file-writer.js 2.4 KB

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  1. module.exports = FileWriter
  2. var fs = require("graceful-fs")
  3. , mkdir = require("mkdirp")
  4. , Writer = require("./writer.js")
  5. , inherits = require("inherits")
  6. , EOF = {}
  7. inherits(FileWriter, Writer)
  8. function FileWriter (props) {
  9. var me = this
  10. if (!(me instanceof FileWriter)) throw new Error(
  11. "FileWriter must be called as constructor.")
  12. // should already be established as a File type
  13. if (props.type !== "File" || !props.File) {
  14. throw new Error("Non-file type "+ props.type)
  15. }
  16. me._buffer = []
  17. me._bytesWritten = 0
  18. Writer.call(this, props)
  19. }
  20. FileWriter.prototype._create = function () {
  21. var me = this
  22. if (me._stream) return
  23. var so = {}
  24. if (me.props.flags) so.flags = me.props.flags
  25. so.mode = Writer.filemode
  26. if (me._old && me._old.blksize) so.bufferSize = me._old.blksize
  27. me._stream = fs.createWriteStream(me._path, so)
  28. me._stream.on("open", function (fd) {
  29. // console.error("FW open", me._buffer, me._path)
  30. me.ready = true
  31. me._buffer.forEach(function (c) {
  32. if (c === EOF) me._stream.end()
  33. else me._stream.write(c)
  34. })
  35. me.emit("ready")
  36. // give this a kick just in case it needs it.
  37. me.emit("drain")
  38. })
  39. me._stream.on("drain", function () { me.emit("drain") })
  40. me._stream.on("close", function () {
  41. // console.error("\n\nFW Stream Close", me._path, me.size)
  42. me._finish()
  43. })
  44. }
  45. FileWriter.prototype.write = function (c) {
  46. var me = this
  47. me._bytesWritten += c.length
  48. if (!me.ready) {
  49. if (!Buffer.isBuffer(c) && typeof c !== 'string')
  50. throw new Error('invalid write data')
  51. me._buffer.push(c)
  52. return false
  53. }
  54. var ret = me._stream.write(c)
  55. // console.error("\t-- fw wrote, _stream says", ret, me._stream._queue.length)
  56. // allow 2 buffered writes, because otherwise there's just too
  57. // much stop and go bs.
  58. if (ret === false && me._stream._queue) {
  59. return me._stream._queue.length <= 2;
  60. } else {
  61. return ret;
  62. }
  63. }
  64. FileWriter.prototype.end = function (c) {
  65. var me = this
  66. if (c) me.write(c)
  67. if (!me.ready) {
  68. me._buffer.push(EOF)
  69. return false
  70. }
  71. return me._stream.end()
  72. }
  73. FileWriter.prototype._finish = function () {
  74. var me = this
  75. if (typeof me.size === "number" && me._bytesWritten != me.size) {
  76. me.error(
  77. "Did not get expected byte count.\n" +
  78. "expect: " + me.size + "\n" +
  79. "actual: " + me._bytesWritten)
  80. }
  81. Writer.prototype._finish.call(me)
  82. }