/// <summary>
/// Copy constructor.
/// </summary>
/// <param name="source">The FieldLogItem instance to copy from.</param>
protected FieldLogItem(FieldLogItem source)
{
Size = source.Size;
EventCounter = source.EventCounter;
Time = source.Time;
Priority = source.Priority;
SessionId = source.SessionId;
ThreadId = source.ThreadId;
WebRequestId = source.WebRequestId;
LogItemSourceFileName = source.LogItemSourceFileName;
FileFormatVersion = source.FileFormatVersion;
}
public static FieldLogItemViewModel Create(FieldLogItem item)
{
FieldLogTextItem textItem = item as FieldLogTextItem;
if (textItem != null)
{
return new FieldLogTextItemViewModel(textItem);
}
FieldLogDataItem dataItem = item as FieldLogDataItem;
if (dataItem != null)
{
return new FieldLogDataItemViewModel(dataItem);
}
FieldLogExceptionItem exceptionItem = item as FieldLogExceptionItem;
if (exceptionItem != null)
{
return new FieldLogExceptionItemViewModel(exceptionItem);
}
FieldLogScopeItem scopeItem = item as FieldLogScopeItem;
if (scopeItem != null)
{
return new FieldLogScopeItemViewModel(scopeItem);
}
return null;
}
/// <summary>
/// Reads the next complete log item from the file.
/// </summary>
/// <returns>The next log item in the file.</returns>
/// <remarks>
/// This method will block until a complete log item is available in the file.
/// </remarks>
public FieldLogItem ReadLogItem()
{
byte[] bytes;
FieldLogItemType type;
int pos = -1, length;
try
{
do
{
// Remember the log item start position in the file
pos = (int)fileStream.Position;
bool localWaitMode = WaitMode;
if (!localWaitMode && pos == fileStream.Length)
{
return(null);
}
// Read the item type and length
bytes = ReadBytes(4);
if (bytes == null)
{
if (closeEvent.WaitOne(0))
{
// Close was requested
isClosing = true;
WaitMode = false;
return(null);
}
if (!WaitMode && localWaitMode)
{
// Follow-up file has been noticed
return(null);
}
if (!localWaitMode)
{
throw new EndOfStreamException("Unexpected end of file.");
}
}
// Parse type and length data
type = (FieldLogItemType)((bytes[0] & 0xF0) >> 4);
bytes[0] = (byte)(bytes[0] & 0x0F);
if (BitConverter.IsLittleEndian)
{
Array.Reverse(bytes);
}
length = BitConverter.ToInt32(bytes, 0);
// Check whether this is a text item
if (type == FieldLogItemType.StringData)
{
// Read the item and add it to the text cache
byte[] stringBytes = ReadBytes(length);
// Parse the text data
string str = Encoding.UTF8.GetString(stringBytes);
// Add text to the cache
textCache[pos] = str;
}
}while (type == FieldLogItemType.StringData);
itemCount++;
return(FieldLogItem.Read(this, type));
}
catch (Exception ex)
{
throw new Exception(
"Error reading from the log file \"" + FileName + "\" at position " + fileStream.Position + " (starting at " + pos + "). " + ex.Message,
ex);
}
}
/// <summary>
/// Reads the next log item from the log file group. If all files have been read until the
/// end, this method blocks until a new log item was written to any file, or until the
/// close event was set.
/// </summary>
/// <returns>The next log item, or null if there are no more log items and the waiting was cancelled.</returns>
public FieldLogItem ReadLogItem()
{
while (true)
{
Task <bool>[] availableTasks;
lock (readerLock)
{
availableTasks = readTasks
.Where(t => t != null)
.Concat(new Task <bool>[] { waitForNewFilePrioTask })
.Concat(new Task <bool>[] { closeTask })
.ToArray();
}
Task.WaitAny(availableTasks);
// We don't care about which task has finished. It may actually be multiple tasks.
// We just test them all and use the result of all tasks that have finished.
// Compare all completed readers' current value, find the smallest time and move
// that enumerator one further.
DateTime minTime = DateTime.MaxValue;
FieldLogItem minTimeItem = null;
FieldLogPriority minTimePrio = 0;
foreach (var availableTask in availableTasks)
{
if (availableTask.IsCompleted)
{
// Search from the lowest priority up, as lower priorities appear more often
for (int prioInt = 0; prioInt < readTasks.Length; prioInt++)
{
if (availableTask == readTasks[prioInt])
{
// A reader enumerator task has finished, consider its result
FieldLogPriority prio = (FieldLogPriority)prioInt;
if (availableTask.Result)
{
// A new item of this priority is available.
// Fetch the item from the reader.
FieldLogItem item = readers[prio].Current;
if (item.Time < minTime)
{
// The item's time is before any other item in this run, remember it
minTime = item.Time;
minTimeItem = item;
minTimePrio = prio;
}
}
else
{
// This priority's reader has finished, remove it.
// Lock so that AddNewReader won't mess up if it finds a new file for this priority.
lock (readerLock)
{
readers[prio].Dispose();
readers[prio] = null;
readTasks[prioInt] = null;
}
}
}
}
if (availableTask == waitForNewFilePrioTask)
{
// A file of a new priority was added and the WaitAny was interrupted,
// to restart with the newly added reader added to the list of
// available tasks.
// Recreate the signal task and continue.
waitForNewFilePrioTask = Task <bool> .Factory.StartNew(WaitForNewFilePrio);
}
if (availableTask == closeTask)
{
// The reader was requested to close.
// Close all current enumerators, which then close all readers and
// everything should tidy up itself...
if (fsw != null)
{
fsw.EnableRaisingEvents = false;
fsw.Dispose();
}
foreach (var reader in readers.Values)
{
if (reader != null)
{
reader.Close();
}
}
return(null);
}
}
}
if (minTimeItem != null)
{
// We found an item.
// Create new task for the next item of this priority
var task = Task <bool> .Factory.StartNew(readers[minTimePrio].MoveNext);
readTasks[(int)minTimePrio] = task;
// Now return the next log item in time of all that are currently available
return(minTimeItem);
}
// Restart this loop and wait for the next event
}
}
/// <summary>
/// Copy constructor.
/// </summary>
/// <param name="source">The FieldLogItem instance to copy from.</param>
protected FieldLogItem(FieldLogItem source)
{
Size = source.Size;
EventCounter = source.EventCounter;
Time = source.Time;
Priority = source.Priority;
SessionId = source.SessionId;
ThreadId = source.ThreadId;
WebRequestId = source.WebRequestId;
LogItemSourceFileName = source.LogItemSourceFileName;
FileFormatVersion = source.FileFormatVersion;
}
