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Optimization: don't nest at every boolean op

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This commit is contained in:
Henri DF 2016-03-16 13:25:50 -07:00
parent bbcedef54a
commit aa31d0a0fb
1 changed files with 17 additions and 6 deletions
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23
userspace/digwatch/lua/rule_loader.lua
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@ -36,15 +36,25 @@ end
--[[
Take a filter AST and set it up in the libsinsp runtime, using the filter API.
--]]
local function install_filter(node)
local function install_filter(node, parent_bool_op)
local t = node.type
if t == "BinaryBoolOp" then
filter.nest() --io.write("(")
install_filter(node.left)
filter.bool_op(node.operator) --io.write(" "..node.operator.." ")
install_filter(node.right)
filter.unnest() --io.write(")")
-- "nesting" (the runtime equivalent of placing parens in syntax) is
-- never necessary when we have identical successive operators. so we
-- avoid it as a runtime performance optimization.
if (not(node.operator == parent_bool_op)) then
filter.nest() -- io.write("(")
end
install_filter(node.left, node.operator)
filter.bool_op(node.operator) -- io.write(" "..node.operator.." ")
install_filter(node.right, node.operator)
if (not (node.operator == parent_bool_op)) then
filter.unnest() -- io.write(")")
end
elseif t == "UnaryBoolOp" then
filter.nest() --io.write("(")
@ -135,6 +145,7 @@ end
function on_done()
install_filter(state.filter_ast)
io.flush()
end
evt = nil