Throw error when a macro terminates while a local q-reg is edited.

This is only a problem if the macro created the local Q-Register table
(i.e. not when called with ":M") but resulted in segfaults.
Since we do not want to save in a Q-Reg whether it is local
(and that wouldn't suffice anyway), we do it in the Q-Register table
cleanup. The corresponding QRegisterTable::clear() must be called
explicitly, since the RBTree::clear() called on destruction does not
and cannot throw errors.
If QRegisterTable::clear() has been called successfully, the default object
destructor will not do much. If it has thrown an error, the destructor
will clean up the remaining Q-Registers.

1 files changed, 24 insertions, 0 deletions

diff --git a/src/qregisters.cpp b/src/qregisters.cpp
index fdb804b..223a707 100644
--- a/src/qregisters.cpp
+++ b/src/qregisters.cpp
@@ -275,6 +275,30 @@ QRegisterTable::edit(QRegister *reg)
 	QRegisters::current = reg;
 }
 
+/*
+ * This is similar to RBTree::clear() but
+ * has the advantage that we can check whether some
+ * register is currently edited.
+ * Since this is not a destructor, we can throw
+ * errors.
+ * Therefore this method should be called before
+ * a (local) QRegisterTable is deleted.
+ */
+void
+QRegisterTable::clear(void)
+{
+	QRegister *cur;
+
+	while ((cur = (QRegister *)min())) {
+		if (cur == QRegisters::current)
+			throw Error("Currently edited Q-Register \"%s\" "
+			            "cannot be discarded", cur->name);
+
+		remove(cur);
+		delete cur;
+	}
+}
+
 void
 QRegisterStack::UndoTokenPush::run(void)
 {