1/*
 2 *
 3 * Licensed to the Apache Software Foundation (ASF) under one
 4 * or more contributor license agreements.  See the NOTICE file
 5 * distributed with this work for additional information
 6 * regarding copyright ownership.  The ASF licenses this file
 7 * to you under the Apache License, Version 2.0 (the
 8 * "License"); you may not use this file except in compliance
 9 * with the License.  You may obtain a copy of the License at
10 *
11 *   http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied.  See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 *
20*/
21
22/* 
23 * truncate
24 * 
25 * IN:
26 *  args
27 *   0 - URL of file to truncate
28 *   1 - start position
29 * OUT:
30 *  success - new length of file
31 *  fail - FileError
32 */
33
34var resolve = cordova.require('cordova-plugin-file.resolveLocalFileSystemURIProxy'),
35    requestAnimationFrame = cordova.require('cordova-plugin-file.bb10RequestAnimationFrame');
36
37module.exports = function (success, fail, args) {
38    var uri = args[0],
39        length = args[1],
40        onSuccess = function (data) {
41            if (typeof success === 'function') {
42                success(data.loaded);
43            }
44        },
45        onFail = function (error) {
46            if (typeof fail === 'function') {
47                if (error && error.code) {
48                    fail(error.code);
49                } else {
50                    fail(error);
51                }
52            }
53        };
54    resolve(function (fs) {
55        requestAnimationFrame(function () {
56            fs.nativeEntry.file(function (file) {
57                var reader = new FileReader()._realReader;
58                reader.onloadend = function () {
59                    var contents = new Uint8Array(this.result).subarray(0, length),
60                        blob = new Blob([contents]);
61                    window.requestAnimationFrame(function () {
62                        fs.nativeEntry.createWriter(function (fileWriter) {
63                            fileWriter.onwriteend = onSuccess;
64                            fileWriter.onerror = onFail;
65                            fileWriter.write(blob);
66                        }, onFail);
67                    });
68                };
69                reader.onerror = onFail;
70                reader.readAsArrayBuffer(file);
71            }, onFail);
72        });
73    }, onFail, [uri]);
74};