DkmStackWalkFrame[] IDkmCallStackFilter.FilterNextFrame(DkmStackContext stackContext, DkmStackWalkFrame input)
{
// The HelloWorld sample is a very simple debugger component which modified the call stack
// so that there is a '[Hello World]' frame at the top of the call stack. All the frames
// below this are left the same.
if (input == null) // null input frame indicates the end of the call stack. This sample does nothing on end-of-stack.
{
return(null);
}
// Get the HelloWorldDataItem which is associated with this stack walk. This
// lets us keep data associated with this stack walk.
HelloWordDataItem dataItem = HelloWordDataItem.GetInstance(stackContext);
DkmStackWalkFrame[] frames;
// Now use this data item to see if we are looking at the first (top-most) frame
if (dataItem.State == State.Initial)
{
// On the top most frame, we want to return back two different frames. First
// we place the '[Hello World]' frame, and under that we put the input frame.
frames = new DkmStackWalkFrame[2];
// Create the hello world frame object, and stick it in the array
frames[0] = DkmStackWalkFrame.Create(
stackContext.Thread,
null, // Annotated frame, so no instruction address
input.FrameBase, // Use the same frame base as the input frame
0, // annoted frame uses zero bytes
DkmStackWalkFrameFlags.None,
"[Hello World]", // Description of the frame which will appear in the call stack
null, // Annotated frame, so no registers
null
);
// Add the input frame into the array as well
frames[1] = input;
// Update our state so that on the next frame we know not to add '[Hello World]' again.
dataItem.State = State.HelloWorldFrameAdded;
}
else
{
// We have already added '[Hello World]' to this call stack, so just return
// the input frame.
frames = new DkmStackWalkFrame[1] {
input
};
}
return(frames);
}
/// <summary>
/// Returns the instance of HelloWorldDataItem associated with the input DkmStackContext
/// object. If there is not currently an associated HelloWorldDataItem, a new data item
/// will be created.
/// </summary>
/// <param name="context">Object to obtain the data item from</param>
/// <returns>The associated data item</returns>
public static HelloWordDataItem GetInstance(DkmStackContext context)
{
HelloWordDataItem item = GetExistingInstance(context);
if (item != null)
return item;
item = new HelloWordDataItem();
context.SetDataItem<HelloWordDataItem>(DkmDataCreationDisposition.CreateNew, item);
return item;
}
/// <summary>
/// Returns the instance of HelloWorldDataItem associated with the input DkmStackContext
/// object. If there is not currently an associated HelloWorldDataItem, a new data item
/// will be created.
/// </summary>
/// <param name="context">Object to obtain the data item from</param>
/// <returns>The associated data item</returns>
public static HelloWordDataItem GetInstance(DkmStackContext context)
{
HelloWordDataItem item = GetExistingInstance(context);
if (item != null)
{
return(item);
}
item = new HelloWordDataItem();
context.SetDataItem <HelloWordDataItem>(DkmDataCreationDisposition.CreateNew, item);
return(item);
}
