1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
|
var expect = require('chai').expect;
var util = require('./util');
var Flow = require('../lib/protocol/flow').Flow;
var MAX_PAYLOAD_SIZE = 16384;
function createFlow(log) {
var flowControlId = util.random(10, 100);
var flow = new Flow(flowControlId);
flow._log = util.log.child(log || {});
return flow;
}
describe('flow.js', function() {
describe('Flow class', function() {
var flow;
beforeEach(function() {
flow = createFlow();
});
describe('._receive(frame, callback) method', function() {
it('is called when there\'s a frame in the input buffer to be consumed', function(done) {
var frame = { type: 'PRIORITY', flags: {}, priority: 1 };
flow._receive = function _receive(receivedFrame, callback) {
expect(receivedFrame).to.equal(frame);
callback();
};
flow.write(frame, done);
});
it('has to be overridden by the child class, otherwise it throws', function() {
expect(flow._receive.bind(flow)).to.throw(Error);
});
});
describe('._send() method', function() {
it('is called when the output buffer should be filled with more frames and the flow' +
'control queue is empty', function() {
var notFlowControlledFrame = { type: 'PRIORITY', flags: {}, priority: 1 };
flow._send = function _send() {
this.push(notFlowControlledFrame);
};
expect(flow.read()).to.equal(notFlowControlledFrame);
flow._window = 0;
flow._queue.push({ type: 'DATA', flags: {}, data: { length: 1 } });
var frame = flow.read();
while (frame.type === notFlowControlledFrame.type) frame = flow.read();
expect(frame.type).to.equal('BLOCKED');
expect(flow.read()).to.equal(null);
});
it('has to be overridden by the child class, otherwise it throws', function() {
expect(flow._send.bind(flow)).to.throw(Error);
});
});
describe('._increaseWindow(size) method', function() {
it('should increase `this._window` by `size`', function() {
flow._send = util.noop;
flow._window = 0;
var increase1 = util.random(0,100);
var increase2 = util.random(0,100);
flow._increaseWindow(increase1);
flow._increaseWindow(increase2);
expect(flow._window).to.equal(increase1 + increase2);
flow._increaseWindow(Infinity);
expect(flow._window).to.equal(Infinity);
});
it('should emit error when increasing with a finite `size` when `_window` is infinite', function() {
flow._send = util.noop;
flow._increaseWindow(Infinity);
var increase = util.random(1,100);
expect(flow._increaseWindow.bind(flow, increase)).to.throw('Uncaught, unspecified "error" event.');
});
it('should emit error when `_window` grows over the window limit', function() {
var WINDOW_SIZE_LIMIT = Math.pow(2, 31) - 1;
flow._send = util.noop;
flow._window = 0;
flow._increaseWindow(WINDOW_SIZE_LIMIT);
expect(flow._increaseWindow.bind(flow, 1)).to.throw('Uncaught, unspecified "error" event.');
});
});
describe('.read() method', function() {
describe('when the flow control queue is not empty', function() {
it('should return the first item in the queue if the window is enough', function() {
var priorityFrame = { type: 'PRIORITY', flags: {}, priority: 1 };
var dataFrame = { type: 'DATA', flags: {}, data: { length: 10 } };
flow._send = util.noop;
flow._window = 10;
flow._queue = [priorityFrame, dataFrame];
expect(flow.read()).to.equal(priorityFrame);
expect(flow.read()).to.equal(dataFrame);
});
it('should also split DATA frames when needed', function() {
var buffer = Buffer.alloc(10);
var dataFrame = { type: 'DATA', flags: {}, stream: util.random(0, 100), data: buffer };
flow._send = util.noop;
flow._window = 5;
flow._queue = [dataFrame];
var expectedFragment = { flags: {}, type: 'DATA', stream: dataFrame.stream, data: buffer.slice(0,5) };
expect(flow.read()).to.deep.equal(expectedFragment);
expect(dataFrame.data).to.deep.equal(buffer.slice(5));
});
});
});
describe('.push(frame) method', function() {
it('should push `frame` into the output queue or the flow control queue', function() {
var priorityFrame = { type: 'PRIORITY', flags: {}, priority: 1 };
var dataFrame = { type: 'DATA', flags: {}, data: { length: 10 } };
flow._window = 10;
flow.push(dataFrame); // output queue
flow.push(dataFrame); // flow control queue, because of depleted window
flow.push(priorityFrame); // flow control queue, because it's not empty
expect(flow.read()).to.be.equal(dataFrame);
expect(flow._queue[0]).to.be.equal(dataFrame);
expect(flow._queue[1]).to.be.equal(priorityFrame);
});
});
describe('.write() method', function() {
it('call with a DATA frame should trigger sending WINDOW_UPDATE if remote flow control is not' +
'disabled', function(done) {
flow._window = 100;
flow._send = util.noop;
flow._receive = function(frame, callback) {
callback();
};
var buffer = Buffer.alloc(util.random(10, 100));
flow.write({ type: 'DATA', flags: {}, data: buffer });
flow.once('readable', function() {
expect(flow.read()).to.be.deep.equal({
type: 'WINDOW_UPDATE',
flags: {},
stream: flow._flowControlId,
window_size: buffer.length
});
done();
});
});
});
});
describe('test scenario', function() {
var flow1, flow2;
beforeEach(function() {
flow1 = createFlow({ flow: 1 });
flow2 = createFlow({ flow: 2 });
flow1._flowControlId = flow2._flowControlId;
flow1._send = flow2._send = util.noop;
flow1._receive = flow2._receive = function(frame, callback) { callback(); };
});
describe('sending a large data stream', function() {
it('should work as expected', function(done) {
// Sender side
var frameNumber = util.random(5, 8);
var input = [];
flow1._send = function _send() {
if (input.length >= frameNumber) {
this.push({ type: 'DATA', flags: { END_STREAM: true }, data: Buffer.alloc(0) });
this.push(null);
} else {
var buffer = Buffer.allocUnsafe(util.random(1000, 100000));
input.push(buffer);
this.push({ type: 'DATA', flags: {}, data: buffer });
}
};
// Receiver side
var output = [];
flow2._receive = function _receive(frame, callback) {
if (frame.type === 'DATA') {
expect(frame.data.length).to.be.lte(MAX_PAYLOAD_SIZE);
output.push(frame.data);
}
if (frame.flags.END_STREAM) {
this.emit('end_stream');
}
callback();
};
// Checking results
flow2.on('end_stream', function() {
input = util.concat(input);
output = util.concat(output);
expect(input).to.deep.equal(output);
done();
});
// Start piping
flow1.pipe(flow2).pipe(flow1);
});
});
describe('when running out of window', function() {
it('should send a BLOCKED frame', function(done) {
// Sender side
var frameNumber = util.random(5, 8);
var input = [];
flow1._send = function _send() {
if (input.length >= frameNumber) {
this.push({ type: 'DATA', flags: { END_STREAM: true }, data: Buffer.alloc(0) });
this.push(null);
} else {
var buffer = Buffer.allocUnsafe(util.random(1000, 100000));
input.push(buffer);
this.push({ type: 'DATA', flags: {}, data: buffer });
}
};
// Receiver side
// Do not send WINDOW_UPDATESs except when the other side sends BLOCKED
var output = [];
flow2._restoreWindow = util.noop;
flow2._receive = function _receive(frame, callback) {
if (frame.type === 'DATA') {
expect(frame.data.length).to.be.lte(MAX_PAYLOAD_SIZE);
output.push(frame.data);
}
if (frame.flags.END_STREAM) {
this.emit('end_stream');
}
if (frame.type === 'BLOCKED') {
setTimeout(function() {
this._push({
type: 'WINDOW_UPDATE',
flags: {},
stream: this._flowControlId,
window_size: this._received
});
this._received = 0;
}.bind(this), 20);
}
callback();
};
// Checking results
flow2.on('end_stream', function() {
input = util.concat(input);
output = util.concat(output);
expect(input).to.deep.equal(output);
done();
});
// Start piping
flow1.pipe(flow2).pipe(flow1);
});
});
});
});
|
