--[[

Copyright 2016 GitHub, Inc

Licensed under the Apache License, Version 2.0 (the "License");

you may not use this file except in compliance with the License.

You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

]]

local TracerPipe = class("TracerPipe")

TracerPipe.static.TRACEFS = "/sys/kernel/debug/tracing"

TracerPipe.static.fields = "%s+(.-)%-(%d+)%s+%[(%d+)%]%s+(....)%s+([%d%.]+):.-:%s+(.+)"

function TracerPipe:close()

if self.pipe ~= nil then

self.pipe:close()

end

end

function TracerPipe:open()

if self.pipe == nil then

self.pipe = assert(io.open(TracerPipe.TRACEFS .. "/trace_pipe"))

end

return self.pipe

end

function TracerPipe:readline()

return self:open():read()

end

function TracerPipe:trace_fields()

while true do

local line = self:readline()

if not line and self.nonblocking then

return nil

end

if not line:starts("CPU:") then

local task, pid, cpu, flags, ts, msg = line:match(TracerPipe.fields)

if task ~= nil then

return task, tonumber(pid), tonumber(cpu), flags, tonumber(ts), msg

end

end

end

end

function TracerPipe:initialize(nonblocking)

self.nonblocking = nonblocking

end

return TracerPipe