Fix QTextEngine overflow caused by extremely long text

Internally, QTextEngine use int to calculate most of the layout data
required. If a string longer than 2^24 is passed into either QTextEngine
or classes using it (QStackTextEngine, QPainter, QFontMetrics, etc.),
overflow will happen because the memory size required to allocate for
layout will become too large for int to handle. This patch will prevent
these cases and add error handling mechanism for relevant code.

Task-number: QT-3658
Reviewed-by: Eskil Abrahamsen Blomfeldt
(cherry picked from commit 05bb249c2ad3ee15eb205a806f8546c105683096)

0 files changed, 0 insertions, 0 deletions