[log,override,main,tool] move logging functionality into separate file

1 files changed, 406 insertions, 0 deletions

diff --git a/luaotfload-log.lua b/luaotfload-log.lua
new file mode 100644
index 0000000..938050a
--- /dev/null
+++ b/luaotfload-log.lua
@@ -0,0 +1,406 @@
+if not modules then modules = { } end modules ["luaotfload-log"] = {
+    version   = "2.5",
+    comment   = "companion to Luaotfload",
+    author    = "Khaled Hosny, Elie Roux, Philipp Gesang",
+    copyright = "Luaotfload Development Team",
+    license   = "GNU GPL v2.0"
+}
+
+--[[doc--
+The logging system is slow in general, as we always have the function
+call overhead even if we aren’t going to output anything. On the other
+hand, the more efficient approach followed by Context isn’t an option
+because we lack a user interface to toggle per-subsystem tracing.
+--doc]]--
+
+local module_name       = "luaotfload" --- prefix for messages
+
+local ioopen            = io.open
+local iowrite           = io.write
+local lfsisdir          = lfs.isdir
+local lfsisfile         = lfs.isfile
+local md5sumhexa        = md5.sumhexa
+local osdate            = os.date
+local ostime            = os.time
+local select            = select
+local stringformat      = string.format
+local stringsub         = string.sub
+local tableconcat       = table.concat
+local texiowrite_nl     = texio.write_nl
+local texiowrite        = texio.write
+local type              = type
+
+local dummyfunction     = function () end
+
+local texjob = false
+if tex and (tex.jobname or tex.formatname) then
+    --- TeX
+    texjob = true
+end
+
+local loglevel = 0 --- default
+local logout   = "log"
+
+--- int -> bool
+local set_loglevel = function (n)
+    if type(n) == "number" then
+        loglevel = n
+    end
+    return true
+end
+logs.setloglevel    = set_loglevel
+logs.set_loglevel   = set_loglevel
+logs.set_log_level  = set_loglevel --- accomodating lazy typists
+
+--- unit -> int
+local get_loglevel = function ( )
+    return loglevel
+end
+logs.getloglevel    = get_loglevel
+logs.get_loglevel   = get_loglevel
+logs.get_log_level  = get_loglevel
+
+local writeln  --- pointer to terminal/log writer
+local statusln --- terminal writer that reuses the current line
+local first_status = true --- indicate the begin of a status region
+
+local log_msg = [[
+logging output redirected to %s
+to monitor the progress run "tail -f %s" in another terminal
+]]
+
+local tmppath = os.getenv "TMPDIR" or "/tmp"
+
+local choose_logfile = function ( )
+    if lfsisdir (tmppath) then
+        local fname
+        repeat --- ensure that file of that name doesn’t exist
+            --- TODO this could use os.uuid() instead of md5
+            fname = tmppath .. "/luaotfload-log-"
+                            .. stringsub (md5sumhexa (ostime ()), 1, 8)
+        until not lfsisfile (fname)
+        iowrite (stringformat (log_msg, fname, fname))
+        return ioopen (fname, "w")
+    end
+    --- missing /tmp
+    return false
+end
+
+local set_logout = function (s, finalizers)
+    if s == "stdout" then
+        logout = "redirect"
+    elseif s == "file" then --- inject custom logger
+        logout = "redirect"
+        local chan = choose_logfile ()
+        chan:write (stringformat ("logging initiated at %s",
+                                  osdate ("%F %T", ostime ())))
+        local writefile = function (...)
+            if select ("#", ...) == 2 then
+                chan:write (select (2, ...))
+            else
+                chan:write (select (1, ...))
+            end
+        end
+        local writefile_nl= function (...)
+            chan:write "\n"
+            if select ("#", ...) == 2 then
+                chan:write (select (2, ...))
+            else
+                chan:write (select (1, ...))
+            end
+        end
+
+        local writeln_orig = writeln
+
+        texiowrite    = writefile
+        texiowrite_nl = writefile_nl
+        writeln       = writefile_nl
+        statusln      = dummyfunction
+
+        finalizers[#finalizers+1] = function ()
+            chan:write (stringformat ("\nlogging finished at %s\n",
+                                      osdate ("%F %T", ostime ())))
+            chan:close ()
+            texiowrite    = texio.write
+            texiowrite_nl = texio.write_nl
+            writeln       = writeln_orig
+        end
+    --else --- remains “log”
+    end
+    return finalizers
+end
+
+logs.set_logout = set_logout
+
+local log = function (category, fmt, ...)
+    local res = { module_name, "|", category, ":" }
+    if fmt then
+        res [#res + 1] = stringformat (fmt, ...)
+    end
+    texiowrite_nl (logout, tableconcat(res, " "))
+end
+
+--- with faux db update with maximum verbosity:
+---
+---     ---------   --------
+---     buffering   time (s)
+---     ---------   --------
+---     full        4.12
+---     line        4.20
+---     none        4.39
+---     ---------   --------
+---
+
+io.stdout:setvbuf "no"
+io.stderr:setvbuf "no"
+
+local kill_line = "\r\x1b[K"
+
+if texjob == true then
+    --- We imitate the texio.* functions so the output is consistent.
+    writeln = function (str)
+        iowrite "\n"
+        iowrite(str)
+    end
+    statusln = function (str)
+        if first_status == false then
+            iowrite (kill_line)
+        else
+            iowrite "\n"
+        end
+        iowrite (str)
+    end
+else
+    writeln = function (str)
+        iowrite(str)
+        iowrite "\n"
+    end
+    statusln = function (str)
+        if first_status == false then
+            iowrite (kill_line)
+        end
+        iowrite (str)
+    end
+end
+
+stdout = function (writer, category, ...)
+    local res = { module_name, "|", category, ":" }
+    local nargs = select("#", ...)
+    if nargs == 0 then
+        --writeln tableconcat(res, " ")
+        --return
+    elseif nargs == 1 then
+        res[#res+1] = select(1, ...) -- around 30% faster than unpack()
+    else
+        res[#res+1] = stringformat(...)
+    end
+    writer (tableconcat(res, " "))
+end
+
+--- at default (zero), we aim to be quiet
+local level_ids = { common  = 1, loading = 2, search  = 3 }
+
+--[[doc--
+
+    The names_report logger is used more or less all over luaotfload.
+    Its requirements are twofold:
+
+    1) Provide two logging channels, the terminal and the log file;
+    2) Allow for control over verbosity levels.
+
+    The first part is addressed by specifying the log *mode* as the
+    first argument that can be either “log”, meaning the log file, or
+    “both”: log file and stdout. Anything else is taken as referring to
+    stdout only.
+
+    Verbosity levels, though not as fine-grained as e.g. Context’s
+    system of tracers, allow keeping the logging spam caused by
+    different subsystems manageable. By default, luaotfload will not
+    emit anything if things are running smoothly on level zero. Only
+    warning messages are relayed, while the other messages are skipped
+    over. (This is a little sub-optimal performance-wise since the
+    function calls to the logger are executed regardless.) The log
+    level during a Luatex run can be adjusted by setting the “loglevel”
+    field in config.luaotfload, or by calling logs.set_loglevel() as
+    defined above.
+
+--doc]]--
+
+local names_report = function (mode, lvl, ...)
+    if type(lvl) == "string" then
+        lvl = level_ids[lvl]
+    end
+    if not lvl then lvl = 0 end
+
+    if loglevel >= lvl then
+        if mode == "log" then
+            log (...)
+        elseif mode == "both" and logout ~= "redirect" then
+            log (...)
+            stdout (writeln, ...)
+        else
+            stdout (writeln, ...)
+        end
+    end
+end
+
+logs.names_report = names_report
+
+--[[doc--
+
+    status_logger -- Overwrites the most recently printed line of the
+    terminal. Its purpose is to provide feedback without spamming
+    stdout with irrelevant messages, i.e. when building the database.
+
+    Status logging must be initialized by calling status_start() and
+    properly reset via status_stop().
+
+    The arguments low and high indicate the loglevel threshold at which
+    linewise and full logging is triggered, respectively. E.g.
+
+            names_status (1, 4, "term", "Hello, world!")
+
+    will print nothing if the loglevel is less than one, reuse the
+    current line if the loglevel ranges from one to three inclusively,
+    and output the message on a separate line otherwise.
+
+--doc]]--
+
+local status_logger = function (mode, ...)
+    if mode == "log" then
+        log (...)
+    else
+        if mode == "both" and logout ~= "redirect" then
+            log (...)
+            stdout (statusln, ...)
+        else
+            stdout (statusln, ...)
+        end
+        first_status = false
+    end
+end
+
+--[[doc--
+
+    status_start -- Initialize status logging. This installs the status
+        logger if the loglevel is in the specified range, and the normal
+        logger otherwise.  It also resets the first line state which
+        causing the next line printed using the status logger to not kill
+        the current line.
+
+--doc]]--
+
+local status_writer
+local status_low  = 99
+local status_high = 99
+
+local status_start = function (low, high)
+    first_status = true
+    status_low   = low
+    status_high  = high
+
+    if os.type == "windows" --- Assume broken terminal.
+    or os.getenv "TERM" == "dumb"
+    then
+        status_writer = function (mode, ...)
+            names_report (mode, high, ...)
+        end
+        return
+    end
+
+    if low <= loglevel and loglevel < high then
+        status_writer = status_logger
+    else
+        status_writer = function (mode, ...)
+            names_report (mode, high, ...)
+        end
+    end
+end
+
+--[[doc--
+
+    status_stop -- Finalize a status region by outputting a newline and
+    printing a message.
+
+--doc]]--
+
+local status_stop = function (...)
+    if first_status == false then
+        status_writer(...)
+        if texjob == false then
+            writeln ""
+        end
+    end
+end
+
+logs.names_status = function (...) status_writer (...) end
+logs.names_status_start = status_start
+logs.names_status_stop  = status_stop
+
+--[[doc--
+
+    The fontloader comes with the Context logging mechanisms
+    inaccessible. Instead, it provides dumb fallbacks based
+    on the functions in texio.write*() that can be overridden
+    by providing a function texio.reporter().
+
+    The fontloader output can be quite verbose, so we disable
+    it entirely by default.
+
+--doc]]--
+
+local texioreporter = function (message)
+    names_report("log", 2, message)
+end
+
+texio.reporter = texioreporter
+
+--[[doc--
+
+    Adobe Glyph List.
+    -------------------------------------------------------------------
+
+    Context provides a somewhat different font-age.lua from an unclear
+    origin. Unfortunately, the file name it reads from is hard-coded
+    in font-enc.lua, so we have to replace the entire table.
+
+    This shouldn’t cause any complications. Due to its implementation
+    the glyph list will be loaded upon loading a OTF or TTF for the
+    first time during a TeX run. (If one sticks to TFM/OFM then it is
+    never read at all.) For this reason we can install a metatable that
+    looks up the file of our choosing and only falls back to the
+    Context one in case it cannot be found.
+
+--doc]]--
+
+if fonts then --- need to be running TeX
+    if next(fonts.encodings.agl) then
+        --- unnecessary because the file shouldn’t be loaded at this time
+        --- but we’re just making sure
+        fonts.encodings.agl = nil
+        collectgarbage"collect"
+    end
+
+
+    fonts.encodings.agl = { }
+
+    setmetatable(fonts.encodings.agl, { __index = function (t, k)
+        if k == "unicodes" then
+            local glyphlist = resolvers.findfile"luaotfload-glyphlist.lua"
+            if glyphlist then
+                names_report("log", 1, "load", "loading the Adobe glyph list")
+            else
+                glyphlist = resolvers.findfile"font-age.lua"
+                names_report("both", 0, "load",
+                    "loading the extended glyph list from ConTeXt")
+            end
+            local unicodes      = dofile(glyphlist)
+            fonts.encodings.agl = { unicodes = unicodes }
+            return unicodes
+        else
+            return nil
+        end
+    end })
+end
+
+-- vim:tw=71:sw=4:ts=4:expandtab