Fixed previous transactionless cursor patch

With Hbtree it is no longer possible to open a read transaction while write
transaction is active, or worse to begin a read transaction, and then begin a
write transaction that can rewrite pages that were supposed to be held by the
read transaction.

Change-Id: Ie008883b959772ae9f2f31173c3176198c556f2b
Reviewed-by: Ali Akhtarzada <ali.akhtarzada@nokia.com>

5 files changed, 41 insertions, 41 deletions

diff --git a/src/daemon/jsondbindex.cpp b/src/daemon/jsondbindex.cpp
index 891d7a6..90ce8fa 100644
--- a/src/daemon/jsondbindex.cpp
+++ b/src/daemon/jsondbindex.cpp
@@ -432,7 +432,8 @@ void JsonDbIndex::checkIndex()
 
     qDebug() << "checkIndex" << mPropertyName;
     int countf = 0;
-    JsonDbBtree::Transaction *txnf = mBdb.data()->btree()->beginRead();
+    bool isInTransaction = mBdb.data()->btree()->writeTransaction();
+    JsonDbBtree::Transaction *txnf = mBdb.data()->btree()->writeTransaction() ? mBdb.data()->btree()->writeTransaction() : mBdb.data()->btree()->beginWrite();
     JsonDbBtree::Cursor cursorf(txnf);
     bool ok = cursorf.first();
     if (ok) {
@@ -452,12 +453,14 @@ void JsonDbIndex::checkIndex()
             outkey1 = outkey2;
         }
     }
-    txnf->abort();
+    if (!isInTransaction)
+        txnf->abort();
 
     qDebug() << "checkIndex" << mPropertyName << "reversed";
     // now check other direction
     int countr = 0;
-    JsonDbBtree::Transaction *txnr = mBdb.data()->btree()->beginRead();
+    isInTransaction = mBdb.data()->btree()->writeTransaction();
+    JsonDbBtree::Transaction *txnr = mBdb.data()->btree()->writeTransaction() ? mBdb.data()->btree()->writeTransaction() : mBdb.data()->btree()->beginWrite();
     JsonDbBtree::Cursor cursorr(txnr);
     ok = cursorr.last();
     if (ok) {
@@ -477,7 +480,8 @@ void JsonDbIndex::checkIndex()
             outkey1 = outkey2;
         }
     }
-    txnr->abort();
+    if (!isInTransaction)
+        txnr->abort();
     qDebug() << "checkIndex" << mPropertyName << "done" << countf << countr << "entries checked";
 
 }
@@ -489,15 +493,17 @@ void JsonDbIndex::setCacheSize(quint32 cacheSize)
         mBdb->setCacheSize(cacheSize);
 }
 
-JsonDbIndexCursor::JsonDbIndexCursor(JsonDbIndex *index) :
-    mTxn(index->bdb()->btree()->beginRead()),
-    mCursor(mTxn)
+JsonDbIndexCursor::JsonDbIndexCursor(JsonDbIndex *index)
+    : isOwnTransaction(!index->bdb()->btree()->writeTransaction()),
+      mTxn(isOwnTransaction ? index->bdb()->btree()->beginWrite() : index->bdb()->btree()->writeTransaction()),
+      mCursor(mTxn)
 {
 }
 
 JsonDbIndexCursor::~JsonDbIndexCursor()
 {
-    mTxn->abort();
+    if (isOwnTransaction)
+        mTxn->abort();
 }
 
 bool JsonDbIndexCursor::seek(const QJsonValue &value)
diff --git a/src/daemon/jsondbindex.h b/src/daemon/jsondbindex.h
index 534880c..97520fa 100644
--- a/src/daemon/jsondbindex.h
+++ b/src/daemon/jsondbindex.h
@@ -147,6 +147,7 @@ public:
     bool prev();
 
 private:
+    bool isOwnTransaction;
     JsonDbBtree::Transaction *mTxn;
     JsonDbBtree::Cursor mCursor;
     JsonDbIndex *mIndex;
diff --git a/src/daemon/jsondbindexquery.cpp b/src/daemon/jsondbindexquery.cpp
index 9f77d97..a8140cc 100644
--- a/src/daemon/jsondbindexquery.cpp
+++ b/src/daemon/jsondbindexquery.cpp
@@ -84,27 +84,23 @@ JsonDbIndexQuery::JsonDbIndexQuery(JsonDbPartition *partition, JsonDbObjectTable
 {
     if (propertyName != JsonDbString::kUuidStr) {
         mBdbIndex = table->indexSpec(propertyName)->index->bdb();
-        mTxn = mBdbIndex->btree()->beginRead();
+        isOwnTransaction = !mBdbIndex->btree()->writeTransaction();
+        mTxn = isOwnTransaction ? mBdbIndex->btree()->beginWrite() : mBdbIndex->btree()->writeTransaction();
         mCursor = new JsonDbBtree::Cursor(mTxn);
     } else {
-        mTxn = table->bdb()->btree()->beginRead();
+        isOwnTransaction = !table->bdb()->btree()->writeTransaction();
+        mTxn = isOwnTransaction ? table->bdb()->btree()->beginWrite() : table->bdb()->btree()->writeTransaction();
         mCursor = new JsonDbBtree::Cursor(mTxn);
     }
 }
 JsonDbIndexQuery::~JsonDbIndexQuery()
 {
-    if (mResidualQuery) {
-        delete mResidualQuery;
-        mResidualQuery = 0;
-    }
-    if (mTxn && mCursor) {
+    delete mResidualQuery;
+    if (isOwnTransaction)
         mTxn->abort();
-        delete mCursor;
-        mCursor = 0;
-    }
-    for (int i = 0; i < mQueryConstraints.size(); i++) {
+    delete mCursor;
+    for (int i = 0; i < mQueryConstraints.size(); i++)
         delete mQueryConstraints[i];
-    }
 }
 
 QString JsonDbIndexQuery::partition() const
diff --git a/src/daemon/jsondbindexquery.h b/src/daemon/jsondbindexquery.h
index a5614c1..cc21517 100644
--- a/src/daemon/jsondbindexquery.h
+++ b/src/daemon/jsondbindexquery.h
@@ -109,6 +109,7 @@ protected:
     JsonDbPartition *mPartition;
     JsonDbObjectTable   *mObjectTable;
     JsonDbBtree *mBdbIndex;
+    bool isOwnTransaction;
     JsonDbBtree::Transaction *mTxn;
     JsonDbBtree::Cursor *mCursor;
     const JsonDbOwner *mOwner;
diff --git a/src/daemon/jsondbobjecttable.cpp b/src/daemon/jsondbobjecttable.cpp
index 560bfdc..807afff 100644
--- a/src/daemon/jsondbobjecttable.cpp
+++ b/src/daemon/jsondbobjecttable.cpp
@@ -349,15 +349,11 @@ void JsonDbObjectTable::reindexObjects(const QString &indexName, const QStringLi
 
     IndexSpec &indexSpec = mIndexes[indexName];
     JsonDbIndex *index = indexSpec.index;
-    bool inTransaction = index->bdb()->writeTransaction();
-    bool inObjectTableTransaction = mBdb->writeTransaction();
-    JsonDbBtree::Transaction *bdbTxn = 0;
-    if (!inObjectTableTransaction)
-         bdbTxn = mBdb->btree()->beginRead();
-    else
-         bdbTxn = mBdb->writeTransaction();
+    bool isInIndexTransaction = index->bdb()->writeTransaction();
+    bool isInObjectTableTransaction = mBdb->writeTransaction();
+    JsonDbBtree::Transaction *bdbTxn = mBdb->writeTransaction() ? mBdb->writeTransaction() : mBdb->btree()->beginWrite();
     JsonDbBtree::Cursor cursor(bdbTxn);
-    if (!inTransaction)
+    if (!isInIndexTransaction)
         index->begin();
     for (bool ok = cursor.first(); ok; ok = cursor.next()) {
         QByteArray baKey, baObject;
@@ -373,9 +369,9 @@ void JsonDbObjectTable::reindexObjects(const QString &indexName, const QStringLi
         if (!fieldValue.isNull())
             index->indexObject(objectKey, object, stateNumber);
     }
-    if (!inTransaction)
+    if (!isInIndexTransaction)
         index->commit(stateNumber);
-    if (!inObjectTableTransaction)
+    if (!isInObjectTableTransaction)
         bdbTxn->abort();
     if (jsondbSettings->verbose())
         qDebug() << "} reindexObjects";
@@ -504,7 +500,8 @@ GetObjectsResult JsonDbObjectTable::getObjects(const QString &keyName, const QJs
     }
 
     if (!mIndexes.contains(keyName) && (keyName == JsonDbString::kTypeStr)) {
-        JsonDbBtree::Transaction *txn = mBdb->btree()->beginRead();
+        bool isInTransaction = mBdb->btree()->writeTransaction();
+        JsonDbBtree::Transaction *txn = mBdb->btree()->writeTransaction() ? mBdb->btree()->writeTransaction() : mBdb->btree()->beginWrite();
         JsonDbBtree::Cursor cursor(txn);
         for (bool ok = cursor.first(); ok; ok = cursor.next()) {
             QByteArray baKey, baObject;
@@ -518,7 +515,8 @@ GetObjectsResult JsonDbObjectTable::getObjects(const QString &keyName, const QJs
                 continue;
             objectList.append(object);
         }
-        txn->abort();
+        if (!isInTransaction)
+            txn->abort();
         result.data = objectList;
         return result;
     }
@@ -528,12 +526,8 @@ GetObjectsResult JsonDbObjectTable::getObjects(const QString &keyName, const QJs
     //fprintf(stderr, "getObject bdb=%p\n", indexSpec->index->bdb());
     if (indexSpec->lazy)
         updateIndex(indexSpec->index);
-    JsonDbBtree::Transaction *txn;
-    bool activeWriteTransaction = indexSpec->index->bdb()->writeTransaction();
-    if (activeWriteTransaction)
-        txn = indexSpec->index->bdb()->writeTransaction();
-    else
-        txn = indexSpec->index->bdb()->btree()->beginRead();
+    bool isInTransaction = indexSpec->index->bdb()->writeTransaction();
+    JsonDbBtree::Transaction *txn = indexSpec->index->bdb()->writeTransaction() ? indexSpec->index->bdb()->writeTransaction() : indexSpec->index->bdb()->btree()->beginWrite();
     JsonDbBtree::Cursor cursor(txn);
     if (cursor.seekRange(forwardKey)) {
         do {
@@ -565,7 +559,7 @@ GetObjectsResult JsonDbObjectTable::getObjects(const QString &keyName, const QJs
             }
         } while (cursor.next());
     }
-    if (!activeWriteTransaction)
+    if (!isInTransaction)
         txn->abort();
 
     result.data = objectList;
@@ -612,7 +606,8 @@ void JsonDbObjectTable::changesSince(quint32 stateNumber, QMap<ObjectKey,ObjectC
     QElapsedTimer timer;
     if (jsondbSettings->performanceLog())
         timer.start();
-    JsonDbBtree::Transaction *txn = mBdb->btree()->beginRead();
+    bool inTransaction = mBdb->btree()->writeTransaction();
+    JsonDbBtree::Transaction *txn = mBdb->btree()->writeTransaction() ? mBdb->btree()->writeTransaction() : mBdb->btree()->beginWrite();
     JsonDbBtree::Cursor cursor(txn);
     QByteArray baStateKey(5, 0);
     makeStateKey(baStateKey, stateNumber);
@@ -670,7 +665,8 @@ void JsonDbObjectTable::changesSince(quint32 stateNumber, QMap<ObjectKey,ObjectC
         } while (cursor.next());
     }
     *changes = changeMap;
-    txn->abort();
+    if (!inTransaction)
+        txn->abort();
 
     if (jsondbSettings->performanceLog())
         qDebug() << "changesSince" << mFilename << timer.elapsed() << "ms";