if not modules then modules = { } end modules ['data-con'] = { version = 1.100, 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 format, lower, gsub = string.format, string.lower, string.gsub local trace_cache = false trackers.register("resolvers.cache", function(v) trace_cache = v end) local trace_containers = false trackers.register("resolvers.containers", function(v) trace_containers = v end) local trace_storage = false trackers.register("resolvers.storage", function(v) trace_storage = v end) --[[ldx--
Once we found ourselves defining similar cache constructs several times, containers were introduced. Containers are used to collect tables in memory and reuse them when possible based on (unique) hashes (to be provided by the calling function).
Caching to disk is disabled by default. Version numbers are stored in the saved table which makes it possible to change the table structures without bothering about the disk cache.
Examples of usage can be found in the font related code.
--ldx]]-- containers = containers or { } containers.usecache = true local function report(container,tag,name) if trace_cache or trace_containers then logs.report(format("%s cache",container.subcategory),"%s: %s",tag,name or 'invalid') end end local allocated = { } local mt = { __index = function(t,k) if k == "writable" then local writable = caches.getwritablepath(t.category,t.subcategory) or { "." } t.writable = writable return writable elseif k == "readables" then local readables = caches.getreadablepaths(t.category,t.subcategory) or { "." } t.readables = readables return readables end end } function containers.define(category, subcategory, version, enabled) if category and subcategory then local c = allocated[category] if not c then c = { } allocated[category] = c end local s = c[subcategory] if not s then s = { category = category, subcategory = subcategory, storage = { }, enabled = enabled, version = version or math.pi, -- after all, this is TeX trace = false, -- writable = caches.getwritablepath and caches.getwritablepath (category,subcategory) or { "." }, -- readables = caches.getreadablepaths and caches.getreadablepaths(category,subcategory) or { "." }, } setmetatable(s,mt) c[subcategory] = s end return s end end function containers.is_usable(container, name) return container.enabled and caches and caches.iswritable(container.writable, name) end function containers.is_valid(container, name) if name and name ~= "" then local storage = container.storage[name] return storage and storage.cache_version == container.version else return false end end function containers.read(container,name) local storage = container.storage local stored = storage[name] if not stored and container.enabled and caches and containers.usecache then stored = caches.loaddata(container.readables,name) if stored and stored.cache_version == container.version then report(container,"loaded",name) else stored = nil end storage[name] = stored elseif stored then report(container,"reusing",name) end return stored end function containers.write(container, name, data) if data then data.cache_version = container.version if container.enabled and caches then local unique, shared = data.unique, data.shared data.unique, data.shared = nil, nil caches.savedata(container.writable, name, data) report(container,"saved",name) data.unique, data.shared = unique, shared end report(container,"stored",name) container.storage[name] = data end return data end function containers.content(container,name) return container.storage[name] end function containers.cleanname(name) return (gsub(lower(name),"[^%w%d]+","-")) end