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if not modules then modules = { } end modules ['trac-pro'] = {
version = 1.001,
comment = "companion to luat-lib.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local getmetatable, setmetatable, rawset, type = getmetatable, setmetatable, rawset, type
-- The protection implemented here is probably not that tight but good enough to catch
-- problems due to naive usage.
--
-- There's a more extensive version (trac-xxx.lua) that supports nesting.
--
-- This will change when we have _ENV in lua 5.2+
local trace_namespaces = false trackers.register("system.namespaces", function(v) trace_namespaces = v end)
local report_system = logs.reporter("system","protection")
namespaces = namespaces or { }
local namespaces = namespaces
local registered = { }
local function report_index(k,name)
if trace_namespaces then
report_system("reference to %a in protected namespace %a: %s",k,name)
debugger.showtraceback(report_system)
else
report_system("reference to %a in protected namespace %a",k,name)
end
end
local function report_newindex(k,name)
if trace_namespaces then
report_system("assignment to %a in protected namespace %a: %s",k,name)
debugger.showtraceback(report_system)
else
report_system("assignment to %a in protected namespace %a",k,name)
end
end
local function register(name)
local data = name == "global" and _G or _G[name]
if not data then
return -- error
end
registered[name] = data
local m = getmetatable(data)
if not m then
m = { }
setmetatable(data,m)
end
local index, newindex = { }, { }
m.__saved__index = m.__index
m.__no__index = function(t,k)
if not index[k] then
index[k] = true
report_index(k,name)
end
return nil
end
m.__saved__newindex = m.__newindex
m.__no__newindex = function(t,k,v)
if not newindex[k] then
newindex[k] = true
report_newindex(k,name)
end
rawset(t,k,v)
end
m.__protection__depth = 0
end
local function private(name) -- maybe save name
local data = registered[name]
if not data then
data = _G[name]
if not data then
data = { }
_G[name] = data
end
register(name)
end
return data
end
local function protect(name)
local data = registered[name]
if not data then
return
end
local m = getmetatable(data)
local pd = m.__protection__depth
if pd > 0 then
m.__protection__depth = pd + 1
else
m.__save_d_index, m.__saved__newindex = m.__index, m.__newindex
m.__index, m.__newindex = m.__no__index, m.__no__newindex
m.__protection__depth = 1
end
end
local function unprotect(name)
local data = registered[name]
if not data then
return
end
local m = getmetatable(data)
local pd = m.__protection__depth
if pd > 1 then
m.__protection__depth = pd - 1
else
m.__index, m.__newindex = m.__saved__index, m.__saved__newindex
m.__protection__depth = 0
end
end
local function protectall()
for name, _ in next, registered do
if name ~= "global" then
protect(name)
end
end
end
local function unprotectall()
for name, _ in next, registered do
if name ~= "global" then
unprotect(name)
end
end
end
namespaces.register = register -- register when defined
namespaces.private = private -- allocate and register if needed
namespaces.protect = protect
namespaces.unprotect = unprotect
namespaces.protectall = protectall
namespaces.unprotectall = unprotectall
namespaces.private("namespaces") registered = { } register("global") -- unreachable
directives.register("system.protect", function(v)
if v then
protectall()
else
unprotectall()
end
end)
directives.register("system.checkglobals", function(v)
if v then
report_system("enabling global namespace guard")
protect("global")
else
report_system("disabling global namespace guard")
unprotect("global")
end
end)
-- dummy section (will go to luat-dum.lua)
--~ if not namespaces.private then
--~ -- somewhat protected
--~ local registered = { }
--~ function namespaces.private(name)
--~ local data = registered[name]
--~ if data then
--~ return data
--~ end
--~ local data = _G[name]
--~ if not data then
--~ data = { }
--~ _G[name] = data
--~ end
--~ registered[name] = data
--~ return data
--~ end
--~ function namespaces.protectall(list)
--~ for name, data in next, list or registered do
--~ setmetatable(data, { __newindex = function() print(string.format("table %s is protected",name)) end })
--~ end
--~ end
--~ namespaces.protectall { namespaces = namespaces }
--~ end
--~ directives.enable("system.checkglobals")
--~ namespaces.register("resolvers","trackers")
--~ namespaces.protect("resolvers")
--~ namespaces.protect("resolvers")
--~ namespaces.protect("resolvers")
--~ namespaces.unprotect("resolvers")
--~ namespaces.unprotect("resolvers")
--~ namespaces.unprotect("resolvers")
--~ namespaces.protect("trackers")
--~ resolvers.x = true
--~ resolvers.y = true
--~ trackers.a = ""
--~ resolvers.z = true
--~ oeps = { }
--~ resolvers = namespaces.private("resolvers")
--~ fonts = namespaces.private("fonts")
--~ directives.enable("system.protect")
--~ namespaces.protectall()
--~ resolvers.xx = { }
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