Method IsJumpValid

source/script2.cpp:9117–9153

Label *Line::IsJumpValid(Label &aTargetLabel, bool aSilent)
// Returns aTargetLabel is the jump is valid, or NULL otherwise.
{
	// aTargetLabel can be NULL if this Goto's target is the physical end of the script.
	// And such a destination is always valid, regardless of where aOrigin is.
	// UPDATE: It's no longer possible for the destination of a Goto to be
	// NULL because the script loader has ensured that the end of the script always has
	// an extra ACT_EXIT that serves as an anchor for any final labels in the script:
	//if (aTargetLabel == NULL)
	//	return OK;
	// The above check is also necessary to avoid dereferencing a NULL pointer below.

	if (!CheckValidFinallyJump(aTargetLabel.mJumpToLine, aSilent))
		return NULL;

	Line *parent_line_of_label_line;
	if (   !(parent_line_of_label_line = aTargetLabel.mJumpToLine->mParentLine)   )
		// A Goto can always jump to a point anywhere in the outermost layer
		// (i.e. outside all blocks) without restriction (except from inside a
		// function to outside, but in that case the label would not be found):
		return &aTargetLabel; // Indicate success.

	// So now we know this Goto is attempting to jump into a block somewhere.  Is that
	// block a legal place to jump?:

	for (Line *ancestor = mParentLine; ancestor != NULL; ancestor = ancestor->mParentLine)
		if (parent_line_of_label_line == ancestor)
			// Since aTargetLabel is in the same block as the Goto line itself (or a block
			// that encloses that block), it's allowed:
			return &aTargetLabel; // Indicate success.
	// This can happen if the Goto's target is at a deeper level than it, or if the target
	// is at a more shallow level but is in some block totally unrelated to it!
	// Returns FAIL by default, which is what we want because that value is zero:
	if (!aSilent)
		LineError(_T("A Goto must not jump into a block that doesn't enclose it."));
	return NULL;
}


BOOL Line::CheckValidFinallyJump(Line* jumpTarget, bool aSilent)