fixes #2737 (Dbx_mdbx: sometimes MDBX_SET doesn't work as expected, nobody knows why)

1 files changed, 28 insertions, 25 deletions

diff --git a/plugins/Dbx_mdbx/src/dbevents.cpp b/plugins/Dbx_mdbx/src/dbevents.cpp
index cbbc3faa58..2c9a1d71f0 100644
--- a/plugins/Dbx_mdbx/src/dbevents.cpp
+++ b/plugins/Dbx_mdbx/src/dbevents.cpp
@@ -496,6 +496,9 @@ MEVENT CDbxMDBX::FindFirstEvent(MCONTACT contactID)
 		return cc->t_evLast = 0;

 

 	const DBEventSortingKey *pKey = (const DBEventSortingKey*)key.iov_base;

+	if (pKey->hContact != contactID)

+		return cc->t_evLast = 0;

+

 	cc->t_tsLast = pKey->ts;

 	return cc->t_evLast = (pKey->hContact == contactID) ? pKey->hEvent : 0;

 }

@@ -535,6 +538,9 @@ MEVENT CDbxMDBX::FindLastEvent(MCONTACT contactID)
 	}

 

 	const DBEventSortingKey *pKey = (const DBEventSortingKey*)key.iov_base;

+	if (pKey->hContact != contactID)

+		return cc->t_evLast = 0;

+

 	cc->t_tsLast = pKey->ts;

 	return cc->t_evLast = (pKey->hContact == contactID) ? pKey->hEvent : 0;

 }

@@ -623,7 +629,7 @@ class CMdbxEventCursor : public DB::EventCursor
 	friend class CDbxMDBX;

 	CDbxMDBX *m_pOwner;

 

-	bool m_bForward;

+	bool m_bForward, m_bFirst = true;

 	DBCachedContact *m_cc;

 	DBEventSortingKey m_key;

 

@@ -635,41 +641,38 @@ public:
 		m_cc(cc)

 	{

 		m_key.hContact = hContact;

-		if (bForward) {

-			m_key.hEvent = 0;

-			m_key.ts = 0;

-		}

-		else {

-			m_key.hEvent = 0xFFFFFFFF;

-			m_key.ts = 0xFFFFFFFFFFFFFFFF;

-		}

+		if (bForward)

+			m_key.hEvent = pDb->FindFirstEvent(hContact);

+		else

+			m_key.hEvent = pDb->FindLastEvent(hContact);

+

+		if (m_key.hEvent != 0)

+			m_key.ts = cc->t_tsLast;

 	}

 

 	MEVENT FetchNext() override

 	{

-		mdbx_cursor_bind(m_pOwner->StartTran(), m_pOwner->m_curEventsSort, m_pOwner->m_dbEventsSort);

-

-		MDBX_cursor_op op = (m_bForward) ? MDBX_NEXT : MDBX_PREV;

+		// if initial seek returned nothing, keep returning 0 forever

+		if (m_bFirst) {

+			if (m_key.hEvent == 0)

+				return 0;

 

-		MDBX_val key = { &m_key, sizeof(m_key) }, data;

-		switch (mdbx_cursor_get(m_pOwner->m_curEventsSort, &key, &data, MDBX_SET)) {

-		case MDBX_NOTFOUND:

-			// for forward cursors we're already on the first record after set

-			// for reverse cursors that means that we moved a pointer after last record, so we need to fetch

-			if (m_bForward)

-				op = MDBX_GET_CURRENT;

-			break;

+			m_bFirst = false;

+			return m_key.hEvent;

+		}

 

-		case MDBX_SUCCESS:

-			break;

+		mdbx_cursor_bind(m_pOwner->StartTran(), m_pOwner->m_curEventsSort, m_pOwner->m_dbEventsSort);

 

-		default:

+		// this is precise key position, if it doesn't exist - return

+		MDBX_val key = { &m_key, sizeof(m_key) }, data;

+		if (mdbx_cursor_get(m_pOwner->m_curEventsSort, &key, &data, MDBX_SET) != MDBX_SUCCESS)

 			return 0;

-		}

 

-		if (mdbx_cursor_get(m_pOwner->m_curEventsSort, &key, &data, op) != MDBX_SUCCESS)

+		// move one record ahead or backward

+		if (mdbx_cursor_get(m_pOwner->m_curEventsSort, &key, &data, (m_bForward) ? MDBX_NEXT : MDBX_PREV) != MDBX_SUCCESS)

 			return 0;

 

+		// and this record should belong to the same contact

 		DBEventSortingKey dbKey = *(const DBEventSortingKey *)key.iov_base;

 		if (dbKey.hContact != hContact)

 			return 0;