static TRI_aql_node_t* OptimiseConstantFilter (TRI_aql_node_t* const node) {
if (TRI_GetBooleanNodeValueAql(node)) {
// filter expression is always true => remove it
LOG_TRACE("optimised away constant (true) filter");
return TRI_GetDummyNopNodeAql();
}
// filter expression is always false => invalidate surrounding scope(s)
LOG_TRACE("optimised away scope");
return TRI_GetDummyReturnEmptyNodeAql();
}
static TRI_aql_node_t* OptimiseFor (TRI_aql_statement_walker_t* const walker,
TRI_aql_node_t* node) {
TRI_aql_node_t* expression = TRI_AQL_NODE_MEMBER(node, 1);
if (expression->_type == TRI_AQL_NODE_LIST) {
// for statement with a list expression
if (expression->_members._length == 0) {
// list is empty => we can eliminate the for statement
LOG_TRACE("optimised away empty for loop");
return TRI_GetDummyReturnEmptyNodeAql();
}
}
return node;
}
size_t TRI_InvalidateStatementListAql (TRI_aql_statement_list_t* const list,
const size_t position) {
size_t i, n;
size_t start;
size_t scopes;
size_t ignoreScopes;
assert(list);
assert(position >= 0);
n = list->_statements._length;
// walk the scope from the specified position backwards until we find the start of the scope
scopes = 1;
ignoreScopes = 0;
i = position;
while (true) {
TRI_aql_node_t* node = StatementAt(list, i);
TRI_aql_node_type_e type = node->_type;
list->_statements._buffer[i] = TRI_GetDummyNopNodeAql();
start = i;
if (type == TRI_AQL_NODE_SCOPE_START) {
// node is a scope start
TRI_aql_scope_t* scope = (TRI_aql_scope_t*) TRI_AQL_NODE_DATA(node);
if (ignoreScopes > 0) {
// this is an inner, parallel scope that we can ignore
--ignoreScopes;
}
else {
if (scope->_type != TRI_AQL_SCOPE_FOR_NESTED) {
// we have reached the scope and need to stop
break;
}
scopes++;
}
}
else if (type == TRI_AQL_NODE_SCOPE_END) {
// we found the end of another scope
// we must remember how many other scopes we passed
ignoreScopes++;
}
if (i-- == 0) {
break;
}
}
assert(ignoreScopes == 0);
// remove from position forwards to scope end
i = position;
while (true) {
TRI_aql_node_t* node = StatementAt(list, i);
TRI_aql_node_type_e type = node->_type;
list->_statements._buffer[i] = TRI_GetDummyNopNodeAql();
if (type == TRI_AQL_NODE_SCOPE_START) {
++scopes;
}
else if (type == TRI_AQL_NODE_SCOPE_END) {
assert(scopes > 0);
if (--scopes == 0) {
break;
}
}
if (++i == n) {
break;
}
}
list->_statements._buffer[start] = TRI_GetDummyReturnEmptyNodeAql();
return start + 1;
}
size_t TRI_InvalidateStatementListAql (TRI_aql_statement_list_t* const list,
const size_t position) {
size_t i, n;
size_t start;
size_t scopes;
assert(list);
assert(position >= 0);
n = list->_statements._length;
// remove from position backwards to scope start
scopes = 1;
i = position;
while (true) {
TRI_aql_node_t* node = StatementAt(list, i);
TRI_aql_node_type_e type = node->_type;
list->_statements._buffer[i] = TRI_GetDummyNopNodeAql();
start = i;
if (type == TRI_AQL_NODE_SCOPE_START) {
TRI_aql_scope_t* scope = (TRI_aql_scope_t*) TRI_AQL_NODE_DATA(node);
if (scope->_type != TRI_AQL_SCOPE_FOR_NESTED) {
break;
}
scopes++;
}
if (i-- == 0) {
break;
}
}
// remove from position forwards to scope end
i = position;
while (true) {
TRI_aql_node_t* node = StatementAt(list, i);
TRI_aql_node_type_e type = node->_type;
list->_statements._buffer[i] = TRI_GetDummyNopNodeAql();
if (type == TRI_AQL_NODE_SCOPE_START) {
++scopes;
}
else if (type == TRI_AQL_NODE_SCOPE_END) {
assert(scopes > 0);
if (--scopes == 0) {
break;
}
}
if (++i == n) {
break;
}
}
list->_statements._buffer[start] = TRI_GetDummyReturnEmptyNodeAql();
return start + 1;
}
