/// <summary>
/// Saves the contents of this result set to a file using the IFileStreamFactory provided
/// </summary>
/// <param name="saveParams">Parameters for saving the results to a file</param>
/// <param name="fileFactory">
/// Factory for creating a stream reader/writer combo for writing results to disk
/// </param>
/// <param name="successHandler">Handler for a successful write of all rows</param>
/// <param name="failureHandler">Handler for unsuccessful write of all rows</param>
public void SaveAs(SaveResultsRequestParams saveParams, IFileStreamFactory fileFactory,
SaveAsAsyncEventHandler successHandler, SaveAsFailureAsyncEventHandler failureHandler)
{
// Sanity check the save params and file factory
Validate.IsNotNull(nameof(saveParams), saveParams);
Validate.IsNotNull(nameof(fileFactory), fileFactory);
// Make sure the resultset has finished being read
if (!hasBeenRead)
{
throw new InvalidOperationException(SR.QueryServiceSaveAsResultSetNotComplete);
}
// Make sure there isn't a task for this file already
Task existingTask;
if (SaveTasks.TryGetValue(saveParams.FilePath, out existingTask))
{
if (existingTask.IsCompleted)
{
// The task has completed, so let's attempt to remove it
if (!SaveTasks.TryRemove(saveParams.FilePath, out existingTask))
{
throw new InvalidOperationException(SR.QueryServiceSaveAsMiscStartingError);
}
}
else
{
// The task hasn't completed, so we shouldn't continue
throw new InvalidOperationException(SR.QueryServiceSaveAsInProgress);
}
}
// Create the new task
Task saveAsTask = new Task(async() =>
{
try
{
// Set row counts depending on whether save request is for entire set or a subset
long rowEndIndex = RowCount;
int rowStartIndex = 0;
if (saveParams.IsSaveSelection)
{
// ReSharper disable PossibleInvalidOperationException IsSaveSelection verifies these values exist
rowEndIndex = saveParams.RowEndIndex.Value + 1;
rowStartIndex = saveParams.RowStartIndex.Value;
// ReSharper restore PossibleInvalidOperationException
}
using (var fileReader = fileFactory.GetReader(outputFileName))
using (var fileWriter = fileFactory.GetWriter(saveParams.FilePath))
{
// Iterate over the rows that are in the selected row set
for (long i = rowStartIndex; i < rowEndIndex; ++i)
{
var row = fileReader.ReadRow(fileOffsets[i], i, Columns);
fileWriter.WriteRow(row, Columns);
}
if (successHandler != null)
{
await successHandler(saveParams);
}
}
}
catch (Exception e)
{
fileFactory.DisposeFile(saveParams.FilePath);
if (failureHandler != null)
{
await failureHandler(saveParams, e.Message);
}
}
});
// Add exception handling to the save task
Task taskWithHandling = saveAsTask.ContinueWithOnFaulted(async t =>
{
if (failureHandler != null)
{
await failureHandler(saveParams, t.Exception.Message);
}
});
// If saving the task fails, return a failure
if (!SaveTasks.TryAdd(saveParams.FilePath, taskWithHandling))
{
throw new InvalidOperationException(SR.QueryServiceSaveAsMiscStartingError);
}
// Task was saved, so start up the task
saveAsTask.Start();
}
