Optimize QMetaObject::indexOf* functions

Comparing the first character before calling strcmp gives big
speedup, as it avoid the overhead of calling the strcmp function
in many cases.

In indexOfMethodRelative, fix the normalize case. The computation
of the normalized string was put outside of the for loop, but it should
have been inside.  This was not detected by the test because the wrong
string is at the end.

In IndexOfMethodRelative, we do not need to check if the method is a signal
or a slot, because we only iterate over the right interval.
This is only true for code generated by moc since Qt 4.6.
Which means that in application compiled with Qt 4.5 and older,
indexOfSignal could now return a slot with the same name (and vice-versa),
but I this it is safe to ignore that "problem".

Reviewed-by: Roberto Raggi
Reviewed-by: Kent Hansen

1 files changed, 32 insertions, 31 deletions

diff --git a/src/corelib/kernel/qmetaobject.cpp b/src/corelib/kernel/qmetaobject.cpp
index 312c4b2..4ad78fd 100644
--- a/src/corelib/kernel/qmetaobject.cpp
+++ b/src/corelib/kernel/qmetaobject.cpp
@@ -483,38 +483,37 @@ int QMetaObject::classInfoCount() const
 }
 
 /** \internal
-* helper class for indexOf{Method,Slot,Signal}, returns the relative index of the method within
+* helper function for indexOf{Method,Slot,Signal}, returns the relative index of the method within
 * the baseObject
 * \a MethodType might be MethodSignal or MethodSlot, or 0 to match everything.
+* \a normalizeStringData set to true if we should do a second pass for old moc generated files normalizing all the symbols.
 */
 template<int MethodType>
 static inline int indexOfMethodRelative(const QMetaObject **baseObject,
                                         const char *method,
                                         bool normalizeStringData)
 {
-    const QMetaObject *m;
-    for (m = *baseObject; m; m = *baseObject = m->d.superdata) {
-        const QMetaObject *const m = *baseObject;
+    for (const QMetaObject *m = *baseObject; m; m = m->d.superdata) {
         int i = (MethodType == MethodSignal && priv(m->d.data)->revision >= 4)
                 ? (priv(m->d.data)->signalCount - 1) : (priv(m->d.data)->methodCount - 1);
-        if (i < 0)
-            continue;
-
         const int end = (MethodType == MethodSlot && priv(m->d.data)->revision >= 4)
                         ? (priv(m->d.data)->signalCount) : 0;
         if (!normalizeStringData) {
             for (; i >= end; --i) {
-                if ((MethodType == 0 || (m->d.data[priv(m->d.data)->methodData + 5*i + 4] & MethodTypeMask) == MethodType)
-                    && strcmp(method, m->d.stringdata + m->d.data[priv(m->d.data)->methodData + 5*i]) == 0)
+                const char *stringdata = m->d.stringdata + m->d.data[priv(m->d.data)->methodData + 5*i];
+                if (method[0] == stringdata[0] && strcmp(method + 1, stringdata + 1) == 0) {
+                    *baseObject = m;
                     return i;
+                }
             }
         } else if (priv(m->d.data)->revision < 5) {
-            const char *stringdata = (m->d.stringdata + m->d.data[priv(m->d.data)->methodData + 5 * i]);
-            const QByteArray normalizedSignature = QMetaObject::normalizedSignature(stringdata);
             for (; i >= end; --i) {
-                if ((MethodType == 0|| (m->d.data[priv(m->d.data)->methodData + 5*i + 4] & MethodTypeMask) == MethodType)
-                    && normalizedSignature == method)
+                const char *stringdata = (m->d.stringdata + m->d.data[priv(m->d.data)->methodData + 5 * i]);
+                const QByteArray normalizedSignature = QMetaObject::normalizedSignature(stringdata);
+                if (normalizedSignature == method) {
+                    *baseObject = m;
                     return i;
+                }
             }
         }
     }
@@ -537,8 +536,8 @@ int QMetaObject::indexOfConstructor(const char *constructor) const
     if (priv(d.data)->revision < 2)
         return -1;
     for (int i = priv(d.data)->constructorCount-1; i >= 0; --i) {
-        if (strcmp(constructor, d.stringdata
-                   + d.data[priv(d.data)->constructorData + 5*i]) == 0) {
+        const char *data = d.stringdata + d.data[priv(d.data)->constructorData + 5*i];
+        if (data[0] == constructor[0] && strcmp(constructor + 1, data + 1) == 0) {
             return i;
         }
     }
@@ -682,18 +681,19 @@ static const QMetaObject *QMetaObject_findMetaObject(const QMetaObject *self, co
 */
 int QMetaObject::indexOfEnumerator(const char *name) const
 {
-    int i = -1;
     const QMetaObject *m = this;
-    while (m && i < 0) {
-        for (i = priv(m->d.data)->enumeratorCount-1; i >= 0; --i)
-            if (strcmp(name, m->d.stringdata
-                       + m->d.data[priv(m->d.data)->enumeratorData + 4*i]) == 0) {
+    while (m) {
+        const QMetaObjectPrivate *d = priv(m->d.data);
+        for (int i = d->enumeratorCount - 1; i >= 0; --i) {
+            const char *prop = m->d.stringdata + m->d.data[d->enumeratorData + 4*i];
+            if (name[0] == prop[0] && strcmp(name + 1, prop + 1) == 0) {
                 i += m->enumeratorOffset();
-                break;
+                return i;
             }
+        }
         m = m->d.superdata;
     }
-    return i;
+    return -1;
 }
 
 /*!
@@ -704,26 +704,27 @@ int QMetaObject::indexOfEnumerator(const char *name) const
 */
 int QMetaObject::indexOfProperty(const char *name) const
 {
-    int i = -1;
     const QMetaObject *m = this;
-    while (m && i < 0) {
-        for (i = priv(m->d.data)->propertyCount-1; i >= 0; --i)
-            if (strcmp(name, m->d.stringdata
-                       + m->d.data[priv(m->d.data)->propertyData + 3*i]) == 0) {
+    while (m) {
+        const QMetaObjectPrivate *d = priv(m->d.data);
+        for (int i = d->propertyCount-1; i >= 0; --i) {
+            const char *prop = m->d.stringdata + m->d.data[d->propertyData + 3*i];
+            if (name[0] == prop[0] && strcmp(name + 1, prop + 1) == 0) {
                 i += m->propertyOffset();
-                break;
+                return i;
             }
+        }
         m = m->d.superdata;
     }
 
-    if (i == -1 && priv(this->d.data)->revision >= 3 && (priv(this->d.data)->flags & DynamicMetaObject)){
+    if (priv(this->d.data)->revision >= 3 && (priv(this->d.data)->flags & DynamicMetaObject)) {
         QAbstractDynamicMetaObject *me = 
             const_cast<QAbstractDynamicMetaObject *>(static_cast<const QAbstractDynamicMetaObject *>(this));
 
-        i = me->createProperty(name, 0);
+        return me->createProperty(name, 0);
     }
 
-    return i;
+    return -1;
 }
 
 /*!