/// <summary>
/// Pushes a new context message into this stack.
/// </summary>
/// <param name="message">The new context message.</param>
/// <returns>
/// An <see cref="IDisposable"/> that can be used to clean up the context stack.
/// </returns>
/// <remarks>
/// <para>
/// Pushes a new context onto this stack. An <see cref="IDisposable"/>
/// is returned that can be used to clean up this stack. This
/// can be easily combined with the <c>using</c> keyword to scope the
/// context.
/// </para>
/// </remarks>
/// <example>Simple example of using the <c>Push</c> method with the <c>using</c> keyword.
/// <code lang="C#">
/// using(log4net.LogicalThreadContext.Stacks["NDC"].Push("Stack_Message"))
/// {
/// log.Warn("This should have an ThreadContext Stack message");
/// }
/// </code>
/// </example>
public IDisposable Push(string message)
{
// do modifications on a copy
Stack stack = new Stack(new Stack(m_stack));
stack.Push(new StackFrame(message, (stack.Count > 0) ? (StackFrame)stack.Peek() : null));
LogicalThreadContextStack contextStack = new LogicalThreadContextStack(m_propertyKey, m_registerNew);
contextStack.m_stack = stack;
m_registerNew(m_propertyKey, contextStack);
return(new AutoPopStackFrame(contextStack, stack.Count - 1));
}
/// <summary>
/// Removes the top context from this stack.
/// </summary>
/// <returns>The message in the context that was removed from the top of this stack.</returns>
/// <remarks>
/// <para>
/// Remove the top context from this stack, and return
/// it to the caller. If this stack is empty then an
/// empty string (not <see langword="null"/>) is returned.
/// </para>
/// </remarks>
public string Pop()
{
// copy current stack
Stack stack = new Stack(new Stack(m_stack));
string result = "";
if (stack.Count > 0)
{
result = ((StackFrame)(stack.Pop())).Message;
}
LogicalThreadContextStack ltcs = new LogicalThreadContextStack(m_propertyKey, m_registerNew);
ltcs.m_stack = stack;
m_registerNew(m_propertyKey, ltcs);
return(result);
}
/// <summary>
/// Returns the stack to the correct depth.
/// </summary>
/// <remarks>
/// <para>
/// Returns the stack to the correct depth.
/// </para>
/// </remarks>
public void Dispose()
{
if (m_frameDepth >= 0 && m_logicalThreadContextStack.m_stack != null)
{
Stack stack = new Stack(new Stack(m_logicalThreadContextStack.m_stack));
while (stack.Count > m_frameDepth)
{
stack.Pop();
}
LogicalThreadContextStack ltcs = new LogicalThreadContextStack(m_logicalThreadContextStack.m_propertyKey, m_logicalThreadContextStack.m_registerNew);
ltcs.m_stack = stack;
// 每次 Pop() 后，用新的栈，将原来的替换掉
m_logicalThreadContextStack.m_registerNew(m_logicalThreadContextStack.m_propertyKey,
ltcs);
}
}
/// <summary>
/// 线程栈索引器
/// 只读，如果键没找到，会自动添加一个键，然后返回一个空栈
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public LogicalThreadContextStack this[string key]
{
get
{
LogicalThreadContextStack stack = null;
object propertyValue = m_properties[key];
if (propertyValue == null)
{
// Stack does not exist, create
stack = new LogicalThreadContextStack(key, new TwoArgAction(registerNew));
m_properties[key] = stack;
}
else
{
// Look for existing stack
stack = propertyValue as LogicalThreadContextStack;
if (stack == null)
{
// Property is not set to a stack!
string propertyValueString = SystemInfo.NullText;
try
{
propertyValueString = propertyValue.ToString();
}
catch
{
}
LogLog.Error(declaringType, "ThreadContextStacks: Request for stack named [" + key + "] failed because a property with the same name exists which is a [" + propertyValue.GetType().Name + "] with value [" + propertyValueString + "]");
stack = new LogicalThreadContextStack(key, new TwoArgAction(registerNew));
}
}
return(stack);
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="logicalThreadContextStack">The internal stack used by the ThreadContextStack.</param>
/// <param name="frameDepth">The depth to return the stack to when this object is disposed.</param>
/// <remarks>
/// <para>
/// Initializes a new instance of the <see cref="AutoPopStackFrame" /> class with
/// the specified stack and return depth.
/// </para>
/// </remarks>
internal AutoPopStackFrame(LogicalThreadContextStack logicalThreadContextStack, int frameDepth)
{
m_frameDepth = frameDepth;
m_logicalThreadContextStack = logicalThreadContextStack;
}
/// <summary>
/// 在属性字典中，添加一个新的键值对或者将旧值覆盖掉
/// </summary>
/// <param name="stackName"></param>
/// <param name="stack"></param>
private void registerNew(string stackName, LogicalThreadContextStack stack)
{
m_properties[stackName] = stack;
}
