| 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 |
1
1
500
500
500
500
500
500
500
1
1
9460
9460
9460
9460
1
503
503
503
503
503
503
162
503
1
323
323
323
162
162
162
1
1
162
162
1
175
175
175
175
175
1
10125
9773
9773
491
491
491
491
491
491
9282
8806
8806
8806
8786
8786
8786
8786
8296
8806
393
8806
8806
476
10125
162
| // Copyright (c) 2012 Kuba Niegowski
//
// 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.
'use strict';
var util = require('util'),
Stream = require('stream');
var ChunkStream = module.exports = function() {
Stream.call(this);
this._buffers = [];
this._buffered = 0;
this._reads = [];
this._paused = false;
this._encoding = 'utf8';
this.writable = true;
};
util.inherits(ChunkStream, Stream);
ChunkStream.prototype.read = function(length, callback) {
this._reads.push({
length: Math.abs(length), // if length < 0 then at most this length
allowLess: length < 0,
func: callback
});
process.nextTick(function() {
this._process();
// its paused and there is not enought data then ask for more
Iif (this._paused && this._reads.length > 0) {
this._paused = false;
this.emit('drain');
}
}.bind(this));
};
ChunkStream.prototype.write = function(data, encoding) {
Iif (!this.writable) {
this.emit('error', new Error('Stream not writable'));
return false;
}
Iif (!Buffer.isBuffer(data))
data = new Buffer(data, encoding || this._encoding);
this._buffers.push(data);
this._buffered += data.length;
this._process();
// ok if there are no more read requests
if (this._reads && this._reads.length == 0)
this._paused = true;
return this.writable && !this._paused;
};
ChunkStream.prototype.end = function(data, encoding) {
Iif (data) this.write(data, encoding);
this.writable = false;
// already destroyed
if (!this._buffers) return;
// enqueue or handle end
Iif (this._buffers.length == 0) {
this._end();
} else {
this._buffers.push(null);
this._process();
}
};
ChunkStream.prototype.destroySoon = ChunkStream.prototype.end;
ChunkStream.prototype._end = function() {
Iif (this._reads.length > 0) {
this.emit('error',
new Error('There are some read requests waitng on finished stream')
);
}
this.destroy();
};
ChunkStream.prototype.destroy = function() {
Iif (!this._buffers) return;
this.writable = false;
this._reads = null;
this._buffers = null;
this.emit('close');
};
ChunkStream.prototype._process = function() {
// as long as there is any data and read requests
while (this._buffered > 0 && this._reads && this._reads.length > 0) {
var read = this._reads[0];
// read any data (but no more than length)
if (read.allowLess) {
// ok there is any data so that we can satisfy this request
this._reads.shift(); // == read
// first we need to peek into first buffer
var buf = this._buffers[0];
// ok there is more data than we need
Eif (buf.length > read.length) {
this._buffered -= read.length;
this._buffers[0] = buf.slice(read.length);
read.func.call(this, buf.slice(0, read.length));
} else {
// ok this is less than maximum length so use it all
this._buffered -= buf.length;
this._buffers.shift(); // == buf
read.func.call(this, buf);
}
} else if (this._buffered >= read.length) {
// ok we can meet some expectations
this._reads.shift(); // == read
var pos = 0,
count = 0,
data = new Buffer(read.length);
// create buffer for all data
while (pos < read.length) {
var buf = this._buffers[count++],
len = Math.min(buf.length, read.length - pos);
buf.copy(data, pos, 0, len);
pos += len;
// last buffer wasn't used all so just slice it and leave
if (len != buf.length)
this._buffers[--count] = buf.slice(len);
}
// remove all used buffers
if (count > 0)
this._buffers.splice(0, count);
this._buffered -= read.length;
read.func.call(this, data);
} else {
// not enought data to satisfy first request in queue
// so we need to wait for more
break;
}
}
if (this._buffers && this._buffers.length > 0 && this._buffers[0] == null) {
this._end();
}
};
|