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--[[
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  A low-overhead minimal lua profiler.
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  It requires cooperation from the lua interpreter itself, which we patch, and then
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  compile a custom pandoc binary.
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  In other words, this is not meant to be used by regular quarto users.
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]]
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local getTime = os.clock
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local category = "unknown"
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local module = {}
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local outputfile
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local stack_count = 0
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-- don't colect coverage for this module
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-- luacov: disable
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local onDebugHook = function(hookType, line)
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  if hookType ~= "alarm" then
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    print("Internal Error - Unexpected hook type in debug hook: " .. hookType)
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    print("For Quarto profiling to work, you need to run a patched version of Pandoc.")
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    print("This feature is currently only meant to be used by Quarto developers.")
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    os.exit(1)
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  end
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  local no = 2
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  local information = debug.getinfo(no, "nS")
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  local now = os.clock()
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  while information ~= nil do
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    local source = information.source or "unknown"
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    local name = information.name or "anon"
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    if source:sub(1, 1) == "@" then
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      outputfile:write(name, " ", source, " ", information.linedefined, "\n")
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    else
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      outputfile:write(name, " ", "<inline>", " ", 0, "\n")
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    end
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    no = no + 1
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    information = debug.getinfo(no, "nS")
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  end
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  outputfile:write(stack_count, " ", now, " ", category, " ", line, "\n")
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  stack_count = stack_count + 1
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end
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function module.setcategory(c)
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  category = c
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end
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function module.start(filename, ms)
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  outputfile = io.open(filename, "a")
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  if outputfile == nil then
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    error("Could not open " .. filename .. " for writing")
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    return
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  end
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  debug.sethook(onDebugHook, "t", ms or 5) -- NB: "t" debugging only exists in our patched Lua interpreter/pandoc binary!
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end
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function module.stop()
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  debug.sethook()
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  outputfile:close()
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end
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-- luacov: enable
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return module
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