2022.07.20 16:18:09 更新订阅

utils/rm/node_modules/fd-slicer/.npmignore

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+/coverage
+/node_modules

utils/rm/node_modules/fd-slicer/.travis.yml

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+language: node_js
+node_js:
+  - "0.10"
+script:
+  - "npm run test-travis"
+after_script:
+  - "npm install coveralls@2 && cat ./coverage/lcov.info | ./node_modules/.bin/coveralls"

utils/rm/node_modules/fd-slicer/CHANGELOG.md

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+### 1.0.1
+
+ * use `setImmediate` instead of `nextTick`
+
+### 1.0.0
+
+ * `new FdSlicer(fd, options)` must now be `fdSlicer.createFromFd(fd, options)`
+ * fix behavior when `end` is 0.
+ * fix `createWriteStream` when using `createFromBuffer`
+
+### 0.4.0
+
+ * add ability to create an FdSlicer instance from a Buffer
+
+### 0.3.2
+
+ * fix write stream and read stream destroy behavior
+
+### 0.3.1
+
+ * write stream: fix end option behavior
+
+### 0.3.0
+
+ * write stream emits 'progress' events
+ * write stream supports 'end' option which causes the stream to emit an error
+   if a maximum size is exceeded
+ * improve documentation
+
+### 0.2.1
+
+ * Update pend dependency to latest bugfix version.
+
+### 0.2.0
+
+ * Add read and write functions
+
+### 0.1.0
+
+ * Add `autoClose` option and `ref()` and `unref()`.
+
+### 0.0.2
+
+ * Add API documentation
+ * read stream: create buffer at last possible moment
+
+### 0.0.1
+
+ * Initial release

utils/rm/node_modules/fd-slicer/LICENSE

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+Copyright (c) 2014 Andrew Kelley
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation files
+(the "Software"), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of the Software,
+and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

utils/rm/node_modules/fd-slicer/README.md

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+# fd-slicer
+
+[![Build Status](https://travis-ci.org/andrewrk/node-fd-slicer.svg?branch=master)](https://travis-ci.org/andrewrk/node-fd-slicer)
+
+Safe `fs.ReadStream` and `fs.WriteStream` using the same fd.
+
+Let's say that you want to perform a parallel upload of a file to a remote
+server. To do this, we want to create multiple read streams. The first thing
+you might think of is to use the `{start: 0, end: 0}` API of
+`fs.createReadStream`. This gives you two choices:
+
+ 0. Use the same file descriptor for all `fs.ReadStream` objects.
+ 0. Open the file multiple times, resulting in a separate file descriptor
+    for each read stream.
+
+Neither of these are acceptable options. The first one is a severe bug,
+because the API docs for `fs.write` state:
+
+> Note that it is unsafe to use `fs.write` multiple times on the same file
+> without waiting for the callback. For this scenario, `fs.createWriteStream`
+> is strongly recommended.
+
+`fs.createWriteStream` will solve the problem if you only create one of them
+for the file descriptor, but it will exhibit this unsafety if you create
+multiple write streams per file descriptor.
+
+The second option suffers from a race condition. For each additional time the
+file is opened after the first, it is possible that the file is modified. So
+in our parallel uploading example, we might upload a corrupt file that never
+existed on the client's computer.
+
+This module solves this problem by providing `createReadStream` and
+`createWriteStream` that operate on a shared file descriptor and provides
+the convenient stream API while still allowing slicing and dicing.
+
+This module also gives you some additional power that the builtin
+`fs.createWriteStream` do not give you. These features are:
+
+ * Emitting a 'progress' event on write.
+ * Ability to set a maximum size and emit an error if this size is exceeded.
+ * Ability to create an `FdSlicer` instance from a `Buffer`. This enables you
+   to provide API for handling files as well as buffers using the same API.
+
+## Usage
+
+```js
+var fdSlicer = require('fd-slicer');
+var fs = require('fs');
+
+fs.open("file.txt", 'r', function(err, fd) {
+  if (err) throw err;
+  var slicer = fdSlicer.createFromFd(fd);
+  var firstPart = slicer.createReadStream({start: 0, end: 100});
+  var secondPart = slicer.createReadStream({start: 100});
+  var firstOut = fs.createWriteStream("first.txt");
+  var secondOut = fs.createWriteStream("second.txt");
+  firstPart.pipe(firstOut);
+  secondPart.pipe(secondOut);
+});
+```
+
+You can also create from a buffer:
+
+```js
+var fdSlicer = require('fd-slicer');
+var slicer = FdSlicer.createFromBuffer(someBuffer);
+var firstPart = slicer.createReadStream({start: 0, end: 100});
+var secondPart = slicer.createReadStream({start: 100});
+var firstOut = fs.createWriteStream("first.txt");
+var secondOut = fs.createWriteStream("second.txt");
+firstPart.pipe(firstOut);
+secondPart.pipe(secondOut);
+```
+
+## API Documentation
+
+### fdSlicer.createFromFd(fd, [options])
+
+```js
+var fdSlicer = require('fd-slicer');
+fs.open("file.txt", 'r', function(err, fd) {
+  if (err) throw err;
+  var slicer = fdSlicer.createFromFd(fd);
+  // ...
+});
+```
+
+Make sure `fd` is a properly initialized file descriptor. If you want to
+use `createReadStream` make sure you open it for reading and if you want
+to use `createWriteStream` make sure you open it for writing.
+
+`options` is an optional object which can contain:
+
+ * `autoClose` - if set to `true`, the file descriptor will be automatically
+   closed once the last stream that references it is closed. Defaults to
+   `false`. `ref()` and `unref()` can be used to increase or decrease the
+   reference count, respectively.
+
+### fdSlicer.createFromBuffer(buffer, [options])
+
+```js
+var fdSlicer = require('fd-slicer');
+var slicer = fdSlicer.createFromBuffer(someBuffer);
+// ...
+```
+
+`options` is an optional object which can contain:
+
+ * `maxChunkSize` - A `Number` of bytes. see `createReadStream()`.
+   If falsey, defaults to unlimited.
+
+#### Properties
+
+##### fd
+
+The file descriptor passed in. `undefined` if created from a buffer.
+
+#### Methods
+
+##### createReadStream(options)
+
+Available `options`:
+
+ * `start` - Number. The offset into the file to start reading from. Defaults
+   to 0.
+ * `end` - Number. Exclusive upper bound offset into the file to stop reading
+   from.
+ * `highWaterMark` - Number. The maximum number of bytes to store in the
+   internal buffer before ceasing to read from the underlying resource.
+   Defaults to 16 KB.
+ * `encoding` - String. If specified, then buffers will be decoded to strings
+   using the specified encoding. Defaults to `null`.
+
+The ReadableStream that this returns has these additional methods:
+
+ * `destroy(err)` - stop streaming. `err` is optional and is the error that
+   will be emitted in order to cause the streaming to stop. Defaults to
+   `new Error("stream destroyed")`.
+
+If `maxChunkSize` was specified (see `createFromBuffer()`), the read stream
+will provide chunks of at most that size. Normally, the read stream provides
+the entire range requested in a single chunk, but this can cause performance
+problems in some circumstances.
+See [thejoshwolfe/yauzl#87](https://github.com/thejoshwolfe/yauzl/issues/87).
+
+##### createWriteStream(options)
+
+Available `options`:
+
+ * `start` - Number. The offset into the file to start writing to. Defaults to
+   0.
+ * `end` - Number. Exclusive upper bound offset into the file. If this offset
+   is reached, the write stream will emit an 'error' event and stop functioning.
+   In this situation, `err.code === 'ETOOBIG'`. Defaults to `Infinity`.
+ * `highWaterMark` - Number. Buffer level when `write()` starts returning
+   false. Defaults to 16KB.
+ * `decodeStrings` - Boolean. Whether or not to decode strings into Buffers
+   before passing them to` _write()`. Defaults to `true`.
+
+The WritableStream that this returns has these additional methods:
+
+ * `destroy()` - stop streaming
+
+And these additional properties:
+
+ * `bytesWritten` - number of bytes written to the stream
+
+And these additional events:
+
+ * 'progress' - emitted when `bytesWritten` changes.
+
+##### read(buffer, offset, length, position, callback)
+
+Equivalent to `fs.read`, but with concurrency protection.
+`callback` must be defined.
+
+##### write(buffer, offset, length, position, callback)
+
+Equivalent to `fs.write`, but with concurrency protection.
+`callback` must be defined.
+
+##### ref()
+
+Increase the `autoClose` reference count by 1.
+
+##### unref()
+
+Decrease the `autoClose` reference count by 1.
+
+#### Events
+
+##### 'error'
+
+Emitted if `fs.close` returns an error when auto closing.
+
+##### 'close'
+
+Emitted when fd-slicer closes the file descriptor due to `autoClose`. Never
+emitted if created from a buffer.

utils/rm/node_modules/fd-slicer/index.js

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+var fs = require('fs');
+var util = require('util');
+var stream = require('stream');
+var Readable = stream.Readable;
+var Writable = stream.Writable;
+var PassThrough = stream.PassThrough;
+var Pend = require('pend');
+var EventEmitter = require('events').EventEmitter;
+
+exports.createFromBuffer = createFromBuffer;
+exports.createFromFd = createFromFd;
+exports.BufferSlicer = BufferSlicer;
+exports.FdSlicer = FdSlicer;
+
+util.inherits(FdSlicer, EventEmitter);
+function FdSlicer(fd, options) {
+  options = options || {};
+  EventEmitter.call(this);
+
+  this.fd = fd;
+  this.pend = new Pend();
+  this.pend.max = 1;
+  this.refCount = 0;
+  this.autoClose = !!options.autoClose;
+}
+
+FdSlicer.prototype.read = function(buffer, offset, length, position, callback) {
+  var self = this;
+  self.pend.go(function(cb) {
+    fs.read(self.fd, buffer, offset, length, position, function(err, bytesRead, buffer) {
+      cb();
+      callback(err, bytesRead, buffer);
+    });
+  });
+};
+
+FdSlicer.prototype.write = function(buffer, offset, length, position, callback) {
+  var self = this;
+  self.pend.go(function(cb) {
+    fs.write(self.fd, buffer, offset, length, position, function(err, written, buffer) {
+      cb();
+      callback(err, written, buffer);
+    });
+  });
+};
+
+FdSlicer.prototype.createReadStream = function(options) {
+  return new ReadStream(this, options);
+};
+
+FdSlicer.prototype.createWriteStream = function(options) {
+  return new WriteStream(this, options);
+};
+
+FdSlicer.prototype.ref = function() {
+  this.refCount += 1;
+};
+
+FdSlicer.prototype.unref = function() {
+  var self = this;
+  self.refCount -= 1;
+
+  if (self.refCount > 0) return;
+  if (self.refCount < 0) throw new Error("invalid unref");
+
+  if (self.autoClose) {
+    fs.close(self.fd, onCloseDone);
+  }
+
+  function onCloseDone(err) {
+    if (err) {
+      self.emit('error', err);
+    } else {
+      self.emit('close');
+    }
+  }
+};
+
+util.inherits(ReadStream, Readable);
+function ReadStream(context, options) {
+  options = options || {};
+  Readable.call(this, options);
+
+  this.context = context;
+  this.context.ref();
+
+  this.start = options.start || 0;
+  this.endOffset = options.end;
+  this.pos = this.start;
+  this.destroyed = false;
+}
+
+ReadStream.prototype._read = function(n) {
+  var self = this;
+  if (self.destroyed) return;
+
+  var toRead = Math.min(self._readableState.highWaterMark, n);
+  if (self.endOffset != null) {
+    toRead = Math.min(toRead, self.endOffset - self.pos);
+  }
+  if (toRead <= 0) {
+    self.destroyed = true;
+    self.push(null);
+    self.context.unref();
+    return;
+  }
+  self.context.pend.go(function(cb) {
+    if (self.destroyed) return cb();
+    var buffer = new Buffer(toRead);
+    fs.read(self.context.fd, buffer, 0, toRead, self.pos, function(err, bytesRead) {
+      if (err) {
+        self.destroy(err);
+      } else if (bytesRead === 0) {
+        self.destroyed = true;
+        self.push(null);
+        self.context.unref();
+      } else {
+        self.pos += bytesRead;
+        self.push(buffer.slice(0, bytesRead));
+      }
+      cb();
+    });
+  });
+};
+
+ReadStream.prototype.destroy = function(err) {
+  if (this.destroyed) return;
+  err = err || new Error("stream destroyed");
+  this.destroyed = true;
+  this.emit('error', err);
+  this.context.unref();
+};
+
+util.inherits(WriteStream, Writable);
+function WriteStream(context, options) {
+  options = options || {};
+  Writable.call(this, options);
+
+  this.context = context;
+  this.context.ref();
+
+  this.start = options.start || 0;
+  this.endOffset = (options.end == null) ? Infinity : +options.end;
+  this.bytesWritten = 0;
+  this.pos = this.start;
+  this.destroyed = false;
+
+  this.on('finish', this.destroy.bind(this));
+}
+
+WriteStream.prototype._write = function(buffer, encoding, callback) {
+  var self = this;
+  if (self.destroyed) return;
+
+  if (self.pos + buffer.length > self.endOffset) {
+    var err = new Error("maximum file length exceeded");
+    err.code = 'ETOOBIG';
+    self.destroy();
+    callback(err);
+    return;
+  }
+  self.context.pend.go(function(cb) {
+    if (self.destroyed) return cb();
+    fs.write(self.context.fd, buffer, 0, buffer.length, self.pos, function(err, bytes) {
+      if (err) {
+        self.destroy();
+        cb();
+        callback(err);
+      } else {
+        self.bytesWritten += bytes;
+        self.pos += bytes;
+        self.emit('progress');
+        cb();
+        callback();
+      }
+    });
+  });
+};
+
+WriteStream.prototype.destroy = function() {
+  if (this.destroyed) return;
+  this.destroyed = true;
+  this.context.unref();
+};
+
+util.inherits(BufferSlicer, EventEmitter);
+function BufferSlicer(buffer, options) {
+  EventEmitter.call(this);
+
+  options = options || {};
+  this.refCount = 0;
+  this.buffer = buffer;
+  this.maxChunkSize = options.maxChunkSize || Number.MAX_SAFE_INTEGER;
+}
+
+BufferSlicer.prototype.read = function(buffer, offset, length, position, callback) {
+  var end = position + length;
+  var delta = end - this.buffer.length;
+  var written = (delta > 0) ? delta : length;
+  this.buffer.copy(buffer, offset, position, end);
+  setImmediate(function() {
+    callback(null, written);
+  });
+};
+
+BufferSlicer.prototype.write = function(buffer, offset, length, position, callback) {
+  buffer.copy(this.buffer, position, offset, offset + length);
+  setImmediate(function() {
+    callback(null, length, buffer);
+  });
+};
+
+BufferSlicer.prototype.createReadStream = function(options) {
+  options = options || {};
+  var readStream = new PassThrough(options);
+  readStream.destroyed = false;
+  readStream.start = options.start || 0;
+  readStream.endOffset = options.end;
+  // by the time this function returns, we'll be done.
+  readStream.pos = readStream.endOffset || this.buffer.length;
+
+  // respect the maxChunkSize option to slice up the chunk into smaller pieces.
+  var entireSlice = this.buffer.slice(readStream.start, readStream.pos);
+  var offset = 0;
+  while (true) {
+    var nextOffset = offset + this.maxChunkSize;
+    if (nextOffset >= entireSlice.length) {
+      // last chunk
+      if (offset < entireSlice.length) {
+        readStream.write(entireSlice.slice(offset, entireSlice.length));
+      }
+      break;
+    }
+    readStream.write(entireSlice.slice(offset, nextOffset));
+    offset = nextOffset;
+  }
+
+  readStream.end();
+  readStream.destroy = function() {
+    readStream.destroyed = true;
+  };
+  return readStream;
+};
+
+BufferSlicer.prototype.createWriteStream = function(options) {
+  var bufferSlicer = this;
+  options = options || {};
+  var writeStream = new Writable(options);
+  writeStream.start = options.start || 0;
+  writeStream.endOffset = (options.end == null) ? this.buffer.length : +options.end;
+  writeStream.bytesWritten = 0;
+  writeStream.pos = writeStream.start;
+  writeStream.destroyed = false;
+  writeStream._write = function(buffer, encoding, callback) {
+    if (writeStream.destroyed) return;
+
+    var end = writeStream.pos + buffer.length;
+    if (end > writeStream.endOffset) {
+      var err = new Error("maximum file length exceeded");
+      err.code = 'ETOOBIG';
+      writeStream.destroyed = true;
+      callback(err);
+      return;
+    }
+    buffer.copy(bufferSlicer.buffer, writeStream.pos, 0, buffer.length);
+
+    writeStream.bytesWritten += buffer.length;
+    writeStream.pos = end;
+    writeStream.emit('progress');
+    callback();
+  };
+  writeStream.destroy = function() {
+    writeStream.destroyed = true;
+  };
+  return writeStream;
+};
+
+BufferSlicer.prototype.ref = function() {
+  this.refCount += 1;
+};
+
+BufferSlicer.prototype.unref = function() {
+  this.refCount -= 1;
+
+  if (this.refCount < 0) {
+    throw new Error("invalid unref");
+  }
+};
+
+function createFromBuffer(buffer, options) {
+  return new BufferSlicer(buffer, options);
+}
+
+function createFromFd(fd, options) {
+  return new FdSlicer(fd, options);
+}

utils/rm/node_modules/fd-slicer/package.json

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+{
+  "name": "fd-slicer",
+  "version": "1.1.0",
+  "description": "safely create multiple ReadStream or WriteStream objects from the same file descriptor",
+  "main": "index.js",
+  "scripts": {
+    "test": "mocha --reporter spec --check-leaks",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/test.js",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --timeout 10000 --reporter spec --check-leaks test/test.js"
+  },
+  "author": "Andrew Kelley <superjoe30@gmail.com>",
+  "license": "MIT",
+  "devDependencies": {
+    "istanbul": "~0.3.3",
+    "mocha": "~2.0.1",
+    "stream-equal": "~0.1.5",
+    "streamsink": "~1.2.0"
+  },
+  "dependencies": {
+    "pend": "~1.2.0"
+  },
+  "directories": {
+    "test": "test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/andrewrk/node-fd-slicer.git"
+  },
+  "bugs": {
+    "url": "https://github.com/andrewrk/node-fd-slicer/issues"
+  },
+  "keywords": [
+    "createReadStream",
+    "createWriteStream"
+  ]
+}

utils/rm/node_modules/fd-slicer/test/test.js

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+var fdSlicer = require('../');
+var fs = require('fs');
+var crypto = require('crypto');
+var path = require('path');
+var streamEqual = require('stream-equal');
+var assert = require('assert');
+var Pend = require('pend');
+var StreamSink = require('streamsink');
+
+var describe = global.describe;
+var it = global.it;
+var before = global.before;
+var beforeEach = global.beforeEach;
+var after = global.after;
+
+var testBlobFile = path.join(__dirname, "test-blob.bin");
+var testBlobFileSize = 20 * 1024 * 1024;
+var testOutBlobFile = path.join(__dirname, "test-blob-out.bin");
+
+describe("FdSlicer", function() {
+  before(function(done) {
+    var out = fs.createWriteStream(testBlobFile);
+    for (var i = 0; i < testBlobFileSize / 1024; i += 1) {
+      out.write(crypto.pseudoRandomBytes(1024));
+    }
+    out.end();
+    out.on('close', done);
+  });
+  beforeEach(function() {
+    try {
+      fs.unlinkSync(testOutBlobFile);
+    } catch (err) {
+    }
+  });
+  after(function() {
+    try {
+      fs.unlinkSync(testBlobFile);
+      fs.unlinkSync(testOutBlobFile);
+    } catch (err) {
+    }
+  });
+  it("reads a 20MB file (autoClose on)", function(done) {
+    fs.open(testBlobFile, 'r', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var actualStream = slicer.createReadStream();
+      var expectedStream = fs.createReadStream(testBlobFile);
+
+      var pend = new Pend();
+      pend.go(function(cb) {
+        slicer.on('close', cb);
+      });
+      pend.go(function(cb) {
+        streamEqual(expectedStream, actualStream, function(err, equal) {
+          if (err) return done(err);
+          assert.ok(equal);
+          cb();
+        });
+      });
+      pend.wait(done);
+    });
+  });
+  it("reads 4 chunks simultaneously", function(done) {
+    fs.open(testBlobFile, 'r', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd);
+      var actualPart1 = slicer.createReadStream({start: testBlobFileSize * 0/4, end: testBlobFileSize * 1/4});
+      var actualPart2 = slicer.createReadStream({start: testBlobFileSize * 1/4, end: testBlobFileSize * 2/4});
+      var actualPart3 = slicer.createReadStream({start: testBlobFileSize * 2/4, end: testBlobFileSize * 3/4});
+      var actualPart4 = slicer.createReadStream({start: testBlobFileSize * 3/4, end: testBlobFileSize * 4/4});
+      var expectedPart1 = slicer.createReadStream({start: testBlobFileSize * 0/4, end: testBlobFileSize * 1/4});
+      var expectedPart2 = slicer.createReadStream({start: testBlobFileSize * 1/4, end: testBlobFileSize * 2/4});
+      var expectedPart3 = slicer.createReadStream({start: testBlobFileSize * 2/4, end: testBlobFileSize * 3/4});
+      var expectedPart4 = slicer.createReadStream({start: testBlobFileSize * 3/4, end: testBlobFileSize * 4/4});
+      var pend = new Pend();
+      pend.go(function(cb) {
+        streamEqual(expectedPart1, actualPart1, function(err, equal) {
+          assert.ok(equal);
+          cb(err);
+        });
+      });
+      pend.go(function(cb) {
+        streamEqual(expectedPart2, actualPart2, function(err, equal) {
+          assert.ok(equal);
+          cb(err);
+        });
+      });
+      pend.go(function(cb) {
+        streamEqual(expectedPart3, actualPart3, function(err, equal) {
+          assert.ok(equal);
+          cb(err);
+        });
+      });
+      pend.go(function(cb) {
+        streamEqual(expectedPart4, actualPart4, function(err, equal) {
+          assert.ok(equal);
+          cb(err);
+        });
+      });
+      pend.wait(function(err) {
+        if (err) return done(err);
+        fs.close(fd, done);
+      });
+    });
+  });
+
+  it("writes a 20MB file (autoClose on)", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var actualStream = slicer.createWriteStream();
+      var inStream = fs.createReadStream(testBlobFile);
+
+      slicer.on('close', function() {
+        var expected = fs.createReadStream(testBlobFile);
+        var actual = fs.createReadStream(testOutBlobFile);
+
+        streamEqual(expected, actual, function(err, equal) {
+          if (err) return done(err);
+          assert.ok(equal);
+          done();
+        });
+      });
+      inStream.pipe(actualStream);
+    });
+  });
+
+  it("writes 4 chunks simultaneously", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd);
+      var actualPart1 = slicer.createWriteStream({start: testBlobFileSize * 0/4});
+      var actualPart2 = slicer.createWriteStream({start: testBlobFileSize * 1/4});
+      var actualPart3 = slicer.createWriteStream({start: testBlobFileSize * 2/4});
+      var actualPart4 = slicer.createWriteStream({start: testBlobFileSize * 3/4});
+      var in1 = fs.createReadStream(testBlobFile, {start: testBlobFileSize * 0/4, end: testBlobFileSize * 1/4});
+      var in2 = fs.createReadStream(testBlobFile, {start: testBlobFileSize * 1/4, end: testBlobFileSize * 2/4});
+      var in3 = fs.createReadStream(testBlobFile, {start: testBlobFileSize * 2/4, end: testBlobFileSize * 3/4});
+      var in4 = fs.createReadStream(testBlobFile, {start: testBlobFileSize * 3/4, end: testBlobFileSize * 4/4});
+      var pend = new Pend();
+      pend.go(function(cb) {
+        actualPart1.on('finish', cb);
+      });
+      pend.go(function(cb) {
+        actualPart2.on('finish', cb);
+      });
+      pend.go(function(cb) {
+        actualPart3.on('finish', cb);
+      });
+      pend.go(function(cb) {
+        actualPart4.on('finish', cb);
+      });
+      in1.pipe(actualPart1);
+      in2.pipe(actualPart2);
+      in3.pipe(actualPart3);
+      in4.pipe(actualPart4);
+      pend.wait(function() {
+        fs.close(fd, function(err) {
+          if (err) return done(err);
+          var expected = fs.createReadStream(testBlobFile);
+          var actual = fs.createReadStream(testOutBlobFile);
+          streamEqual(expected, actual, function(err, equal) {
+            if (err) return done(err);
+            assert.ok(equal);
+            done();
+          });
+        });
+      });
+    });
+  });
+
+  it("throws on invalid ref", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      assert.throws(function() {
+        slicer.unref();
+      }, /invalid unref/);
+      fs.close(fd, done);
+    });
+  });
+
+  it("write stream emits error when max size exceeded", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var ws = slicer.createWriteStream({start: 0, end: 1000});
+      ws.on('error', function(err) {
+        assert.strictEqual(err.code, 'ETOOBIG');
+        slicer.on('close', done);
+      });
+      ws.end(new Buffer(1001));
+    });
+  });
+
+  it("write stream does not emit error when max size not exceeded", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var ws = slicer.createWriteStream({end: 1000});
+      slicer.on('close', done);
+      ws.end(new Buffer(1000));
+    });
+  });
+
+  it("write stream start and end work together", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var ws = slicer.createWriteStream({start: 1, end: 1000});
+      ws.on('error', function(err) {
+        assert.strictEqual(err.code, 'ETOOBIG');
+        slicer.on('close', done);
+      });
+      ws.end(new Buffer(1000));
+    });
+  });
+
+  it("write stream emits progress events", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var ws = slicer.createWriteStream();
+      var progressEventCount = 0;
+      var prevBytesWritten = 0;
+      ws.on('progress', function() {
+        progressEventCount += 1;
+        assert.ok(ws.bytesWritten > prevBytesWritten);
+        prevBytesWritten = ws.bytesWritten;
+      });
+      slicer.on('close', function() {
+        assert.ok(progressEventCount > 5);
+        done();
+      });
+      for (var i = 0; i < 10; i += 1) {
+        ws.write(new Buffer(16 * 1024 * 2));
+      }
+      ws.end();
+    });
+  });
+
+  it("write stream unrefs when destroyed", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var ws = slicer.createWriteStream();
+      slicer.on('close', done);
+      ws.write(new Buffer(1000));
+      ws.destroy();
+    });
+  });
+
+  it("read stream unrefs when destroyed", function(done) {
+    fs.open(testBlobFile, 'r', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd, {autoClose: true});
+      var rs = slicer.createReadStream();
+      rs.on('error', function(err) {
+        assert.strictEqual(err.message, "stream destroyed");
+        slicer.on('close', done);
+      });
+      rs.destroy();
+    });
+  });
+
+  it("fdSlicer.read", function(done) {
+    fs.open(testBlobFile, 'r', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd);
+      var outBuf = new Buffer(1024);
+      slicer.read(outBuf, 0, 10, 0, function(err, bytesRead, buf) {
+        assert.strictEqual(bytesRead, 10);
+        fs.close(fd, done);
+      });
+    });
+  });
+
+  it("fdSlicer.write", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var slicer = fdSlicer.createFromFd(fd);
+      slicer.write(new Buffer("blah\n"), 0, 5, 0, function() {
+        if (err) return done(err);
+        fs.close(fd, done);
+      });
+    });
+  });
+});
+
+describe("BufferSlicer", function() {
+  it("invalid ref", function() {
+    var slicer = fdSlicer.createFromBuffer(new Buffer(16));
+    slicer.ref();
+    slicer.unref();
+    assert.throws(function() {
+      slicer.unref();
+    }, /invalid unref/);
+  });
+  it("read and write", function(done) {
+    var buf = new Buffer("through the tangled thread the needle finds its way");
+    var slicer = fdSlicer.createFromBuffer(buf);
+    var outBuf = new Buffer(1024);
+    slicer.read(outBuf, 10, 11, 8, function(err) {
+      if (err) return done(err);
+      assert.strictEqual(outBuf.toString('utf8', 10, 21), "the tangled");
+      slicer.write(new Buffer("derp"), 0, 4, 7, function(err) {
+        if (err) return done(err);
+        assert.strictEqual(buf.toString('utf8', 7, 19), "derp tangled");
+        done();
+      });
+    });
+  });
+  it("createReadStream", function(done) {
+    var str = "I never conquered rarely came, 16 just held such better days";
+    var buf = new Buffer(str);
+    var slicer = fdSlicer.createFromBuffer(buf);
+    var inStream = slicer.createReadStream();
+    var sink = new StreamSink();
+    inStream.pipe(sink);
+    sink.on('finish', function() {
+      assert.strictEqual(sink.toString(), str);
+      inStream.destroy();
+      done();
+    });
+  });
+  it("createWriteStream exceed buffer size", function(done) {
+    var slicer = fdSlicer.createFromBuffer(new Buffer(4));
+    var outStream = slicer.createWriteStream();
+    outStream.on('error', function(err) {
+      assert.strictEqual(err.code, 'ETOOBIG');
+      done();
+    });
+    outStream.write("hi!\n");
+    outStream.write("it warked\n");
+    outStream.end();
+  });
+  it("createWriteStream ok", function(done) {
+    var buf = new Buffer(1024);
+    var slicer = fdSlicer.createFromBuffer(buf);
+    var outStream = slicer.createWriteStream();
+    outStream.on('finish', function() {
+      assert.strictEqual(buf.toString('utf8', 0, "hi!\nit warked\n".length), "hi!\nit warked\n");
+      outStream.destroy();
+      done();
+    });
+    outStream.write("hi!\n");
+    outStream.write("it warked\n");
+    outStream.end();
+  });
+});