path: root/src/luaotfload-main.lua

-----------------------------------------------------------------------
--         FILE:  luaotfload-main.lua
--  DESCRIPTION:  Luaotfload entry point
-- REQUIREMENTS:  luatex v.0.80 or later; packages lualibs, luatexbase
--       AUTHOR:  Élie Roux, Khaled Hosny, Philipp Gesang
--      VERSION:  same as Luaotfload
--     MODIFIED:  2015-06-09 23:08:18+0200
-----------------------------------------------------------------------
--
--- Note:
--- This file was part of the original luaotfload.dtx and has been
--- converted to a pure Lua file during the transition from Luaotfload
--- version 2.4 to 2.5. Thus, the comments are still in TeX (Latex)
--- markup.

local initial_log_level           = 0
luaotfload                        = luaotfload or { }
local luaotfload                  = luaotfload
luaotfload.log                    = luaotfload.log or { }
luaotfload.version                = "2.6"
luaotfload.loaders                = { }
luaotfload.min_luatex_version     = 79             --- i. e. 0.79
luaotfload.fontloader_package     = "reference"    --- default: from current Context

local authors = "\z
    Hans Hagen,\z
    Khaled Hosny,\z
    Elie Roux,\z
    Will Robertson,\z
    Philipp Gesang,\z
    Dohyun Kim,\z
    Reuben Thomas\z
"


luaotfload.module = {
    name          = "luaotfload-main",
    version       = 2.60001,
    date          = "2015/05/26",
    description   = "OpenType layout system.",
    author        = authors,
    copyright     = authors,
    license       = "GPL v2.0"
}

--[[doc--

    This file initializes the system and loads the font loader. To
    minimize potential conflicts between other packages and the code
    imported from \CONTEXT, several precautions are in order. Some of
    the functionality that the font loader expects to be present, like
    raw access to callbacks, are assumed to have been disabled by
    \identifier{luatexbase} when this file is processed. In some cases
    it is possible to trick it by putting dummies into place and
    restoring the behavior from \identifier{luatexbase} after
    initilization. Other cases such as attribute allocation require
    that we hook the functionality from \identifier{luatexbase} into
    locations where they normally wouldn’t be.

    Anyways we can import the code base without modifications, which is
    due mostly to the extra effort by Hans Hagen to make \LUATEX-Fonts
    self-contained and encapsulate it, and especially due to his
    willingness to incorporate our suggestions.

--doc]]--

local luatexbase       = luatexbase
local require          = require
local type             = type
local add_to_callback  = luatexbase.add_to_callback
local create_callback  = luatexbase.create_callback
local reset_callback   = luatexbase.reset_callback
local call_callback    = luatexbase.call_callback

local dummy_function = function () end --- XXX this will be moved to the luaotfload namespace when we have the init module

local error, warning, info, log =
    luatexbase.provides_module(luaotfload.module)

luaotfload.log.tex        = {
    error        = error,
    warning      = warning,
    info         = info,
    log          = log,
}

--[[doc--

     We set the minimum version requirement for \LUATEX to v0.76,
     because the font loader requires recent features like direct
     attribute indexing and \luafunction{node.end_of_math()} that aren’t
     available in earlier versions.\footnote{%
      See Taco’s announcement of v0.76:
      \url{http://comments.gmane.org/gmane.comp.tex.luatex.user/4042}
      and this commit by Hans that introduced those features.
      \url{http://repo.or.cz/w/context.git/commitdiff/a51f6cf6ee087046a2ae5927ed4edff0a1acec1b}.
    }

--doc]]--

if tex.luatexversion < luaotfload.min_luatex_version then
    warning ("LuaTeX v%.2f is old, v%.2f or later is recommended.",
             tex.luatexversion  / 100,
             luaotfload.min_luatex_version / 100)
    warning ("using fallback fontloader -- newer functionality not available")
    luaotfload.fontloader_package = "tl2014" --- TODO fallback should be configurable too
    --- we install a fallback for older versions as a safety
end

--[[doc--

    \subsection{Module loading}
    We load the files imported from \CONTEXT with function derived this way. It
    automatically prepends a prefix to its argument, so we can refer to the
    files with their actual \CONTEXT name.

--doc]]--

local make_loader_name = function (prefix, name)
    local msg = luaotfload.log and luaotfload.log.report or print
    if prefix then
        msg ("log", 7, "load",
             "Composing fontloader name from constitutents %s, %s",
             prefix, name)
        return prefix .. "-" .. name .. ".lua"
    end
    msg ("log", 7, "load",
         "Loading fontloader file %s literally.",
         name)
    return name
end

local make_loader = function (prefix)
    return function (name)
        local modname = make_loader_name (prefix, name)
        return require (modname)
    end
end

local load_luaotfload_module = make_loader "luaotfload"
----- load_luaotfload_module = make_loader "luatex" --=> for Luatex-Plain
local load_fontloader_module = make_loader "fontloader"

luaotfload.loaders.luaotfload = load_luaotfload_module
luaotfload.loaders.fontloader = load_fontloader_module

luaotfload.init = load_luaotfload_module "init" --- fontloader initialization

local store           = luaotfload.init.early ()
local log             = luaotfload.log
local logreport       = log.report

--[[doc--

    Now we load the modules written for \identifier{luaotfload}.

--doc]]--

load_luaotfload_module "parsers"         --- fonts.conf and syntax
load_luaotfload_module "configuration"   --- configuration options

if not config.actions.apply_defaults () then
    logreport ("log", 0, "load", "Configuration unsuccessful.")
end

luaotfload.init.main (store)

load_luaotfload_module "loaders"         --- Type1 font wrappers
load_luaotfload_module "database"        --- Font management.
load_luaotfload_module "colors"          --- Per-font colors.

luaotfload.resolvers = load_luaotfload_module "resolvers" --- Font lookup

luaotfload.resolvers.install ()

if not config.actions.reconfigure () then
    logreport ("log", 0, "load", "Post-configuration hooks failed.")
end

--[[doc--

    We create callbacks for patching fonts on the fly, to be used by
    other packages. In addition to the regular \identifier{patch_font}
    callback there is an unsafe variant \identifier{patch_font_unsafe}
    that will be invoked even if the target font lacks certain essential
    tfmdata tables.

    The callbacks initially contain the empty function that we are going to
    override below.

--doc]]--

create_callback("luaotfload.patch_font",        "simple", dummy_function)
create_callback("luaotfload.patch_font_unsafe", "simple", dummy_function)

--[[doc--

    \subsection{\CONTEXT override}
    \label{define-font}
    We provide a simplified version of the original font definition
    callback.

--doc]]--


local definers = { } --- (string, spec -> size -> id -> tmfdata) hash_t
do
    local read = fonts.definers.read

    local patch = function (specification, size, id)
        local fontdata = read (specification, size, id)
        if type (fontdata) == "table" and fontdata.shared then
            --- We need to test for the “shared” field here
            --- or else the fontspec capheight callback will
            --- operate on tfm fonts.
            call_callback ("luaotfload.patch_font", fontdata, specification)
        else
            call_callback ("luaotfload.patch_font_unsafe", fontdata, specification)
        end
        return fontdata
    end

    local mk_info = function (name)
        local definer = name == "patch" and patch or read
        return function (specification, size, id)
            logreport ("both", 0, "main", "defining font no. %d", id)
            logreport ("both", 0, "main", "   > active font definer: %q", name)
            logreport ("both", 0, "main", "   > spec %q", specification)
            logreport ("both", 0, "main", "   > at size %.2f pt", size / 2^16)
            local result = definer (specification, size, id)
            if not result then
                logreport ("both", 0, "main", "   > font definition failed")
                return
            elseif type (result) == "number" then
                logreport ("both", 0, "main", "   > font definition yielded id %d", result)
                return result
            end
            logreport ("both", 0, "main", "   > font definition successful")
            logreport ("both", 0, "main", "   > name %q",     result.name     or "<nil>")
            logreport ("both", 0, "main", "   > fontname %q", result.fontname or "<nil>")
            logreport ("both", 0, "main", "   > fullname %q", result.fullname or "<nil>")
            return result
        end
    end

    definers.patch          = patch
    definers.generic        = read
    definers.info_patch     = mk_info "patch"
    definers.info_generic   = mk_info "generic"
end

reset_callback "define_font"

--[[doc--

    Finally we register the callbacks.

--doc]]--

local definer = config.luaotfload.run.definer
add_to_callback ("define_font", definers[definer], "luaotfload.define_font", 1)

load_luaotfload_module "features"     --- font request and feature handling
load_luaotfload_module "letterspace"  --- extra character kerning
load_luaotfload_module "auxiliary"    --- additional high-level functionality

luaotfload.aux.start_rewrite_fontname () --- to be migrated to fontspec

luaotfload.main = function ()
    local starttime = os.gettimeofday ()
    --- XXX stub
    logreport ("both", 0, "main",
               "initialization completed in %0.3f seconds",
               os.gettimeofday() - starttime)
end

-- vim:tw=79:sw=4:ts=4:et