-/* Copyright (C) 1995,1996,1997,1998, 1999 Free Software Foundation, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this software; see the file COPYING. If not, write to
- * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307 USA
- *
- * As a special exception, the Free Software Foundation gives permission
- * for additional uses of the text contained in its release of GUILE.
- *
- * The exception is that, if you link the GUILE library with other files
- * to produce an executable, this does not by itself cause the
- * resulting executable to be covered by the GNU General Public License.
- * Your use of that executable is in no way restricted on account of
- * linking the GUILE library code into it.
- *
- * This exception does not however invalidate any other reasons why
- * the executable file might be covered by the GNU General Public License.
- *
- * This exception applies only to the code released by the
- * Free Software Foundation under the name GUILE. If you copy
- * code from other Free Software Foundation releases into a copy of
- * GUILE, as the General Public License permits, the exception does
- * not apply to the code that you add in this way. To avoid misleading
- * anyone as to the status of such modified files, you must delete
- * this exception notice from them.
- *
- * If you write modifications of your own for GUILE, it is your choice
- * whether to permit this exception to apply to your modifications.
- * If you do not wish that, delete this exception notice. */
-
-/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
- gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
-
-\f
-
-#include <stdio.h>
-#include "_scm.h"
-#include "stackchk.h"
-#include "dynwind.h"
-#include "eval.h"
-#include "smob.h"
-#include "pairs.h"
-#include "throw.h"
-#include "fluids.h"
-#include "ports.h"
-
-#include "root.h"
-\f
-
-/* Define this if you want to try out the stack allocation of cwdr's
- jumpbuf. It works for me but I'm still worried that the dynwinds
- might be able to make a mess. */
-
-#undef USE_STACKJMPBUF
-
-SCM scm_sys_protects[SCM_NUM_PROTECTS];
-
-long scm_tc16_root;
-
-#ifndef USE_THREADS
-struct scm_root_state *scm_root;
-#endif
-
-\f
-
-static SCM
-mark_root (SCM root)
-{
- scm_root_state *s = SCM_ROOT_STATE (root);
-
- scm_gc_mark (s->rootcont);
- scm_gc_mark (s->dynwinds);
- scm_gc_mark (s->continuation_stack);
- scm_gc_mark (s->continuation_stack_ptr);
- scm_gc_mark (s->progargs);
- scm_gc_mark (s->exitval);
- scm_gc_mark (s->cur_inp);
- scm_gc_mark (s->cur_outp);
- scm_gc_mark (s->cur_errp);
- scm_gc_mark (s->def_inp);
- scm_gc_mark (s->def_outp);
- scm_gc_mark (s->def_errp);
- /* No need to gc mark def_loadp */
- scm_gc_mark (s->fluids);
- scm_gc_mark (s->top_level_lookup_closure_var);
- scm_gc_mark (s->system_transformer);
- return SCM_ROOT_STATE (root) -> parent;
-}
-
-
-static int
-print_root (SCM exp,SCM port,scm_print_state *pstate)
-{
- scm_puts ("#<root ", port);
- scm_intprint(SCM_SEQ (SCM_ROOT_STATE (exp) -> rootcont), 16, port);
- scm_putc('>', port);
- return 1;
-}
-
-
-\f
-
-SCM
-scm_make_root (SCM parent)
-{
- SCM root;
- scm_root_state *root_state;
-
- root_state = (scm_root_state *) scm_must_malloc (sizeof (scm_root_state),
- "scm_make_root");
- if (SCM_ROOTP (parent))
- {
- memcpy (root_state, SCM_ROOT_STATE (parent), sizeof (scm_root_state));
- scm_copy_fluids (root_state);
- root_state->parent = parent;
- }
- else
- {
- root_state->parent = SCM_BOOL_F;
-
- /* Initialize everything right now, in case a GC happens early. */
- root_state->rootcont
- = root_state->dynwinds
- = root_state->continuation_stack
- = root_state->continuation_stack_ptr
- = root_state->progargs
- = root_state->exitval
- = root_state->cur_inp
- = root_state->cur_outp
- = root_state->cur_errp
- = root_state->def_inp
- = root_state->def_outp
- = root_state->def_errp
- = root_state->cur_loadp
- = root_state->fluids
- = root_state->system_transformer
- = root_state->top_level_lookup_closure_var
- = root_state->handle
- = root_state->parent
- = SCM_BOOL_F;
- }
- SCM_REDEFER_INTS;
- SCM_NEWSMOB (root, scm_tc16_root, root_state);
- root_state->handle = root;
- SCM_REALLOW_INTS;
- return root;
-}
-
-/* {call-with-dynamic-root}
- *
- * Suspending the current thread to evaluate a thunk on the
- * same C stack but under a new root.
- *
- * Calls to call-with-dynamic-root return exactly once (unless
- * the process is somehow exitted). */
-
-/* Some questions about cwdr:
-
- Couldn't the body just be a closure? Do we really need to pass
- args through to it?
-
- The semantics are a lot like catch's; in fact, we call
- scm_internal_catch to take care of that part of things. Wouldn't
- it be cleaner to say that uncaught throws just disappear into the
- ether (or print a message to stderr), and let the caller use catch
- themselves if they want to?
-
- -JimB */
-
-#if 0
-SCM scm_exitval; /* INUM with return value */
-#endif
-static int n_dynamic_roots = 0;
-
-
-/* cwdr fills out both of these structures, and then passes a pointer
- to them through scm_internal_catch to the cwdr_body and
- cwdr_handler functions, to tell them how to behave and to get
- information back from them.
-
- A cwdr is a lot like a catch, except there is no tag (all
- exceptions are caught), and the body procedure takes the arguments
- passed to cwdr as A1 and ARGS. The handler is also special since
- it is not directly run from scm_internal_catch. It is executed
- outside the new dynamic root. */
-
-struct cwdr_body_data {
- /* Arguments to pass to the cwdr body function. */
- SCM a1, args;
-
- /* Scheme procedure to use as body of cwdr. */
- SCM body_proc;
-};
-
-struct cwdr_handler_data {
- /* Do we need to run the handler? */
- int run_handler;
-
- /* The tag and args to pass it. */
- SCM tag, args;
-};
-
-
-/* Invoke the body of a cwdr, assuming that the throw handler has
- already been set up. DATA points to a struct set up by cwdr that
- says what proc to call, and what args to apply it to.
-
- With a little thought, we could replace this with scm_body_thunk,
- but I don't want to mess with that at the moment. */
-static SCM
-cwdr_body (void *data)
-{
- struct cwdr_body_data *c = (struct cwdr_body_data *) data;
-
- return scm_apply (c->body_proc, c->a1, c->args);
-}
-
-/* Record the fact that the body of the cwdr has thrown. Record
- enough information to invoke the handler later when the dynamic
- root has been deestablished. */
-
-static SCM
-cwdr_handler (void *data, SCM tag, SCM args)
-{
- struct cwdr_handler_data *c = (struct cwdr_handler_data *) data;
-
- c->run_handler = 1;
- c->tag = tag;
- c->args = args;
- return SCM_UNSPECIFIED;
-}
-
-/* This is the basic code for new root creation.
- *
- * WARNING! The order of actions in this routine is in many ways
- * critical. E. g., it is essential that an error doesn't leave Guile
- * in a messed up state. */
-
-SCM
-scm_internal_cwdr (scm_catch_body_t body, void *body_data,
- scm_catch_handler_t handler, void *handler_data,
- SCM_STACKITEM *stack_start)
-{
-#ifdef USE_STACKJMPBUF
- scm_contregs static_contregs;
-#endif
- int old_ints_disabled = scm_ints_disabled;
- SCM old_rootcont, old_winds;
- struct cwdr_handler_data my_handler_data;
- SCM answer;
-
- /* Create a fresh root continuation. */
- {
- SCM new_rootcont;
- SCM_NEWCELL (new_rootcont);
- SCM_REDEFER_INTS;
-#ifdef USE_STACKJMPBUF
- SCM_SET_CONTREGS (new_rootcont, &static_contregs);
-#else
- SCM_SET_CONTREGS (new_rootcont,
- scm_must_malloc (sizeof (scm_contregs),
- "inferior root continuation"));
-#endif
- SCM_SETCAR (new_rootcont, scm_tc7_contin);
- SCM_DYNENV (new_rootcont) = SCM_EOL;
- SCM_BASE (new_rootcont) = stack_start;
- SCM_SEQ (new_rootcont) = ++n_dynamic_roots;
-#ifdef DEBUG_EXTENSIONS
- SCM_DFRAME (new_rootcont) = 0;
-#endif
- old_rootcont = scm_rootcont;
- scm_rootcont = new_rootcont;
- SCM_REALLOW_INTS;
- }
-
- /* Exit caller's dynamic state.
- */
- old_winds = scm_dynwinds;
- scm_dowinds (SCM_EOL, scm_ilength (scm_dynwinds));
-#ifdef DEBUG_EXTENSIONS
- SCM_DFRAME (old_rootcont) = scm_last_debug_frame;
- scm_last_debug_frame = 0;
-#endif
-
- {
- my_handler_data.run_handler = 0;
- answer = scm_internal_catch (SCM_BOOL_T,
- body, body_data,
- cwdr_handler, &my_handler_data);
- }
-
- scm_dowinds (old_winds, - scm_ilength (old_winds));
- SCM_REDEFER_INTS;
-#ifdef USE_STACKCJMPBUF
- SCM_SET_CONTREGS (scm_rootcont, NULL);
-#endif
-#ifdef DEBUG_EXTENSIONS
- scm_last_debug_frame = SCM_DFRAME (old_rootcont);
-#endif
- scm_rootcont = old_rootcont;
- SCM_REALLOW_INTS;
- scm_ints_disabled = old_ints_disabled;
-
- /* Now run the real handler iff the body did a throw. */
- if (my_handler_data.run_handler)
- return handler (handler_data, my_handler_data.tag, my_handler_data.args);
- else
- return answer;
-}
-
-/* The original CWDR for invoking Scheme code with a Scheme handler. */
-
-static SCM
-cwdr (SCM proc, SCM a1, SCM args, SCM handler, SCM_STACKITEM *stack_start)
-{
- struct cwdr_body_data c;
-
- c.a1 = a1;
- c.args = args;
- c.body_proc = proc;
-
- return scm_internal_cwdr (cwdr_body, &c,
- scm_handle_by_proc, &handler,
- stack_start);
-}
-
-SCM_DEFINE (scm_call_with_dynamic_root, "call-with-dynamic-root", 2, 0, 0,
- (SCM thunk, SCM handler),
- "Evaluate @var{(thunk)} in a new dynamic context, returning its value.\n\n"
- "If an error occurs during evaluation, apply @var{handler} to the\n"
- "arguments to the throw, just as @code{throw} would. If this happens,\n"
- "@var{handler} is called outside the scope of the new root -- it is\n"
- "called in the same dynamic context in which\n"
- "@code{call-with-dynamic-root} was evaluated.\n\n"
- "If @var{thunk} captures a continuation, the continuation is rooted at\n"
- "the call to @var{thunk}. In particular, the call to\n"
- "@code{call-with-dynamic-root} is not captured. Therefore,\n"
- "@code{call-with-dynamic-root} always returns at most one time.\n\n"
- "Before calling @var{thunk}, the dynamic-wind chain is un-wound back to\n"
- "the root and a new chain started for @var{thunk}. Therefore, this call\n"
- "may not do what you expect:\n\n"
- "@example\n"
- ";; Almost certainly a bug:\n"
- "(with-output-to-port\n"
- " some-port\n\n"
- " (lambda ()\n"
- " (call-with-dynamic-root\n"
- " (lambda ()\n"
- " (display 'fnord)\n"
- " (newline))\n"
- " (lambda (errcode) errcode))))\n"
- "@end example\n\n"
- "The problem is, on what port will @samp{fnord\n"
- "} be displayed? You\n"
- "might expect that because of the @code{with-output-to-port} that\n"
- "it will be displayed on the port bound to @code{some-port}. But it\n"
- "probably won't -- before evaluating the thunk, dynamic winds are\n"
- "unwound, including those created by @code{with-output-to-port}.\n"
- "So, the standard output port will have been re-set to its default value\n"
- "before @code{display} is evaluated.\n\n"
- "(This function was added to Guile mostly to help calls to functions in C\n"
- "libraries that can not tolerate non-local exits or calls that return\n"
- "multiple times. If such functions call back to the interpreter, it should\n"
- "be under a new dynamic root.)")
-#define FUNC_NAME s_scm_call_with_dynamic_root
-{
- SCM_STACKITEM stack_place;
- return cwdr (thunk, SCM_EOL, SCM_EOL, handler, &stack_place);
-}
-#undef FUNC_NAME
-
-SCM_DEFINE (scm_dynamic_root, "dynamic-root", 0, 0, 0,
- (),
- "Return an object representing the current dynamic root.\n\n"
- "These objects are only useful for comparison using @code{eq?}.\n"
- "They are currently represented as numbers, but your code should\n"
- "in no way depend on this.")
-#define FUNC_NAME s_scm_dynamic_root
-{
- return scm_ulong2num (SCM_SEQ (scm_root->rootcont));
-}
-#undef FUNC_NAME
-
-SCM
-scm_apply_with_dynamic_root (SCM proc, SCM a1, SCM args, SCM handler)
-{
- SCM_STACKITEM stack_place;
- return cwdr (proc, a1, args, handler, &stack_place);
-}
-
-\f
-
-/* Call thunk(closure) underneath a top-level error handler.
- * If an error occurs, pass the exitval through err_filter and return it.
- * If no error occurs, return the value of thunk.
- */
-
-
-#ifdef _UNICOS
-typedef int setjmp_type;
-#else
-typedef long setjmp_type;
-#endif
-
-
-
-SCM
-scm_call_catching_errors (SCM (*thunk)(), SCM (*err_filter)(), void *closure)
-{
- SCM answer;
- setjmp_type i;
-#ifdef DEBUG_EXTENSIONS
- SCM_DFRAME (scm_rootcont) = scm_last_debug_frame;
-#endif
- i = setjmp (SCM_JMPBUF (scm_rootcont));
- scm_stack_checking_enabled_p = SCM_STACK_CHECKING_P;
- if (!i)
- {
- scm_gc_heap_lock = 0;
- answer = thunk (closure);
- }
- else
- {
- scm_gc_heap_lock = 1;
- answer = err_filter (scm_exitval, closure);
- }
- return answer;
-}
-
-void
-scm_init_root ()
-{
- scm_tc16_root = scm_make_smob_type_mfpe ("root", sizeof (struct scm_root_state),
- mark_root, NULL, print_root, NULL);
-
-#include "root.x"
-}
-
-/*
- Local Variables:
- c-file-style: "gnu"
- End:
-*/
+/* Copyright (C) 1995,1996,1997,1998,1999,2000, 2001, 2002, 2006, 2008 Free Software Foundation, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+
+\f
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+
+#include "libguile/_scm.h"
+#include "libguile/stackchk.h"
+#include "libguile/dynwind.h"
+#include "libguile/eval.h"
+#include "libguile/smob.h"
+#include "libguile/pairs.h"
+#include "libguile/throw.h"
+#include "libguile/fluids.h"
+#include "libguile/ports.h"
+
+#include "libguile/root.h"
+\f
+
+SCM scm_sys_protects[SCM_NUM_PROTECTS];
+
+\f
+
+/* {call-with-dynamic-root}
+ *
+ * Suspending the current thread to evaluate a thunk on the
+ * same C stack but under a new root.
+ *
+ * Calls to call-with-dynamic-root return exactly once (unless
+ * the process is somehow exitted). */
+
+/* cwdr fills out both of these structures, and then passes a pointer
+ to them through scm_internal_catch to the cwdr_body and
+ cwdr_handler functions, to tell them how to behave and to get
+ information back from them.
+
+ A cwdr is a lot like a catch, except there is no tag (all
+ exceptions are caught), and the body procedure takes the arguments
+ passed to cwdr as A1 and ARGS. The handler is also special since
+ it is not directly run from scm_internal_catch. It is executed
+ outside the new dynamic root. */
+
+struct cwdr_body_data {
+ /* Arguments to pass to the cwdr body function. */
+ SCM a1, args;
+
+ /* Scheme procedure to use as body of cwdr. */
+ SCM body_proc;
+};
+
+struct cwdr_handler_data {
+ /* Do we need to run the handler? */
+ int run_handler;
+
+ /* The tag and args to pass it. */
+ SCM tag, args;
+};
+
+
+/* Invoke the body of a cwdr, assuming that the throw handler has
+ already been set up. DATA points to a struct set up by cwdr that
+ says what proc to call, and what args to apply it to.
+
+ With a little thought, we could replace this with scm_body_thunk,
+ but I don't want to mess with that at the moment. */
+static SCM
+cwdr_body (void *data)
+{
+ struct cwdr_body_data *c = (struct cwdr_body_data *) data;
+
+ return scm_apply (c->body_proc, c->a1, c->args);
+}
+
+/* Record the fact that the body of the cwdr has thrown. Record
+ enough information to invoke the handler later when the dynamic
+ root has been deestablished. */
+
+static SCM
+cwdr_handler (void *data, SCM tag, SCM args)
+{
+ struct cwdr_handler_data *c = (struct cwdr_handler_data *) data;
+
+ c->run_handler = 1;
+ c->tag = tag;
+ c->args = args;
+ return SCM_UNSPECIFIED;
+}
+
+SCM
+scm_internal_cwdr (scm_t_catch_body body, void *body_data,
+ scm_t_catch_handler handler, void *handler_data,
+ SCM_STACKITEM *stack_start)
+{
+ struct cwdr_handler_data my_handler_data;
+ SCM answer, old_winds;
+
+ /* Exit caller's dynamic state.
+ */
+ old_winds = scm_i_dynwinds ();
+ scm_dowinds (SCM_EOL, scm_ilength (old_winds));
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+ scm_dynwind_current_dynamic_state (scm_make_dynamic_state (SCM_UNDEFINED));
+
+ my_handler_data.run_handler = 0;
+ answer = scm_i_with_continuation_barrier (body, body_data,
+ cwdr_handler, &my_handler_data,
+ NULL, NULL);
+
+ scm_dynwind_end ();
+
+ /* Enter caller's dynamic state.
+ */
+ scm_dowinds (old_winds, - scm_ilength (old_winds));
+
+ /* Now run the real handler iff the body did a throw. */
+ if (my_handler_data.run_handler)
+ return handler (handler_data, my_handler_data.tag, my_handler_data.args);
+ else
+ return answer;
+}
+
+/* The original CWDR for invoking Scheme code with a Scheme handler. */
+
+static SCM
+cwdr (SCM proc, SCM a1, SCM args, SCM handler, SCM_STACKITEM *stack_start)
+{
+ struct cwdr_body_data c;
+
+ c.a1 = a1;
+ c.args = args;
+ c.body_proc = proc;
+
+ return scm_internal_cwdr (cwdr_body, &c,
+ scm_handle_by_proc, &handler,
+ stack_start);
+}
+
+SCM_DEFINE (scm_call_with_dynamic_root, "call-with-dynamic-root", 2, 0, 0,
+ (SCM thunk, SCM handler),
+ "Call @var{thunk} with a new dynamic state and within"
+ "a continuation barrier. The @var{handler} catches all"
+ "otherwise uncaught throws and executes within the same"
+ "dynamic context as @var{thunk}.")
+#define FUNC_NAME s_scm_call_with_dynamic_root
+{
+ SCM_STACKITEM stack_place;
+ return cwdr (thunk, SCM_EOL, SCM_EOL, handler, &stack_place);
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_dynamic_root, "dynamic-root", 0, 0, 0,
+ (),
+ "Return an object representing the current dynamic root.\n\n"
+ "These objects are only useful for comparison using @code{eq?}.\n")
+#define FUNC_NAME s_scm_dynamic_root
+{
+ return SCM_I_CURRENT_THREAD->continuation_root;
+}
+#undef FUNC_NAME
+
+SCM
+scm_apply_with_dynamic_root (SCM proc, SCM a1, SCM args, SCM handler)
+{
+ SCM_STACKITEM stack_place;
+ return cwdr (proc, a1, args, handler, &stack_place);
+}
+
+\f
+
+void
+scm_init_root ()
+{
+#include "libguile/root.x"
+}
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/
HCoop / bpt / guile.git / blobdiff