protected override CrawlerQueueEntry PopImpl()
{
return(m_EsentInstance.Cursor((session, dbid) =>
{
using (Transaction transaction = new Transaction(session))
{
using (Table table = new Table(session, dbid, EsentTableDefinitions.QueueTableName, OpenTableGrbit.None))
{
if (Api.TryMoveFirst(session, table))
{
var data = Api.RetrieveColumnAsString(session, table, dataColumn.columnid, Encoding.Unicode);
Api.JetDelete(session, table);
using (Table table2 = new Table(session, dbid, EsentTableDefinitions.GlobalsTableName, OpenTableGrbit.None))
{
Api.EscrowUpdate(session, table2, queueCountColumn.columnid, -1);
}
transaction.Commit(CommitTransactionGrbit.None);
return data.FromJson <CrawlerQueueEntry>();
}
}
transaction.Rollback();
return null;
}
}));
}
public EsentCrawlQueueService(Uri baseUri, bool resume)
{
m_DatabaseFileName = Path.GetFullPath("NCrawlQueue{0}\\Queue.edb".FormatWith(baseUri.GetHashCode()));
if (!resume && File.Exists(m_DatabaseFileName))
{
ClearQueue();
}
m_EsentInstance = new EsentInstance(m_DatabaseFileName, (session, dbid) =>
{
EsentTableDefinitions.CreateGlobalsTable(session, dbid);
EsentTableDefinitions.CreateQueueTable(session, dbid);
});
// Get columns
m_EsentInstance.Cursor((session, dbid) =>
{
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.GlobalsTableName,
EsentTableDefinitions.GlobalsCountColumnName,
out queueCountColumn);
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.QueueTableName,
EsentTableDefinitions.QueueTableDataColumnName,
out dataColumn);
});
}
public EsentCrawlerHistoryService(Uri baseUri, bool resume)
{
m_Resume = resume;
m_DatabaseFileName = Path.GetFullPath("NCrawlHist{0}\\Hist.edb".FormatWith(baseUri.GetHashCode()));
if (!resume)
{
ClearHistory();
}
m_EsentInstance = new EsentInstance(m_DatabaseFileName, (session, dbid) =>
{
EsentTableDefinitions.CreateGlobalsTable(session, dbid);
EsentTableDefinitions.CreateHistoryTable(session, dbid);
});
// Get columns
m_EsentInstance.Cursor((session, dbid) =>
{
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.GlobalsTableName,
EsentTableDefinitions.GlobalsCountColumnName, out historyCountColumn);
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.HistoryTableName,
EsentTableDefinitions.HistoryTableUrlColumnName, out historyUrlColumn);
});
}
public EsentCrawlQueueService(Uri baseUri, bool resume)
{
m_DatabaseFileName = Path.GetFullPath("NCrawlQueue{0}\\Queue.edb".FormatWith(baseUri.GetHashCode()));
if (!resume && File.Exists(m_DatabaseFileName))
{
ClearQueue();
}
m_EsentInstance = new EsentInstance(m_DatabaseFileName, (session, dbid) =>
{
EsentTableDefinitions.CreateGlobalsTable(session, dbid);
EsentTableDefinitions.CreateQueueTable(session, dbid);
});
// Get columns
m_EsentInstance.Cursor((session, dbid) =>
{
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.GlobalsTableName,
EsentTableDefinitions.GlobalsCountColumnName,
out queueCountColumn);
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.QueueTableName,
EsentTableDefinitions.QueueTableDataColumnName,
out dataColumn);
});
}
public EsentCrawlerHistoryService(Uri baseUri, bool resume)
{
m_Resume = resume;
m_DatabaseFileName = Path.GetFullPath("NCrawlHist{0}\\Hist.edb".FormatWith(baseUri.GetHashCode()));
if (!resume)
{
ClearHistory();
}
m_EsentInstance = new EsentInstance(m_DatabaseFileName, (session, dbid) =>
{
EsentTableDefinitions.CreateGlobalsTable(session, dbid);
EsentTableDefinitions.CreateHistoryTable(session, dbid);
});
// Get columns
m_EsentInstance.Cursor((session, dbid) =>
{
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.GlobalsTableName,
EsentTableDefinitions.GlobalsCountColumnName, out historyCountColumn);
Api.JetGetColumnInfo(session, dbid, EsentTableDefinitions.HistoryTableName,
EsentTableDefinitions.HistoryTableUrlColumnName, out historyUrlColumn);
});
}
protected override void Add(string key)
{
m_EsentInstance.Cursor((session, dbid) =>
{
using (Transaction transaction = new Transaction(session))
{
using (Table table = new Table(session, dbid, EsentTableDefinitions.HistoryTableName, OpenTableGrbit.None))
{
using (Update update = new Update(session, table, JET_prep.Insert))
{
Api.SetColumn(session, table, historyUrlColumn.columnid, key, Encoding.Unicode);
update.Save();
}
}
using (Table table = new Table(session, dbid, EsentTableDefinitions.GlobalsTableName, OpenTableGrbit.None))
{
Api.EscrowUpdate(session, table, historyCountColumn.columnid, 1);
}
transaction.Commit(CommitTransactionGrbit.None);
}
});
}
