/**
* Helper Constructor.
*
* This is called when we join two flow scope chains. For example, when we combine the outcomes of the ON_TRUE
* and the ON_FALSE branch of an IF clause.
*
* @param \Scrutinizer\PhpAnalyzer\DataFlow\TypeInference\LinkedFlowScope $joinedScopeA
* @param \Scrutinizer\PhpAnalyzer\DataFlow\TypeInference\LinkedFlowScope $joinedScopeB
*
* @return FlatFlowScopeCache
*/
public static function createFromLinkedScopes(LinkedFlowScope $joinedScopeA, LinkedFlowScope $joinedScopeB)
{
$cache = new self();
// Always prefer the "real" scope to the faked-out bottom scope.
$cache->functionScope = $joinedScopeA->flowsFromBottom() ? $joinedScopeB->getFunctionScope() : $joinedScopeA->getFunctionScope();
$slotsA = $cache->symbols = $joinedScopeA->allFlowSlots();
$slotsB = $joinedScopeB->allFlowSlots();
// There are 5 different join cases:
// 1) The type is declared in joinedScopeA, not in joinedScopeB,
// and not in functionScope. Just use the one in A.
// 2) The type is declared in joinedScopeB, not in joinedScopeA,
// and not in functionScope. Just use the one in B.
// 3) The type is declared in functionScope and joinedScopeA, but
// not in joinedScopeB. Join the two types.
// 4) The type is declared in functionScope and joinedScopeB, but
// not in joinedScopeA. Join the two types.
// 5) The type is declared in joinedScopeA and joinedScopeB. Join
// the two types.
$symbolNames = array_unique(array_merge(array_keys($slotsA), array_keys($slotsB)));
foreach ($symbolNames as $name) {
$slotA = isset($slotsA[$name]) ? $slotsA[$name] : null;
$slotB = isset($slotsB[$name]) ? $slotsB[$name] : null;
$joinedType = null;
if (null === $slotB || $slotB->getType() === null) {
$fnSlot = $joinedScopeB->getFunctionScope()->getVar($name);
$fnSlotType = null === $fnSlot ? null : $fnSlot->getType();
if (null === $fnSlotType) {
// Case #1 -- The symbol was already inserted from A slots.
} else {
// Case #3
$joinedType = $slotA->getType()->getLeastSuperType($fnSlotType);
}
} else {
if (null === $slotA || $slotA->getType() === null) {
$fnSlot = $joinedScopeA->getFunctionScope()->getVar($name);
$fnSlotType = null === $fnSlot ? null : $fnSlot->getType();
if (null === $fnSlotType) {
// Case #2
$cache->symbols[$name] = $slotB;
} else {
// Case #4
$joinedType = $slotB->getType()->getLeastSuperType($fnSlotType);
}
} else {
// Case #5
$joinedType = $slotA->getType()->getLeastSuperType($slotB->getType());
}
}
if (null !== $joinedType) {
$cache->symbols[$name] = new SimpleSlot($name, $joinedType, true);
}
}
return $cache;
}
