// internal
bool asCModule::AreInterfacesEqual(asCObjectType *a, asCObjectType *b, asCArray<sObjectTypePair> &equals)
{
// An interface is considered equal to another if the following criterias apply:
//
// - The interface names are equal
// - The number of methods is equal
// - All the methods are equal
// - The order of the methods is equal
// - If a method returns or takes an interface by handle or reference, both interfaces must be equal
// ------------
// TODO: Study the possiblity of allowing interfaces where methods are declared in different orders to
// be considered equal. The compiler and VM can handle this, but it complicates the comparison of interfaces
// where multiple methods take different interfaces as parameters (or return values). Example:
//
// interface A
// {
// void f(B, C);
// void f(B);
// void f(C);
// }
//
// If 'void f(B)' in module A is compared against 'void f(C)' in module B, then the code will assume
// interface B in module A equals interface C in module B. Thus 'void f(B, C)' in module A won't match
// 'void f(C, B)' in module B.
// ------------
// Are both interfaces?
if( !a->IsInterface() || !b->IsInterface() )
return false;
// Are the names equal?
if( a->name != b->name )
return false;
// Are the number of methods equal?
if( a->methods.GetLength() != b->methods.GetLength() )
return false;
// Keep the number of equals in the list so we can restore it later if necessary
int prevEquals = (int)equals.GetLength();
// Are the methods equal to each other?
bool match = true;
for( unsigned int n = 0; n < a->methods.GetLength(); n++ )
{
match = false;
asCScriptFunction *funcA = (asCScriptFunction*)engine->GetFunctionDescriptorById(a->methods[n]);
asCScriptFunction *funcB = (asCScriptFunction*)engine->GetFunctionDescriptorById(b->methods[n]);
// funcB can be null if the module that created the interface has been
// discarded but the type has not yet been released by the engine.
if( funcB == 0 )
break;
// The methods must have the same name and the same number of parameters
if( funcA->name != funcB->name ||
funcA->parameterTypes.GetLength() != funcB->parameterTypes.GetLength() )
break;
// The return types must be equal. If the return type is an interface the interfaces must match.
if( !AreTypesEqual(funcA->returnType, funcB->returnType, equals) )
break;
match = true;
for( unsigned int p = 0; p < funcA->parameterTypes.GetLength(); p++ )
{
if( !AreTypesEqual(funcA->parameterTypes[p], funcB->parameterTypes[p], equals) ||
funcA->inOutFlags[p] != funcB->inOutFlags[p] )
{
match = false;
break;
}
}
if( !match )
break;
}
// For each of the new interfaces that we're assuming to be equal, we need to validate this
if( match )
{
for( unsigned int n = prevEquals; n < equals.GetLength(); n++ )
{
if( !AreInterfacesEqual(equals[n].a, equals[n].b, equals) )
{
match = false;
break;
}
}
}
if( !match )
{
// The interfaces doesn't match.
// Restore the list of previous equals before we go on, so
// the caller can continue comparing with another interface
equals.SetLength(prevEquals);
}
return match;
}
