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/* A stack holds a frame chain
* Copyright (C) 1996,1997,2000,2001, 2006, 2007, 2008, 2009 Free Software Foundation
*
* 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
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "libguile/_scm.h"
#include "libguile/eval.h"
#include "libguile/debug.h"
#include "libguile/continuations.h"
#include "libguile/struct.h"
#include "libguile/macros.h"
#include "libguile/procprop.h"
#include "libguile/modules.h"
#include "libguile/root.h"
#include "libguile/strings.h"
#include "libguile/vm.h" /* to capture vm stacks */
#include "libguile/frames.h" /* vm frames */
#include "libguile/validate.h"
#include "libguile/stacks.h"
#include "libguile/private-options.h"
/* {Stacks}
*
* The stack is represented as a struct that holds a frame. The frame itself is
* linked to the next frame, or #f.
*
* Stacks
* Constructor
* make-stack
* Selectors
* stack-id
* stack-ref
* Inspector
* stack-length
*/
static SCM stack_id_with_fp (SCM frame, SCM **fp);
/* Count number of debug info frames on a stack, beginning with FRAME.
*/
static long
stack_depth (SCM frame, SCM *fp)
{
long n;
/* count frames, skipping boot frames */
for (; scm_is_true (frame) && SCM_VM_FRAME_FP (frame) > fp;
frame = scm_frame_previous (frame))
++n;
return n;
}
/* Narrow STACK by cutting away stackframes (mutatingly).
*
* Inner frames (most recent) are cut by advancing the frames pointer.
* Outer frames are cut by decreasing the recorded length.
*
* Cut maximally INNER inner frames and OUTER outer frames using
* the keys INNER_KEY and OUTER_KEY.
*
* Frames are cut away starting at the end points and moving towards
* the center of the stack. The key is normally compared to the
* operator in application frames. Frames up to and including the key
* are cut.
*
* If INNER_KEY is #t a different scheme is used for inner frames:
*
* Frames up to but excluding the first source frame originating from
* a user module are cut, except for possible application frames
* between the user frame and the last system frame previously
* encountered.
*/
static void
narrow_stack (SCM stack, long inner, SCM inner_key, long outer, SCM outer_key)
{
unsigned long int len;
SCM frame;
len = SCM_STACK_LENGTH (stack);
frame = SCM_STACK_FRAME (stack);
/* Cut inner part. */
if (scm_is_eq (inner_key, SCM_BOOL_T))
{
/* Cut specified number of frames. */
for (; inner && len; --inner)
{
len--;
frame = scm_frame_previous (frame);
}
}
else
{
/* Cut until the given procedure is seen. */
for (; inner && len ; --inner)
{
SCM proc = scm_frame_procedure (frame);
len--;
frame = scm_frame_previous (frame);
if (scm_is_eq (proc, inner_key))
break;
}
}
SCM_SET_STACK_LENGTH (stack, len);
SCM_SET_STACK_FRAME (stack, frame);
/* Cut outer part. */
for (; outer && len ; --outer)
{
frame = scm_stack_ref (stack, scm_from_long (len - 1));
len--;
if (scm_is_eq (scm_frame_procedure (frame), outer_key))
break;
}
SCM_SET_STACK_LENGTH (stack, len);
}
/* Stacks
*/
SCM scm_stack_type;
SCM_DEFINE (scm_stack_p, "stack?", 1, 0, 0,
(SCM obj),
"Return @code{#t} if @var{obj} is a calling stack.")
#define FUNC_NAME s_scm_stack_p
{
return scm_from_bool(SCM_STACKP (obj));
}
#undef FUNC_NAME
SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
(SCM obj, SCM args),
"Create a new stack. If @var{obj} is @code{#t}, the current\n"
"evaluation stack is used for creating the stack frames,\n"
"otherwise the frames are taken from @var{obj} (which must be\n"
"either a debug object or a continuation).\n\n"
"@var{args} should be a list containing any combination of\n"
"integer, procedure and @code{#t} values.\n\n"
"These values specify various ways of cutting away uninteresting\n"
"stack frames from the top and bottom of the stack that\n"
"@code{make-stack} returns. They come in pairs like this:\n"
"@code{(@var{inner_cut_1} @var{outer_cut_1} @var{inner_cut_2}\n"
"@var{outer_cut_2} @dots{})}.\n\n"
"Each @var{inner_cut_N} can be @code{#t}, an integer, or a\n"
"procedure. @code{#t} means to cut away all frames up to but\n"
"excluding the first user module frame. An integer means to cut\n"
"away exactly that number of frames. A procedure means to cut\n"
"away all frames up to but excluding the application frame whose\n"
"procedure matches the specified one.\n\n"
"Each @var{outer_cut_N} can be an integer or a procedure. An\n"
"integer means to cut away that number of frames. A procedure\n"
"means to cut away frames down to but excluding the application\n"
"frame whose procedure matches the specified one.\n\n"
"If the @var{outer_cut_N} of the last pair is missing, it is\n"
"taken as 0.")
#define FUNC_NAME s_scm_make_stack
{
long n;
int maxp;
SCM frame;
SCM stack;
SCM id, *id_fp;
SCM inner_cut, outer_cut;
/* Extract a pointer to the innermost frame of whatever object
scm_make_stack was given. */
if (scm_is_eq (obj, SCM_BOOL_T))
{
SCM cont;
struct scm_vm_cont *c;
cont = scm_cdar (scm_vm_capture_continuations ());
c = SCM_VM_CONT_DATA (cont);
frame = scm_c_make_frame (cont, c->fp + c->reloc,
c->sp + c->reloc, c->ip,
c->reloc);
}
else if (SCM_VM_FRAME_P (obj))
frame = obj;
else if (SCM_CONTINUATIONP (obj))
{
scm_t_contregs *cont = SCM_CONTREGS (obj);
if (!scm_is_null (cont->vm_conts))
{ SCM vm_cont;
struct scm_vm_cont *data;
vm_cont = scm_cdr (scm_car (cont->vm_conts));
data = SCM_VM_CONT_DATA (vm_cont);
frame = scm_c_make_frame (vm_cont,
data->fp + data->reloc,
data->sp + data->reloc,
data->ip,
data->reloc);
} else
frame = SCM_BOOL_F;
}
else
{
SCM_WRONG_TYPE_ARG (SCM_ARG1, obj);
/* not reached */
}
/* FIXME: is this even possible? */
if (scm_is_true (frame)
&& SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
frame = scm_frame_previous (frame);
if (scm_is_false (frame))
return SCM_BOOL_F;
/* Get ID of the stack corresponding to the given frame. */
id = stack_id_with_fp (frame, &id_fp);
/* Count number of frames. Also get stack id tag and check whether
there are more stackframes than we want to record
(SCM_BACKTRACE_MAXDEPTH). */
id = SCM_BOOL_F;
maxp = 0;
n = stack_depth (frame, id_fp);
/* Make the stack object. */
stack = scm_make_struct (scm_stack_type, SCM_INUM0, SCM_EOL);
SCM_SET_STACK_LENGTH (stack, n);
SCM_SET_STACK_ID (stack, id);
SCM_SET_STACK_FRAME (stack, frame);
/* Narrow the stack according to the arguments given to scm_make_stack. */
SCM_VALIDATE_REST_ARGUMENT (args);
while (n > 0 && !scm_is_null (args))
{
inner_cut = SCM_CAR (args);
args = SCM_CDR (args);
if (scm_is_null (args))
{
outer_cut = SCM_INUM0;
}
else
{
outer_cut = SCM_CAR (args);
args = SCM_CDR (args);
}
narrow_stack (stack,
scm_is_integer (inner_cut) ? scm_to_int (inner_cut) : n,
scm_is_integer (inner_cut) ? 0 : inner_cut,
scm_is_integer (outer_cut) ? scm_to_int (outer_cut) : n,
scm_is_integer (outer_cut) ? 0 : outer_cut);
n = SCM_STACK_LENGTH (stack);
}
if (n > 0)
return stack;
else
return SCM_BOOL_F;
}
#undef FUNC_NAME
SCM_DEFINE (scm_stack_id, "stack-id", 1, 0, 0,
(SCM stack),
"Return the identifier given to @var{stack} by @code{start-stack}.")
#define FUNC_NAME s_scm_stack_id
{
SCM frame, *id_fp;
if (scm_is_eq (stack, SCM_BOOL_T))
{
struct scm_vm *vp = SCM_VM_DATA (scm_the_vm ());
frame = scm_c_make_frame (scm_the_vm (), vp->fp, vp->sp, vp->ip, 0);
}
else if (SCM_VM_FRAME_P (stack))
frame = stack;
else if (SCM_CONTINUATIONP (stack))
{
scm_t_contregs *cont = SCM_CONTREGS (stack);
if (!scm_is_null (cont->vm_conts))
{ SCM vm_cont;
struct scm_vm_cont *data;
vm_cont = scm_cdr (scm_car (cont->vm_conts));
data = SCM_VM_CONT_DATA (vm_cont);
frame = scm_c_make_frame (vm_cont,
data->fp + data->reloc,
data->sp + data->reloc,
data->ip,
data->reloc);
} else
frame = SCM_BOOL_F;
}
else
{
SCM_WRONG_TYPE_ARG (SCM_ARG1, stack);
/* not reached */
}
return stack_id_with_fp (frame, &id_fp);
}
#undef FUNC_NAME
static SCM
stack_id_with_fp (SCM frame, SCM **fp)
{
SCM holder = SCM_VM_FRAME_STACK_HOLDER (frame);
if (SCM_VM_CONT_P (holder))
{
*fp = NULL;
return SCM_BOOL_F;
}
else
{
*fp = NULL;
return SCM_BOOL_F;
}
}
SCM_DEFINE (scm_stack_ref, "stack-ref", 2, 0, 0,
(SCM stack, SCM index),
"Return the @var{index}'th frame from @var{stack}.")
#define FUNC_NAME s_scm_stack_ref
{
unsigned long int c_index;
SCM frame;
SCM_VALIDATE_STACK (1, stack);
c_index = scm_to_unsigned_integer (index, 0, SCM_STACK_LENGTH(stack)-1);
frame = SCM_STACK_FRAME (stack);
while (c_index--)
frame = scm_frame_previous (frame);
return frame;
}
#undef FUNC_NAME
SCM_DEFINE (scm_stack_length, "stack-length", 1, 0, 0,
(SCM stack),
"Return the length of @var{stack}.")
#define FUNC_NAME s_scm_stack_length
{
SCM_VALIDATE_STACK (1, stack);
return scm_from_long (SCM_STACK_LENGTH (stack));
}
#undef FUNC_NAME
void
scm_init_stacks ()
{
scm_stack_type = scm_make_vtable (scm_from_locale_string (SCM_STACK_LAYOUT),
SCM_UNDEFINED);
scm_set_struct_vtable_name_x (scm_stack_type,
scm_from_locale_symbol ("stack"));
#include "libguile/stacks.x"
}
/*
Local Variables:
c-file-style: "gnu"
End:
*/
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