ede/ede-panel/applets/start-menu/MenuRules.cpp

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2009-10-03 11:33:08 +04:00
#include <edelib/Debug.h>
#include "MenuRules.h"
#include "DesktopEntry.h"
typedef list<bool> Stack;
typedef list<bool>::iterator StackIt;
#if 0
static char *rules_str[] = {
"None",
"Filename",
"Category",
"And",
"Or",
"Not",
"All"
};
#endif
MenuRules *menu_rules_new(void) {
MenuRules *r = new MenuRules;
r->rule_operator = MENU_RULES_OPERATOR_NONE;
return r;
}
MenuRules *menu_rules_append_rule(MenuRulesList &rules, short rule, const char *data) {
MenuRules *r = menu_rules_new();
r->rule_operator = rule;
if(data)
r->data = data;
/* NOTE: things are evaluated recursively, so we push deepest rule at the top */
rules.push_front(r);
return r;
}
void menu_rules_delete(MenuRules *r) {
if(!r->subrules.empty()) {
MenuRulesListIt it = r->subrules.begin(), it_end = r->subrules.end();
while(it != it_end) {
menu_rules_delete(*it);
it = r->subrules.erase(it);
}
}
delete r;
}
/*
* Rules are evaluated starting from the deepest one, and are much more like
* lisp expressions. Each rule behaves like function, returning false or true and top function
* gets applied on those results.
*
* TODO: this case will not work (KDE 3.5.x applications.menu):
* <And>
* <Or>
* <Category>c1</Category>
* <Category>c2</Category>
* <Category>c3</Category>
* </Or>
* <Not><Category>c4</Category></Not>
* </And>
*
* because due recrusion '<Not>...</Not>' result will be calculated inside '<Or>...</Or>' expression and
* '<And>' will receive the only one value.
*/
static void eval_with_stack(MenuRules *m, DesktopEntry *en, Stack &result_stack) {
if(!m->subrules.empty()) {
MenuRulesListIt it = m->subrules.begin(), it_end = m->subrules.end();
/* go to the deepest node */
for(; it != it_end; ++it)
eval_with_stack(*it, en, result_stack);
}
/* this will always evaluate to true so all items can be included */
if(m->rule_operator == MENU_RULES_OPERATOR_ALL) {
result_stack.push_front(true);
return;
}
if(m->rule_operator == MENU_RULES_OPERATOR_FILENAME) {
bool st = (m->data == en->get_id());
result_stack.push_front(st);
return;
}
if(m->rule_operator == MENU_RULES_OPERATOR_CATEGORY) {
bool st = en->in_category(m->data.c_str());
result_stack.push_front(st);
return;
}
if(m->rule_operator == MENU_RULES_OPERATOR_AND) {
StackIt it = result_stack.begin(), it_end = result_stack.end();
/* 'and' always evalutes to true */
bool st = true;
while(it != it_end) {
st &= *it;
it = result_stack.erase(it);
}
result_stack.push_front(st);
return;
}
/* operators 'not' and 'or' behaves much the same, except 'not' reverse the result additionally */
if(m->rule_operator == MENU_RULES_OPERATOR_OR || m->rule_operator == MENU_RULES_OPERATOR_NOT) {
StackIt it = result_stack.begin(), it_end = result_stack.end();
/* 'or' and 'not' always evalutes to false */
bool st = false;
while(it != it_end) {
st |= *it;
it = result_stack.erase(it);
}
if(m->rule_operator == MENU_RULES_OPERATOR_NOT)
st = !st;
result_stack.push_front(st);
return;
}
}
bool menu_rules_eval(MenuRules *m, DesktopEntry *en) {
Stack result_stack;
eval_with_stack(m, en, result_stack);
if(result_stack.size() == 1)
goto get_first;
else {
/*
* From the spec: "Each rule in a list of rules has a logical OR relationship, that is, desktop entries
* which match any rule are included in the menu."
*/
bool result = false;
StackIt it = result_stack.begin(), it_end = result_stack.end();
while(it != it_end) {
result |= *it;
result_stack.erase(it);
}
return result;
}
get_first:
return result_stack.front();
}