inline-ova70-fixer.lua

#!/usr/bin/env lua

-- pattern to disable as comment (in lua regexp % is the backquote character)
local pat1=[[<vmw:Config ovf:required="false" vmw:key="cpuAllocation%.shares%.shares" vmw:value="[^"]*"/>]]
local pat2=[[<vmw:Config ovf:required="false" vmw:key="cpuAllocation%.shares%.level" vmw:value="[^"]*"/>]]

-- pattern to enable a comment entry (in lua regexp % is the backquote character)
local patu=[[<!%-%-:Config ovf:required="false" vmw:key="[^"]*" vmw:value="[^"]*%-%->]]

-- read blocksize
local BS = 1024

local maxread = 10*1024*1024 -- work only in the first 10MB
--local maxread = nil -- uncomment it to search in the whole file

local function comment(data)
	assert(data:sub(1,1) == "<", "capture data didn't start by '<'")
	assert(data:sub(-1,-1)==">", "capture data didn't end by '>'")
	assert(#data > 4+3, "capture data is too short") -- '<!--' + '-->'
	return "<!--"..data:sub(5,-4).."-->"
end
local function uncomment(data)
	assert(data:sub(1,1) == "<", "capture data didn't start by '<'")
	assert(data:sub(-1,-1)==">", "capture data didn't end by '>'")
	assert(#data > 4+3, "capture data is too short") -- '<!--' + '-->'
	assert(data:sub(1,11)=="<!--:Config", "seems not like a vmw:Config xml entry :"..tostring(data:sub(1,11)))
	return "<vmw"..data:sub(5,-4)..'"/>'
end

local function inline_search_and_apply(fd, pat, apply)
	local lastline = ""
	while true do
		local seg =  fd:read(BS)
		if not seg then break end
		if maxread and (fd:seek() > maxread) then break end

		local line = lastline .. seg
		local s1,e1 = line:find(pat)
		if s1 then
			local pos = fd:seek()
			local rel_start = s1 -#line
			local abs_start = pos + rel_start -1
			local matchsize = e1 -s1 +1

			fd:seek("set", abs_start)
			local capture = fd:read(matchsize)
			local replace = apply(capture)

			print("at offset ".. abs_start)
			print("-"..capture)
			print("+"..replace)

			fd:seek("set", abs_start)
			fd:write(replace)
			fd:flush()
			break
		end

		lastline=seg
	end
end

local action=comment

if arg[1] == "-u" then
	--print("ACTION: uncomment")
	pat1 = patu
	pat2 = patu
	action = uncomment
	table.remove(arg, 1)
	assert(arg[1]~="-u")
end

local file = assert(arg[1], "argument #1 must be the file to patch")

local fd = assert(io.open(file, "r+"))
inline_search_and_apply(fd, pat1, action)
fd:seek("set", 0) -- rewind
inline_search_and_apply(fd, pat2, action)

fd:close()