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
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
|
#!/bin/sh
# This is a shell archive (produced by GNU sharutils 4.2).
# To extract the files from this archive, save it to some FILE, remove
# everything before the `!/bin/sh' line above, then type `sh FILE'.
#
# Made on 1998-10-29 15:09 EST by <jcej@caldera.lads.com>.
# Source directory was `/scsiA/home/jcej/projects/ACE_wrappers/docs/tutorials/016'.
#
# Existing files will *not* be overwritten unless `-c' is specified.
#
# This shar contains:
# length mode name
# ------ ---------- ------------------------------------------
# 422 -rw-rw-r-- hdr
# 50 -rw-rw-r-- bodies
# 789 -rw-rw-r-- page01.pre
# 1350 -rw-rw-r-- page02.pre
# 248 -rw-rw-r-- page03.pre
# 309 -rw-rw-r-- page04.pre
# 605 -rw-rw-r-- page05.pre
#
save_IFS="${IFS}"
IFS="${IFS}:"
gettext_dir=FAILED
locale_dir=FAILED
first_param="$1"
for dir in $PATH
do
if test "$gettext_dir" = FAILED && test -f $dir/gettext \
&& ($dir/gettext --version >/dev/null 2>&1)
then
set `$dir/gettext --version 2>&1`
if test "$3" = GNU
then
gettext_dir=$dir
fi
fi
if test "$locale_dir" = FAILED && test -f $dir/shar \
&& ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
then
locale_dir=`$dir/shar --print-text-domain-dir`
fi
done
IFS="$save_IFS"
if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED
then
echo=echo
else
TEXTDOMAINDIR=$locale_dir
export TEXTDOMAINDIR
TEXTDOMAIN=sharutils
export TEXTDOMAIN
echo="$gettext_dir/gettext -s"
fi
touch -am 1231235999 $$.touch >/dev/null 2>&1
if test ! -f 1231235999 && test -f $$.touch; then
shar_touch=touch
else
shar_touch=:
echo
$echo 'WARNING: not restoring timestamps. Consider getting and'
$echo "installing GNU \`touch', distributed in GNU File Utilities..."
echo
fi
rm -f 1231235999 $$.touch
#
if mkdir _sh03957; then
$echo 'x -' 'creating lock directory'
else
$echo 'failed to create lock directory'
exit 1
fi
# ============= hdr ==============
if test -f 'hdr' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'hdr' '(file already exists)'
else
$echo 'x -' extracting 'hdr' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'hdr' &&
<HTML>
<HEAD>
X <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
X <META NAME="Author" CONTENT="James CE Johnson">
X <TITLE>ACE Tutorial 016</TITLE>
</HEAD>
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F">
X
<CENTER><B><FONT SIZE=+2>ACE Tutorial 016</FONT></B></CENTER>
X
<CENTER><B><FONT SIZE=+2>Making ACE_Condition easier to use</FONT></B></CENTER>
X
<P>
<HR WIDTH="100%">
SHAR_EOF
$shar_touch -am 1029153498 'hdr' &&
chmod 0664 'hdr' ||
$echo 'restore of' 'hdr' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'hdr:' 'MD5 check failed'
34600093c989939b7a2a6806f2b18f22 hdr
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'hdr'`"
test 422 -eq "$shar_count" ||
$echo 'hdr:' 'original size' '422,' 'current size' "$shar_count!"
fi
fi
# ============= bodies ==============
if test -f 'bodies' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'bodies' '(file already exists)'
else
$echo 'x -' extracting 'bodies' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'bodies' &&
PAGE=2
Condition_i.h
Condition_i.cpp
condition.cpp
SHAR_EOF
$shar_touch -am 1029153398 'bodies' &&
chmod 0664 'bodies' ||
$echo 'restore of' 'bodies' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'bodies:' 'MD5 check failed'
06c11389b22b88d88110d2338c4dbaaf bodies
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`"
test 50 -eq "$shar_count" ||
$echo 'bodies:' 'original size' '50,' 'current size' "$shar_count!"
fi
fi
# ============= page01.pre ==============
if test -f 'page01.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page01.pre' '(file already exists)'
else
$echo 'x -' extracting 'page01.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page01.pre' &&
The ACE framework has quite a few objects for syncronizing your
threads and even processes. We've mentioned a few in passing already:
X ACE_Thread_Mutex and ACE_Barrier for instance.
<P>
Another interesting one is the ACE_Condition template. By using an
ACE_Condition you can have your code wait for an arbitrary condition
to occur. That condition is "embodied" in a variable of your choice.
That variable can, in turn, be any data type you wish. This makes
ACE_Condition much more flexible than a simple mutex, barrier or
semaphore.
<P>
In this tutorial, I'll create a wrapper class around the ACE_Condition
and the assorted housekeeping items necessary to make it work. I'll
use a simple integer as the condition variable but keep in mind that
you can use any data type you want.
SHAR_EOF
$shar_touch -am 1029153198 'page01.pre' &&
chmod 0664 'page01.pre' ||
$echo 'restore of' 'page01.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page01.pre:' 'MD5 check failed'
aa9f5774f5415d7a430891e9296bfab0 page01.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`"
test 789 -eq "$shar_count" ||
$echo 'page01.pre:' 'original size' '789,' 'current size' "$shar_count!"
fi
fi
# ============= page02.pre ==============
if test -f 'page02.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page02.pre' '(file already exists)'
else
$echo 'x -' extracting 'page02.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page02.pre' &&
We'll look first at the declaration of the wrapper class.
<P>
The way you use ACE_Condition is something like this:
<UL>
<LI>First, the setup...
<UL>
<LI>Create a variable using your choice of data types
<LI>Create a mutex that will provide thread-safe access to that
variable
<LI>Create an ACE_Condition that uses the mutex
</UL>
<P>
<LI>Waiting for the condition...
<UL>
<PRE>
the_mutex.acquire();
while( the_variable != some_desired_state_or_value )
X the_condition.wait();
the_mutex.release();
</PRE>
Note that when <i>the_condition</i> is created, it must be given a
reference to the mutex. That's because the wait() method will release
the mutex before waiting and reacquire it after being signaled.
</UL>
<P>
<LI>Setting the condition...
<UL>
<PRE>
the_mutex.acquire();
the_variable = some_new_value_or_state;
the_condition.signal() <i>OR</i> the_condition.broadcast()
</pre>
</UL>
</UL>
<P>
The problem I have is remembering to setup everything and co-ordinate
the locking, waiting and signaling. Even if I remember it all
correctly it just makes my application code more complex than it
should be.
<P>
To help out with that, I've created the class below to encapsulate the
three elements necessary for the condition to work. I've then added
methods for manipulation of the condition variable and waiting for the
condition to occur.
<HR>
SHAR_EOF
$shar_touch -am 1029191498 'page02.pre' &&
chmod 0664 'page02.pre' ||
$echo 'restore of' 'page02.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page02.pre:' 'MD5 check failed'
ccf4d7623038838df6249b5134827402 page02.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`"
test 1350 -eq "$shar_count" ||
$echo 'page02.pre:' 'original size' '1350,' 'current size' "$shar_count!"
fi
fi
# ============= page03.pre ==============
if test -f 'page03.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page03.pre' '(file already exists)'
else
$echo 'x -' extracting 'page03.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page03.pre' &&
Ok, now we'll take a look at the definition of the class. You already
know how to use an ACE_Condition & it's not really that difficult.
Still, imagine how much more cluttered your code would be if it had to
include the mess I've got below!
<HR>
SHAR_EOF
$shar_touch -am 1029162998 'page03.pre' &&
chmod 0664 'page03.pre' ||
$echo 'restore of' 'page03.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page03.pre:' 'MD5 check failed'
51c4ebc7f5c67e072fed8f76bd7be62d page03.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`"
test 248 -eq "$shar_count" ||
$echo 'page03.pre:' 'original size' '248,' 'current size' "$shar_count!"
fi
fi
# ============= page04.pre ==============
if test -f 'page04.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page04.pre' '(file already exists)'
else
$echo 'x -' extracting 'page04.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page04.pre' &&
We finally get to the main() application. I create a simple Task
derivative that will serve as a baseclass for other objects that test
specific functions of the Condition class. Notice how easy it is to
integrate a Condition into the application without keeping track of
three related member variables.
<HR>
SHAR_EOF
$shar_touch -am 1029185698 'page04.pre' &&
chmod 0664 'page04.pre' ||
$echo 'restore of' 'page04.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page04.pre:' 'MD5 check failed'
b6694ddc18814a64feeb56f46ffd7d17 page04.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`"
test 309 -eq "$shar_count" ||
$echo 'page04.pre:' 'original size' '309,' 'current size' "$shar_count!"
fi
fi
# ============= page05.pre ==============
if test -f 'page05.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page05.pre' '(file already exists)'
else
$echo 'x -' extracting 'page05.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page05.pre' &&
And that's all...
<P>
For general use, it would make sense to convert Condition into a
template and get rid of some of the operators that don't make sense.
Using an integer as the condition type probably isn't realistic since
you could just use a semaphore or barrier for that case. Still, the
Tutorial shows the basics and provides a foundation on which you can
create a more useful class for your application.
<P>
<UL>
<LI><A HREF="Condition_i.h">Condition_i.h</A>
<LI><A HREF="Condition_i.cpp">Condition_i.cpp</A>
<LI><A HREF="condition.cpp">condition.cpp</A>
<LI><A HREF="Makefile">Makefile</A>
</UL>
SHAR_EOF
$shar_touch -am 1029192198 'page05.pre' &&
chmod 0664 'page05.pre' ||
$echo 'restore of' 'page05.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page05.pre:' 'MD5 check failed'
f63c4bfe37b1fe5785a6af9b204cb0bf page05.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`"
test 605 -eq "$shar_count" ||
$echo 'page05.pre:' 'original size' '605,' 'current size' "$shar_count!"
fi
fi
rm -fr _sh03957
exit 0
|
