jbe@287: local seq = 0
jbe@287: local saved_tree
jbe@287: 
jbe@287: request.for_each(function()
jbe@287:   if seq == 0 then
jbe@287:     -- prepare for configuration/initialization phase
jbe@287:     trace._disabled = false
jbe@287:     trace._tree = { type = "root", start_hires_time = extos.monotonic_hires_time() }
jbe@287:     trace._stack = { trace._tree }
jbe@287:     seq = 1
jbe@287:   elseif seq == 1 then
jbe@287:     -- save current state before processing first request
jbe@287:     if not (trace._stack[1] == trace._tree and trace._stack[2] == nil) then
jbe@287:       error("Trace stack unbalanced after initialization")
jbe@287:     end
jbe@287:     if not trace._disabled then
jbe@287:       saved_tree = table.new(trace._tree)
jbe@287:     end
jbe@287:     seq = 2
jbe@287:   elseif saved_tree then
jbe@287:     -- restore state before processing next request
jbe@287:     if saved_tree then
jbe@287:       trace._disabled = false
jbe@287:       trace._tree = table.new(saved_tree)
jbe@287:       trace._stack = { trace._tree }
jbe@287:     end
jbe@287:   end
jbe@287: end)