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Comparing Coro/Coro/Semaphore.pm (file contents):
Revision 1.72 by root, Tue Sep 30 17:12:35 2008 UTC vs.
Revision 1.82 by root, Wed Nov 19 11:11:10 2008 UTC

… …
35 35
36no warnings; 36no warnings;
37 37
38use Coro (); 38use Coro ();
39 39
40$VERSION = 4.8; 40$VERSION = 5.0;
41 41
42=item new [inital count] 42=item new [inital count]
43 43
44Creates a new sempahore object with the given initial lock count. The 44Creates a new sempahore object with the given initial lock count. The
45default lock count is 1, which means it is unlocked by default. Zero (or 45default lock count is 1, which means it is unlocked by default. Zero (or
46negative values) are also allowed, in which case the semaphore is locked 46negative values) are also allowed, in which case the semaphore is locked
47by default. 47by default.
48 48
49=cut
50
51sub new {
52 bless [defined $_[1] ? $_[1] : 1], $_[0];
53}
54
55=item $sem->count 49=item $sem->count
56 50
57Returns the current semaphore count. 51Returns the current semaphore count.
58
59=cut
60
61sub count {
62 $_[0][0]
63}
64 52
65=item $sem->adjust ($diff) 53=item $sem->adjust ($diff)
66 54
67Atomically adds the amount given to the current semaphore count. If the 55Atomically adds the amount given to the current semaphore count. If the
68count becomes positive, wakes up any waiters. Does not block if the count 56count becomes positive, wakes up any waiters. Does not block if the count
69becomes negative, however. 57becomes negative, however.
70 58
71=cut
72
73sub adjust {
74 # basically a weird copy of up
75 if (($_[0][0] += $_[1]) > 0) {
76 (shift @{$_[0][1]})->ready if @{$_[0][1]};
77 }
78}
79
80=item $sem->down 59=item $sem->down
81 60
82Decrement the counter, therefore "locking" the semaphore. This method 61Decrement the counter, therefore "locking" the semaphore. This method
83waits until the semaphore is available if the counter is zero. 62waits until the semaphore is available if the counter is zero.
84 63
85=item $status = $sem->timed_down ($timeout) 64=item $sem->wait
86 65
87Like C<down>, but returns false if semaphore couldn't be acquired within 66Similar to C<down>, but does not actually decrement the counter. Instead,
88$timeout seconds, otherwise true. 67when this function returns, a following call to C<down> or C<try> is
68guaranteed to succeed without blocking, until the next coroutine switch
69(C<cede> etc.).
70
71Note that using C<wait> is much less efficient than using C<down>, so try
72to prefer C<down> whenever possible.
73
74=item $sem->wait ($callback)
75
76If you pass a callback argument to C<wait>, it will not wait, but
77immediately return. The callback will be called as soon as the semaphore
78becomes available (which might be instantly), and gets passed the
79semaphore as first argument.
80
81The callback might C<down> the semaphore exactly once, might wake up other
82coroutines, but is I<NOT> allowed to block (switch to other coroutines).
83
84This is considered a rather experimental interface, and is subject to
85change.
89 86
90=cut 87=cut
91 88
92sub down { 89#=item $status = $sem->timed_down ($timeout)
93 while ($_[0][0] <= 0) { 90#
94 push @{$_[0][1]}, $Coro::current; 91#Like C<down>, but returns false if semaphore couldn't be acquired within
95 &Coro::schedule; 92#$timeout seconds, otherwise true.
96 }
97 --$_[0][0];
98}
99 93
100sub timed_down { 94#sub timed_down {
101 require Coro::Timer; 95# require Coro::Timer;
102 my $timeout = Coro::Timer::timeout ($_[1]); 96# my $timeout = Coro::Timer::timeout ($_[1]);
103 97#
104 while ($_[0][0] <= 0) { 98# while ($_[0][0] <= 0) {
105 push @{$_[0][1]}, $Coro::current; 99# push @{$_[0][1]}, $Coro::current;
106 &Coro::schedule; 100# &Coro::schedule;
107 if ($timeout) { 101# if ($timeout) {
108 # ugly as hell. slow, too, btw! 102# # ugly as hell. slow, too, btw!
109 for (0..$#{$_[0][1]}) { 103# for (0..$#{$_[0][1]}) {
110 if ($_[0][1][$_] == $Coro::current) { 104# if ($_[0][1][$_] == $Coro::current) {
111 splice @{$_[0][1]}, $_, 1; 105# splice @{$_[0][1]}, $_, 1;
112 return; 106# return;
113 } 107# }
114 } 108# }
115 die; 109# die;
116 } 110# }
117 } 111# }
118 112#
119 --$_[0][0]; 113# --$_[0][0];
120 return 1; 114# return 1;
121} 115#}
122 116
123=item $sem->up 117=item $sem->up
124 118
125Unlock the semaphore again. 119Unlock the semaphore again.
126
127=cut
128
129sub up {
130 if (++$_[0][0] > 0) {
131 (shift @{$_[0][1]})->ready if @{$_[0][1]};
132 }
133}
134 120
135=item $sem->try 121=item $sem->try
136 122
137Try to C<down> the semaphore. Returns true when this was possible, 123Try to C<down> the semaphore. Returns true when this was possible,
138otherwise return false and leave the semaphore unchanged. 124otherwise return false and leave the semaphore unchanged.
139 125
140=cut
141
142sub try {
143 if ($_[0][0] > 0) {
144 --$_[0][0];
145 return 1;
146 } else {
147 return 0;
148 }
149}
150
151=item $sem->waiters 126=item $sem->waiters
152 127
153In scalar context, returns the number of coroutines waiting for this 128In scalar context, returns the number of coroutines waiting for this
154semaphore. 129semaphore.
155 130
156=cut
157
158sub waiters {
159 @{$_[0][1]};
160}
161
162=item $guard = $sem->guard 131=item $guard = $sem->guard
163 132
164This method calls C<down> and then creates a guard object. When the guard 133This method calls C<down> and then creates a guard object. When the guard
165object is destroyed it automatically calls C<up>. 134object is destroyed it automatically calls C<up>.
166
167=item $guard = $sem->timed_guard ($timeout)
168
169Like C<guard>, but returns undef if semaphore couldn't be acquired within
170$timeout seconds, otherwise the guard object.
171 135
172=cut 136=cut
173 137
174sub guard { 138sub guard {
175 &down; 139 &down;
176 # double indirection because bless works on the referenced 140 # double indirection because bless works on the referenced
177 # object, not (only) on the reference itself. 141 # object, not (only) on the reference itself.
178 bless \\$_[0], Coro::Semaphore::guard::; 142 bless \\$_[0], Coro::Semaphore::guard::;
179} 143}
180 144
145#=item $guard = $sem->timed_guard ($timeout)
146#
147#Like C<guard>, but returns undef if semaphore couldn't be acquired within
148#$timeout seconds, otherwise the guard object.
149
181sub timed_guard { 150#sub timed_guard {
182 &timed_down 151# &timed_down
183 ? bless \\$_[0], Coro::Semaphore::guard:: 152# ? bless \\$_[0], Coro::Semaphore::guard::
184 : (); 153# : ();
185} 154#}
186 155
187sub Coro::Semaphore::guard::DESTROY { 156sub Coro::Semaphore::guard::DESTROY {
188 &up(${${$_[0]}}); 157 &up(${${$_[0]}});
189} 158}
190 159

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