SQL: use qsizetype and range-based for loops where possible

Some public functions are still using int instead qsizetype which
can't be changed until Qt7.

Change-Id: Ib6f210c344acce9f3836e8a5493a741eb8b2b385
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

6 files changed, 45 insertions, 50 deletions

diff --git a/src/sql/kernel/qsqlcachedresult.cpp b/src/sql/kernel/qsqlcachedresult.cpp
index 477cf6da11..3cc0b6419a 100644
--- a/src/sql/kernel/qsqlcachedresult.cpp
+++ b/src/sql/kernel/qsqlcachedresult.cpp
@@ -20,7 +20,7 @@ QT_BEGIN_NAMESPACE
    to indicate that we are not interested in the actual values.
 */
 
-static const uint initial_cache_size = 128;
+static constexpr qsizetype initial_cache_size = 128;
 
 void QSqlCachedResultPrivate::cleanup()
 {
diff --git a/src/sql/kernel/qsqldatabase.cpp b/src/sql/kernel/qsqldatabase.cpp
index ee8ebcb8c7..8e896314eb 100644
--- a/src/sql/kernel/qsqldatabase.cpp
+++ b/src/sql/kernel/qsqldatabase.cpp
@@ -499,19 +499,18 @@ QStringList QSqlDatabase::drivers()
 
     if (QFactoryLoader *fl = loader()) {
         typedef QMultiMap<int, QString> PluginKeyMap;
-        typedef PluginKeyMap::const_iterator PluginKeyMapConstIterator;
 
         const PluginKeyMap keyMap = fl->keyMap();
-        const PluginKeyMapConstIterator cend = keyMap.constEnd();
-        for (PluginKeyMapConstIterator it = keyMap.constBegin(); it != cend; ++it)
-            if (!list.contains(it.value()))
-                list << it.value();
+        for (const QString &val : keyMap) {
+            if (!list.contains(val))
+                list << val;
+        }
     }
 
-    DriverDict dict = QSqlDatabasePrivate::driverDict();
-    for (DriverDict::const_iterator i = dict.constBegin(); i != dict.constEnd(); ++i) {
-        if (!list.contains(i.key()))
-            list << i.key();
+    const DriverDict dict = QSqlDatabasePrivate::driverDict();
+    for (const auto &[k, _] : dict.asKeyValueRange()) {
+        if (!list.contains(k))
+            list << k;
     }
 
     return list;
diff --git a/src/sql/kernel/qsqldriver.cpp b/src/sql/kernel/qsqldriver.cpp
index 6102aece24..f30fcfd349 100644
--- a/src/sql/kernel/qsqldriver.cpp
+++ b/src/sql/kernel/qsqldriver.cpp
@@ -8,6 +8,7 @@
 #include "qsqlfield.h"
 #include "qsqlindex.h"
 #include "private/qsqldriver_p.h"
+#include "private/qtools_p.h"
 
 #include <limits.h>
 
@@ -445,12 +446,11 @@ QString QSqlDriver::sqlStatement(StatementType type, const QString &tableName,
 {
     const auto tableNameString = tableName.isEmpty() ? QString()
                                     : prepareIdentifier(tableName, QSqlDriver::TableName, this);
-    int i;
     QString s;
     s.reserve(128);
     switch (type) {
     case SelectStatement:
-        for (i = 0; i < rec.count(); ++i) {
+        for (qsizetype i = 0; i < rec.count(); ++i) {
             if (rec.isGenerated(i))
                 s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this)).append(", "_L1);
         }
@@ -463,7 +463,7 @@ QString QSqlDriver::sqlStatement(StatementType type, const QString &tableName,
     {
         const QString tableNamePrefix = tableNameString.isEmpty()
                                             ? QString() : tableNameString + u'.';
-        for (int i = 0; i < rec.count(); ++i) {
+        for (qsizetype i = 0; i < rec.count(); ++i) {
             if (!rec.isGenerated(i))
                 continue;
             s.append(s.isEmpty() ? "WHERE "_L1 : " AND "_L1);
@@ -480,7 +480,7 @@ QString QSqlDriver::sqlStatement(StatementType type, const QString &tableName,
     }
     case UpdateStatement:
         s = s + "UPDATE "_L1 + tableNameString + " SET "_L1;
-        for (i = 0; i < rec.count(); ++i) {
+        for (qsizetype i = 0; i < rec.count(); ++i) {
             if (!rec.isGenerated(i))
                 continue;
             s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this)).append(u'=');
@@ -501,7 +501,7 @@ QString QSqlDriver::sqlStatement(StatementType type, const QString &tableName,
     case InsertStatement: {
         s = s + "INSERT INTO "_L1 + tableNameString + " ("_L1;
         QString vals;
-        for (i = 0; i < rec.count(); ++i) {
+        for (qsizetype i = 0; i < rec.count(); ++i) {
             if (!rec.isGenerated(i))
                 continue;
             s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this)).append(", "_L1);
@@ -612,15 +612,15 @@ QString QSqlDriver::formatValue(const QSqlField &field, bool trimStrings) const
             break;
         case QMetaType::QByteArray : {
             if (hasFeature(BLOB)) {
-                QByteArray ba = field.value().toByteArray();
-                QString res;
-                static const char hexchars[] = "0123456789abcdef";
-                for (int i = 0; i < ba.size(); ++i) {
-                    uchar s = (uchar) ba[i];
-                    res += QLatin1Char(hexchars[s >> 4]);
-                    res += QLatin1Char(hexchars[s & 0x0f]);
+                const QByteArray ba = field.value().toByteArray();
+                r.reserve((ba.size() + 1) * 2);
+                r += u'\'';
+                for (const char c : ba) {
+                    const uchar s = uchar(c);
+                    r += QLatin1Char(QtMiscUtils::toHexLower(s >> 4));
+                    r += QLatin1Char(QtMiscUtils::toHexLower(s & 0x0f));
                 }
-                r = u'\'' + res +  u'\'';
+                r += u'\'';
                 break;
             }
         }
diff --git a/src/sql/kernel/qsqlquery.cpp b/src/sql/kernel/qsqlquery.cpp
index d729dbda6b..14a3dc4130 100644
--- a/src/sql/kernel/qsqlquery.cpp
+++ b/src/sql/kernel/qsqlquery.cpp
@@ -336,7 +336,7 @@ bool QSqlQuery::isNull(int field) const
 
 bool QSqlQuery::isNull(const QString &name) const
 {
-    int index = d->sqlResult->record().indexOf(name);
+    qsizetype index = d->sqlResult->record().indexOf(name);
     if (index > -1)
         return isNull(index);
     qWarning("QSqlQuery::isNull: unknown field name '%s'", qPrintable(name));
@@ -447,7 +447,7 @@ QVariant QSqlQuery::value(int index) const
 
 QVariant QSqlQuery::value(const QString& name) const
 {
-    int index = d->sqlResult->record().indexOf(name);
+    qsizetype index = d->sqlResult->record().indexOf(name);
     if (index > -1)
         return value(index);
     qWarning("QSqlQuery::value: unknown field name '%s'", qPrintable(name));
@@ -920,7 +920,7 @@ QSqlRecord QSqlQuery::record() const
     QSqlRecord rec = d->sqlResult->record();
 
     if (isValid()) {
-        for (int i = 0; i < rec.count(); ++i)
+        for (qsizetype i = 0; i < rec.count(); ++i)
             rec.setValue(i, value(i));
     }
     return rec;
diff --git a/src/sql/kernel/qsqlresult.cpp b/src/sql/kernel/qsqlresult.cpp
index d283e1212e..c1d8ec31f4 100644
--- a/src/sql/kernel/qsqlresult.cpp
+++ b/src/sql/kernel/qsqlresult.cpp
@@ -23,7 +23,7 @@ QString QSqlResultPrivate::holderAt(int index) const
     return holders.size() > index ? holders.at(index).holderName : fieldSerial(index);
 }
 
-QString QSqlResultPrivate::fieldSerial(int i) const
+QString QSqlResultPrivate::fieldSerial(qsizetype i) const
 {
     return QString(":%1"_L1).arg(i);
 }
@@ -37,15 +37,15 @@ static bool qIsAlnum(QChar ch)
 
 QString QSqlResultPrivate::positionalToNamedBinding(const QString &query) const
 {
-    int n = query.size();
+    const qsizetype n = query.size();
 
     QString result;
     result.reserve(n * 5 / 4);
     QChar closingQuote;
-    int count = 0;
+    qsizetype count = 0;
     bool ignoreBraces = (sqldriver->dbmsType() == QSqlDriver::PostgreSQL);
 
-    for (int i = 0; i < n; ++i) {
+    for (qsizetype i = 0; i < n; ++i) {
         QChar ch = query.at(i);
         if (!closingQuote.isNull()) {
             if (ch == closingQuote) {
@@ -84,13 +84,13 @@ QString QSqlResultPrivate::namedToPositionalBinding(const QString &query)
         query.trimmed().startsWith("EXECUTE BLOCK"_L1, Qt::CaseInsensitive))
         return query;
 
-    int n = query.size();
+    const qsizetype n = query.size();
 
     QString result;
     result.reserve(n);
     QChar closingQuote;
     int count = 0;
-    int i = 0;
+    qsizetype i = 0;
     bool ignoreBraces = (sqldriver->dbmsType() == QSqlDriver::PostgreSQL);
 
     while (i < n) {
@@ -624,12 +624,9 @@ bool QSqlResult::exec()
     // fake preparation - just replace the placeholders..
     QString query = lastQuery();
     if (d->binds == NamedBinding) {
-        int i;
-        QVariant val;
-        QString holder;
-        for (i = d->holders.size() - 1; i >= 0; --i) {
-            holder = d->holders.at(i).holderName;
-            val = d->values.value(d->indexes.value(holder).value(0,-1));
+        for (qsizetype i = d->holders.size() - 1; i >= 0; --i) {
+            const QString &holder = d->holders.at(i).holderName;
+            const QVariant val = d->values.value(d->indexes.value(holder).value(0,-1));
             QSqlField f(""_L1, val.metaType());
             if (QSqlResultPrivate::isVariantNull(val))
                 f.setValue(QVariant());
@@ -639,21 +636,18 @@ bool QSqlResult::exec()
                                    holder.size(), driver()->formatValue(f));
         }
     } else {
-        QString val;
         qsizetype i = 0;
-        int idx = 0;
-        for (idx = 0; idx < d->values.size(); ++idx) {
+        for (const QVariant &var : std::as_const(d->values)) {
             i = query.indexOf(u'?', i);
             if (i == -1)
                 continue;
-            QVariant var = d->values.value(idx);
             QSqlField f(""_L1, var.metaType());
             if (QSqlResultPrivate::isVariantNull(var))
                 f.clear();
             else
                 f.setValue(var);
-            val = driver()->formatValue(f);
-            query = query.replace(i, 1, driver()->formatValue(f));
+            const QString val = driver()->formatValue(f);
+            query = query.replace(i, 1, val);
             i += val.size();
         }
     }
@@ -945,11 +939,13 @@ bool QSqlResult::execBatch(bool arrayBind)
     Q_UNUSED(arrayBind);
     Q_D(QSqlResult);
 
-    QList<QVariant> values = d->values;
+    const QList<QVariant> values = d->values;
     if (values.size() == 0)
         return false;
-    for (int i = 0; i < values.at(0).toList().size(); ++i) {
-        for (int j = 0; j < values.size(); ++j)
+    const qsizetype batchCount = values.at(0).toList().size();
+    const qsizetype valueCount = values.size();
+    for (qsizetype i = 0; i < batchCount; ++i) {
+        for (qsizetype j = 0; j < valueCount; ++j)
             bindValue(j, values.at(j).toList().at(i), QSql::In);
         if (!exec())
             return false;
diff --git a/src/sql/kernel/qsqlresult_p.h b/src/sql/kernel/qsqlresult_p.h
index 7e84283b4f..1e8e8a3033 100644
--- a/src/sql/kernel/qsqlresult_p.h
+++ b/src/sql/kernel/qsqlresult_p.h
@@ -30,11 +30,11 @@ QT_BEGIN_NAMESPACE
     inline Class##Private* drv_d_func()  { return !sqldriver ? nullptr : reinterpret_cast<Class *>(static_cast<QSqlDriver*>(sqldriver))->d_func(); }
 
 struct QHolder {
-    QHolder(const QString &hldr = QString(), int index = -1): holderName(hldr), holderPos(index) { }
+    QHolder(const QString &hldr = QString(), qsizetype index = -1): holderName(hldr), holderPos(index) { }
     bool operator==(const QHolder &h) const { return h.holderPos == holderPos && h.holderName == holderName; }
     bool operator!=(const QHolder &h) const { return h.holderPos != holderPos || h.holderName != holderName; }
     QString holderName;
-    int holderPos;
+    qsizetype holderPos;
 };
 
 class Q_SQL_EXPORT QSqlResultPrivate
@@ -72,7 +72,7 @@ public:
         clearIndex();
     }
 
-    virtual QString fieldSerial(int) const;
+    virtual QString fieldSerial(qsizetype) const;
     QString positionalToNamedBinding(const QString &query) const;
     QString namedToPositionalBinding(const QString &query);
     QString holderAt(int index) const;