| … | |
… | |
| 31 | |
31 | |
| 32 | =cut |
32 | =cut |
| 33 | |
33 | |
| 34 | package Coro::Semaphore; |
34 | package Coro::Semaphore; |
| 35 | |
35 | |
|
|
36 | no warnings; |
|
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37 | |
| 36 | use Coro (); |
38 | use Coro (); |
| 37 | |
39 | |
| 38 | $VERSION = 0.5; |
40 | $VERSION = 4.747; |
| 39 | |
41 | |
| 40 | =item new [inital count] |
42 | =item new [inital count] |
| 41 | |
43 | |
| 42 | Creates a new sempahore object with the given initial lock count. The |
44 | Creates a new sempahore object with the given initial lock count. The |
| 43 | default lock count is 1, which means it is unlocked by default. Zero (or |
45 | default lock count is 1, which means it is unlocked by default. Zero (or |
| … | |
… | |
| 48 | |
50 | |
| 49 | sub new { |
51 | sub new { |
| 50 | bless [defined $_[1] ? $_[1] : 1], $_[0]; |
52 | bless [defined $_[1] ? $_[1] : 1], $_[0]; |
| 51 | } |
53 | } |
| 52 | |
54 | |
|
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55 | =item $sem->count |
|
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56 | |
|
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57 | Returns the current semaphore count. |
|
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58 | |
|
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59 | =cut |
|
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60 | |
|
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61 | sub count { |
|
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62 | $_[0][0] |
|
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63 | } |
|
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64 | |
|
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65 | =item $sem->adjust ($diff) |
|
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66 | |
|
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67 | Atomically adds the amount given to the current semaphore count. If the |
|
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68 | count becomes positive, wakes up any waiters. Does not block if the count |
|
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69 | becomes negative, however. |
|
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70 | |
|
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71 | =cut |
|
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72 | |
|
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73 | sub adjust { |
|
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74 | # basically a weird copy of up |
|
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75 | if (($_[0][0] += $_[1]) > 0) { |
|
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76 | (shift @{$_[0][1]})->ready if @{$_[0][1]}; |
|
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77 | } |
|
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78 | } |
|
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79 | |
| 53 | =item $sem->down |
80 | =item $sem->down |
| 54 | |
81 | |
| 55 | Decrement the counter, therefore "locking" the semaphore. This method |
82 | Decrement the counter, therefore "locking" the semaphore. This method |
| 56 | waits until the semaphore is available if the counter is zero. |
83 | waits until the semaphore is available if the counter is zero. |
|
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84 | |
|
|
85 | =item $status = $sem->timed_down ($timeout) |
|
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86 | |
|
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87 | Like C<down>, but returns false if semaphore couldn't be acquired within |
|
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88 | $timeout seconds, otherwise true. |
| 57 | |
89 | |
| 58 | =cut |
90 | =cut |
| 59 | |
91 | |
| 60 | sub down { |
92 | sub down { |
| 61 | while ($_[0][0] <= 0) { |
93 | while ($_[0][0] <= 0) { |
| 62 | push @{$_[0][1]}, $Coro::current; |
94 | push @{$_[0][1]}, $Coro::current; |
| 63 | Coro::schedule; |
95 | &Coro::schedule; |
| 64 | } |
96 | } |
| 65 | --$_[0][0]; |
97 | --$_[0][0]; |
|
|
98 | } |
|
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99 | |
|
|
100 | sub timed_down { |
|
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101 | require Coro::Timer; |
|
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102 | my $timeout = Coro::Timer::timeout ($_[1]); |
|
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103 | |
|
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104 | while ($_[0][0] <= 0) { |
|
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105 | push @{$_[0][1]}, $Coro::current; |
|
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106 | &Coro::schedule; |
|
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107 | if ($timeout) { |
|
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108 | # ugly as hell. slow, too, btw! |
|
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109 | for (0..$#{$_[0][1]}) { |
|
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110 | if ($_[0][1][$_] == $Coro::current) { |
|
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111 | splice @{$_[0][1]}, $_, 1; |
|
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112 | return; |
|
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113 | } |
|
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114 | } |
|
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115 | die; |
|
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116 | } |
|
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117 | } |
|
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118 | |
|
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119 | --$_[0][0]; |
|
|
120 | return 1; |
| 66 | } |
121 | } |
| 67 | |
122 | |
| 68 | =item $sem->up |
123 | =item $sem->up |
| 69 | |
124 | |
| 70 | Unlock the semaphore again. |
125 | Unlock the semaphore again. |
| … | |
… | |
| 107 | =item $guard = $sem->guard |
162 | =item $guard = $sem->guard |
| 108 | |
163 | |
| 109 | This method calls C<down> and then creates a guard object. When the guard |
164 | This method calls C<down> and then creates a guard object. When the guard |
| 110 | object is destroyed it automatically calls C<up>. |
165 | object is destroyed it automatically calls C<up>. |
| 111 | |
166 | |
|
|
167 | =item $guard = $sem->timed_guard ($timeout) |
|
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168 | |
|
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169 | Like C<guard>, but returns undef if semaphore couldn't be acquired within |
|
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170 | $timeout seconds, otherwise the guard object. |
|
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171 | |
| 112 | =cut |
172 | =cut |
| 113 | |
173 | |
| 114 | sub guard { |
174 | sub guard { |
| 115 | &down; |
175 | &down; |
| 116 | # double indirection because bless works on the referenced |
176 | # double indirection because bless works on the referenced |
| 117 | # object, not (only) on the reference itself. |
177 | # object, not (only) on the reference itself. |
| 118 | bless \\$_[0], Coro::Semaphore::Guard::; |
178 | bless \\$_[0], Coro::Semaphore::guard::; |
| 119 | } |
179 | } |
| 120 | |
180 | |
|
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181 | sub timed_guard { |
|
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182 | &timed_down |
|
|
183 | ? bless \\$_[0], Coro::Semaphore::guard:: |
|
|
184 | : (); |
|
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185 | } |
|
|
186 | |
| 121 | sub Coro::Semaphore::Guard::DESTROY { |
187 | sub Coro::Semaphore::guard::DESTROY { |
| 122 | &up(${${$_[0]}}); |
188 | &up(${${$_[0]}}); |
| 123 | } |
189 | } |
| 124 | |
190 | |
| 125 | 1; |
|
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| 126 | |
|
|
| 127 | =back |
191 | =back |
| 128 | |
192 | |
| 129 | =head1 AUTHOR |
193 | =head1 AUTHOR |
| 130 | |
194 | |
| 131 | Marc Lehmann <pcg@goof.com> |
195 | Marc Lehmann <schmorp@schmorp.de> |
| 132 | http://www.goof.com/pcg/marc/ |
196 | http://home.schmorp.de/ |
| 133 | |
197 | |
| 134 | =cut |
198 | =cut |
| 135 | |
199 | |
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200 | 1 |
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201 | |
