[conf,tool] implement configuration writer

Now ``luaotfload-tool --dumpconf`` can be used to output the current
configuration to a file.

2 files changed, 153 insertions, 17 deletions

diff --git a/src/luaotfload-configuration.lua b/src/luaotfload-configuration.lua
index dfa222c..10e791a 100644
--- a/src/luaotfload-configuration.lua
+++ b/src/luaotfload-configuration.lua
@@ -5,7 +5,7 @@
 -- REQUIREMENTS:  Luaotfload 2.5 or above
 --       AUTHOR:  Philipp Gesang (Phg), <phg42.2a@gmail.com>
 --      VERSION:  same as Luaotfload
---     MODIFIED:  2014-07-13 14:19:32+0200
+--     MODIFIED:  2014-07-24 21:49:31+0200
 -------------------------------------------------------------------------------
 --
 
@@ -24,16 +24,17 @@ config.luaotfload             = { }
 local status_file             = "luaotfload-status"
 local luaotfloadstatus        = require (status_file)
 
-local string                  = string
-local stringsub               = string.sub
 local stringexplode           = string.explode
-local stringstrip             = string.strip
 local stringfind              = string.find
+local stringformat            = string.format
+local string                  = string
+local stringstrip             = string.strip
+local stringsub               = string.sub
 
-local table                   = table
 local tableappend             = table.append
-local tablecopy               = table.copy
 local tableconcat             = table.concat
+local tablecopy               = table.copy
+local table                   = table
 local tabletohash             = table.tohash
 
 local math                    = math
@@ -42,8 +43,10 @@ local mathfloor               = math.floor
 local io                      = io
 local ioloaddata              = io.loaddata
 local iopopen                 = io.popen
+local iowrite                 = io.write
 
 local os                      = os
+local osdate                  = os.date
 local osgetenv                = os.getenv
 
 local lpeg                    = require "lpeg"
@@ -475,6 +478,92 @@ local option_spec = {
 }
 
 -------------------------------------------------------------------------------
+---                               FORMATTERS
+-------------------------------------------------------------------------------
+
+local indent = "  "
+local format_string = function (var, val)
+  return stringformat (indent .. "%s = %s", var, val)
+end
+
+local format_integer = function (var, val)
+  return stringformat (indent .. "%s = %d", var, val)
+end
+
+local format_boolean = function (var, val)
+  return stringformat (indent .. "%s = %s", var, val == true and "true" or "false")
+end
+
+local format_section = function (title)
+  return stringformat ("[%s]", title)
+end
+
+local commented = function (str)
+  return ";" .. str
+end
+
+local underscore_replacer = lpeg.replacer ("_", "-", true)
+
+local dashed = function (var)
+  --- INI spec dictates that dashes are valid in variable names, not
+  --- underscores.
+  return underscore_replacer (var) or var
+end
+
+local conf_header = [==[
+;;-----------------------------------------------------------------------------
+;; Luaotfload Configuration
+;;-----------------------------------------------------------------------------
+;;
+;; This file was generated by luaotfload-tool
+;; on %s. Configuration variables
+;; are documented in the manual to luaotfload.conf(5).
+;;
+;;-----------------------------------------------------------------------------
+
+]==]
+
+local conf_footer = [==[
+
+;; vim:filetype=dosini:expandtab:shiftwidth=2
+]==]
+
+--- Each dumpable variable (the ones mentioned in the man page) receives a
+--- formatter that will be used in dumping the variable. Each value receives a
+--- “commented” flag that indicates whether or not the line should be printed
+--- as a comment.
+
+local formatters = {
+  db = {
+    compress    = { false, format_boolean },
+    formats     = { false, format_string  },
+    max_fonts   = { false, format_integer },
+    scan_local  = { false, format_boolean },
+    skip_read   = { false, format_boolean },
+    strip       = { false, format_boolean },
+    update_live = { false, format_boolean },
+  },
+  misc = {
+    bisect     = { false, format_boolean },
+    statistics = { false, format_boolean },
+    termwidth  = { true , format_integer },
+    version    = { true , format_string  },
+  },
+  paths = {
+    cache_dir    = { false, format_string },
+    names_dir    = { false, format_string },
+    index_file   = { false, format_string },
+    lookups_file = { false, format_string },
+  },
+  run = {
+    color_callback  = { false, format_string  },
+    definer         = { false, format_string  },
+    log_level       = { false, format_integer },
+    resolver        = { false, format_string  },
+  },
+}
+
+-------------------------------------------------------------------------------
 ---                           MAIN FUNCTIONALITY
 -------------------------------------------------------------------------------
 
@@ -689,6 +778,40 @@ local apply_defaults = function ()
   return reconfigure ()
 end
 
+local dump = function ()
+  local sections = table.sortedkeys (config.luaotfload)
+  local confdata = { }
+  for i = 1, #sections do
+    local section    = sections[i]
+    local vars       = config.luaotfload[section]
+    local varnames   = table.sortedkeys (vars)
+    local sformats   = formatters[section]
+    if sformats then
+      confdata[#confdata + 1] = format_section (section)
+      for j = 1, #varnames do
+        local var = varnames[j]
+        local val = vars[var]
+        local comment, sformat = unpack (sformats[var] or { })
+        if sformat then
+          local dashedvar = dashed (var)
+          if comment then
+            confdata[#confdata + 1] = commented (sformat (dashedvar, val))
+          else
+            confdata[#confdata + 1] = sformat (dashedvar, val)
+          end
+        end
+      end
+      confdata[#confdata + 1] = ""
+    end
+  end
+  if next(confdata) then
+    iowrite (stringformat (conf_header,
+                           osdate ("%Y-%m-d %H:%M:%S", os.time ())))
+    iowrite (tableconcat (confdata, "\n"))
+    iowrite (conf_footer)
+  end
+end
+
 -------------------------------------------------------------------------------
 ---                                 EXPORTS
 -------------------------------------------------------------------------------
@@ -700,5 +823,6 @@ config.actions = {
   apply            = apply,
   apply_defaults   = apply_defaults,
   reconfigure      = reconfigure,
+  dump             = dump,
 }
 
diff --git a/src/luaotfload-tool.lua b/src/luaotfload-tool.lua
index 754f5c7..02c5a45 100755
--- a/src/luaotfload-tool.lua
+++ b/src/luaotfload-tool.lua
@@ -6,7 +6,7 @@
 --       AUTHOR:  Khaled Hosny, Élie Roux, Philipp Gesang
 --      VERSION:  2.5
 --      LICENSE:  GPL v2.0
---     MODIFIED:  2014-07-24 22:07:35+0200
+--     MODIFIED:  2014-07-24 22:10:32+0200
 -----------------------------------------------------------------------
 
 luaotfload          = luaotfload or { }
@@ -739,9 +739,10 @@ set.
 --]]--
 
 local action_sequence = {
-    "config",   "loglevel",  "help",  "version",
-    "diagnose", "blacklist", "cache", "flush",
-    "bisect",   "generate",  "list",  "query",
+    "config"   , "loglevel" , "help"      , "version" ,
+    "dumpconf" , "diagnose" , "blacklist" , "cache"   ,
+    "flush"    , "bisect"   , "generate"  , "list"    ,
+    "query"    ,
 }
 
 local action_pending  = tabletohash(action_sequence, false)
@@ -781,6 +782,11 @@ actions.version = function (job)
     return true, false
 end
 
+actions.dumpconf = function (job)
+    config.actions.dump ()
+    return true, false
+end
+
 actions.help = function (job)
     help_msg (job.help_version or "luaotfload-tool")
     return true, false
@@ -1413,6 +1419,7 @@ local process_cmdline = function ( ) -- unit -> jobspec
         cache              = 1,
         conf               = 1,
         diagnose           = 1,
+        dumpconf           = 0,
         ["dry-run"]        = "D",
         ["flush-lookups"]  = "l",
         fields             = 1,
@@ -1551,15 +1558,20 @@ local process_cmdline = function ( ) -- unit -> jobspec
             result.bisect         = optarg[n]
             action_pending.bisect = true
         elseif v == "conf" then
-            local extra = stringexplode (optarg[n], ",+")
-            if extra then
-                local extra_config = result.extra_config
-                if extra_config then
-                    table.append (extra_config, extra)
-                else
-                    result.extra_config = extra
+            local confname = optarg[n]
+            if confname then
+                local extra = stringexplode (optarg[n], ",+")
+                if extra then
+                    local extra_config = result.extra_config
+                    if extra_config then
+                        table.append (extra_config, extra)
+                    else
+                        result.extra_config = extra
+                    end
                 end
             end
+        elseif v == "dumpconf" then
+            action_pending["dumpconf"] = true
         elseif v == "print-conf" then
             result.print_config = true
         end