1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 | 1 1 1 1 1 1 1 1 1 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 21 41 1 1 41 41 41 41 41 41 1 129 8 8 129 1 77 77 77 1 35 1 143 143 37 37 37 106 29 77 77 77 77 41 41 41 41 36 36 36 1 35 35 36 17 36 36 36 36 1 3 3 3 3 3 3 1 86 1 62 62 62 62 62 1 8 1 8 8 8 1 8 8 8 8 8 8 8 1 | // // Copyright (c) Microsoft and contributors. All rights reserved. // // 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. // var stream = require('stream'); var crypto = require('crypto'); var util = require('util'); var fs = require('fs'); var validator = require('validator'); var Constants = require('../util/constants'); var bufferSize = Constants.BlobConstants.DEFAULT_WRITE_BLOCK_SIZE_IN_BYTES; var EventEmitter = require('events').EventEmitter; /** * File read stream * 1. Calculate md5 * 2. Track reading offset * 3. Work with customize memory allocator * 4. Buffer data from stream. * @param {object} options stream.Readable options */ function FileReadStream(path, options) { stream.Stream.call(this); this.readable = true; Iif(!options) { options = {}; } this._destroyed = false; this._streamEnded = false; this._fd = null; this._fileName = undefined; this._highWaterMark = options.highWaterMark || bufferSize; this._offset = 0; this._paused = undefined; this._allocator = options.allocator; this._fileName = path; this._md5hash = null; this._md5sum = undefined; if (options.calcContentMd5) { this._md5hash = crypto.createHash('md5'); } this._open(); } util.inherits(FileReadStream, stream.Stream); /** * Open file */ FileReadStream.prototype._open = function () { var flags = 'r'; var self = this; fs.open(this._fileName, flags, function(error, fd) { Iif (error) { self.emit('error', error); } else { self._fd = fd; self.emit('open', fd); } }); }; /** * Add event listener */ FileReadStream.prototype.on = function(event, listener) { if (event === 'data' && this._paused === undefined) { this._paused = false; this._emitData(); } return EventEmitter.prototype.on.call(this, event, listener); }; /** * Get buffer */ FileReadStream.prototype._getBuffer = function(size) { Iif(this._allocator && this._allocator.getBuffer) { return this._allocator.getBuffer(size); } else { var buffer = new Buffer(size); return buffer; } }; /** * Release buffer */ FileReadStream.prototype._releaseBuffer = function(buffer) { Iif(this._allocator && this._allocator.releaseBuffer) { this._allocator.releaseBuffer(buffer); } }; /** * Emit the data from file */ FileReadStream.prototype._emitData = function() { var self = this; if(!this._fd) { this.once('open', function() { self._emitData(); }); return; } if (this._paused || this._streamEnded) { return; } var buffer = this._getBuffer(this._highWaterMark); fs.read(this._fd, buffer, 0, this._highWaterMark, this._offset, function(error, bytesRead, readBuffer) { Iif (error) { self.emit('error', error); return; } if(bytesRead === 0) { Eif(!self._streamEnded) { self._streamEnded = true; self.emit('end'); } return; } var range = { start : self._offset, end : self._offset + bytesRead - 1, size : bytesRead }; var data; if(bytesRead == self._highWaterMark) { data = readBuffer; } else { data = readBuffer.slice(0, bytesRead); //Release the current buffer since we created a new one self._releaseBuffer(readBuffer); } if(self._md5hash) { self._md5hash.update(data); } self.emit('data', data, range); // cleanup self._offset += bytesRead; buffer = readBuffer = data = null; self._emitData(); }); }; /** * Get file content md5 when read completely. */ FileReadStream.prototype.getContentMd5 = function(encoding) { Iif (!encoding) encoding = 'base64'; Iif(!this._md5hash) { throw new Error('Can\'t get content md5, please set the calcContentMd5 option for FileReadStream.'); } else { Eif (this._streamEnded) { Eif (!this._md5sum) { this._md5sum = this._md5hash.digest(encoding); } return this._md5sum; } else { throw new Error('FileReadStream has not ended.'); } } }; /** * Pause chunk stream */ FileReadStream.prototype.pause = function() { this._paused = true; }; /** * Resume read stream */ FileReadStream.prototype.resume = function() { var previousState = this._paused; Eif (this._paused) { this._paused = false; Eif(previousState === true) { //Only start to emit data when it's in pause state this._emitData(); } } }; FileReadStream.prototype.finish = function () { this.destroy(); }; FileReadStream.prototype.destroy = function () { Iif (this._destroyed) { return; } var self = this; this.readable = false; function close(fd) { fs.close(fd || self._fd, function(err) { Iif (err) { self.emit('error', err); } else { self.emit('close'); } }); self._fd = null; self._destroyed = true; } // when the stream is closed immediately after creating it Iif (!validator.isInt(this._fd)) { this.once('open', close); return; } close(); }; module.exports = FileReadStream; |