/*
 * Copyright (C) 2009 Dan Carpenter.
 *
 * 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, see http://www.gnu.org/copyleft/gpl.txt
 */

/*
 * This is not a check.  It just saves an struct expression pointer 
 * whenever something is assigned.  This can be used later on by other scripts.
 */

#include "smatch.h"
#include "smatch_slist.h"
#include "smatch_extra.h"

int check_assigned_expr_id;
static int my_id;
static int link_id;

static struct expression *skip_mod;

static void undef(struct sm_state *sm, struct expression *mod_expr)
{
        if (mod_expr == skip_mod)
                return;
        set_state(my_id, sm->name, sm->sym, &undefined);
}

struct expression *get_assigned_expr(struct expression *expr)
{
        struct smatch_state *state;

        state = get_state_expr(my_id, expr);
        if (!state)
                return NULL;
        return (struct expression *)state->data;
}

struct expression *get_assigned_expr_name_sym(const char *name, struct symbol *sym)
{
        struct smatch_state *state;

        state = __get_state(my_id, name, sym);
        if (!state)
                return NULL;
        return (struct expression *)state->data;
}

static void match_assignment(struct expression *expr)
{
        static struct expression *ignored_expr;
        struct symbol *left_sym, *right_sym;
        char *left_name = NULL;
        char *right_name = NULL;

        if (expr->op != '=')
                return;
        if (is_fake_call(expr->right))
                return;
        if (__in_fake_struct_assign) {
                struct range_list *rl;

                if (!get_implied_rl(expr->right, &rl))
                        return;
                if (is_whole_rl(rl))
                        return;
        }

        if (expr->left == ignored_expr)
                return;
        ignored_expr = NULL;
        if (__in_fake_parameter_assign)
                ignored_expr = expr->left;

        left_name = expr_to_var_sym(expr->left, &left_sym);
        if (!left_name || !left_sym)
                goto free;
        set_state(my_id, left_name, left_sym, alloc_state_expr(strip_expr(expr->right)));

        right_name = expr_to_var_sym(expr->right, &right_sym);
        if (!right_name || !right_sym)
                goto free;

        store_link(link_id, right_name, right_sym, left_name, left_sym);

free:
        free_string(left_name);
        free_string(right_name);
}

static void record_param_assignment(struct expression *expr, int param, char *key, char *value)
{
        struct expression *arg, *right;
        struct symbol *sym;
        char *name;
        char *p;
        int right_param;

        while (expr->type == EXPR_ASSIGNMENT)
                expr = strip_expr(expr->right);
        if (!expr || expr->type != EXPR_CALL)
                return;

        p = strstr(value, "[$");
        if (!p)
                return;

        p += 2;
        right_param = strtol(p, &p, 10);
        if (*p != ']')
                return;

        arg = get_argument_from_call_expr(expr->args, param);
        right = get_argument_from_call_expr(expr->args, right_param);
        if (!right || !arg)
                return;
        name = get_variable_from_key(arg, key, &sym);
        if (!name || !sym)
                goto free;

        skip_mod = expr;
        set_state(my_id, name, sym, alloc_state_expr(right));
free:
        free_string(name);
}

void register_assigned_expr(int id)
{
        my_id = check_assigned_expr_id = id;
        set_dynamic_states(check_assigned_expr_id);
        add_hook(&match_assignment, ASSIGNMENT_HOOK_AFTER);
        add_modification_hook(my_id, &undef);
        select_return_states_hook(PARAM_SET, &record_param_assignment);
}

void register_assigned_expr_links(int id)
{
        link_id = id;
        set_dynamic_states(link_id);
        db_ignore_states(link_id);
        set_up_link_functions(my_id, link_id);
}