// Process a constant within the code. This is a direct copy of ScanAddress::ScanConstant
// with the addition of the locking.
void MTGCProcessMarkPointers::ScanConstant(byte *addressOfConstant, ScanRelocationKind code)
{
// If this code is in the local area there's the possibility that
// ScanObjectAddress could return an updated address for a
// constant within the code. This could happen if the code is
// in the allocation area or if it has been moved into the
// mutable/immutable area by the last incomplete partial GC.
// Constants can be aligned on any byte offset so another thread
// scanning the same code could see an invalid address if it read
// the constant while it was being updated. We put a lock round
// this just in case.
LocalMemSpace *space = gMem.LocalSpaceForAddress(addressOfConstant);
if (space != 0)
space->spaceLock.Lock();
PolyWord p = GetConstantValue(addressOfConstant, code);
if (space != 0)
space->spaceLock.Unlock();
if (! IS_INT(p))
{
PolyWord oldValue = p;
ScanAddress::ScanAddressAt(&p);
if (p != oldValue) // Update it if it has changed.
{
if (space != 0)
space->spaceLock.Lock();
SetConstantValue(addressOfConstant, p, code);
if (space != 0)
space->spaceLock.Unlock();
}
}
}
// The default action is to call the DEFAULT ScanAddressAt NOT the virtual which means that it calls
// ScanObjectAddress for the base address of the object referred to.
void ScanAddress::ScanConstant(byte *addressOfConstant, ScanRelocationKind code)
{
PolyWord p = GetConstantValue(addressOfConstant, code);
if (! IS_INT(p))
{
PolyWord oldValue = p;
ScanAddress::ScanAddressAt(&p);
if (p != oldValue) // Update it if it has changed.
SetConstantValue(addressOfConstant, p, code);
}
}
// How a button loads itself from a file
int MyButton::LoadLayout(FILE *fp, int &line, std::string &errmsg) {
char s[1024], arg[1024];
int braces = 0;
while ( fgets(s, sizeof(s)-1, fp) != 0 ) {
line++;
char *ss = skipwhite(s);
if ( *ss == '\n' || *ss == '\r' || *ss == 0 || *ss == '#' ) { // skip blank lines + comments
continue;
}
if ( *ss == '{' ) { // count open braces
++braces;
continue;
}
if ( *ss == '}' ) { // count close braces
if ( --braces <= 0 ) { break; }
else { continue; }
}
if ( sscanf(ss, "dtype %79s", arg) == 1 ) {
if ( SetDataTypeStr(arg) < 0 ) {
errmsg = std::string("unknown data type '") +
std::string(arg) +
std::string("'") +
std::string("\n") + std::string(s);
return(-1);
}
continue;
}
if ( sscanf(ss, "const %1023[^\n]\n", arg) == 1 ) {
SetConstantValue(arg);
continue;
}
// Got this far? Unknown command
errmsg = std::string("unknown button command") +
std::string("\n") + std::string(s);
return(-1);
}
return(0);
}
