FileWriter.js

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 *
*/

var exec = require('cordova/exec'),
    FileError = require('./FileError'),
    ProgressEvent = require('./ProgressEvent');

function write(data) {
    var that=this;
    var supportsBinary = (typeof window.Blob !== 'undefined' && typeof window.ArrayBuffer !== 'undefined');
    var isBinary;

    // Check to see if the incoming data is a blob
    if (data instanceof File || (supportsBinary && data instanceof Blob)) {
        var fileReader = new FileReader();
        fileReader.onload = function() {
            // Call this method again, with the arraybuffer as argument
            FileWriter.prototype.write.call(that, this.result);
        };
        if (supportsBinary) {
            fileReader.readAsArrayBuffer(data);
        } else {
            fileReader.readAsText(data);
        }
        return;
    }

    // Mark data type for safer transport over the binary bridge
    isBinary = supportsBinary && (data instanceof ArrayBuffer);

    // Throw an exception if we are already writing a file
    if (this.readyState === FileWriter.WRITING) {
        throw new FileError(FileError.INVALID_STATE_ERR);
    }

    // WRITING state
    this.readyState = FileWriter.WRITING;

    var me = this;

    // If onwritestart callback
    if (typeof me.onwritestart === "function") {
        me.onwritestart(new ProgressEvent("writestart", {"target":me}));
    }

    if (data instanceof ArrayBuffer || data.buffer instanceof ArrayBuffer) {
        data = new Uint8Array(data);
    var binary = "";
    for (var i = 0; i < data.byteLength; i++) {
            binary += String.fromCharCode(data[i]);
    }
        data = binary;
    }

    var prefix = "file://localhost";
    var path = this.localURL;
    if (path.substr(0, prefix.length) == prefix) {
        path = path.substr(prefix.length);
    }
    // Write file
    exec(
        // Success callback
        function(r) {
            // If DONE (cancelled), then don't do anything
            if (me.readyState === FileWriter.DONE) {
                return;
            }

            // position always increases by bytes written because file would be extended
            me.position += r;
            // The length of the file is now where we are done writing.

            me.length = me.position;

            // DONE state
            me.readyState = FileWriter.DONE;

            // If onwrite callback
            if (typeof me.onwrite === "function") {
                me.onwrite(new ProgressEvent("write", {"target":me}));
            }

            // If onwriteend callback
            if (typeof me.onwriteend === "function") {
                me.onwriteend(new ProgressEvent("writeend", {"target":me}));
            }
        },
        // Error callback
        function(e) {
            // If DONE (cancelled), then don't do anything
            if (me.readyState === FileWriter.DONE) {
                return;
            }

            // DONE state
            me.readyState = FileWriter.DONE;

            // Save error
            me.error = new FileError(e);

            // If onerror callback
            if (typeof me.onerror === "function") {
                me.onerror(new ProgressEvent("error", {"target":me}));
            }

            // If onwriteend callback
            if (typeof me.onwriteend === "function") {
                me.onwriteend(new ProgressEvent("writeend", {"target":me}));
            }
        }, "File", "write", [path, data, this.position, isBinary]);
}

module.exports = {
    write: write
};

require("cordova/exec/proxy").add("FileWriter", module.exports);