///////////////////////////////////////////////////////////////////////////////////////////////
/// <summary>
/// Creates a <see cref="SQLiteBlob" /> object. This will not work
/// for tables that were created WITHOUT ROWID.
/// </summary>
/// <param name="connection">
/// The connection to use when opening the blob object.
/// </param>
/// <param name="databaseName">
/// The name of the database containing the blob object.
/// </param>
/// <param name="tableName">
/// The name of the table containing the blob object.
/// </param>
/// <param name="columnName">
/// The name of the column containing the blob object.
/// </param>
/// <param name="rowId">
/// The integer identifier for the row associated with the desired
/// blob object.
/// </param>
/// <param name="readOnly">
/// Non-zero to open the blob object for read-only access.
/// </param>
/// <returns>
/// The newly created <see cref="SQLiteBlob" /> instance -OR- null
/// if an error occurs.
/// </returns>
public static SQLiteBlob Create(
SQLiteConnection connection,
string databaseName,
string tableName,
string columnName,
long rowId,
bool readOnly
)
{
if (connection == null)
{
throw new ArgumentNullException("connection");
}
SQLite3 sqlite3 = connection._sql as SQLite3;
if (sqlite3 == null)
{
throw new InvalidOperationException("Connection has no wrapper");
}
SQLiteConnectionHandle handle = sqlite3._sql;
if (handle == null)
{
throw new InvalidOperationException("Connection has an invalid handle.");
}
SQLiteBlobHandle blob = null;
try
{
// do nothing.
}
finally /* NOTE: Thread.Abort() protection. */
{
IntPtr ptrBlob = IntPtr.Zero;
SQLiteErrorCode rc = UnsafeNativeMethods.sqlite3_blob_open(
handle, SQLiteConvert.ToBytes(databaseName),
SQLiteConvert.ToBytes(tableName), SQLiteConvert.ToBytes(
columnName), rowId, readOnly ? 0 : 1, ref ptrBlob);
if (rc != SQLiteErrorCode.Ok)
{
throw new SQLiteException(rc, null);
}
blob = new SQLiteBlobHandle(handle, ptrBlob);
}
SQLiteConnection.OnChanged(connection, new ConnectionEventArgs(
SQLiteConnectionEventType.NewCriticalHandle, null, null,
null, null, blob, null, new object[] { typeof(SQLiteBlob),
databaseName, tableName, columnName, rowId, readOnly }));
return(new SQLiteBlob(sqlite3, blob));
}
