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
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2005-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.actors
private[actors] class MQueueElement[Msg >: Null](val msg: Msg, val session: OutputChannel[Any], var next: MQueueElement[Msg]) {
def this() = this(null, null, null)
def this(msg: Msg, session: OutputChannel[Any]) = this(msg, session, null)
}
private[actors] class MQueue[Msg >: Null](protected val label: String) {
protected var first: MQueueElement[Msg] = null
protected var last: MQueueElement[Msg] = null // last eq null iff list is empty
private var _size = 0
def size = _size
final def isEmpty = last eq null
protected def changeSize(diff: Int) {
_size += diff
}
def prepend(other: MQueue[Msg]) {
if (!other.isEmpty) {
other.last.next = first
first = other.first
}
}
def clear() {
first = null
last = null
_size = 0
}
def append(msg: Msg, session: OutputChannel[Any]) {
changeSize(1) // size always increases by 1
val el = new MQueueElement(msg, session)
if (isEmpty) first = el
else last.next = el
last = el
}
def append(el: MQueueElement[Msg]) {
changeSize(1) // size always increases by 1
if (isEmpty) first = el
else last.next = el
last = el
}
def foreach(f: (Msg, OutputChannel[Any]) => Unit) {
var curr = first
while (curr != null) {
f(curr.msg, curr.session)
curr = curr.next
}
}
def foreachAppend(target: MQueue[Msg]) {
var curr = first
while (curr != null) {
target.append(curr)
curr = curr.next
}
}
def foreachDequeue(target: MQueue[Msg]) {
var curr = first
while (curr != null) {
target.append(curr)
curr = curr.next
}
first = null
last = null
_size = 0
}
def foldLeft[B](z: B)(f: (B, Msg) => B): B = {
var acc = z
var curr = first
while (curr != null) {
acc = f(acc, curr.msg)
curr = curr.next
}
acc
}
/** Returns the n-th message that satisfies the predicate `p`
* without removing it.
*/
def get(n: Int)(p: Msg => Boolean): Option[Msg] = {
var pos = 0
def test(msg: Msg): Boolean =
p(msg) && (pos == n || { pos += 1; false })
var curr = first
while (curr != null)
if (test(curr.msg)) return Some(curr.msg) // early return
else curr = curr.next
None
}
/** Removes the n-th message that satisfies the predicate <code>p</code>.
*/
def remove(n: Int)(p: (Msg, OutputChannel[Any]) => Boolean): Option[(Msg, OutputChannel[Any])] =
removeInternal(n)(p) map (x => (x.msg, x.session))
/** Extracts the first message that satisfies the predicate `p`
* or `'''null'''` if `p` fails for all of them.
*/
def extractFirst(p: (Msg, OutputChannel[Any]) => Boolean): MQueueElement[Msg] =
removeInternal(0)(p).orNull
def extractFirst(pf: PartialFunction[Msg, Any]): MQueueElement[Msg] = {
if (isEmpty) // early return
return null
// special handling if returning the head
if (pf.isDefinedAt(first.msg)) {
val res = first
first = first.next
if (res eq last)
last = null
changeSize(-1)
res
}
else {
var curr = first.next // init to element #2
var prev = first
while (curr != null) {
if (pf.isDefinedAt(curr.msg)) {
prev.next = curr.next
if (curr eq last)
last = prev
changeSize(-1)
return curr // early return
}
else {
prev = curr
curr = curr.next
}
}
// not found
null
}
}
private def removeInternal(n: Int)(p: (Msg, OutputChannel[Any]) => Boolean): Option[MQueueElement[Msg]] = {
var pos = 0
def foundMsg(x: MQueueElement[Msg]) = {
changeSize(-1)
Some(x)
}
def test(msg: Msg, session: OutputChannel[Any]): Boolean =
p(msg, session) && (pos == n || { pos += 1 ; false })
if (isEmpty) // early return
return None
// special handling if returning the head
if (test(first.msg, first.session)) {
val res = first
first = first.next
if (res eq last)
last = null
foundMsg(res)
}
else {
var curr = first.next // init to element #2
var prev = first
while (curr != null) {
if (test(curr.msg, curr.session)) {
prev.next = curr.next
if (curr eq last)
last = prev
return foundMsg(curr) // early return
}
else {
prev = curr
curr = curr.next
}
}
// not found
None
}
}
}
/** Debugging trait.
*/
private[actors] trait MessageQueueTracer extends MQueue[Any]
{
private val queueNumber = MessageQueueTracer.getQueueNumber
override def append(msg: Any, session: OutputChannel[Any]) {
super.append(msg, session)
printQueue("APPEND %s" format msg)
}
override def get(n: Int)(p: Any => Boolean): Option[Any] = {
val res = super.get(n)(p)
printQueue("GET %s" format res)
res
}
override def remove(n: Int)(p: (Any, OutputChannel[Any]) => Boolean): Option[(Any, OutputChannel[Any])] = {
val res = super.remove(n)(p)
printQueue("REMOVE %s" format res)
res
}
override def extractFirst(p: (Any, OutputChannel[Any]) => Boolean): MQueueElement[Any] = {
val res = super.extractFirst(p)
printQueue("EXTRACT_FIRST %s" format res)
res
}
private def printQueue(msg: String) = {
def firstMsg = if (first eq null) "null" else first.msg
def lastMsg = if (last eq null) "null" else last.msg
println("[%s size=%d] [%s] first = %s, last = %s".format(this, size, msg, firstMsg, lastMsg))
}
override def toString() = "%s:%d".format(label, queueNumber)
}
private[actors] object MessageQueueTracer {
// for tracing purposes
private var queueNumberAssigner = 0
private def getQueueNumber = synchronized {
queueNumberAssigner += 1
queueNumberAssigner
}
}
|
