mirror of
https://git.savannah.gnu.org/git/guile.git
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401 lines
10 KiB
C
401 lines
10 KiB
C
/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2004 Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#if HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <signal.h>
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#include "libguile/_scm.h"
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#include "libguile/eval.h"
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#include "libguile/throw.h"
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#include "libguile/root.h"
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#include "libguile/smob.h"
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#include "libguile/lang.h"
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#include "libguile/dynwind.h"
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#include "libguile/deprecation.h"
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#include "libguile/validate.h"
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#include "libguile/async.h"
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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/* {Asynchronous Events}
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*
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* There are two kinds of asyncs: system asyncs and user asyncs. The
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* two kinds have some concepts in commen but work slightly
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* differently and are not interchangeable.
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*
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* System asyncs are used to run arbitrary code at the next safe point
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* in a specified thread. You can use them to trigger execution of
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* Scheme code from signal handlers or to interrupt a thread, for
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* example.
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*
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* Each thread has a list of 'activated asyncs', which is a normal
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* Scheme list of procedures with zero arguments. When a thread
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* executes a SCM_ASYNC_TICK statement (which is included in
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* SCM_TICK), it will call all procedures on this list.
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*
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* Also, a thread will wake up when a procedure is added to its list
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* of active asyncs and call them. After that, it will go to sleep
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* again. (Not implemented yet.)
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*
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*
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* User asyncs are a little data structure that consists of a
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* procedure of zero arguments and a mark. There are functions for
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* setting the mark of a user async and for calling all procedures of
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* marked asyncs in a given list. Nothing you couldn't quickly
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* implement yourself.
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*/
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/* User asyncs. */
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static scm_t_bits tc16_async;
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/* cmm: this has SCM_ prefix because SCM_MAKE_VALIDATE expects it.
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this is ugly. */
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#define SCM_ASYNCP(X) SCM_TYP16_PREDICATE (tc16_async, X)
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#define VALIDATE_ASYNC(pos, a) SCM_MAKE_VALIDATE_MSG(pos, a, ASYNCP, "user async")
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#define ASYNC_GOT_IT(X) (SCM_CELL_WORD_0 (X) >> 16)
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#define SET_ASYNC_GOT_IT(X, V) (SCM_SET_CELL_WORD_0 ((X), SCM_TYP16 (X) | ((V) << 16)))
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#define ASYNC_THUNK(X) SCM_CELL_OBJECT_1 (X)
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static SCM
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async_gc_mark (SCM obj)
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{
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return ASYNC_THUNK (obj);
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}
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SCM_DEFINE (scm_async, "async", 1, 0, 0,
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(SCM thunk),
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"Create a new async for the procedure @var{thunk}.")
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#define FUNC_NAME s_scm_async
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{
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SCM_RETURN_NEWSMOB (tc16_async, SCM_UNPACK (thunk));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_async_mark, "async-mark", 1, 0, 0,
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(SCM a),
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"Mark the async @var{a} for future execution.")
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#define FUNC_NAME s_scm_async_mark
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{
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VALIDATE_ASYNC (1, a);
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SET_ASYNC_GOT_IT (a, 1);
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return SCM_UNSPECIFIED;
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_run_asyncs, "run-asyncs", 1, 0, 0,
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(SCM list_of_a),
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"Execute all thunks from the asyncs of the list @var{list_of_a}.")
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#define FUNC_NAME s_scm_run_asyncs
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{
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while (! SCM_NULL_OR_NIL_P (list_of_a))
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{
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SCM a;
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SCM_VALIDATE_CONS (1, list_of_a);
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a = SCM_CAR (list_of_a);
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VALIDATE_ASYNC (SCM_ARG1, a);
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if (ASYNC_GOT_IT (a))
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{
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SET_ASYNC_GOT_IT (a, 0);
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scm_call_0 (ASYNC_THUNK (a));
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}
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list_of_a = SCM_CDR (list_of_a);
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}
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return SCM_BOOL_T;
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}
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#undef FUNC_NAME
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/* System asyncs. */
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void
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scm_async_click ()
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{
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/* Reset pending_asyncs even when asyncs are blocked and not really
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executed.
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*/
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scm_root->pending_asyncs = 0;
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if (scm_root->block_asyncs == 0)
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{
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SCM asyncs;
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while (!scm_is_null(asyncs = scm_root->active_asyncs))
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{
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scm_root->active_asyncs = SCM_EOL;
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do
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{
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scm_call_0 (SCM_CAR (asyncs));
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asyncs = SCM_CDR (asyncs);
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}
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while (!scm_is_null(asyncs));
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}
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for (asyncs = scm_root->signal_asyncs; !scm_is_null(asyncs);
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asyncs = SCM_CDR (asyncs))
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{
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if (scm_is_true (SCM_CAR (asyncs)))
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{
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SCM proc = SCM_CAR (asyncs);
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SCM_SETCAR (asyncs, SCM_BOOL_F);
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scm_call_0 (proc);
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}
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}
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}
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}
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#if (SCM_ENABLE_DEPRECATED == 1)
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SCM_DEFINE (scm_system_async, "system-async", 1, 0, 0,
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(SCM thunk),
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"This function is deprecated. You can use @var{thunk} directly\n"
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"instead of explicitely creating an async object.\n")
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#define FUNC_NAME s_scm_system_async
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{
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scm_c_issue_deprecation_warning
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("'system-async' is deprecated. "
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"Use the procedure directly with 'system-async-mark'.");
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return thunk;
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}
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#undef FUNC_NAME
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#endif /* SCM_ENABLE_DEPRECATED == 1 */
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void
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scm_i_queue_async_cell (SCM c, scm_root_state *root)
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{
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SCM p = root->active_asyncs;
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SCM_SETCDR (c, SCM_EOL);
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if (p == SCM_EOL)
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root->active_asyncs = c;
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else
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{
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SCM pp;
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while ((pp = SCM_CDR(p)) != SCM_EOL)
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{
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if (SCM_CAR (p) == SCM_CAR (c))
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return;
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p = pp;
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}
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SCM_SETCDR (p, c);
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}
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root->pending_asyncs = 1;
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}
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SCM_DEFINE (scm_system_async_mark_for_thread, "system-async-mark", 1, 1, 0,
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(SCM proc, SCM thread),
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"Mark @var{proc} (a procedure with zero arguments) for future execution\n"
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"in @var{thread}. If @var{proc} has already been marked for\n"
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"@var{thread} but has not been executed yet, this call has no effect.\n"
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"If @var{thread} is omitted, the thread that called\n"
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"@code{system-async-mark} is used.\n\n"
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"This procedure is not safe to be called from C signal handlers. Use\n"
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"@code{scm_sigaction} or @code{scm_sigaction_for_thread} to install\n"
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"signal handlers.")
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#define FUNC_NAME s_scm_system_async_mark_for_thread
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{
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if (SCM_UNBNDP (thread))
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thread = scm_current_thread ();
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else
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{
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SCM_VALIDATE_THREAD (2, thread);
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if (scm_c_thread_exited_p (thread))
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SCM_MISC_ERROR ("thread has already exited", SCM_EOL);
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}
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scm_i_queue_async_cell (scm_cons (proc, SCM_BOOL_F),
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scm_i_thread_root (thread));
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return SCM_UNSPECIFIED;
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}
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#undef FUNC_NAME
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SCM
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scm_system_async_mark (SCM proc)
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#define FUNC_NAME s_scm_system_async_mark_for_thread
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{
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return scm_system_async_mark_for_thread (proc, SCM_UNDEFINED);
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_noop, "noop", 0, 0, 1,
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(SCM args),
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"Do nothing. When called without arguments, return @code{#f},\n"
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"otherwise return the first argument.")
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#define FUNC_NAME s_scm_noop
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{
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SCM_VALIDATE_REST_ARGUMENT (args);
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return (SCM_NULL_OR_NIL_P (args) ? SCM_BOOL_F : SCM_CAR (args));
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}
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#undef FUNC_NAME
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#if (SCM_ENABLE_DEPRECATED == 1)
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SCM_DEFINE (scm_unmask_signals, "unmask-signals", 0, 0, 0,
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(),
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"Unmask signals. The returned value is not specified.")
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#define FUNC_NAME s_scm_unmask_signals
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{
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scm_c_issue_deprecation_warning
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("'unmask-signals' is deprecated. "
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"Use 'call-with-blocked-asyncs' instead.");
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if (scm_root->block_asyncs == 0)
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SCM_MISC_ERROR ("signals already unmasked", SCM_EOL);
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scm_root->block_asyncs = 0;
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scm_async_click ();
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return SCM_UNSPECIFIED;
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_mask_signals, "mask-signals", 0, 0, 0,
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(),
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"Mask signals. The returned value is not specified.")
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#define FUNC_NAME s_scm_mask_signals
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{
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scm_c_issue_deprecation_warning
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("'mask-signals' is deprecated. Use 'call-with-blocked-asyncs' instead.");
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if (scm_root->block_asyncs > 0)
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SCM_MISC_ERROR ("signals already masked", SCM_EOL);
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scm_root->block_asyncs = 1;
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return SCM_UNSPECIFIED;
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}
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#undef FUNC_NAME
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#endif /* SCM_ENABLE_DEPRECATED == 1 */
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static void
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increase_block (void *unused)
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{
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scm_root->block_asyncs++;
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}
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static void
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decrease_block (void *unused)
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{
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scm_root->block_asyncs--;
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if (scm_root->block_asyncs == 0)
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scm_async_click ();
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}
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SCM_DEFINE (scm_call_with_blocked_asyncs, "call-with-blocked-asyncs", 1, 0, 0,
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(SCM proc),
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"Call @var{proc} with no arguments and block the execution\n"
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"of system asyncs by one level for the current thread while\n"
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"it is running. Return the value returned by @var{proc}.\n")
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#define FUNC_NAME s_scm_call_with_blocked_asyncs
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{
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return scm_internal_dynamic_wind (increase_block,
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(scm_t_inner) scm_call_0,
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decrease_block,
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(void *)proc, NULL);
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}
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#undef FUNC_NAME
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void *
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scm_c_call_with_blocked_asyncs (void *(*proc) (void *data), void *data)
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{
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return (void *)scm_internal_dynamic_wind (increase_block,
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(scm_t_inner) proc,
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decrease_block,
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data, NULL);
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}
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SCM_DEFINE (scm_call_with_unblocked_asyncs, "call-with-unblocked-asyncs", 1, 0, 0,
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(SCM proc),
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"Call @var{proc} with no arguments and unblock the execution\n"
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"of system asyncs by one level for the current thread while\n"
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"it is running. Return the value returned by @var{proc}.\n")
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#define FUNC_NAME s_scm_call_with_unblocked_asyncs
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{
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if (scm_root->block_asyncs == 0)
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SCM_MISC_ERROR ("asyncs already unblocked", SCM_EOL);
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return scm_internal_dynamic_wind (decrease_block,
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(scm_t_inner) scm_call_0,
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increase_block,
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(void *)proc, NULL);
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}
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#undef FUNC_NAME
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void *
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scm_c_call_with_unblocked_asyncs (void *(*proc) (void *data), void *data)
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{
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if (scm_root->block_asyncs == 0)
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scm_misc_error ("scm_c_call_with_unblocked_asyncs",
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"asyncs already unblocked", SCM_EOL);
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return (void *)scm_internal_dynamic_wind (decrease_block,
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(scm_t_inner) proc,
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increase_block,
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data, NULL);
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}
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void
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scm_frame_block_asyncs ()
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{
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scm_frame_rewind_handler (increase_block, NULL, SCM_F_WIND_EXPLICITLY);
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scm_frame_unwind_handler (decrease_block, NULL, SCM_F_WIND_EXPLICITLY);
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}
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void
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scm_frame_unblock_asyncs ()
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{
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if (scm_root->block_asyncs == 0)
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scm_misc_error ("scm_with_unblocked_asyncs",
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"asyncs already unblocked", SCM_EOL);
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scm_frame_rewind_handler (decrease_block, NULL, SCM_F_WIND_EXPLICITLY);
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scm_frame_unwind_handler (increase_block, NULL, SCM_F_WIND_EXPLICITLY);
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}
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void
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scm_init_async ()
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{
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scm_asyncs = SCM_EOL;
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tc16_async = scm_make_smob_type ("async", 0);
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scm_set_smob_mark (tc16_async, async_gc_mark);
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#include "libguile/async.x"
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}
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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