1 |
root |
1.1 |
=head1 NAME |
2 |
|
|
|
3 |
|
|
Coro::State - create and manage simple coroutines |
4 |
|
|
|
5 |
|
|
=head1 SYNOPSIS |
6 |
|
|
|
7 |
|
|
use Coro::State; |
8 |
|
|
|
9 |
|
|
$new = new Coro::State sub { |
10 |
root |
1.3 |
print "in coroutine (called with @_), switching back\n"; |
11 |
root |
1.43 |
$new->transfer ($main); |
12 |
root |
1.1 |
print "in coroutine again, switching back\n"; |
13 |
root |
1.43 |
$new->transfer ($main); |
14 |
root |
1.3 |
}, 5; |
15 |
root |
1.1 |
|
16 |
|
|
$main = new Coro::State; |
17 |
|
|
|
18 |
|
|
print "in main, switching to coroutine\n"; |
19 |
root |
1.43 |
$main->transfer ($new); |
20 |
root |
1.1 |
print "back in main, switch to coroutine again\n"; |
21 |
root |
1.43 |
$main->transfer ($new); |
22 |
root |
1.1 |
print "back in main\n"; |
23 |
|
|
|
24 |
|
|
=head1 DESCRIPTION |
25 |
|
|
|
26 |
|
|
This module implements coroutines. Coroutines, similar to continuations, |
27 |
|
|
allow you to run more than one "thread of execution" in parallel. Unlike |
28 |
root |
1.42 |
threads, there is no parallelism and only voluntary switching is used so |
29 |
|
|
locking problems are greatly reduced. |
30 |
|
|
|
31 |
|
|
This can be used to implement non-local jumps, exception handling, |
32 |
root |
1.94 |
(non-clonable) continuations and more. |
33 |
root |
1.1 |
|
34 |
|
|
This module provides only low-level functionality. See L<Coro> and related |
35 |
root |
1.42 |
modules for a higher level process abstraction including scheduling. |
36 |
root |
1.1 |
|
37 |
root |
1.86 |
=head2 MODEL |
38 |
|
|
|
39 |
|
|
Coro::State implements two different coroutine models: Perl and C. The |
40 |
|
|
C coroutines (called cctx's) are basically simplified perl interpreters |
41 |
|
|
running/interpreting the Perl coroutines. A single interpreter can run any |
42 |
|
|
number of Perl coroutines, so usually there are very few C coroutines. |
43 |
|
|
|
44 |
|
|
When Perl code calls a C function (e.g. in an extension module) and that |
45 |
|
|
C function then calls back into Perl or does a coroutine switch the C |
46 |
|
|
coroutine can no longer execute other Perl coroutines, so it stays tied to |
47 |
|
|
the specific coroutine until it returns to the original Perl caller, after |
48 |
|
|
which it is again avaikable to run other Perl coroutines. |
49 |
|
|
|
50 |
|
|
The main program always has its own "C coroutine" (which really is |
51 |
|
|
*the* Perl interpreter running the whole program), so there will always |
52 |
root |
1.94 |
be at least one additional C coroutine. You can use the debugger (see |
53 |
root |
1.86 |
L<Coro::Debug>) to find out which coroutines are tied to their cctx and |
54 |
|
|
which aren't. |
55 |
|
|
|
56 |
root |
1.9 |
=head2 MEMORY CONSUMPTION |
57 |
|
|
|
58 |
|
|
A newly created coroutine that has not been used only allocates a |
59 |
root |
1.84 |
relatively small (a hundred bytes) structure. Only on the first |
60 |
root |
1.94 |
C<transfer> will perl allocate stacks (a few kb, 64 bit architetcures |
61 |
|
|
use twice as much, i.e. a few kb :) and optionally a C stack/coroutine |
62 |
|
|
(cctx) for coroutines that recurse through C functions. All this is very |
63 |
|
|
system-dependent. On my x86-pc-linux-gnu system this amounts to about 2k |
64 |
|
|
per (non-trivial but simple) coroutine. |
65 |
|
|
|
66 |
|
|
You can view the actual memory consumption using Coro::Debug. Keep in mind |
67 |
|
|
that a for loop or other block constructs can easily consume 100-200 bytes |
68 |
|
|
per nesting level. |
69 |
root |
1.1 |
|
70 |
|
|
=cut |
71 |
|
|
|
72 |
|
|
package Coro::State; |
73 |
|
|
|
74 |
root |
1.47 |
use strict; |
75 |
|
|
no warnings "uninitialized"; |
76 |
|
|
|
77 |
root |
1.84 |
use Carp; |
78 |
root |
1.87 |
|
79 |
root |
1.109 |
use Time::HiRes (); # currently only used for PerlIO::cede |
80 |
|
|
|
81 |
root |
1.87 |
our $DIEHOOK; |
82 |
|
|
our $WARNHOOK; |
83 |
|
|
|
84 |
|
|
BEGIN { |
85 |
|
|
$DIEHOOK = sub { }; |
86 |
|
|
$WARNHOOK = sub { warn $_[0] }; |
87 |
|
|
} |
88 |
|
|
|
89 |
|
|
sub diehook { &$DIEHOOK } |
90 |
|
|
sub warnhook { &$WARNHOOK } |
91 |
root |
1.84 |
|
92 |
root |
1.47 |
use XSLoader; |
93 |
root |
1.18 |
|
94 |
root |
1.1 |
BEGIN { |
95 |
root |
1.108 |
our $VERSION = 4.748; |
96 |
root |
1.1 |
|
97 |
root |
1.67 |
# must be done here because the xs part expects it to exist |
98 |
|
|
# it might exist already because Coro::Specific created it. |
99 |
|
|
$Coro::current ||= { }; |
100 |
|
|
|
101 |
root |
1.101 |
{ |
102 |
|
|
# save/restore the handlers before/after overwriting %SIG magic |
103 |
|
|
local $SIG{__DIE__}; |
104 |
|
|
local $SIG{__WARN__}; |
105 |
|
|
|
106 |
|
|
XSLoader::load __PACKAGE__, $VERSION; |
107 |
|
|
} |
108 |
|
|
|
109 |
|
|
# need to do it after overwriting the %SIG magic |
110 |
|
|
$SIG{__DIE__} ||= \&diehook; |
111 |
|
|
$SIG{__WARN__} ||= \&warnhook; |
112 |
root |
1.1 |
} |
113 |
|
|
|
114 |
root |
1.51 |
use Exporter; |
115 |
root |
1.47 |
use base Exporter::; |
116 |
root |
1.5 |
|
117 |
root |
1.84 |
=head2 GLOBAL VARIABLES |
118 |
|
|
|
119 |
|
|
=over 4 |
120 |
|
|
|
121 |
|
|
=item $Coro::State::DIEHOOK |
122 |
|
|
|
123 |
|
|
This works similarly to C<$SIG{__DIE__}> and is used as the default die |
124 |
|
|
hook for newly created coroutines. This is useful if you want some generic |
125 |
|
|
logging function that works for all coroutines that don't set their own |
126 |
|
|
hook. |
127 |
|
|
|
128 |
|
|
When Coro::State is first loaded it will install these handlers for the |
129 |
root |
1.101 |
main program, too, unless they have been overwritten already. |
130 |
root |
1.84 |
|
131 |
root |
1.100 |
The default handlers provided will behave like the built-in ones (as if |
132 |
root |
1.84 |
they weren't there). |
133 |
|
|
|
134 |
root |
1.94 |
Note 1: You I<must> store a valid code reference in these variables, |
135 |
|
|
C<undef> will I<not> do. |
136 |
root |
1.84 |
|
137 |
root |
1.89 |
Note 2: The value of this variable will be shared among all coroutines, so |
138 |
root |
1.100 |
changing its value will change it in all coroutines that don't have their |
139 |
|
|
own die handler. |
140 |
root |
1.84 |
|
141 |
|
|
=item $Coro::State::WARNHOOK |
142 |
|
|
|
143 |
|
|
Similar to above die hook, but augments C<$SIG{__WARN__}>. |
144 |
|
|
|
145 |
|
|
=back |
146 |
|
|
|
147 |
|
|
=head2 FUNCTIONS |
148 |
|
|
|
149 |
|
|
=over 4 |
150 |
|
|
|
151 |
root |
1.65 |
=item $coro = new Coro::State [$coderef[, @args...]] |
152 |
root |
1.1 |
|
153 |
|
|
Create a new coroutine and return it. The first C<transfer> call to this |
154 |
root |
1.94 |
coroutine will start execution at the given coderef. |
155 |
|
|
|
156 |
|
|
If the subroutine returns the program will be terminated as if execution |
157 |
|
|
of the main program ended. |
158 |
|
|
|
159 |
|
|
If it throws an exception the program will terminate unless the exception |
160 |
|
|
is caught, exactly like in the main program. |
161 |
root |
1.74 |
|
162 |
|
|
Calling C<exit> in a coroutine does the same as calling it in the main |
163 |
|
|
program. |
164 |
root |
1.1 |
|
165 |
|
|
If the coderef is omitted this function will create a new "empty" |
166 |
|
|
coroutine, i.e. a coroutine that cannot be transfered to but can be used |
167 |
root |
1.104 |
to save the current coroutine state in (note that this is dangerous, as no |
168 |
|
|
reference is taken to ensure that the "current coroutine state" survives, |
169 |
|
|
the caller is responsible to ensure that the cloned state does not go |
170 |
|
|
away). |
171 |
root |
1.1 |
|
172 |
root |
1.55 |
The returned object is an empty hash which can be used for any purpose |
173 |
|
|
whatsoever, for example when subclassing Coro::State. |
174 |
|
|
|
175 |
root |
1.79 |
Certain variables are "localised" to each coroutine, that is, certain |
176 |
|
|
"global" variables are actually per coroutine. Not everything that would |
177 |
|
|
sensibly be localised currently is, and not everything that is localised |
178 |
|
|
makes sense for every application, and the future might bring changes. |
179 |
root |
1.1 |
|
180 |
root |
1.84 |
The following global variables can have different values per coroutine, |
181 |
|
|
and have the stated initial values: |
182 |
root |
1.5 |
|
183 |
root |
1.83 |
Variable Initial Value |
184 |
|
|
@_ whatever arguments were passed to the Coro |
185 |
|
|
$_ undef |
186 |
|
|
$@ undef |
187 |
|
|
$/ "\n" |
188 |
root |
1.88 |
$SIG{__DIE__} aliased to $Coro::State::DIEHOOK(*) |
189 |
|
|
$SIG{__WARN__} aliased to $Coro::State::WARNHOOK(*) |
190 |
root |
1.83 |
(default fh) *STDOUT |
191 |
root |
1.84 |
$1, $2... all regex results are initially undefined |
192 |
root |
1.2 |
|
193 |
root |
1.88 |
(*) reading the value from %SIG is not supported, but local'ising is. |
194 |
|
|
|
195 |
root |
1.70 |
If you feel that something important is missing then tell me. Also |
196 |
root |
1.2 |
remember that every function call that might call C<transfer> (such |
197 |
|
|
as C<Coro::Channel::put>) might clobber any global and/or special |
198 |
|
|
variables. Yes, this is by design ;) You can always create your own |
199 |
|
|
process abstraction model that saves these variables. |
200 |
root |
1.1 |
|
201 |
root |
1.9 |
The easiest way to do this is to create your own scheduling primitive like |
202 |
root |
1.94 |
in the code below, and use it in your coroutines: |
203 |
root |
1.1 |
|
204 |
root |
1.84 |
sub my_cede { |
205 |
root |
1.80 |
local ($;, ...); |
206 |
root |
1.84 |
Coro::cede; |
207 |
root |
1.1 |
} |
208 |
|
|
|
209 |
root |
1.79 |
=cut |
210 |
|
|
|
211 |
|
|
# this is called for each newly created C coroutine, |
212 |
|
|
# and is being artificially injected into the opcode flow. |
213 |
|
|
# its sole purpose is to call transfer() once so it knows |
214 |
|
|
# the stop level stack frame for stack sharing. |
215 |
|
|
sub _cctx_init { |
216 |
|
|
_set_stacklevel $_[0]; |
217 |
|
|
} |
218 |
|
|
|
219 |
root |
1.76 |
=item $state->call ($coderef) |
220 |
|
|
|
221 |
root |
1.94 |
Try to call the given C<$coderef> in the context of the given state. This |
222 |
root |
1.76 |
works even when the state is currently within an XS function, and can |
223 |
|
|
be very dangerous. You can use it to acquire stack traces etc. (see the |
224 |
|
|
Coro::Debug module for more details). The coderef MUST NOT EVER transfer |
225 |
|
|
to another state. |
226 |
|
|
|
227 |
|
|
=item $state->eval ($string) |
228 |
|
|
|
229 |
root |
1.94 |
Like C<call>, but eval's the string. Dangerous. |
230 |
root |
1.76 |
|
231 |
root |
1.90 |
=item $state->throw ($exception) |
232 |
|
|
|
233 |
|
|
Makes the coroutine throw the given exception as soon as it regains |
234 |
root |
1.94 |
control. |
235 |
root |
1.90 |
|
236 |
|
|
=item $state->swap_defsv |
237 |
|
|
|
238 |
|
|
=item $state->swap_defav |
239 |
|
|
|
240 |
|
|
Swap the current C<$_> (swap_defsv) or C<@_> (swap_defav) with the |
241 |
|
|
equivalent in the saved state of C<$state>. This can be used to give the |
242 |
|
|
coroutine a defined content for C<@_> and C<$_> before transfer'ing to it. |
243 |
|
|
|
244 |
root |
1.77 |
=item $state->trace ($flags) |
245 |
|
|
|
246 |
|
|
Internal function to control tracing. I just mention this so you can stay |
247 |
root |
1.90 |
away from abusing it. |
248 |
root |
1.77 |
|
249 |
root |
1.70 |
=item $prev->transfer ($next) |
250 |
|
|
|
251 |
|
|
Save the state of the current subroutine in C<$prev> and switch to the |
252 |
|
|
coroutine saved in C<$next>. |
253 |
|
|
|
254 |
|
|
The "state" of a subroutine includes the scope, i.e. lexical variables and |
255 |
|
|
the current execution state (subroutine, stack). |
256 |
|
|
|
257 |
root |
1.94 |
=item $state->has_cctx |
258 |
|
|
|
259 |
root |
1.105 |
Returns whether the state currently uses a cctx/C coroutine. An active |
260 |
root |
1.94 |
state always has a cctx, as well as the main program. Other states only |
261 |
|
|
use a cctxts when needed. |
262 |
|
|
|
263 |
|
|
=item $bytes = $state->rss |
264 |
|
|
|
265 |
|
|
Returns the memory allocated by the coroutine (which includes |
266 |
|
|
static structures, various perl stacks but NOT local variables, |
267 |
|
|
arguments or any C stack). |
268 |
|
|
|
269 |
root |
1.64 |
=item Coro::State::cctx_count |
270 |
|
|
|
271 |
|
|
Returns the number of C-level coroutines allocated. If this number is |
272 |
|
|
very high (more than a dozen) it might help to identify points of C-level |
273 |
|
|
recursion in your code and moving this into a separate coroutine. |
274 |
|
|
|
275 |
|
|
=item Coro::State::cctx_idle |
276 |
|
|
|
277 |
|
|
Returns the number of allocated but idle (free for reuse) C level |
278 |
root |
1.76 |
coroutines. Currently, Coro will limit the number of idle/unused cctxs to |
279 |
|
|
8. |
280 |
root |
1.64 |
|
281 |
root |
1.72 |
=item Coro::State::cctx_stacksize [$new_stacksize] |
282 |
|
|
|
283 |
|
|
Returns the current C stack size and optionally sets the new I<minimum> |
284 |
|
|
stack size to C<$new_stacksize> I<long>s. Existing stacks will not |
285 |
|
|
be changed, but Coro will try to replace smaller stacks as soon as |
286 |
root |
1.91 |
possible. Any Coro::State that starts to use a stack after this call is |
287 |
root |
1.94 |
guaranteed this minimum stack size. |
288 |
|
|
|
289 |
|
|
Please note that Coroutines will only need to use a C-level stack if the |
290 |
|
|
interpreter recurses or calls a function in a module that calls back into |
291 |
|
|
the interpreter, so use of this feature is usually never needed. |
292 |
root |
1.72 |
|
293 |
root |
1.92 |
=item Coro::State::force_cctx |
294 |
|
|
|
295 |
|
|
Forces the allocation of a C context for the currently running coroutine |
296 |
|
|
(if not already done). Apart from benchmarking there is little point |
297 |
|
|
in doing so, however. |
298 |
|
|
|
299 |
root |
1.76 |
=item @states = Coro::State::list |
300 |
|
|
|
301 |
|
|
Returns a list of all states currently allocated. |
302 |
|
|
|
303 |
root |
1.1 |
=cut |
304 |
|
|
|
305 |
root |
1.75 |
sub debug_desc { |
306 |
|
|
$_[0]{desc} |
307 |
|
|
} |
308 |
|
|
|
309 |
root |
1.1 |
1; |
310 |
|
|
|
311 |
|
|
=back |
312 |
|
|
|
313 |
|
|
=head1 BUGS |
314 |
|
|
|
315 |
root |
1.5 |
This module is not thread-safe. You must only ever use this module from |
316 |
root |
1.94 |
the same thread (this requirement might be removed in the future). |
317 |
root |
1.1 |
|
318 |
|
|
=head1 SEE ALSO |
319 |
|
|
|
320 |
|
|
L<Coro>. |
321 |
|
|
|
322 |
|
|
=head1 AUTHOR |
323 |
|
|
|
324 |
root |
1.41 |
Marc Lehmann <schmorp@schmorp.de> |
325 |
root |
1.39 |
http://home.schmorp.de/ |
326 |
root |
1.1 |
|
327 |
|
|
=cut |
328 |
|
|
|