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-rw-r--r--otfl-data-con.lua118
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diff --git a/otfl-data-con.lua b/otfl-data-con.lua
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+if not modules then modules = { } end modules ['data-con'] = {
+ version = 1.001,
+ comment = "companion to luat-lib.tex",
+ 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)
+local trace_verbose = false trackers.register("resolvers.verbose", function(v) trace_verbose = v end)
+local trace_locating = false trackers.register("resolvers.locating", function(v) trace_locating = v trackers.enable("resolvers.verbose") end)
+
+--[[ldx--
+<p>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).</p>
+
+<p>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.</p>
+
+<p>Examples of usage can be found in the font related code.</p>
+--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 = { }
+
+-- tracing
+
+function containers.define(category, subcategory, version, enabled)
+ return function()
+ 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 1.000,
+ trace = false,
+ path = caches and caches.setpath(category,subcategory),
+ }
+ c[subcategory] = s
+ end
+ return s
+ else
+ return nil
+ end
+ end
+end
+
+function containers.is_usable(container, name)
+ return container.enabled and caches and caches.iswritable(container.path, name)
+end
+
+function containers.is_valid(container, name)
+ if name and name ~= "" then
+ local storage = container.storage[name]
+ return storage and not table.is_empty(storage) and storage.cache_version == container.version
+ else
+ return false
+ end
+end
+
+function containers.read(container,name)
+ if container.enabled and caches and not container.storage[name] and containers.usecache then
+ container.storage[name] = caches.loaddata(container.path,name)
+ if containers.is_valid(container,name) then
+ report(container,"loaded",name)
+ else
+ container.storage[name] = nil
+ end
+ end
+ if container.storage[name] then
+ report(container,"reusing",name)
+ end
+ return container.storage[name]
+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.path, 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