/* Copyright (C) 1997, 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id: icontext.c,v 1.6 2000/09/19 19:00:42 lpd Exp $ */
/* Context state operations */
#include "ghost.h"
#include "gsstruct.h"		/* for gxalloc.h */
#include "gxalloc.h"
#include "errors.h"
#include "stream.h"		/* for files.h */
#include "files.h"
#include "idict.h"
#include "igstate.h"
#include "icontext.h"
#include "interp.h"
#include "isave.h"
#include "dstack.h"
#include "estack.h"
#include "store.h"

/* Declare the GC descriptors for embedded objects. */
extern_st(st_gs_dual_memory);
extern_st(st_ref_stack);
extern_st(st_dict_stack);
extern_st(st_exec_stack);
extern_st(st_op_stack);

/* GC descriptors */
private 
CLEAR_MARKS_PROC(context_state_clear_marks)
{
    gs_context_state_t *const pcst = vptr;

    r_clear_attrs(&pcst->stdio[0], l_mark);
    r_clear_attrs(&pcst->stdio[1], l_mark);
    r_clear_attrs(&pcst->stdio[2], l_mark);
    r_clear_attrs(&pcst->userparams, l_mark);
}
private 
ENUM_PTRS_WITH(context_state_enum_ptrs, gs_context_state_t *pcst) {
    index -= 5;
    if (index < st_gs_dual_memory_num_ptrs)
	return ENUM_USING(st_gs_dual_memory, &pcst->memory,
			  sizeof(pcst->memory), index);
    index -= st_gs_dual_memory_num_ptrs;
    if (index < st_dict_stack_num_ptrs)
	return ENUM_USING(st_dict_stack, &pcst->dict_stack,
			  sizeof(pcst->dict_stack), index);
    index -= st_dict_stack_num_ptrs;
    if (index < st_exec_stack_num_ptrs)
	return ENUM_USING(st_exec_stack, &pcst->exec_stack,
			  sizeof(pcst->exec_stack), index);
    index -= st_exec_stack_num_ptrs;
    return ENUM_USING(st_op_stack, &pcst->op_stack,
		      sizeof(pcst->op_stack), index);
    }
    ENUM_PTR(0, gs_context_state_t, pgs);
    case 1: ENUM_RETURN_REF(&pcst->stdio[0]);
    case 2: ENUM_RETURN_REF(&pcst->stdio[1]);
    case 3: ENUM_RETURN_REF(&pcst->stdio[2]);
    case 4: ENUM_RETURN_REF(&pcst->userparams);
ENUM_PTRS_END
private RELOC_PTRS_WITH(context_state_reloc_ptrs, gs_context_state_t *pcst);
    RELOC_PTR(gs_context_state_t, pgs);
    RELOC_USING(st_gs_dual_memory, &pcst->memory, sizeof(pcst->memory));
    RELOC_REF_VAR(pcst->stdio[0]);
    RELOC_REF_VAR(pcst->stdio[1]);
    RELOC_REF_VAR(pcst->stdio[2]);
    RELOC_REF_VAR(pcst->userparams);
    r_clear_attrs(&pcst->userparams, l_mark);
    RELOC_USING(st_dict_stack, &pcst->dict_stack, sizeof(pcst->dict_stack));
    RELOC_USING(st_exec_stack, &pcst->exec_stack, sizeof(pcst->exec_stack));
    RELOC_USING(st_op_stack, &pcst->op_stack, sizeof(pcst->op_stack));
RELOC_PTRS_END
public_st_context_state();

/* Allocate the state of a context. */
int
context_state_alloc(gs_context_state_t ** ppcst,
		    const ref *psystem_dict,
		    const gs_dual_memory_t * dmem)
{
    gs_ref_memory_t *mem = dmem->space_local;
    gs_context_state_t *pcst = *ppcst;
    int code;
    int i;

    if (pcst == 0) {
	pcst = gs_alloc_struct((gs_memory_t *) mem, gs_context_state_t,
			       &st_context_state, "context_state_alloc");
	if (pcst == 0)
	    return_error(e_VMerror);
    }
    code = gs_interp_alloc_stacks(mem, pcst);
    if (code < 0)
	goto x0;
    /*
     * We have to initialize the dictionary stack early,
     * for far-off references to systemdict.
     */
    pcst->dict_stack.system_dict = *psystem_dict;
    pcst->dict_stack.min_size = 0;
    pcst->pgs = int_gstate_alloc(dmem);
    if (pcst->pgs == 0) {
	code = gs_note_error(e_VMerror);
	goto x1;
    }
    pcst->memory = *dmem;
    pcst->language_level = 1;
    make_false(&pcst->array_packing);
    make_int(&pcst->binary_object_format, 0);
    pcst->rand_state = rand_state_initial;
    pcst->usertime_total = 0;
    pcst->keep_usertime = false;
    pcst->in_superexec = 0;
    {	/*
	 * Create an empty userparams dictionary of the right size.
	 * If we can't determine the size, pick an arbitrary one.
	 */
	ref *puserparams;
	uint size;
	ref *system_dict = &pcst->dict_stack.system_dict;

	if (dict_find_string(system_dict, "userparams", &puserparams) >= 0)
	    size = dict_length(puserparams);
	else
	    size = 20;
	code = dict_alloc(pcst->memory.space_local, size, &pcst->userparams);
	if (code < 0)
	    goto x2;
	/* PostScript code initializes the user parameters. */
    }
    pcst->scanner_options = 0;
    /* The initial stdio values are bogus.... */
    make_file(&pcst->stdio[0], a_readonly | avm_invalid_file_entry, 1,
	      invalid_file_entry);
    make_file(&pcst->stdio[1], a_all | avm_invalid_file_entry, 1,
	      invalid_file_entry);
    make_file(&pcst->stdio[2], a_all | avm_invalid_file_entry, 1,
	      invalid_file_entry);
    for (i = countof(pcst->memory.spaces_indexed); --i >= 0;)
	if (dmem->spaces_indexed[i] != 0)
	    ++(dmem->spaces_indexed[i]->num_contexts);
    *ppcst = pcst;
    return 0;
  x2:gs_state_free(pcst->pgs);
  x1:gs_interp_free_stacks(mem, pcst);
  x0:if (*ppcst == 0)
	gs_free_object((gs_memory_t *) mem, pcst, "context_state_alloc");
    return code;
}

/* Load the interpreter state from a context. */
int
context_state_load(gs_context_state_t * i_ctx_p)
{
    gs_ref_memory_t *lmem = iimemory_local;
    ref *system_dict = systemdict;
    uint space = r_space(system_dict);
    dict_stack_t *dstack = &idict_stack;
    int code;

    /*
     * Disable save checking, and space check for systemdict, while
     * copying dictionaries.
     */
    alloc_set_not_in_save(idmemory);
    r_set_space(system_dict, avm_max);
    /*
     * Switch references from systemdict to local objects.
     * userdict.localdicts holds these objects.  We could optimize this by
     * only doing it if we're changing to a different local VM relative to
     * the same global VM, but the cost is low enough relative to other
     * things that we don't bother.
     */
    {
	ref_stack_t *rdstack = &dstack->stack;
	const ref *puserdict =
	    ref_stack_index(rdstack, ref_stack_count(rdstack) - 1 -
			    dstack->userdict_index);
	ref *plocaldicts;

	if (dict_find_string(puserdict, "localdicts", &plocaldicts) > 0 &&
	    r_has_type(plocaldicts, t_dictionary)
	    ) {
	    dict_copy(plocaldicts, system_dict, dstack);
	}
    }
    /*
     * Set systemdict.userparams to the saved copy, and then
     * set the actual user parameters.  Note that we must disable both
     * space checking and save checking while doing this.  Also,
     * we must do this after copying localdicts (if required), because
     * userparams also appears in localdicts.
     */
    code = dict_put_string(system_dict, "userparams", &i_ctx_p->userparams,
			   dstack);
    if (code >= 0)
	code = set_user_params(i_ctx_p, &i_ctx_p->userparams);
    r_set_space(system_dict, space);
    if (lmem->save_level > 0)
	alloc_set_in_save(idmemory);
    estack_clear_cache(&iexec_stack);
    dstack_set_top(&idict_stack);
    return code;
}

/* Store the interpreter state in a context. */
int
context_state_store(gs_context_state_t * pcst)
{
    ref_stack_cleanup(&pcst->dict_stack.stack);
    ref_stack_cleanup(&pcst->exec_stack.stack);
    ref_stack_cleanup(&pcst->op_stack.stack);
    /*
     * The user parameters in systemdict.userparams are kept
     * up to date by PostScript code, but we still need to save
     * systemdict.userparams to get the correct l_new flag.
     */
    {
	ref *puserparams;
	/* We need i_ctx_p for access to the d_stack. */
	i_ctx_t *i_ctx_p = pcst;

	if (dict_find_string(systemdict, "userparams", &puserparams) < 0)
	    return_error(e_Fatal);
	pcst->userparams = *puserparams;
    }
    return 0;
}

/* Free the contents of the state of a context, always to its local VM. */
/* Return a mask of which of its VMs, if any, we freed. */
int
context_state_free(gs_context_state_t * pcst)
{
    gs_ref_memory_t *mem = pcst->memory.space_local;
    int freed = 0;
    int i;

    /*
     * If this context is the last one referencing a particular VM
     * (local / global / system), free the entire VM space;
     * otherwise, just free the context-related structures.
     */
    for (i = countof(pcst->memory.spaces_indexed); --i >= 0;) {
	if (pcst->memory.spaces_indexed[i] != 0 &&
	    !--(pcst->memory.spaces_indexed[i]->num_contexts)
	    ) {
/****** FREE THE ENTIRE SPACE ******/
	    freed |= 1 << i;
	}
    }
    /*
     * If we freed any spaces at all, we must have freed the local
     * VM where the context structure and its substructures were
     * allocated.
     */
    if (freed)
	return freed;
    {
	gs_state *pgs = pcst->pgs;

	gs_grestoreall(pgs);
	/* Patch the saved pointer so we can do the last grestore. */
	{
	    gs_state *saved = gs_state_saved(pgs);

	    gs_state_swap_saved(saved, saved);
	}
	gs_grestore(pgs);
	gs_state_swap_saved(pgs, (gs_state *) 0);
	gs_state_free(pgs);
    }
/****** FREE USERPARAMS ******/
    gs_interp_free_stacks(mem, pcst);
    return 0;
}
