Quick: Sanitize reading environment variables.

Where possible, use qEnvironmentVariableIsSet()/
qEnvironmentVariableIsEmpty() instead of checking on the
return value of qgetenv().
Where the value is required, add a check using one of
qEnvironmentVariableIsSet()/Empty().

Move QSGAtlasTexture::qsg_envInt() to qsgrenderer.cpp
for reuse as qt_sg_envInt() and add qt_sg_envFloat().

Change-Id: I4c93f16c228d4f537154f389a0fa1427654485f7
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

3 files changed, 19 insertions, 18 deletions

diff --git a/src/quick/scenegraph/util/qsgatlastexture.cpp b/src/quick/scenegraph/util/qsgatlastexture.cpp
index 8c649fb6bd..8e8e870505 100644
--- a/src/quick/scenegraph/util/qsgatlastexture.cpp
+++ b/src/quick/scenegraph/util/qsgatlastexture.cpp
@@ -54,21 +54,13 @@ QT_BEGIN_NAMESPACE
 #define GL_BGRA 0x80E1
 #endif
 
+int qt_sg_envInt(const char *name, int defaultValue);
 
 static QElapsedTimer qsg_renderer_timer;
 
 namespace QSGAtlasTexture
 {
 
-static int qsg_envInt(const char *name, int defaultValue)
-{
-    QByteArray content = qgetenv(name);
-
-    bool ok = false;
-    int value = content.toInt(&ok);
-    return ok ? value : defaultValue;
-}
-
 Manager::Manager()
     : m_atlas(0)
 {
@@ -79,8 +71,8 @@ Manager::Manager()
     int max;
     gl->functions()->glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max);
 
-    int w = qMin(max, qsg_envInt("QSG_ATLAS_WIDTH", qMax(512U, qNextPowerOfTwo(surfaceSize.width() - 1))));
-    int h = qMin(max, qsg_envInt("QSG_ATLAS_HEIGHT", qMax(512U, qNextPowerOfTwo(surfaceSize.height() - 1))));
+    int w = qMin(max, qt_sg_envInt("QSG_ATLAS_WIDTH", qMax(512U, qNextPowerOfTwo(surfaceSize.width() - 1))));
+    int h = qMin(max, qt_sg_envInt("QSG_ATLAS_HEIGHT", qMax(512U, qNextPowerOfTwo(surfaceSize.height() - 1))));
 
     if (surface->surfaceClass() == QSurface::Window) {
         QWindow *window = static_cast<QWindow *>(surface);
@@ -91,7 +83,7 @@ Manager::Manager()
         }
     }
 
-    m_atlas_size_limit = qsg_envInt("QSG_ATLAS_SIZE_LIMIT", qMax(w, h) / 2);
+    m_atlas_size_limit = qt_sg_envInt("QSG_ATLAS_SIZE_LIMIT", qMax(w, h) / 2);
     m_atlas_size = QSize(w, h);
 
     qCDebug(QSG_LOG_INFO, "texture atlas dimensions: %dx%d", w, h);
diff --git a/src/quick/scenegraph/util/qsgdistancefieldutil.cpp b/src/quick/scenegraph/util/qsgdistancefieldutil.cpp
index 8e02681703..96b606aa3c 100644
--- a/src/quick/scenegraph/util/qsgdistancefieldutil.cpp
+++ b/src/quick/scenegraph/util/qsgdistancefieldutil.cpp
@@ -39,18 +39,27 @@
 
 QT_BEGIN_NAMESPACE
 
+static float qt_sg_envFloat(const char *name, float defaultValue)
+{
+    if (Q_LIKELY(!qEnvironmentVariableIsSet(name)))
+        return defaultValue;
+    bool ok = false;
+    const float value = qgetenv(name).toFloat(&ok);
+    return ok ? value : defaultValue;
+}
+
 static float defaultThresholdFunc(float glyphScale)
 {
-    static float base = qgetenv("QT_DF_BASE").isEmpty() ? 0.5f : qgetenv("QT_DF_BASE").toFloat();
-    static float baseDev = qgetenv("QT_DF_BASEDEVIATION").isEmpty() ? 0.065f : qgetenv("QT_DF_BASEDEVIATION").toFloat();
-    static float devScaleMin = qgetenv("QT_DF_SCALEFORMAXDEV").isEmpty() ? 0.15f : qgetenv("QT_DF_SCALEFORMAXDEV").toFloat();
-    static float devScaleMax = qgetenv("QT_DF_SCALEFORNODEV").isEmpty() ? 0.3f : qgetenv("QT_DF_SCALEFORNODEV").toFloat();
+    static const float base = qt_sg_envFloat("QT_DF_BASE", 0.5f);
+    static const float baseDev = qt_sg_envFloat("QT_DF_BASEDEVIATION", 0.065f);
+    static const float devScaleMin = qt_sg_envFloat("QT_DF_SCALEFORMAXDEV", 0.15f);
+    static const float devScaleMax = qt_sg_envFloat("QT_DF_SCALEFORNODEV", 0.3f);
     return base - ((qBound(devScaleMin, glyphScale, devScaleMax) - devScaleMin) / (devScaleMax - devScaleMin) * -baseDev + baseDev);
 }
 
 static float defaultAntialiasingSpreadFunc(float glyphScale)
 {
-    static float range = qgetenv("QT_DF_RANGE").isEmpty() ? 0.06f : qgetenv("QT_DF_RANGE").toFloat();
+    static const float range = qt_sg_envFloat("QT_DF_RANGE", 0.06f);
     return range / glyphScale;
 }
 
diff --git a/src/quick/scenegraph/util/qsgtexture.cpp b/src/quick/scenegraph/util/qsgtexture.cpp
index c89ad7a608..df9e569ca3 100644
--- a/src/quick/scenegraph/util/qsgtexture.cpp
+++ b/src/quick/scenegraph/util/qsgtexture.cpp
@@ -65,7 +65,7 @@
 static QElapsedTimer qsg_renderer_timer;
 
 #ifndef QT_NO_DEBUG
-static bool qsg_leak_check = !qgetenv("QML_LEAK_CHECK").isEmpty();
+static const bool qsg_leak_check = !qEnvironmentVariableIsEmpty("QML_LEAK_CHECK");
 #endif