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some thoughts about cursors, nothing special yet

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Blue 2023-08-07 18:27:44 -03:00
parent 69bf1fcc3d
commit 5fba60f7f0
Signed by untrusted user: blue
GPG key ID: 9B203B252A63EE38
4 changed files with 144 additions and 11 deletions
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109
src/cursor.hpp
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@ -23,19 +23,122 @@
template<class K, class V>
LMDBAL::Cursor<K, V>::Cursor(Storage<K, V>* parent):
storage(parent)
storage(parent),
cursor(nullptr),
state(closed)
{
}
template<class K, class V>
LMDBAL::Cursor<K, V>::~Cursor () {
close();
}
template<class K, class V>
void LMDBAL::Cursor<K, V>::terminated () {
void LMDBAL::Cursor<K, V>::terminated () const {
close(); //for now it's the same, but if I ever going to make writable cursor - here is where it's gonna be different
}
template<class K, class V>
void LMDBAL::Cursor<K, V>::open () const {
storage->ensureOpened(openRecordMethodName);
switch (state) {
case closed: {
TransactionID txn = storage->beginReadOnlyTransaction();
int result = mdb_cursor_open(txn, storage->dbi, &cursor);
if (result != MDB_SUCCESS)
storage->throwUnknown(result, txn);
storage->transactionStarted(txn, true);
state = openedPrivate;
} break;
default:
break;
}
}
template<class K, class V>
void LMDBAL::Cursor<K, V>::open (TransactionID txn) const {
storage->ensureOpened(openRecordMethodName);
switch (state) {
case closed: {
int result = mdb_cursor_open(txn, storage->dbi, &cursor);
if (result != MDB_SUCCESS)
storage->throwUnknown(result);
state = openedPublic;
} break;
default:
break;
}
}
template<class K, class V>
void LMDBAL::Cursor<K, V>::renew () const {
storage->ensureOpened(openRecordMethodName);
switch (state) {
case openedPrivate: {
TransactionID txn = mdb_cursor_txn(cursor);
storage->abortTransaction(txn);
storage->transactionAborted(txn);
[[fallthrough]];
}
case openedPublic: {
TransactionID txn = storage->beginReadOnlyTransaction();
int result = mdb_cursor_renew(txn, cursor);
if (result != MDB_SUCCESS)
storage->throwUnknown(result, txn);
storage->transactionStarted(txn, true);
state = openedPrivate;
} break;
default:
break;
}
}
template<class K, class V>
void LMDBAL::Cursor<K, V>::renew (TransactionID txn) const {
storage->ensureOpened(openRecordMethodName);
switch (state) {
case openedPrivate: {
TransactionID txn = mdb_cursor_txn(cursor);
storage->abortTransaction(txn);
storage->transactionAborted(txn);
[[fallthrough]];
}
case openedPublic: {
int result = mdb_cursor_renew(txn, cursor);
if (result != MDB_SUCCESS)
storage->throwUnknown(result);
state = openedPublic;
} break;
default:
break;
}
}
template<class K, class V>
void LMDBAL::Cursor<K, V>::close () const {
switch (state) {
case openedPublic: {
mdb_cursor_close(cursor);
state = closed;
} break;
case openedPrivate: {
TransactionID txn = mdb_cursor_txn(cursor);
mdb_cursor_close(cursor);
storage->abortTransaction(txn);
storage->transactionAborted(txn);
state = closed;
} break;
default:
break;
}
}
#endif //LMDBAL_CURSOR_HPP