qEnvironmentVariableIntValue: fix the case of a non-numeric value

The documentation says that it's equivalent to
    qgetenv(varName).toInt()

But the implementation wasn't. QByteArray::toInt() verifies that the
entire string was consumed, so QByteArray("1a").toInt() == 0, but
qstrtoll alone doesn't. That is, qstrtoll("1a", ...) == 1.

The implementation also detected the base, a behavior I kept. Instead, I
updated the documentation.

Change-Id: I0031aa609e714ae983c3fffd14676ea6061a9268
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

1 files changed, 14 insertions, 7 deletions

diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index 22fc20d47e..14853b3687 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -3259,20 +3259,26 @@ bool qEnvironmentVariableIsEmpty(const char *varName) Q_DECL_NOEXCEPT
 
     Equivalent to
     \code
-    qgetenv(varName).toInt()
+    qgetenv(varName).toInt(ok, 0)
     \endcode
     except that it's much faster, and can't throw exceptions.
 
+    \note there's a limit on the length of the value, which is sufficient for
+    all valid values of int, not counting leading zeroes or spaces. Values that
+    are too long will either be truncated or this function will set \a ok to \c
+    false.
+
     \sa qgetenv(), qEnvironmentVariableIsSet()
 */
 int qEnvironmentVariableIntValue(const char *varName, bool *ok) Q_DECL_NOEXCEPT
 {
-    QMutexLocker locker(&environmentMutex);
-#if defined(_MSC_VER) && _MSC_VER >= 1400
-    // we provide a buffer that can hold any int value:
     static const int NumBinaryDigitsPerOctalDigit = 3;
     static const int MaxDigitsForOctalInt =
         (std::numeric_limits<uint>::digits + NumBinaryDigitsPerOctalDigit - 1) / NumBinaryDigitsPerOctalDigit;
+
+    QMutexLocker locker(&environmentMutex);
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+    // we provide a buffer that can hold any int value:
     char buffer[MaxDigitsForOctalInt + 2]; // +1 for NUL +1 for optional '-'
     size_t dummy;
     if (getenv_s(&dummy, buffer, sizeof buffer, varName) != 0) {
@@ -3282,15 +3288,16 @@ int qEnvironmentVariableIntValue(const char *varName, bool *ok) Q_DECL_NOEXCEPT
     }
 #else
     const char * const buffer = ::getenv(varName);
-    if (!buffer || !*buffer) {
+    if (!buffer || strlen(buffer) > MaxDigitsForOctalInt + 2) {
         if (ok)
             *ok = false;
         return 0;
     }
 #endif
     bool ok_ = true;
-    const qlonglong value = qstrtoll(buffer, Q_NULLPTR, 0, &ok_);
-    if (int(value) != value) { // this is the check in QByteArray::toInt(), keep it in sync
+    const char *endptr;
+    const qlonglong value = qstrtoll(buffer, &endptr, 0, &ok_);
+    if (int(value) != value || *endptr != '\0') { // this is the check in QByteArray::toInt(), keep it in sync
         if (ok)
             *ok = false;
         return 0;