/
InterThreadMessaging.h
147 lines (112 loc) · 6.07 KB
/
InterThreadMessaging.h
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
/*-*- Mode: ObjC; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-*/
/*
* InterThreadMessaging -- InterThreadMessaging.h
* Created by toby on Tue Jun 19 2001.
*
* A low-cost-but-not-quite-as-general alternative to D.O.
*
*/
#import <Foundation/Foundation.h>
@interface NSThread (ConnectionInterThreadMessaging)
/* The inter-thread messaging category methods use NSPorts to deliver messages
between threads. In order to receive an inter-thread message, the receiver
must both (1) be running a run loop; and (2) be monitoring this port in its
run loop. You must call this method from the context of the thread you wish
to prepare for inter-thread messages (which is why these are class methods).
Before a thread can receive any inter-thread messages, it must invoke one
of the following methods to prepare the thread and its run loop to receive
these messages. In order to process a message from another thread, the
receiving thread must, of course, be running its run loop. */
+ (void) prepareForConnectionInterThreadMessages; // in NSDefaultRunLoopMode
@end
/* Invoke in the specified thread a method on an object. The target
thread must have been readied for inter-thread messages by invoking
+prepareForConnectionInterThreadMessages. It must be running its run loop in
order to receive the messages.
In some situations, a sender may be able to blast messages to an object
faster than they can be processed in the target thread. To prevent things
from spiraling out of control, the underlying NSPorts implement a throtling
mechanism in the form of a fixed queue size. When this queue is filled, all
further messages are rejected until until a message has been pulled off the
queue. The sender may specify a limit date; if the queue is full, the
sender will block until this limit date expires or until space is made in
the queue. An NSPortTimeoutException exception is thrown if the limit date
expires (or if no limit date is specified) before the message can be
delivered.
There is one very important point to watch out for: to prevent heinously
difficult to debug memory smashers, the receing object and all of its
arguments are retained in the context of the sending thread. When the
message has been delivered in the target thread, these objects are auto-
released IN THE CONTEXT OF THE TARGET THREAD. Thus, it is possible for
the objects to be deallocated in a thread different from the one they were
allocated in. (In general, you don't need to worry about simple/immutable
objects, such as NSString, NSData, etc.) */
@interface NSObject (ConnectionInterThreadMessaging)
- (void) performSelector:(SEL)selector
inThread:(NSThread *)thread; // before date [NSDate distantFuture]
- (void) performSelector:(SEL)selector
inThread:(NSThread *)thread
beforeDate:(NSDate *)limitDate;
- (void) performSelector:(SEL)selector
withObject:(id)object
inThread:(NSThread *)thread; // before date [NSDate distantFuture]
- (void) performSelector:(SEL)selector
withObject:(id)object
inThread:(NSThread *)thread
beforeDate:(NSDate *)limitDate;
- (void) performSelector:(SEL)selector
withObject:(id)object1
withObject:(id)object2
inThread:(NSThread *)thread; // before date [NSDate distantFuture]
- (void) performSelector:(SEL)selector
withObject:(id)object1
withObject:(id)object2
inThread:(NSThread *)thread
beforeDate:(NSDate *)limitDate;
@end
/* Post a notification in the specified thread. The target thread must
have been readied for inter-thread messages by sending itself the
+prepareForConnectionInterThreadMessages. It must be running its run loop in
order to receive the messages.
In some situations, a sender may be able to blast messages to an object
faster than they can be processed in the target thread. To prevent things
from spiraling out of control, the underlying NSPorts implement a throtling
mechanism in the form of a fixed queue size. When this queue is filled, all
further messages are rejected until until a message has been pulled off the
queue. The sender may specify a limit date; if the queue is full, the
sender will block until this limit date expires or until space is made in
the queue. An NSPortTimeoutException exception is thrown if the limit date
expires (or if no limit date is specified) before the message can be
delivered.
There is one very important point to watch out for: to prevent heinously
difficult to debug memory smashers, the notification object (and
consequently the userInfo dictionary) are retained in the context of
the sending thread. When the message has been delivered in the target
thread, the notification object is auto-released IN THE CONTEXT OF THE
TARGET THREAD. Thus, it is possible for objects to be deallocated in a
thread different from the one they were allocated in. (In general, you
don't need to worry about simple/immutable objects, such as NSString,
NSData, etc.) */
@interface NSNotificationCenter (ConnectionInterThreadMessaging)
- (void) postNotification:(NSNotification *)notification
inThread:(NSThread *)thread; // before date [NSDate distantFuture]
- (void) postNotification:(NSNotification *)notification
inThread:(NSThread *)thread
beforeDate:(NSDate *)limitDate;
- (void) postNotificationName:(NSString *)name
object:(id)object
inThread:(NSThread *)thread; // before date [NSDate distantFuture]
- (void) postNotificationName:(NSString *)name
object:(id)object
inThread:(NSThread *)thread
beforeDate:(NSDate *)limitDate;
- (void) postNotificationName:(NSString *)name
object:(id)object
userInfo:(NSDictionary *)userInfo
inThread:(NSThread *)thread; // before date [NSDate distantFuture]
- (void) postNotificationName:(NSString *)name
object:(id)object
userInfo:(NSDictionary *)userInfo
inThread:(NSThread *)thread
beforeDate:(NSDate *)limitDate;
@end