/// <summary>
/// Relay the returned result from sqlite3 callback to the callback func specified
/// when Execute() is called
/// </summary>
/// <param name="pArg">Not used</param>
/// <param name="argc">Number of columns in argv</param>
/// <param name="argv">The column data in this row</param>
/// <param name="columnNames">The column names</param>
internal unsafe int CallBack(IntPtr pArg, int argc, sbyte **argv, sbyte **columnNames)
{
List <string> ar = new List <string>(argc);
// First time in? Add column names
if (this.column_names == null)
{
for (int i = 0; i < argc; ++i)
{
ar.Add(SqliteString.PointerToString(columnNames[i]));
}
}
column_names = ar.ToArray();
// Go through this rows data
ar.Clear();
for (int i = 0; i < argc; ++i)
{
if (argv[i] == ((sbyte *)0))
{
ar.Add(null);
}
//ar[i] = null;
else
{
ar.Add(SqliteString.PointerToString(argv[i]));
}
//ar[i] = SqliteString.PointerToString(argv[i]);
}
return(callbackfunc(param, column_names, ar.ToArray()));
}
/// <summary>
/// Executes the supplied query and calls the callback function for each row of result
/// </summary>
/// <remarks>
/// <p>
/// If the database is busy (ie with another process/thread using it) then
/// this method will call Thread.Sleep(), and then retry the query. Number of
/// retries and retry delay are configurable using the appropriate properties.</p>
/// <p>The result set object may be empty if there are no results, or if the
/// query does not return results (eg. UPDATE, INSERT, DELETE etc)</p>
/// </remarks>
/// <param name="query">The SQL query to execute</param>
/// <param name="callback">The callback function to call
/// (object Param, string[] ColumnNames, ArrayList Data)</param>
/// <param name="Param">A object to pass to the callback function</param>
/// <exception cref="SQLiteException">
/// Thrown if an error occurs or if the database is busy and the retries
/// are exhausted.
/// </exception>
public unsafe void Execute(string query, ResultCallBack callback, object Param)
{
column_names = null; //reset for each new query
param = Param;
callbackfunc = callback;
ResultCode errorCode;
string errorMsg;
int retries = 0;
using (SqliteString sql = new SqliteString(query))
{
while ((errorCode = SQLiteClient.sqlite3_exec(
this.dbHandle,
sql.ToPointer(),
(callbackfunc == null) ? null : new SQLiteCallback(CallBack),
IntPtr.Zero, out errorMsg))
== ResultCode.BUSY && retries < this.busyRetries)
{
Thread.Sleep(this.busyRetryDelay);
++retries;
continue;
}
if (errorCode != ResultCode.OK)
{
throw new SQLiteException(SQLiteClient.GetMessageForError(errorCode) + ":\n"
+ errorMsg + "\n the query string is :\n" + query, errorCode);
}
}
}
