The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 const file = require("sdk/io/file");

 const { pathFor } = require("sdk/system");

 const { Loader } = require("sdk/test/loader");

 const STREAM_CLOSED_ERROR = new RegExp("The stream is closed and cannot be used.");

 // This should match the constant of the same name in text-streams.js.

 const BUFFER_BYTE_LEN = 0x8000;

 exports.testWriteRead = function (assert) {

   let fname = dataFileFilename();

   // Write a small string less than the stream's buffer size...

   let str = "exports.testWriteRead data!";

   let stream = file.open(fname, "w");

   assert.ok(!stream.closed, "stream.closed after open should be false");

   stream.write(str);

   stream.close();

   assert.ok(stream.closed, "stream.closed after close should be true");

   assert.throws(function () stream.close(),

                     STREAM_CLOSED_ERROR,

                     "stream.close after already closed should raise error");

   assert.throws(function () stream.write("This shouldn't be written!"),

                     STREAM_CLOSED_ERROR,

                     "stream.write after close should raise error");

   // ... and read it.

   stream = file.open(fname);

   assert.ok(!stream.closed, "stream.closed after open should be false");

   assert.equal(stream.read(), str,

                    "stream.read should return string written");

   assert.equal(stream.read(), "",

                    "stream.read at EOS should return empty string");

   stream.close();

   assert.ok(stream.closed, "stream.closed after close should be true");

   assert.throws(function () stream.close(),

                     STREAM_CLOSED_ERROR,

                     "stream.close after already closed should raise error");

   assert.throws(function () stream.read(),

                     STREAM_CLOSED_ERROR,

                     "stream.read after close should raise error");

   // Write a big string many times the size of the stream's buffer and read it.

   // Since it comes after the previous test, this also ensures that the file is

   // truncated when it's opened for writing.

   str = "";

   let bufLen = BUFFER_BYTE_LEN;

   let fileSize = bufLen * 10;

   for (let i = 0; i < fileSize; i++)

     str += i % 10;

   stream = file.open(fname, "w");

   stream.write(str);

   stream.close();

   stream = file.open(fname);

   assert.equal(stream.read(), str,

                    "stream.read should return string written");

   stream.close();

   // The same, but write and read in chunks.

   stream = file.open(fname, "w");

   let i = 0;

   while (i < str.length) {

     // Use a chunk length that spans buffers.

     let chunk = str.substr(i, bufLen + 1);

     stream.write(chunk);

     i += bufLen + 1;

   }

   stream.close();

   stream = file.open(fname);

   let readStr = "";

   bufLen = BUFFER_BYTE_LEN;

   let readLen = bufLen + 1;

   do {

     var frag = stream.read(readLen);

     readStr += frag;

   } while (frag);

   stream.close();

   assert.equal(readStr, str,

                    "stream.write and read in chunks should work as expected");

   // Read the same file, passing in strange numbers of bytes to read.

   stream = file.open(fname);

   assert.equal(stream.read(fileSize * 100), str,

                    "stream.read with big byte length should return string " +

                    "written");

   stream.close();

   stream = file.open(fname);

   assert.equal(stream.read(0), "",

                    "string.read with zero byte length should return empty " +

                    "string");

   stream.close();

   stream = file.open(fname);

   assert.equal(stream.read(-1), "",

                    "string.read with negative byte length should return " +

                    "empty string");

   stream.close();

   file.remove(fname);

 };

 exports.testWriteAsync = function (assert, done) {

   let fname = dataFileFilename();

   let str = "exports.testWriteAsync data!";

   let stream = file.open(fname, "w");

   assert.ok(!stream.closed, "stream.closed after open should be false");

   // Write.

   stream.writeAsync(str, function (err) {

     assert.equal(this, stream, "|this| should be the stream object");

     assert.equal(err, undefined,

                      "stream.writeAsync should not cause error");

     assert.ok(stream.closed, "stream.closed after write should be true");

     assert.throws(function () stream.close(),

                       STREAM_CLOSED_ERROR,

                       "stream.close after already closed should raise error");

     assert.throws(function () stream.writeAsync("This shouldn't work!"),

                       STREAM_CLOSED_ERROR,

                       "stream.writeAsync after close should raise error");

     // Read.

     stream = file.open(fname, "r");

     assert.ok(!stream.closed, "stream.closed after open should be false");

     let readStr = stream.read();

     assert.equal(readStr, str,

                      "string.read should yield string written");

     stream.close();

     file.remove(fname);

     done();

   });

 };

 exports.testUnload = function (assert) {

   let loader = Loader(module);

   let file = loader.require("sdk/io/file");

   let filename = dataFileFilename("temp");

   let stream = file.open(filename, "w");

   loader.unload();

   assert.ok(stream.closed, "stream should be closed after module unload");

 };

 // Returns the name of a file that should be used to test writing and reading.

 function dataFileFilename() {

   return file.join(pathFor("ProfD"), "test-text-streams-data");

 }

 require('sdk/test').run(exports);