.getString(R.string.trusted_quick_viewer_package);
76
77        if (!TextUtils.isEmpty(trustedPkg)) {
78            Intent intent = new Intent(Intent.ACTION_QUICK_VIEW);
79            intent.setDataAndType(mDocument.derivedUri, mDocument.mimeType);
80            intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
81            intent.setPackage(trustedPkg);
82            if (hasRegisteredHandler(intent)) {
83                final ArrayList<Uri> uris = new ArrayList<Uri>();
84                final int documentLocation = collectViewableUris(uris);
85                final Range<Integer> range = computeSiblingsRange(uris, documentLocation);
86
87                ClipData clipData = null;
88                ClipData.Item item;
89                Uri uri;
90                for (int i = range.getLower(); i <= range.getUpper(); i++) {
91                    uri = uris.get(i);
92                    item = new ClipData.Item(uri);
93                    if (DEBUG) Log.d(TAG, "Including file: " + uri);
94                    if (clipData == null) {
95                        clipData = new ClipData(
96                                "URIs", new String[] { ClipDescription.MIMETYPE_TEXT_URILIST },
97                                item);
98                    } else {
99                        clipData.addItem(item);
100                    }
101                }
102
103                intent.putExtra(Intent.EXTRA_INDEX, documentLocation);
104                intent.setClipData(clipData);
105
106                return intent;
107            } else {
108                Log.e(TAG, "Can't resolve trusted quick view package: " + trustedPkg);
109            }
110        }
111
112        return null;
113    }
114
115    private int collectViewableUris(ArrayList<Uri> uris) {
116        final List<String> siblingIds = mModel.getModelIds();
117        uris.ensureCapacity(siblingIds.size());
118
119        int documentLocation = 0;
120        Cursor cursor;
121        String mimeType;
122        String id;
123        String authority;
124        Uri uri;
125
126        // Cursor's are not guaranteed to be immutable. Hence, traverse it only once.
127        for (int i = 0; i < siblingIds.size(); i++) {
128            cursor = mModel.getItem(siblingIds.get(i));
129
130            mimeType = getCursorString(cursor, Document.COLUMN_MIME_TYPE);
131            if (Document.MIME_TYPE_DIR.equals(mimeType)) {
132                continue;
133            }
134
135            id = getCursorString(cursor, Document.COLUMN_DOCUMENT_ID);
136            authority = getCursorString(cursor, RootCursorWrapper.COLUMN_AUTHORITY);
137            uri = DocumentsContract.buildDocumentUri(authority, id);
138
139            if (id.equals(mDocument.documentId)) {
140                if (DEBUG) Log.d(TAG, "Found starting point for QV. " + i);
141                documentLocation = i;
142            }
143
144            uris.add(uri);
145        }
146
147        return documentLocation;
148    }
149
150    private static Range<Integer> computeSiblingsRange(List<Uri> uris, int documentLocation) {
151        // Restrict number of siblings to avoid hitting the IPC limit.
152        // TODO: Remove this restriction once ClipData can hold an arbitrary number of
153        // items.
154        int firstSibling;
155        int lastSibling;
156        if (documentLocation < uris.size() / 2) {
157            firstSibling = Math.max(0, documentLocation - MAX_CLIP_ITEMS / 2);
158            lastSibling = Math.min(uris.size() - 1, firstSibling + MAX_CLIP_ITEMS - 1);
159        } else {
160            lastSibling = Math.min(uris.size() - 1, documentLocation + MAX_CLIP_ITEMS / 2);
161            firstSibling = Math.max(0, lastSibling - MAX_CLIP_ITEMS + 1);
162        }
163
164        if (DEBUG) Log.d(TAG, "Copmuted siblings from index: " + firstSibling
165                + " to: " + lastSibling);
166
167        return new Range(firstSibling, lastSibling);
168    }
169
170    private boolean hasRegisteredHandler(Intent intent) {
171        // Try to resolve the intent. If a matching app isn't installed, it won't resolve.
172        return intent.resolveActivity(mPkgManager) != null;
173    }
174}
175