Make Qt exception safer.

Squashed commit of the branch haralds-haralds-qt-s60-topics/topic/exceptions,
which also contains the full history.

Rev-By: Harald Fernengel
Rev-By: Ralf Engels

1 files changed, 18 insertions, 7 deletions

diff --git a/src/corelib/tools/qregexp.cpp b/src/corelib/tools/qregexp.cpp
index e1c3921..f357956 100644
--- a/src/corelib/tools/qregexp.cpp
+++ b/src/corelib/tools/qregexp.cpp
@@ -1297,14 +1297,20 @@ void QRegExpMatchState::prepareForMatch(QRegExpEngine *eng)
     int ns = eng->s.size(); // number of states
     int ncap = eng->ncap;
 #ifndef QT_NO_REGEXP_OPTIM
-    slideTabSize = qMax(eng->minl + 1, 16);
+    int newSlideTabSize = qMax(eng->minl + 1, 16);
 #else
-    slideTabSize = 0;
+    int newSlideTabSize = 0;
 #endif
     int numCaptures = eng->numCaptures();
-    capturedSize = 2 + 2 * numCaptures;
-    bigArray = (int *)realloc(bigArray, ((3 + 4 * ncap) * ns + 4 * ncap + slideTabSize + capturedSize)*sizeof(int));
+    int newCapturedSize = 2 + 2 * numCaptures;
+    bigArray = (int *)realloc(bigArray, ((3 + 4 * ncap) * ns + 4 * ncap + newSlideTabSize + newCapturedSize)*sizeof(int));
+    Q_CHECK_PTR(bigArray);
 
+    // set all internal variables only _after_ bigArray is realloc'ed
+    // to prevent a broken regexp in oom case
+
+    slideTabSize = newSlideTabSize;
+    capturedSize = newCapturedSize;
     inNextStack = bigArray;
     memset(inNextStack, -1, ns * sizeof(int));
     curStack = inNextStack + ns;
@@ -3281,10 +3287,15 @@ static void derefEngine(QRegExpEngine *eng, const QRegExpEngineKey &key)
 #if !defined(QT_NO_REGEXP_OPTIM)
         if (globalEngineCache()) {
             QMutexLocker locker(mutex());
-            globalEngineCache()->insert(key, eng, 4 + key.pattern.length() / 4);
-        }
-        else
+            QT_TRY {
+                globalEngineCache()->insert(key, eng, 4 + key.pattern.length() / 4);
+            } QT_CATCH(const std::bad_alloc &) {
+                // in case of an exception (e.g. oom), just delete the engine
+                delete eng;
+            }
+        } else {
             delete eng;
+        }
 #else
         Q_UNUSED(key);
         delete eng;