/* Copyright (C) 1999 artofcode LLC.  All rights reserved.
  
  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 of the License, 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 program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gsmemret.c,v 1.2.6.1.2.1 2003/01/17 00:49:03 giles Exp $ */
/* Retrying memory allocator */

#include "gx.h"
#include "gsmemret.h"
#include "gserrors.h"

/* Raw memory procedures */
private gs_memory_proc_alloc_bytes(gs_retrying_alloc_bytes_immovable);
private gs_memory_proc_resize_object(gs_retrying_resize_object);
private gs_memory_proc_free_object(gs_forward_free_object);
private gs_memory_proc_stable(gs_retrying_stable);
private gs_memory_proc_status(gs_forward_status);
private gs_memory_proc_free_all(gs_forward_free_all);
private gs_memory_proc_consolidate_free(gs_forward_consolidate_free);

/* Object memory procedures */
private gs_memory_proc_alloc_bytes(gs_retrying_alloc_bytes);
private gs_memory_proc_alloc_struct(gs_retrying_alloc_struct);
private gs_memory_proc_alloc_struct(gs_retrying_alloc_struct_immovable);
private gs_memory_proc_alloc_byte_array(gs_retrying_alloc_byte_array);
private gs_memory_proc_alloc_byte_array(gs_retrying_alloc_byte_array_immovable);
private gs_memory_proc_alloc_struct_array(gs_retrying_alloc_struct_array);
private gs_memory_proc_alloc_struct_array(gs_retrying_alloc_struct_array_immovable);
private gs_memory_proc_object_size(gs_forward_object_size);
private gs_memory_proc_object_type(gs_forward_object_type);
private gs_memory_proc_alloc_string(gs_retrying_alloc_string);
private gs_memory_proc_alloc_string(gs_retrying_alloc_string_immovable);
private gs_memory_proc_resize_string(gs_retrying_resize_string);
private gs_memory_proc_free_string(gs_forward_free_string);
private gs_memory_proc_register_root(gs_retrying_register_root);
private gs_memory_proc_unregister_root(gs_forward_unregister_root);
private gs_memory_proc_enable_free(gs_forward_enable_free);
private const gs_memory_procs_t retrying_procs = {
    /* Raw memory procedures */
    gs_retrying_alloc_bytes_immovable,
    gs_retrying_resize_object,
    gs_forward_free_object,
    gs_retrying_stable,
    gs_forward_status,
    gs_forward_free_all,
    gs_forward_consolidate_free,
    /* Object memory procedures */
    gs_retrying_alloc_bytes,
    gs_retrying_alloc_struct,
    gs_retrying_alloc_struct_immovable,
    gs_retrying_alloc_byte_array,
    gs_retrying_alloc_byte_array_immovable,
    gs_retrying_alloc_struct_array,
    gs_retrying_alloc_struct_array_immovable,
    gs_forward_object_size,
    gs_forward_object_type,
    gs_retrying_alloc_string,
    gs_retrying_alloc_string_immovable,
    gs_retrying_resize_string,
    gs_forward_free_string,
    gs_retrying_register_root,
    gs_forward_unregister_root,
    gs_forward_enable_free
};

/* Define a vacuous recovery procedure. */
private gs_memory_recover_status_t
no_recover_proc(gs_memory_retrying_t *rmem, void *proc_data)
{
    return RECOVER_STATUS_NO_RETRY;
}

/* ---------- Public constructors/destructors ---------- */

/* Initialize a gs_memory_retrying_t */
int				/* -ve error code or 0 */
gs_memory_retrying_init(
		      gs_memory_retrying_t * rmem,	/* allocator to init */
		      gs_memory_t * target	/* allocator to wrap */
)
{
    rmem->stable_memory = 0;
    rmem->procs = retrying_procs;
    rmem->target = target;
    gs_memory_retrying_set_recover(rmem, no_recover_proc, NULL);
    return 0;
}

/* Set the recovery closure of a retrying memory manager. */
void
gs_memory_retrying_set_recover(gs_memory_retrying_t *rmem,
			       gs_memory_recover_proc_t recover_proc,
			       void *recover_proc_data)
{
    rmem->recover_proc = recover_proc;
    rmem->recover_proc_data = recover_proc_data;
}

/* Release a retrying memory manager. */
/* Note that this has no effect on the target. */
void
gs_memory_retrying_release(gs_memory_retrying_t *rmem)
{
    gs_memory_free_all((gs_memory_t *)rmem, FREE_ALL_STRUCTURES,
		       "gs_memory_retrying_release");
}

/* ---------- Accessors ------------- */

/* Retrieve this allocator's target */
gs_memory_t *
gs_memory_retrying_target(const gs_memory_retrying_t *rmem)
{
    return rmem->target;
}

/* -------- Private members just wrap retrying around a gs_memory --- */

/*
 * Contrary to our usual practice, we don't use BEGIN/END here, because
 * that causes some compilers to give bogus error messages.
 */

#define DO_FORWARD(call_target)\
	gs_memory_retrying_t * const rmem = (gs_memory_retrying_t *)mem;\
	gs_memory_t *const target = rmem->target;\
\
	call_target

#define RETURN_RETRYING(result_type, call_target)\
	gs_memory_retrying_t * const rmem = (gs_memory_retrying_t *)mem;\
	gs_memory_t *const target = rmem->target;\
	result_type temp;\
	gs_memory_recover_status_t retry = RECOVER_STATUS_RETRY_OK;\
\
	for (;;) {\
	    temp = call_target;\
	    if (temp != 0 || retry != RECOVER_STATUS_RETRY_OK)\
		break;\
	    retry = rmem->recover_proc(rmem, rmem->recover_proc_data);\
	}\
	return temp

/* Procedures */
private void
gs_forward_free_all(gs_memory_t * mem, uint free_mask, client_name_t cname)
{
    gs_memory_retrying_t * const rmem = (gs_memory_retrying_t *)mem;
    gs_memory_t * const target = rmem->target;

    /* Only free the structures and the allocator itself. */
    rmem->target = 0;
    if (free_mask & FREE_ALL_ALLOCATOR)
	gs_free_object(target, rmem, cname);
}
private void
gs_forward_consolidate_free(gs_memory_t * mem)
{
    DO_FORWARD(target->procs.consolidate_free(target));
}
private byte *
gs_retrying_alloc_bytes(gs_memory_t * mem, uint size, client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.alloc_bytes(target, size, cname)
		    );
}
private byte *
gs_retrying_alloc_bytes_immovable(gs_memory_t * mem, uint size,
				client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.alloc_bytes_immovable(target, size, cname)
		    );
}
private void *
gs_retrying_alloc_struct(gs_memory_t * mem, gs_memory_type_ptr_t pstype,
		       client_name_t cname)
{
    RETURN_RETRYING(
		    void *,
		    target->procs.alloc_struct(target, pstype, cname)
		    );
}
private void *
gs_retrying_alloc_struct_immovable(gs_memory_t * mem,
			   gs_memory_type_ptr_t pstype, client_name_t cname)
{
    RETURN_RETRYING(
		    void *,
		    target->procs.alloc_struct_immovable(target, pstype, cname)
		    );
}
private byte *
gs_retrying_alloc_byte_array(gs_memory_t * mem, uint num_elements, uint elt_size,
			   client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.alloc_byte_array(target, num_elements,
						   elt_size, cname)
		    );
}
private byte *
gs_retrying_alloc_byte_array_immovable(gs_memory_t * mem, uint num_elements,
				     uint elt_size, client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.alloc_byte_array_immovable(target,
							num_elements, elt_size,
							cname)
		    );
}
private void *
gs_retrying_alloc_struct_array(gs_memory_t * mem, uint num_elements,
			   gs_memory_type_ptr_t pstype, client_name_t cname)
{
    RETURN_RETRYING(
		    void *,
		    target->procs.alloc_struct_array(target, num_elements,
						     pstype, cname)
		    );
}
private void *
gs_retrying_alloc_struct_array_immovable(gs_memory_t * mem, uint num_elements,
			   gs_memory_type_ptr_t pstype, client_name_t cname)
{
    RETURN_RETRYING(
		    void *,
		    target->procs.alloc_struct_array_immovable(target,
							num_elements, pstype,
						        cname)
		    );
}
private void *
gs_retrying_resize_object(gs_memory_t * mem, void *obj, uint new_num_elements,
			client_name_t cname)
{
    RETURN_RETRYING(
		    void *,
		    target->procs.resize_object(target, obj, new_num_elements,
						cname)
		    );
}
private uint
gs_forward_object_size(gs_memory_t * mem, const void *ptr)
{
    DO_FORWARD(return target->procs.object_size(target, ptr));
}
private gs_memory_type_ptr_t
gs_forward_object_type(gs_memory_t * mem, const void *ptr)
{
    DO_FORWARD(return target->procs.object_type(target, ptr));
}
private void
gs_forward_free_object(gs_memory_t * mem, void *ptr, client_name_t cname)
{
    DO_FORWARD(target->procs.free_object(target, ptr, cname));
}
private byte *
gs_retrying_alloc_string(gs_memory_t * mem, uint nbytes, client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.alloc_string(target, nbytes, cname)
		    );
}
private byte *
gs_retrying_alloc_string_immovable(gs_memory_t * mem, uint nbytes,
				 client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.alloc_string_immovable(target, nbytes, cname)
		    );
}
private byte *
gs_retrying_resize_string(gs_memory_t * mem, byte * data, uint old_num,
			uint new_num,
			client_name_t cname)
{
    RETURN_RETRYING(
		    byte *,
		    target->procs.resize_string(target, data, old_num, new_num,
						cname)
		    );
}
private void
gs_forward_free_string(gs_memory_t * mem, byte * data, uint nbytes,
		      client_name_t cname)
{
    DO_FORWARD(target->procs.free_string(target, data, nbytes, cname));
}
private int
gs_retrying_register_root(gs_memory_t * mem, gs_gc_root_t * rp,
			gs_ptr_type_t ptype, void **up, client_name_t cname)
{
    RETURN_RETRYING(
		    int,
		    target->procs.register_root(target, rp, ptype, up, cname)
		    );
}
private void
gs_forward_unregister_root(gs_memory_t * mem, gs_gc_root_t * rp,
			  client_name_t cname)
{
    DO_FORWARD(target->procs.unregister_root(target, rp, cname));
}
private gs_memory_t *
gs_retrying_stable(gs_memory_t * mem)
{
    if (!mem->stable_memory) {
	gs_memory_retrying_t * const rmem = (gs_memory_retrying_t *)mem;
	gs_memory_t *stable = gs_memory_stable(rmem->target);

	if (stable == rmem->target)
	    mem->stable_memory = mem;
	else {
	    gs_memory_retrying_t *retrying_stable = (gs_memory_retrying_t *)
		gs_alloc_bytes(stable, sizeof(*rmem), "gs_retrying_stable");

	    if (retrying_stable) {
		int code = gs_memory_retrying_init(retrying_stable, stable);

		if (code < 0)
		    gs_free_object(stable, retrying_stable, "gs_retrying_stable");
		else
		    mem->stable_memory = (gs_memory_t *)retrying_stable;
	    }
	}
    }
    return mem->stable_memory;
}
private void
gs_forward_status(gs_memory_t * mem, gs_memory_status_t * pstat)
{
    DO_FORWARD(target->procs.status(target, pstat));
}
private void
gs_forward_enable_free(gs_memory_t * mem, bool enable)
{
    DO_FORWARD(target->procs.enable_free(target, enable));
}