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/******************************************************************************

 *

 * Module Name: pswalk - Parser routines to walk parsed op tree(s)

 *

 *****************************************************************************/

/*

 * Copyright (C) 2000 - 2004, R. Byron Moore

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions, and the following disclaimer,

 *    without modification.

 * 2. Redistributions in binary form must reproduce at minimum a disclaimer

 *    substantially similar to the "NO WARRANTY" disclaimer below

 *    ("Disclaimer") and any redistribution must be conditioned upon

 *    including a substantially similar Disclaimer requirement for further

 *    binary redistribution.

 * 3. Neither the names of the above-listed copyright holders nor the names

 *    of any contributors may be used to endorse or promote products derived

 *    from this software without specific prior written permission.

 *

 * Alternatively, this software may be distributed under the terms of the

 * GNU General Public License ("GPL") version 2 as published by the Free

 * Software Foundation.

 *

 * NO WARRANTY

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING

 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGES.

 */

#include <acpi/acpi.h>

#include <acpi/acparser.h>

#include <acpi/acdispat.h>

#define _COMPONENT          ACPI_PARSER

         ACPI_MODULE_NAME    ("pswalk")

/*******************************************************************************

 *

 * FUNCTION:    acpi_ps_get_next_walk_op

 *

 * PARAMETERS:  walk_state          - Current state of the walk

 *              Op                  - Current Op to be walked

 *              ascending_callback  - Procedure called when Op is complete

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Get the next Op in a walk of the parse tree.

 *

 ******************************************************************************/

acpi_status

acpi_ps_get_next_walk_op (

        struct acpi_walk_state          *walk_state,

        union acpi_parse_object         *op,

        acpi_parse_upwards              ascending_callback)

{

        union acpi_parse_object         *next;

        union acpi_parse_object         *parent;

        union acpi_parse_object         *grand_parent;

        acpi_status                     status;

        ACPI_FUNCTION_TRACE_PTR ("ps_get_next_walk_op", op);

        /* Check for a argument only if we are descending in the tree */

        if (walk_state->next_op_info != ACPI_NEXT_OP_UPWARD) {

                /* Look for an argument or child of the current op */

                next = acpi_ps_get_arg (op, 0);

                if (next) {

                        /* Still going downward in tree (Op is not completed yet) */

                        walk_state->prev_op     = op;

                        walk_state->next_op     = next;

                        walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;

                        return_ACPI_STATUS (AE_OK);

                }

                /*

                 * No more children, this Op is complete.  Save Next and Parent

                 * in case the Op object gets deleted by the callback routine

                 */

                next    = op->common.next;

                parent  = op->common.parent;

                walk_state->op    = op;

                walk_state->op_info = acpi_ps_get_opcode_info (op->common.aml_opcode);

                walk_state->opcode = op->common.aml_opcode;

                status = ascending_callback (walk_state);

                /*

                 * If we are back to the starting point, the walk is complete.

                 */

                if (op == walk_state->origin) {

                        /* Reached the point of origin, the walk is complete */

                        walk_state->prev_op     = op;

                        walk_state->next_op     = NULL;

                        return_ACPI_STATUS (status);

                }

                /*

                 * Check for a sibling to the current op.  A sibling means

                 * we are still going "downward" in the tree.

                 */

                if (next) {

                        /* There is a sibling, it will be next */

                        walk_state->prev_op     = op;

                        walk_state->next_op     = next;

                        walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;

                        /* Continue downward */

                        return_ACPI_STATUS (status);

                }

                /*

                 * Drop into the loop below because we are moving upwards in

                 * the tree

                 */

        }

        else {

                /*

                 * We are resuming a walk, and we were (are) going upward in the tree.

                 * So, we want to drop into the parent loop below.

                 */

                parent = op;

        }

        /*

         * Look for a sibling of the current Op's parent

         * Continue moving up the tree until we find a node that has not been

         * visited, or we get back to where we started.

         */

        while (parent) {

                /* We are moving up the tree, therefore this parent Op is complete */

                grand_parent = parent->common.parent;

                next        = parent->common.next;

                walk_state->op    = parent;

                walk_state->op_info = acpi_ps_get_opcode_info (parent->common.aml_opcode);

                walk_state->opcode = parent->common.aml_opcode;

                status = ascending_callback (walk_state);

                /*

                 * If we are back to the starting point, the walk is complete.

                 */

                if (parent == walk_state->origin) {

                        /* Reached the point of origin, the walk is complete */

                        walk_state->prev_op     = parent;

                        walk_state->next_op     = NULL;

                        return_ACPI_STATUS (status);

                }

                /*

                 * If there is a sibling to this parent (it is not the starting point

                 * Op), then we will visit it.

                 */

                if (next) {

                        /* found sibling of parent */

                        walk_state->prev_op     = parent;

                        walk_state->next_op     = next;

                        walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;

                        return_ACPI_STATUS (status);

                }

                /* No siblings, no errors, just move up one more level in the tree */

                op                  = parent;

                parent              = grand_parent;

                walk_state->prev_op = op;

        }

        /*

         * Got all the way to the top of the tree, we must be done!

         * However, the code should have terminated in the loop above

         */

        walk_state->next_op     = NULL;

        return_ACPI_STATUS (AE_OK);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ps_delete_completed_op

 *

 * PARAMETERS:  State           - Walk state

 *              Op              - Completed op

 *

 * RETURN:      AE_OK

 *

 * DESCRIPTION: Callback function for acpi_ps_get_next_walk_op(). Used during

 *              acpi_ps_delete_parse tree to delete Op objects when all sub-objects

 *              have been visited (and deleted.)

 *

 ******************************************************************************/

acpi_status

acpi_ps_delete_completed_op (

        struct acpi_walk_state          *walk_state)

{

        acpi_ps_free_op (walk_state->op);

        return (AE_OK);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ps_delete_parse_tree

 *

 * PARAMETERS:  subtree_root        - Root of tree (or subtree) to delete

 *

 * RETURN:      None

 *

 * DESCRIPTION: Delete a portion of or an entire parse tree.

 *

 ******************************************************************************/

void

acpi_ps_delete_parse_tree (

        union acpi_parse_object         *subtree_root)

{

        struct acpi_walk_state          *walk_state;

        struct acpi_thread_state        *thread;

        acpi_status                     status;

        ACPI_FUNCTION_TRACE_PTR ("ps_delete_parse_tree", subtree_root);

        if (!subtree_root) {

                return_VOID;

        }

        /* Create and initialize a new walk list */

        thread = acpi_ut_create_thread_state ();

        if (!thread) {

                return_VOID;

        }

        walk_state = acpi_ds_create_walk_state (0, NULL, NULL, thread);

        if (!walk_state) {

                return_VOID;

        }

        walk_state->parse_flags         = 0;

        walk_state->descending_callback = NULL;

        walk_state->ascending_callback  = NULL;

        walk_state->origin = subtree_root;

        walk_state->next_op = subtree_root;

        /* Head downward in the tree */

        walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;

        /* Visit all nodes in the subtree */

        while (walk_state->next_op) {

                status = acpi_ps_get_next_walk_op (walk_state, walk_state->next_op,

                                 acpi_ps_delete_completed_op);

                if (ACPI_FAILURE (status)) {

                        break;

                }

        }

        /* We are done with this walk */

        acpi_ut_delete_generic_state (ACPI_CAST_PTR (union acpi_generic_state, thread));

        acpi_ds_delete_walk_state (walk_state);

        return_VOID;

}