/// <summary>
/// Reads and returns an <see cref="EventHeader"/> given a <see cref="BuildXLReader"/>.
/// It is the callers responsibility to ensure the reader's initial position is set correctly.
/// </summary>
public static EventHeader ReadFrom(BuildXLReader reader)
{
var eventHeader = new EventHeader();
// Order matters!
eventHeader.EventId = reader.ReadUInt32Compact();
eventHeader.WorkerId = reader.ReadUInt32Compact();
eventHeader.Timestamp = reader.ReadInt64Compact();
eventHeader.EventPayloadSize = reader.ReadInt32Compact();
return(eventHeader);
}
/// <summary>
/// Starts a task that is responsible for deserializing all path events as fed to it through the specified queue
/// </summary>
/// <param name="pathEventsToDeserialize">The queue where path events (as file positions) to deserialize will be fed</param>
/// <returns>A task that will finish when the queue that it consumes from is both marked completed and empty</returns>
private Task CreatePathEventConsumerTask(BlockingCollection <long> pathEventsToDeserialize)
{
return(Task.Run(() =>
{
using (FileStream fileStream = File.Open(m_logFilename, FileMode.Open, FileAccess.Read, FileShare.Read))
{
ParallelEventReader parallelEventReader = new ParallelEventReader(this, fileStream);
while (!pathEventsToDeserialize.IsCompleted)
{
// Get next AddPath event file position
long positionToDeserialize;
try
{
positionToDeserialize = pathEventsToDeserialize.Take();
}
catch (InvalidOperationException)
{
// This exception is thrown when CompleteAdding is called while we are blocked on the call to Take
// If we see this exception, we know we are done processing path events and the task can exit
return;
}
// Seek to the start of the next AddPath event to deserialize
fileStream.Seek(positionToDeserialize, SeekOrigin.Begin);
EventHeader header = EventHeader.ReadFrom(parallelEventReader);
// Ensure event id it is for an AddPath event
Contract.Assert((BinaryLogger.LogSupportEventId)header.EventId == BinaryLogger.LogSupportEventId.AddPath);
// Determine what position the file stream should have after calling the event handler
var startOfNextEvent = fileStream.Position + header.EventPayloadSize;
// Handle the event
ParallelReadPathEvent(parallelEventReader);
// Ensure that the correct number of bytes were read out of the file
Contract.Assert(fileStream.Position == startOfNextEvent);
}
}
}));
}
/// <summary>
/// Reads an event
/// </summary>
/// <returns>the result of reading the next event</returns>
public EventReadResult ReadEvent()
{
try
{
while (true)
{
if (m_nextReadPosition != null && LogStream.Position != m_nextReadPosition.Value)
{
LogStream.Seek(m_nextReadPosition.Value, SeekOrigin.Begin);
}
var position = LogStream.Position;
if (position == LogLength)
{
return(EventReadResult.EndOfStream);
}
// Read the header
EventHeader header = EventHeader.ReadFrom(m_logStreamReader);
m_currentEventPayloadSize = header.EventPayloadSize;
position = LogStream.Position;
// There are less bytes than specified by the payload
// The file is corrupted or truncated
if (position + header.EventPayloadSize > LogLength)
{
return(EventReadResult.UnexpectedEndOfStream);
}
m_nextReadPosition = position + header.EventPayloadSize;
// Handle the internal events
if (header.EventId < (uint)BinaryLogger.LogSupportEventId.Max)
{
switch ((BinaryLogger.LogSupportEventId)header.EventId)
{
case BinaryLogger.LogSupportEventId.StartTime:
ReadStartTimeEvent(m_logStreamReader);
break;
case BinaryLogger.LogSupportEventId.AddPath:
ReadPathEvent(m_logStreamReader);
break;
case BinaryLogger.LogSupportEventId.AddStringId:
ReadStringIdEvent(m_logStreamReader);
break;
}
Contract.Assert(LogStream.Position == (position + header.EventPayloadSize));
continue;
}
else
{
header.EventId -= (uint)BinaryLogger.LogSupportEventId.Max;
}
EventHandler handler;
if ((m_handlers.Length > header.EventId) &&
((handler = m_handlers[header.EventId]) != null))
{
handler(header.EventId, header.WorkerId, header.Timestamp, m_logStreamReader);
Contract.Assert(LogStream.Position <= (position + header.EventPayloadSize), "Event handler read beyond the event payload");
}
// Seek to the start of the next event as we may not have read the entire payload (i.e. EventStatsAnalyzer)
if (LogStream.Position != m_nextReadPosition.Value)
{
LogStream.Seek(m_nextReadPosition.Value, SeekOrigin.Begin);
}
return(EventReadResult.Success);
}
}
catch (EndOfStreamException)
{
return(EventReadResult.UnexpectedEndOfStream);
}
}
/// <summary>
/// Reads all events in the log file and processes them in parallel
/// </summary>
/// <returns>If all events are read successfully, <see cref="BinaryLogReader.EventReadResult.EndOfStream"/> will be returned</returns>
public EventReadResult ReadAllEvents()
{
int numPathEventConsumers = 2;
int numNotPathEventConsumers = 5;
// Create a boolean array to decide which events to process
bool[] shouldProcessEvent = new bool[((int)BinaryLogger.LogSupportEventId.Max) + m_handlers.Length];
for (int i = 0; i < shouldProcessEvent.Length; ++i)
{
if (i < (int)BinaryLogger.LogSupportEventId.Max)
{
// Always process internal events
shouldProcessEvent[i] = true;
}
else if (m_handlers[i - (int)BinaryLogger.LogSupportEventId.Max] != null)
{
// Only process event if handler is defined
shouldProcessEvent[i] = true;
}
else
{
shouldProcessEvent[i] = false;
}
}
BlockingCollection <long>[] addPathEventsToDeserialize = new BlockingCollection <long> [numPathEventConsumers];
BlockingCollection <long>[] notAddPathEventsToDeserialize = new BlockingCollection <long> [numNotPathEventConsumers];
try
{
// Initialize the queues
for (int i = 0; i < addPathEventsToDeserialize.Length; ++i)
{
addPathEventsToDeserialize[i] = new BlockingCollection <long>();
}
for (int i = 0; i < notAddPathEventsToDeserialize.Length; ++i)
{
notAddPathEventsToDeserialize[i] = new BlockingCollection <long>();
}
// Start the event consumers
Task[] pathEventConsumers = new Task[numPathEventConsumers];
for (int i = 0; i < pathEventConsumers.Length; ++i)
{
pathEventConsumers[i] = CreatePathEventConsumerTask(addPathEventsToDeserialize[i]);
}
Task[] notPathEventConsumers = new Task[numNotPathEventConsumers];
for (int i = 0; i < notPathEventConsumers.Length; ++i)
{
notPathEventConsumers[i] = CreateNonPathEventConsumerTask(notAddPathEventsToDeserialize[i]);
}
// Event positions are added to the queues in a round robin manner
// These variables indicate which queue to put the next event position in
int pathEventQueueToAddTo = 0;
int notPathEventQueueToAddTo = 0;
EventReadResult result;
try
{
while (true)
{
if (m_nextReadPosition != null)
{
LogStream.Seek(m_nextReadPosition.Value, SeekOrigin.Begin);
}
var position = LogStream.Position;
if (position == LogLength)
{
result = EventReadResult.EndOfStream;
break;
}
// Read the header
EventHeader header = EventHeader.ReadFrom(m_logStreamReader);
if (shouldProcessEvent[header.EventId])
{
// Add event to appropriate queue
if ((BinaryLogger.LogSupportEventId)header.EventId == BinaryLogger.LogSupportEventId.AddPath)
{
addPathEventsToDeserialize[pathEventQueueToAddTo].Add(position);
pathEventQueueToAddTo++;
pathEventQueueToAddTo %= numPathEventConsumers;
}
else
{
notAddPathEventsToDeserialize[notPathEventQueueToAddTo].Add(position);
notPathEventQueueToAddTo++;
notPathEventQueueToAddTo %= numNotPathEventConsumers;
}
}
m_currentEventPayloadSize = header.EventPayloadSize;
position = LogStream.Position;
// There are less bytes than specified by the payload
// The file is corrupted or truncated
if (position + header.EventId > LogLength)
{
result = EventReadResult.UnexpectedEndOfStream;
break;
}
m_nextReadPosition = position + header.EventPayloadSize;
}
}
catch (EndOfStreamException)
{
result = EventReadResult.UnexpectedEndOfStream;
}
// We are done adding events to the queues so mark all the queues as complete for adding
foreach (var q in addPathEventsToDeserialize)
{
q.CompleteAdding();
}
foreach (var q in notAddPathEventsToDeserialize)
{
q.CompleteAdding();
}
// Wait for all events to be processed
Task.WaitAll(pathEventConsumers);
Task.WaitAll(notPathEventConsumers);
return(result);
}
finally
{
// Dispose the queues
foreach (var q in addPathEventsToDeserialize)
{
q.Dispose();
}
foreach (var q in notAddPathEventsToDeserialize)
{
q.Dispose();
}
}
}
/// <summary>
/// Starts a task that is responsible for deserializing all non-path events as fed to it through the specified queue
/// </summary>
/// <param name="nonPathEventsToDeserialize">The queue where non-path events (as file positions) to deserialize will be fed</param>
/// <returns>A task that will finish when the queue that it consumes from is both marked completed and empty</returns>
private Task CreateNonPathEventConsumerTask(BlockingCollection <long> nonPathEventsToDeserialize)
{
return(Task.Run(() =>
{
using (FileStream fileStream = File.Open(m_logFilename, FileMode.Open, FileAccess.Read, FileShare.Read))
{
ParallelEventReader parallelEventReader = new ParallelEventReader(this, fileStream);
while (!nonPathEventsToDeserialize.IsCompleted)
{
// Get next event file position
long positionToDeserialize;
try
{
positionToDeserialize = nonPathEventsToDeserialize.Take();
}
catch (InvalidOperationException)
{
// This exception is thrown when CompleteAdding is called while we are blocked on the call to Take
// If we see this exception, we know we are done processing events and the task can exit
return;
}
// Seek to the start of the next event to deserialize
fileStream.Seek(positionToDeserialize, SeekOrigin.Begin);
EventHeader header = EventHeader.ReadFrom(parallelEventReader);
// Ensure that event id is NOT an AddPath event
Contract.Assert((BinaryLogger.LogSupportEventId)header.EventId != BinaryLogger.LogSupportEventId.AddPath);
var startOfNextEvent = fileStream.Position + header.EventPayloadSize;
// Handle the internal events
if (header.EventId < (uint)BinaryLogger.LogSupportEventId.Max)
{
switch ((BinaryLogger.LogSupportEventId)header.EventId)
{
case BinaryLogger.LogSupportEventId.StartTime:
ReadStartTimeEvent(parallelEventReader);
break;
case BinaryLogger.LogSupportEventId.AddStringId:
ReadStringIdEvent(parallelEventReader);
break;
}
Contract.Assert(fileStream.Position == startOfNextEvent);
continue;
}
else
{
header.EventId -= (uint)BinaryLogger.LogSupportEventId.Max;
}
EventHandler handler;
if ((m_handlers.Length > header.EventId) &&
((handler = m_handlers[header.EventId]) != null))
{
handler(header.EventId, header.WorkerId, header.Timestamp, parallelEventReader);
Contract.Assert(fileStream.Position <= startOfNextEvent, "Event handler read beyond the event payload");
}
}
}
}));
}
