Q3DataBrowser::Boundary Q3DataBrowser::boundary()
{
Q3SqlCursor* cur = d->cur.cursor();
if (!cur || !cur->isActive())
return Unknown;
if (!cur->isValid()) {
if (cur->at() == QSql::BeforeFirst)
return BeforeBeginning;
if (cur->at() == QSql::AfterLast)
return AfterEnd;
return Unknown;
}
if (cur->at() == 0)
return Beginning;
int currentAt = cur->at();
Boundary b = None;
if (!cur->previous())
b = Beginning;
else
cur->seek(currentAt);
if (b == None && !cur->next())
b = End;
cur->seek(currentAt);
return b;
}
bool Q3DataBrowser::deleteCurrent()
{
if (isReadOnly())
return false;
QSqlRecord* buf = d->frm.record();
Q3SqlCursor* cur = d->cur.cursor();
if (!buf || !cur)
return false;
writeFields();
int n = cur->at();
emit beforeDelete(buf);
int ar = cur->del();
if (ar) {
refresh();
updateBoundary();
cursorChanged(Q3SqlCursor::Delete);
if (!cur->seek(n))
last();
if (cur->isValid()) {
cur->editBuffer(true);
readFields();
} else {
clearValues();
}
return true;
} else {
if (!cur->isActive()) {
handleError(cur->lastError());
refresh();
updateBoundary();
}
}
return false;
}
//## possibly add sizeHint parameter
bool Q3SqlCursorManager::findBuffer(const QSqlIndex& idx, int atHint)
{
#ifdef QT_DEBUG_DATAMANAGER
qDebug("Q3SqlCursorManager::findBuffer:");
#endif
Q3SqlCursor* cur = cursor();
if (!cur)
return false;
if (!cur->isActive())
return false;
if (!idx.count()) {
if (cur->at() == QSql::BeforeFirst)
cur->next();
return false;
}
QSqlRecord* buf = cur->editBuffer();
bool indexEquals = false;
#ifdef QT_DEBUG_DATAMANAGER
qDebug(" Checking hint...");
#endif
/* check the hint */
if (cur->seek(atHint))
indexEquals = index_matches(cur, buf, idx);
if (!indexEquals) {
#ifdef QT_DEBUG_DATAMANAGER
qDebug(" Checking current page...");
#endif
/* check current page */
int pageSize = 20;
int startIdx = qMax(atHint - pageSize, 0);
int endIdx = atHint + pageSize;
for (int j = startIdx; j <= endIdx; ++j) {
if (cur->seek(j)) {
indexEquals = index_matches(cur, buf, idx);
if (indexEquals)
break;
}
}
}
if (!indexEquals && cur->driver()->hasFeature(QSqlDriver::QuerySize)
&& cur->sort().count()) {
#ifdef QT_DEBUG_DATAMANAGER
qDebug(" Using binary search...");
#endif
// binary search based on record buffer and current sort fields
int lo = 0;
int hi = cur->size();
int mid;
if (compare_recs(buf, cur, cur->sort()) >= 0)
lo = cur->at();
while (lo != hi) {
mid = lo + (hi - lo) / 2;
if (!cur->seek(mid))
break;
if (index_matches(cur, buf, idx)) {
indexEquals = true;
break;
}
int c = compare_recs(buf, cur, cur->sort());
if (c < 0) {
hi = mid;
} else if (c == 0) {
// found it, but there may be duplicates
int at = mid;
do {
mid--;
if (!cur->seek(mid))
break;
if (index_matches(cur, buf, idx)) {
indexEquals = true;
break;
}
} while (compare_recs(buf, cur, cur->sort()) == 0);
if (!indexEquals) {
mid = at;
do {
mid++;
if (!cur->seek(mid))
break;
if (index_matches(cur, buf, idx)) {
indexEquals = true;
break;
}
} while (compare_recs(buf, cur, cur->sort()) == 0);
}
break;
} else if (c > 0) {
lo = mid + 1;
}
}
}
if (!indexEquals) {
#ifdef QT_DEBUG_DATAMANAGER
qDebug(" Using brute search...");
#endif
#ifndef QT_NO_CURSOR
QApplication::setOverrideCursor(Qt::WaitCursor);
#endif
/* give up, use brute force */
int startIdx = 0;
if (cur->at() != startIdx) {
cur->seek(startIdx);
}
for (;;) {
indexEquals = false;
indexEquals = index_matches(cur, buf, idx);
if (indexEquals)
break;
if (!cur->next())
break;
}
#ifndef QT_NO_CURSOR
QApplication::restoreOverrideCursor();
#endif
}
#ifdef QT_DEBUG_DATAMANAGER
qDebug(" Done, result:" + QString::number(indexEquals));
#endif
return indexEquals;
}