fd-slicer - npm Package Compare versions

Comparing version 0.2.1 to 0.3.0

CHANGELOG.md

@@ -0,1 +1,8 @@
+### 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
@@ -2,0 +9,0 @@

index.js

@@ -134,2 +134,3 @@ var fs = require('fs');
   this.start = options.start || 0;
+  this.endOffset = options.end || Infinity;
   this.bytesWritten = 0;
@@ -148,2 +149,8 @@ this.pos = this.start;
 
+  if (self.bytesWritten + buffer.length > self.endOffset) {
+    var err = new Error("maximum file length exceeded");
+    err.code = 'ETOOBIG';
+    callback(err);
+    return;
+  }
   self.context.pend.go(function(cb) {
@@ -159,2 +166,3 @@ if (self.destroyed) return cb();
         self.pos += bytes;
+        self.emit('progress');
         cb();
@@ -161,0 +169,0 @@ callback();

package.json

 {
   "name": "fd-slicer",
-  "version": "0.2.1",
+  "version": "0.3.0",
   "description": "safely create multiple ReadStream or WriteStream objects from the same file descriptor",
@@ -12,3 +12,3 @@ "main": "index.js",
   "devDependencies": {
-    "mocha": "~1.21.3",
+    "mocha": "~1.21.5",
     "stream-equal": "~0.1.5"
@@ -15,0 +15,0 @@ },

README.md

@@ -34,2 +34,8 @@ # fd-slicer
 
+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.
+
 ## Usage
@@ -87,16 +93,44 @@
 
-Creates a read stream based on the file descriptor. Passes `options` to
-the `Readable` stream constructor. Accepts `start` and `end` options just
-like `fs.createReadStream`.
+Available `options`:
 
-The stream that this returns supports `destroy()` to cancel it.
+ * `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()` - stop streaming
+
 ##### createWriteStream(options)
 
-Creates a write stream based on the file descriptor. Passes `options` to
-the `Writable` stream constructor. Accepts the `start` option just
-like `fs.createWriteStream`.
+Available `options`:
 
-The stream that this returns supports `destroy()` to cancel it.
+ * `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)
@@ -119,1 +153,11 @@
 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`.

test/test.js

@@ -170,2 +170,48 @@ var FdSlicer = require('../');
   });
+
+  it("write stream emits error when max size exceeded", function(done) {
+    fs.open(testOutBlobFile, 'w', function(err, fd) {
+      if (err) return done(err);
+      var fdSlicer = new FdSlicer(fd);
+      var ws = fdSlicer.createWriteStream({start: 0, end: 1000});
+      ws.on('error', function(err) {
+        assert.strictEqual(err.code, 'ETOOBIG');
+        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 fdSlicer = new FdSlicer(fd, {autoClose: true});
+      var ws = fdSlicer.createWriteStream({end: 1000});
+      fdSlicer.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 fdSlicer = new FdSlicer(fd, {autoClose: true});
+      var ws = fdSlicer.createWriteStream();
+      var progressEventCount = 0;
+      var prevBytesWritten = 0;
+      ws.on('progress', function() {
+        progressEventCount += 1;
+        assert.ok(ws.bytesWritten > prevBytesWritten);
+        prevBytesWritten = ws.bytesWritten;
+      });
+      fdSlicer.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();
+    });
+  });
 });

No alert changes

Improved metrics

Total package byte prevSize

19106

increased by21.29%

Lines of code

354

increased by16.83%

Number of lines in readme file

161

increased by37.61%

No dependency changes