Refactor QTestCharBuffer a bit

Use a static buffer for small strings, and making it oom safe.
We can now see messages up to 512 bytes even if we run out of memory
(important for OOM tests). Also, testlogging (< 512 bytes per line)
should again work without a single allocation.

Reviewed-By: Rohan McGovern <rohan.mcgovern@nokia.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/src/testlib/qabstracttestlogger.cpp b/src/testlib/qabstracttestlogger.cpp
index 6482ec9..2fa535e 100644
--- a/src/testlib/qabstracttestlogger.cpp
+++ b/src/testlib/qabstracttestlogger.cpp
@@ -43,8 +43,11 @@
 #include "QtTest/private/qtestlog_p.h"
 #include "QtTest/qtestassert.h"
 
+#include "QtCore/qbytearray.h"
+
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdarg.h>
 
 #ifndef Q_OS_WIN
 #include <unistd.h>
@@ -106,4 +109,48 @@ void QAbstractTestLogger::stopLogging()
     QTest::stream = 0;
 }
 
+namespace QTest
+{
+
+extern void filter_unprintable(char *str);
+
+/*! \internal
+ */
+int qt_asprintf(QTestCharBuffer *str, const char *format, ...)
+{
+    static const int MAXSIZE = 1024*1024*2;
+
+    Q_ASSERT(str);
+
+    int size = str->size();
+
+    va_list ap;
+    int res = 0;
+
+    for (;;) {
+        va_start(ap, format);
+        res = qvsnprintf(str->data(), size, format, ap);
+        va_end(ap);
+        str->data()[size - 1] = '\0';
+        if (res >= 0 && res < size) {
+            // We succeeded
+            break;
+        }
+        // buffer wasn't big enough, try again.
+        // Note, we're assuming that a result of -1 is always due to running out of space.
+        size *= 2;
+        if (size > MAXSIZE) {
+            break;
+        }
+        if (!str->reset(size))
+            break; // out of memory - take what we have
+    }
+
+    filter_unprintable(str->data());
+
+    return res;
+}
+
+}
+
 QT_END_NAMESPACE