test-byte-streams.js
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim:set ts=2 sw=2 sts=2 et filetype=javascript
* 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 byteStreams = require("sdk/io/byte-streams");
const file = require("sdk/io/file");
const { pathFor } = require("sdk/system");
const { Loader } = require("sdk/test/loader");
const STREAM_CLOSED_ERROR = "The stream is closed and cannot be used.";
// This should match the constant of the same name in byte-streams.js.
const BUFFER_BYTE_LEN = 0x8000;
exports.testWriteRead = function (test) {
let fname = dataFileFilename();
// Write a small string less than the stream's buffer size...
let str = "exports.testWriteRead data!";
let stream = open(test, fname, true);
test.assert(!stream.closed, "stream.closed after open should be false");
stream.write(str);
stream.close();
test.assert(stream.closed, "Stream should be closed after stream.close");
test.assertRaises(function () stream.write("This shouldn't be written!"),
STREAM_CLOSED_ERROR,
"stream.write after close should raise error");
// ... and read it.
stream = open(test, fname);
test.assertEqual(stream.read(), str,
"stream.read should return string written");
test.assertEqual(stream.read(), "",
"stream.read at EOS should return empty string");
stream.close();
test.assert(stream.closed, "Stream should be closed after stream.close");
test.assertRaises(function () stream.read(),
STREAM_CLOSED_ERROR,
"stream.read after close should raise error");
file.remove(fname);
};
// Write a big string many times the size of the stream's buffer and read it.
exports.testWriteReadBig = function (test) {
let str = "";
let bufLen = BUFFER_BYTE_LEN;
let fileSize = bufLen * 10;
for (let i = 0; i < fileSize; i++)
str += i % 10;
let fname = dataFileFilename();
let stream = open(test, fname, true);
stream.write(str);
stream.close();
stream = open(test, fname);
test.assertEqual(stream.read(), str,
"stream.read should return string written");
stream.close();
file.remove(fname);
};
// The same, but write and read in chunks.
exports.testWriteReadChunks = function (test) {
let str = "";
let bufLen = BUFFER_BYTE_LEN;
let fileSize = bufLen * 10;
for (let i = 0; i < fileSize; i++)
str += i % 10;
let fname = dataFileFilename();
let stream = open(test, fname, true);
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 = open(test, fname);
let readStr = "";
bufLen = BUFFER_BYTE_LEN;
let readLen = bufLen + 1;
do {
var frag = stream.read(readLen);
readStr += frag;
} while (frag);
stream.close();
test.assertEqual(readStr, str,
"stream.write and read in chunks should work as expected");
file.remove(fname);
};
exports.testReadLengths = function (test) {
let fname = dataFileFilename();
let str = "exports.testReadLengths data!";
let stream = open(test, fname, true);
stream.write(str);
stream.close();
stream = open(test, fname);
test.assertEqual(stream.read(str.length * 1000), str,
"stream.read with big byte length should return string " +
"written");
stream.close();
stream = open(test, fname);
test.assertEqual(stream.read(0), "",
"string.read with zero byte length should return empty " +
"string");
stream.close();
stream = open(test, fname);
test.assertEqual(stream.read(-1), "",
"string.read with negative byte length should return " +
"empty string");
stream.close();
file.remove(fname);
};
exports.testTruncate = function (test) {
let fname = dataFileFilename();
let str = "exports.testReadLengths data!";
let stream = open(test, fname, true);
stream.write(str);
stream.close();
stream = open(test, fname);
test.assertEqual(stream.read(), str,
"stream.read should return string written");
stream.close();
stream = open(test, fname, true);
stream.close();
stream = open(test, fname);
test.assertEqual(stream.read(), "",
"stream.read after truncate should be empty");
stream.close();
file.remove(fname);
};
exports.testUnload = function (test) {
let loader = Loader(module);
let file = loader.require("sdk/io/file");
let filename = dataFileFilename("temp-b");
let stream = file.open(filename, "wb");
loader.unload();
test.assert(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-byte-streams-data");
}
// Opens and returns the given file and ensures it's of the correct class.
function open(test, filename, forWriting) {
let stream = file.open(filename, forWriting ? "wb" : "b");
let klass = forWriting ? "ByteWriter" : "ByteReader";
test.assert(stream instanceof byteStreams[klass],
"Opened stream should be a " + klass);
return stream;
}