From 8d8d528d2ad52599f11250cfc567fea4f37f2a8b Mon Sep 17 00:00:00 2001
From: Context Git Mirror Bot <phg42.2a@gmail.com>
Date: Tue, 12 Jan 2016 17:15:07 +0100
Subject: 2016-01-12 16:26:00

---
 tex/context/base/mkiv/data-con.lua | 138 +++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 tex/context/base/mkiv/data-con.lua

(limited to 'tex/context/base/mkiv/data-con.lua')

diff --git a/tex/context/base/mkiv/data-con.lua b/tex/context/base/mkiv/data-con.lua
new file mode 100644
index 000000000..240538df2
--- /dev/null
+++ b/tex/context/base/mkiv/data-con.lua
@@ -0,0 +1,138 @@
+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--
+<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 { }
+local containers    = containers
+containers.usecache = true
+
+local report_containers = logs.reporter("resolvers","containers")
+
+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,
+    __storage__ = true
+}
+
+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.is_writable(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
+            if trace_cache or trace_containers then
+                report_containers("action %a, category %a, name %a","load",container.subcategory,name)
+            end
+        else
+            stored = nil
+        end
+        storage[name] = stored
+    elseif stored then
+        if trace_cache or trace_containers then
+            report_containers("action %a, category %a, name %a","reuse",container.subcategory,name)
+        end
+    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)
+            if trace_cache or trace_containers then
+                report_containers("action %a, category %a, name %a","save",container.subcategory,name)
+            end
+            data.unique, data.shared = unique, shared
+        end
+        if trace_cache or trace_containers then
+            report_containers("action %a, category %a, name %a","store",container.subcategory,name)
+        end
+        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]+","-"))
+    return (gsub(lower(name),"[^%w\128-\255]+","-")) -- more utf friendly
+end
-- 
cgit v1.2.3