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QOCIDriver: optimize string handling in tables() 

- Instead of a QStringList, use a const char 2D array
  to hold the system user names. Don't remove the
  current user from that list, skip it duing processing.
- Extract Method make_where_clause, optimize it and
  cache its result. Instead of creating a QStringList
  and join()ing it at the end (sometimes twice), append
  to the result QString directly. Reserve the max size
  of the result string, which is statically known.
- Keep the query select statements in QLatin1String.
  They are only used in QStringBuilder expressions.

Change-Id: I0593d2812da671a541d49a6136f3ff3d784c63d5
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
bb10
Marc Mutz 2016-02-15 13:17:21 +01:00
parent de8229f370
commit 88e043a8bd
1 changed files with 49 additions and 31 deletions
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80
src/sql/drivers/oci/qsql_oci.cpp
View File

@ -2386,17 +2386,46 @@ bool QOCIDriver::rollbackTransaction()
return true;
}
enum Expression {
OrExpression,
AndExpression
};
static QString make_where_clause(const QString &user, Expression e)
{
static const char sysUsers[][8] = {
"MDSYS",
"LBACSYS",
"SYS",
"SYSTEM",
"WKSYS",
"CTXSYS",
"WMSYS",
};
static const char joinC[][4] = { "or" , "and" };
static Q_CONSTEXPR QLatin1Char bang[] = { QLatin1Char(' '), QLatin1Char('!') };
const QLatin1String join(joinC[e], -1); // -1: force strlen call
QString result;
result.reserve(sizeof sysUsers / sizeof *sysUsers *
// max-sizeof(owner != <sysuser> and )
(9 + sizeof *sysUsers + 5));
for (const auto &sysUser : sysUsers) {
const QLatin1String l1(sysUser, -1); // -1: force strlen call
if (l1 != user)
result += QLatin1String("owner ") + bang[e] + QLatin1String("= '") + l1 + QLatin1Char(' ') + join + QLatin1Char(' ');
}
result.chop(join.size() + 2); // remove final " <join> "
return result;
}
QStringList QOCIDriver::tables(QSql::TableType type) const
{
Q_D(const QOCIDriver);
QStringList tl;
QStringList sysUsers = QStringList() << QLatin1String("MDSYS")
<< QLatin1String("LBACSYS")
<< QLatin1String("SYS")
<< QLatin1String("SYSTEM")
<< QLatin1String("WKSYS")
<< QLatin1String("CTXSYS")
<< QLatin1String("WMSYS");
QString user = d->user;
if ( isIdentifierEscaped(user, QSqlDriver::TableName))
@ -2404,21 +2433,15 @@ QStringList QOCIDriver::tables(QSql::TableType type) const
else
user = user.toUpper();
if(sysUsers.contains(user))
sysUsers.removeAll(user);;
if (!isOpen())
return tl;
QSqlQuery t(createResult());
t.setForwardOnly(true);
if (type & QSql::Tables) {
QString query = QLatin1String("select owner, table_name from all_tables where ");
QStringList whereList;
foreach(const QString &sysUserName, sysUsers)
whereList << QLatin1String("owner != '") + sysUserName + QLatin1String("' ");
t.exec(query + whereList.join(QLatin1String(" and ")));
const QLatin1String tableQuery("select owner, table_name from all_tables where ");
const QString where = make_where_clause(user, AndExpression);
t.exec(tableQuery + where);
while (t.next()) {
if (t.value(0).toString().toUpper() != user.toUpper())
tl.append(t.value(0).toString() + QLatin1Char('.') + t.value(1).toString());
@ -2427,8 +2450,8 @@ QStringList QOCIDriver::tables(QSql::TableType type) const
}
// list all table synonyms as well
query = QLatin1String("select owner, synonym_name from all_synonyms where ");
t.exec(query + whereList.join(QLatin1String(" and ")));
const QLatin1String synonymQuery("select owner, synonym_name from all_synonyms where ");
t.exec(synonymQuery + where);
while (t.next()) {
if (t.value(0).toString() != d->user)
tl.append(t.value(0).toString() + QLatin1Char('.') + t.value(1).toString());
@ -2437,11 +2460,9 @@ QStringList QOCIDriver::tables(QSql::TableType type) const
}
}
if (type & QSql::Views) {
QString query = QLatin1String("select owner, view_name from all_views where ");
QStringList whereList;
foreach(const QString &sysUserName, sysUsers)
whereList << QLatin1String("owner != '") + sysUserName + QLatin1String("' ");
t.exec(query + whereList.join(QLatin1String(" and ")));
const QLatin1String query("select owner, view_name from all_views where ");
const QString where = make_where_clause(user, AndExpression);
t.exec(query + where);
while (t.next()) {
if (t.value(0).toString().toUpper() != d->user.toUpper())
tl.append(t.value(0).toString() + QLatin1Char('.') + t.value(1).toString());
@ -2454,12 +2475,9 @@ QStringList QOCIDriver::tables(QSql::TableType type) const
while (t.next()) {
tl.append(t.value(0).toString());
}
QString query = QLatin1String("select owner, table_name from all_tables where ");
QStringList whereList;
foreach(const QString &sysUserName, sysUsers)
whereList << QLatin1String("owner = '") + sysUserName + QLatin1String("' ");
t.exec(query + whereList.join(QLatin1String(" or ")));
const QLatin1String tableQuery("select owner, table_name from all_tables where ");
const QString where = make_where_clause(user, OrExpression);
t.exec(tableQuery + where);
while (t.next()) {
if (t.value(0).toString().toUpper() != user.toUpper())
tl.append(t.value(0).toString() + QLatin1Char('.') + t.value(1).toString());
@ -2468,8 +2486,8 @@ QStringList QOCIDriver::tables(QSql::TableType type) const
}
// list all table synonyms as well
query = QLatin1String("select owner, synonym_name from all_synonyms where ");
t.exec(query + whereList.join(QLatin1String(" or ")));
const QLatin1String synonymQuery("select owner, synonym_name from all_synonyms where ");
t.exec(synonymQuery + where);
while (t.next()) {
if (t.value(0).toString() != d->user)
tl.append(t.value(0).toString() + QLatin1Char('.') + t.value(1).toString());