From a74059f2bd353cdaa97cd71581059c0b88282a1b Mon Sep 17 00:00:00 2001
From: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Date: Wed, 22 Mar 2023 19:51:06 +0100
Subject: [PATCH] SQL/PSQL: remove non utf-8 support

PostgreSQL supports the utf-8 encoding ('UNICODE') since at least
version 7.3 which is the oldest version we support. Therefore remove the
non utf-8 codepath completely.

Change-Id: I64b1a4e7b0b85141fe13f5f57e6f35f9eb7d542e
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
---
 src/plugins/sqldrivers/psql/qsql_psql.cpp | 28 +++++++++++------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/plugins/sqldrivers/psql/qsql_psql.cpp b/src/plugins/sqldrivers/psql/qsql_psql.cpp
index 81d7e14444..ed222990ab 100644
--- a/src/plugins/sqldrivers/psql/qsql_psql.cpp
+++ b/src/plugins/sqldrivers/psql/qsql_psql.cpp
@@ -125,7 +125,6 @@ public:
     int stmtCount = 0;
     mutable bool pendingNotifyCheck = false;
     bool hasBackslashEscape = false;
-    bool isUtf8 = false;
 
     void appendTables(QStringList &tl, QSqlQuery &t, QChar type);
     PGresult *exec(const char *stmt);
@@ -175,7 +174,7 @@ PGresult *QPSQLDriverPrivate::exec(const char *stmt)
 
 PGresult *QPSQLDriverPrivate::exec(const QString &stmt)
 {
-    return exec((isUtf8 ? stmt.toUtf8() : stmt.toLocal8Bit()).constData());
+    return exec(stmt.toUtf8().constData());
 }
 
 StatementId QPSQLDriverPrivate::sendQuery(const QString &stmt)
@@ -183,8 +182,7 @@ StatementId QPSQLDriverPrivate::sendQuery(const QString &stmt)
     // Discard any prior query results that the application didn't eat.
     // This is required for PQsendQuery()
     discardResults();
-    const int result = PQsendQuery(connection,
-                                   (isUtf8 ? stmt.toUtf8() : stmt.toLocal8Bit()).constData());
+    const int result = PQsendQuery(connection, stmt.toUtf8().constData());
     currentStmtId = result ? generateStatementId() : InvalidStatementId;
     return currentStmtId;
 }
@@ -274,7 +272,7 @@ static QSqlError qMakeError(const QString &err, QSqlError::ErrorType type,
                             const QPSQLDriverPrivate *p, PGresult *result = nullptr)
 {
     const char *s = PQerrorMessage(p->connection);
-    QString msg = p->isUtf8 ? QString::fromUtf8(s) : QString::fromLocal8Bit(s);
+    QString msg = QString::fromUtf8(s);
     QString errorCode;
     if (result) {
         errorCode = QString::fromLatin1(PQresultErrorField(result, PG_DIAG_SQLSTATE));
@@ -606,7 +604,7 @@ QVariant QPSQLResult::data(int i)
     case QMetaType::Bool:
         return QVariant((bool)(val[0] == 't'));
     case QMetaType::QString:
-        return d->drv_d_func()->isUtf8 ? QString::fromUtf8(val) : QString::fromLatin1(val);
+        return QString::fromUtf8(val);
     case QMetaType::LongLong:
         if (val[0] == '-')
             return QByteArray::fromRawData(val, qstrlen(val)).toLongLong();
@@ -747,10 +745,7 @@ QSqlRecord QPSQLResult::record() const
     int count = PQnfields(d->result);
     QSqlField f;
     for (int i = 0; i < count; ++i) {
-        if (d->drv_d_func()->isUtf8)
-            f.setName(QString::fromUtf8(PQfname(d->result, i)));
-        else
-            f.setName(QString::fromLocal8Bit(PQfname(d->result, i)));
+        f.setName(QString::fromUtf8(PQfname(d->result, i)));
         const int tableOid = PQftable(d->result, i);
         // WARNING: We cannot execute any other SQL queries on
         // the same db connection while forward-only mode is active
@@ -1125,6 +1120,7 @@ bool QPSQLDriver::hasFeature(DriverFeature f) const
     case EventNotifications:
     case MultipleResultSets:
     case BLOB:
+    case Unicode:
         return true;
     case PreparedQueries:
     case PositionalPlaceholders:
@@ -1135,8 +1131,6 @@ bool QPSQLDriver::hasFeature(DriverFeature f) const
     case FinishQuery:
     case CancelQuery:
         return false;
-    case Unicode:
-        return d->isUtf8;
     }
     return false;
 }
@@ -1194,7 +1188,13 @@ bool QPSQLDriver::open(const QString &db,
 
     d->pro = d->getPSQLVersion();
     d->detectBackslashEscape();
-    d->isUtf8 = d->setEncodingUtf8();
+    if (!d->setEncodingUtf8()) {
+        setLastError(qMakeError(tr("Unable to set client encoding to 'UNICODE'"), QSqlError::ConnectionError, d));
+        setOpenError(true);
+        PQfinish(d->connection);
+        d->connection = nullptr;
+        return false;
+    }
     d->setDatestyle();
     d->setByteaOutput();
 
@@ -1627,7 +1627,7 @@ void QPSQLDriver::_q_handleNotification()
             QString payload;
 #if defined PG_VERSION_NUM && PG_VERSION_NUM-0 >= 70400
             if (notify->extra)
-                payload = d->isUtf8 ? QString::fromUtf8(notify->extra) : QString::fromLatin1(notify->extra);
+                payload = QString::fromUtf8(notify->extra);
 #endif
             QSqlDriver::NotificationSource source = (notify->be_pid == PQbackendPID(d->connection)) ? QSqlDriver::SelfSource : QSqlDriver::OtherSource;
             emit notification(name, source, payload);