From c400e16a58357c01fcc1567a42537be0767efadf Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Mon, 27 Aug 2012 10:39:16 +0200 Subject: QMetaTypeId: use QByteArray, not QVarLengthArray, to construct type names So far, type-name strings for class template instantiations were constructed in QMetaTypeId::qt_metatype_id() by concatenating various bits and pieces into a QVarLengthArray, presumably to avoid the dynamic memory allocation for small strings. Yet, when passing the result to qRegisterNormalisedMetaType, which takes a QByteArray, the QVarLengthArray was copied from, not by QByteArray::fromRawData(), but by QByteArray(const char*,int), which unconditionally results in a dynamic memory allocation after all. What's worse: the characters are copied twice: First into the QVarLengthArray, and then into the QByteArray. Remove the first of these copies by using QByteArray+reserve() to copy directly into the final QByteArray. Change-Id: Id915798a318fe97279a7cc0aca176544f99c7e86 Reviewed-by: Olivier Goffart --- src/corelib/kernel/qmetatype.h | 61 +++++++++++++++++++++++------------------- 1 file changed, 34 insertions(+), 27 deletions(-) (limited to 'src/corelib/kernel') diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h index 16ea1042a2..83f2057eee 100644 --- a/src/corelib/kernel/qmetatype.h +++ b/src/corelib/kernel/qmetatype.h @@ -670,12 +670,12 @@ struct QMetaTypeIdQObject static QBasicAtomicInt metatype_id = Q_BASIC_ATOMIC_INITIALIZER(0); if (const int id = metatype_id.loadAcquire()) return id; - const int len = int(strlen(T::staticMetaObject.className())); - QVarLengthArray classNameStar; - classNameStar.append(T::staticMetaObject.className(), len); - classNameStar.append('*'); - const int newId = qRegisterNormalizedMetaType( \ - QByteArray(classNameStar.constData(), classNameStar.size()), + const char * const cName = T::staticMetaObject.className(); + QByteArray typeName; + typeName.reserve(strlen(cName) + 1); + typeName.append(cName).append('*'); + const int newId = qRegisterNormalizedMetaType( + typeName, reinterpret_cast(quintptr(-1))); metatype_id.storeRelease(newId); return newId; @@ -757,17 +757,18 @@ struct QMetaTypeId< SINGLE_ARG_TEMPLATE > \ static QBasicAtomicInt metatype_id = Q_BASIC_ATOMIC_INITIALIZER(0); \ if (const int id = metatype_id.load()) \ return id; \ - QVarLengthArray name; \ - name.append(#SINGLE_ARG_TEMPLATE, int(sizeof(#SINGLE_ARG_TEMPLATE)) - 1); \ - name.append('<'); \ const char *tName = QMetaType::typeName(qMetaTypeId()); \ Q_ASSERT(tName); \ - name.append(tName, int(strlen(tName))); \ - if (name.last() == '>') \ - name.append(' '); \ - name.append('>'); \ - const int newId = qRegisterNormalizedMetaType< SINGLE_ARG_TEMPLATE >( \ - QByteArray(name.constData(), name.size()), \ + const int tNameLen = qstrlen(tName); \ + QByteArray typeName; \ + typeName.reserve(sizeof(#SINGLE_ARG_TEMPLATE) + 1 + tNameLen + 1 + 1); \ + typeName.append(#SINGLE_ARG_TEMPLATE, sizeof(#SINGLE_ARG_TEMPLATE) - 1) \ + .append('<').append(tName, tNameLen); \ + if (typeName.endsWith('>')) \ + typeName.append(' '); \ + typeName.append('>'); \ + const int newId = qRegisterNormalizedMetaType< SINGLE_ARG_TEMPLATE >( \ + typeName, \ reinterpret_cast< SINGLE_ARG_TEMPLATE *>(quintptr(-1))); \ metatype_id.storeRelease(newId); \ return newId; \ @@ -786,21 +787,21 @@ struct QMetaTypeId< DOUBLE_ARG_TEMPLATE > \ static QBasicAtomicInt metatype_id = Q_BASIC_ATOMIC_INITIALIZER(0); \ if (const int id = metatype_id.loadAcquire()) \ return id; \ - QVarLengthArray name; \ - name.append(#DOUBLE_ARG_TEMPLATE, sizeof(#DOUBLE_ARG_TEMPLATE) - 1); \ - name.append('<'); \ const char *tName = QMetaType::typeName(qMetaTypeId()); \ - Q_ASSERT(tName); \ - name.append(tName, int(strlen(tName))); \ - name.append(','); \ const char *uName = QMetaType::typeName(qMetaTypeId()); \ + Q_ASSERT(tName); \ Q_ASSERT(uName); \ - name.append(uName, int(strlen(uName))); \ - if (name.last() == '>') \ - name.append(' '); \ - name.append('>'); \ + const int tNameLen = qstrlen(tName); \ + const int uNameLen = qstrlen(uName); \ + QByteArray typeName; \ + typeName.reserve(sizeof(#DOUBLE_ARG_TEMPLATE) + 1 + tNameLen + 1 + uNameLen + 1 + 1); \ + typeName.append(#DOUBLE_ARG_TEMPLATE, sizeof(#DOUBLE_ARG_TEMPLATE) - 1) \ + .append('<').append(tName, tNameLen).append(',').append(uName, uNameLen); \ + if (typeName.endsWith('>')) \ + typeName.append(' '); \ + typeName.append('>'); \ const int newId = qRegisterNormalizedMetaType< DOUBLE_ARG_TEMPLATE >(\ - QByteArray(name.constData(), name.size()), \ + typeName, \ reinterpret_cast< DOUBLE_ARG_TEMPLATE *>(quintptr(-1))); \ metatype_id.storeRelease(newId); \ return newId; \ @@ -827,7 +828,13 @@ struct QMetaTypeId_ ## SMART_POINTER ## _QObjectStar \ static QBasicAtomicInt metatype_id = Q_BASIC_ATOMIC_INITIALIZER(0); \ if (const int id = metatype_id.loadAcquire()) \ return id; \ - const int newId = qRegisterNormalizedMetaType< SMART_POINTER >( #SMART_POINTER "<" + QByteArray(T::staticMetaObject.className()) + ">", \ + const char * const cName = T::staticMetaObject.className(); \ + QByteArray typeName; \ + typeName.reserve(sizeof(#SMART_POINTER) + 1 + strlen(cName) + 1); \ + typeName.append(#SMART_POINTER, sizeof(#SMART_POINTER) - 1) \ + .append('<').append(cName).append('>'); \ + const int newId = qRegisterNormalizedMetaType< SMART_POINTER >( \ + typeName, \ reinterpret_cast< SMART_POINTER *>(quintptr(-1))); \ metatype_id.storeRelease(newId); \ return newId; \ -- cgit v1.2.3