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#include "readwritelocker.h"
#include "parser/lexer.h"
#include <QReadWriteLock>
#include <QReadLocker>
#include <QWriteLocker>
ReadWriteLocker::ReadWriteLocker(QReadWriteLock* lock, Mode mode)
{
init(lock, mode);
}
ReadWriteLocker::ReadWriteLocker(QReadWriteLock* lock, const QString& query, Dialect dialect, bool noLock)
{
init(lock, getMode(query, dialect, noLock));
}
ReadWriteLocker::~ReadWriteLocker()
{
if (readLocker)
{
delete readLocker;
readLocker = nullptr;
}
if (writeLocker)
{
delete writeLocker;
writeLocker = nullptr;
}
}
void ReadWriteLocker::init(QReadWriteLock* lock, ReadWriteLocker::Mode mode)
{
switch (mode)
{
case ReadWriteLocker::READ:
readLocker = new QReadLocker(lock);
break;
case ReadWriteLocker::WRITE:
writeLocker = new QWriteLocker(lock);
break;
case ReadWriteLocker::NONE:
// Nothing to lock.
break;
}
}
ReadWriteLocker::Mode ReadWriteLocker::getMode(const QString &query, Dialect dialect, bool noLock)
{
static QStringList readOnlyCommands = {"ANALYZE", "EXPLAIN", "PRAGMA"};
if (noLock)
return ReadWriteLocker::NONE;
TokenList tokens = Lexer::tokenize(query, dialect);
int keywordIdx = tokens.indexOf(Token::KEYWORD);
if (keywordIdx > -1 && readOnlyCommands.contains(tokens[keywordIdx]->value.toUpper()))
return ReadWriteLocker::READ;
if (keywordIdx > -1 && tokens[keywordIdx]->value.toUpper() == "WITH")
{
bool matched = false;
bool isSelect = false;
int depth = 0;
for (TokenPtr token : tokens)
{
switch (token->type)
{
case Token::PAR_LEFT:
depth++;
break;
case Token::PAR_RIGHT:
depth--;
break;
case Token::KEYWORD:
if (depth == 0)
{
QString val = token->value.toUpper();
if (val == "SELECT")
{
matched = true;
isSelect = true;
}
else if (val == "DELETE" || val == "UPDATE" || val == "INSERT")
{
matched = true;
}
}
break;
default:
break;
}
if (matched)
break;
}
if (isSelect)
return ReadWriteLocker::READ;
}
return ReadWriteLocker::WRITE;
}
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