#!/usr/bin/env perl
# fet.wrapper - Launcher for "fet" main program
# License:  Creative Commons Attribution-NonCommercial-ShareAlike 2.5
# Revision: 080704

# Note:  The license indicated above applies to this file.  It doesn't
# apply  to the official FET package, or to any file derived from that
# package.

#---------------------------------------------------------------------
#                         license information
#---------------------------------------------------------------------

# This section may not be modified except as approved by the author or
# licensor, or to make non-content changes such as adjustments to par-
# agraph formatting or white space.

# This  version of this software is  distributed  under  the following
# license:
#
#       Creative Commons Attribution-NonCommercial-ShareAlike 2.5

# You may use, modify, and redistribute this software without fees  or
# royalties, but only under the terms and conditions set forth  by the
# license.  In particular, copies and derived works cannot be used for
# commercial purposes.  Additionally, the license propagates to copies
# and derived works. Furthermore, you must provide attribution "in the
# manner  specified  by the  author or licensor".  The latter point is
# discussed below.

# The author [and licensor] hereby specifies that  attribution must be
# handled in the following manner:  a. If the software is interactive,
# any  About or Credits dialog boxes, windows, or output text provided
# by the  original version must be preserved and readily accessible to
# the end user at runtime.  b. If the software is non-interactive,  or
# if it does not  provide  About or Credits dialog boxes, windows,  or
# output text,  the  operating system and/or  desktop environment used
# must provide attribution that is  visible and/or  readily accessible
# to the end user at runtime.

# The following techniques  do not meet the  attribution requirements:
# Attribution through text  files, attribution  through  printed docu-
# mentation,  verbal  attribution, or postings on  external  web sites
# [i.e.,  web  sites  that are not an intrinsic local component of the
# operating system or  desktop environment used].  These  examples are
# provided for illustrative purposes only.

# It should be noted that trademarks are an additional issue.  If this
# software  uses any  trademarks,  trademark-related  restrictions may
# apply.

# This is not a  complete explanation of the  terms and conditions in-
# volved.  For more information, see the Creative Commons Attribution-
# NonCommercial-ShareAlike 2.5 license.

#---------------------------------------------------------------------
#                             explanation
#---------------------------------------------------------------------

# 1. Overview.

# "fet.wrapper"  is a  wrapper for  the main  FET program file  [which
# must be named "fet.bin"]. This wrapper performs the following opera-
# tions:
#
#     a. It optionally verifies that multiple instances of the program
#        aren't running.  If the test is done,  and multiple instances
#        are running, a fatal-error message is displayed.
#
#     b. It optionally verifies that the program isn't running through
#        VNC. If the test is done, and the program  is running through
#        VNC, a fatal-error message is displayed.
#
#     c. It optionally verifies that  direct rendering  is  available.
#        If the test is done, and direct rendering isn't available,  a
#        fatal-error message is displayed.
#
#     d. It optionally tries to prevent crashes related to system-mem-
#        ory issues.  Specifically,  if memory appears to be low,  the
#        wrapper warns the user and  asks for confirmation before run-
#        ning the main executable.
#
#     e. It optionally  sets  the SDL environment variable  SDL_MOUSE_
#        RELATIVE to a  specified integer [and  exports the variable].
#        This fixes mouse-related problems.
#
#     f. It optionally  adjusts the standard environment variable  LD_
#        LIBRARY_PATH [and exports the variable].  This fixes library-
#        related errors.
#
#     g. It optionally  clips  the system's  Master Volume  setting to
#        predefined minimum and maximum values.
#
#     h. It optionally switches to a specified "run" directory.
#
#     i. If no errors have occurred so far,  the wrapper runs the main
#        executable.
#
#     j. If a crash occurs,  the  wrapper tries  to switch the display
#        back to a usable state.
#
#        Note:  Memory-related crashes may  shut down the network  [by
#        terminating name servers, etc.].  The wrapper  doesn't try to
#        fix network problems.
#
#     k. The original  Master Volume setting is  restored on exit,  if
#        possible.

# To  enable, disable, or configure the  tests  listed here,  edit the
# source code and  modify the  appropriate  settings  in the  "program
# parameters" section.

#---------------------------------------------------------------------

# 2. Requirements.

# Partial list of requirements [not including the main executable]:
#
#     a. Gtk2
#     b. Perl
#     c. Perl-Gtk2
#     d. SDL         - Used by "setx11dim"
#     e. glxinfo     - Used to check the status of direct rendering
#     f. getx11dim   - Distro-specific utility
#     g. setx11dim   - Ditto
#     h. resetpcmvol - Ditto
#     i. LACSUB      - Distro-specific Perl-based framework

# Note: You should be able to obtain source code for the distro-speci-
# fic components from the same site as this file.

#---------------------------------------------------------------------
#                        standard module setup
#---------------------------------------------------------------------

require 5.8.1;
use strict;
use Carp;
use warnings;
                                # Trap warnings
$SIG {__WARN__} = sub { die @_; };

#---------------------------------------------------------------------
#                         add CPAN module[s]
#---------------------------------------------------------------------

use Gtk2 '-init';
use Gtk2::SimpleList;

#---------------------------------------------------------------------
#                        add LACSUB module[s]
#---------------------------------------------------------------------

use LACSUB::GUI
 ( @LACSUB::GUI::EXPORT_OK );

#---------------------------------------------------------------------
#                           basic constants
#---------------------------------------------------------------------

use constant ZERO  => 0;        # Zero
use constant ONE   => 1;        # One

use constant FALSE => 0;        # Boolean FALSE
use constant TRUE  => 1;        # Boolean TRUE

#---------------------------------------------------------------------
#                         program parameters
#---------------------------------------------------------------------

my $DIR_BASE        = '__META_PREFIX__';
my $IE              = 'Internal error';
my $PROGNAME        = 'fet';
my $REVISION        = '080704'; # Revision [or release] string

my $ALERT_ICON_PATH = "$DIR_BASE/misc/alert.png";
my $TARGET_EXE      = "$DIR_BASE/program/$PROGNAME.bin";

#---------------------------------------------------------------------

# If you'd like  to prohibit  multiple instances,  set $FLAG_PROHIBIT_
# MULTI_INSTANCE to TRUE. Otherwise, set this flag to FALSE.

my $FLAG_PROHIBIT_MULTI_INSTANCE = TRUE;

#---------------------------------------------------------------------

# If this program shouldn't try to run under VNC,  set $FLAG_PROHIBIT_
# VNC equal to TRUE. Otherwise, set this flag equal to FALSE.

my $FLAG_PROHIBIT_VNC = FALSE;

#---------------------------------------------------------------------

# If you'd like to enforce a direct-rendering requirement,  set $FLAG_
# REQUIRE_DIRECT_RENDERING to TRUE. Otherwise, set this flag to FALSE.

my $FLAG_REQUIRE_DIRECT_RENDERING = FALSE;

#---------------------------------------------------------------------

# If  you'd  like to enforce  a minimum-memory requirement,  set $MIN_
# FREE_KB to a memory-size value (in KB).  Otherwise, set this parame-
# ter to zero.

# If $MIN_FREE_KB specifies a positive integer,  this program tries to
# estimate the amount of system memory that's available (or that could
# be made available).  If the estimated amount is less than the speci-
# fied amount,  it'll warn the user and prompt for confirmation before
# proceeding.

my $MIN_FREE_KB = 530000;

#---------------------------------------------------------------------

# If $SDL_MOUSE_RELATIVE is defined, and it specifies zero  or a posi-
# tive integer, the wrapper sets the environment  variable  SDL_MOUSE_
# RELATIVE  equal  to the  specified number  [and  exports  the  vari-
# able].  Otherwise, the wrapper doesn't look at or change  SDL_MOUSE_
# RELATIVE.

# This parameter is used to prevent mouse-related problems:
#
#     a. If the  main executable uses SDL,  and  the mouse is  slow or
#        "laggy", try setting $SDL_MOUSE_RELATIVE to ZERO.
#
#     b. If you're experiencing other mouse-related problems, try set-
#        ting this parameter to ONE.
#
#     c. If these settings cause problems,  as opposed to fixing them,
#        set $SDL_MOUSE_RELATIVE to -1 or undefine it.

my $SDL_MOUSE_RELATIVE = -1;

#---------------------------------------------------------------------

# If the main executable requires any special LD_LIBRARY_PATH entries,
# you can specify them here.  Set $EXTRA_LIBPATHS to a colon-delimited
# list of absolute directory paths.  If there's only one entry, no co-
# lons are required.

# If  no special  LD_LIBRARY_PATH entries  are  required,  set $EXTRA_
# LIBPATHS to an empty string.

my $EXTRA_LIBPATHS = "";

#---------------------------------------------------------------------

# If you'd like to specify a minimum initial Master Volume level,  set
# $MINVOL to a positive integer from one to 100.  Otherwise,  set this
# parameter to zero.

# If you'd like to specify a maximum initial Master Volume level,  set
# $MAXVOL to a positive integer from one to 100.  Otherwise,  set this
# parameter to zero.

my $MINVOL = ZERO;
my $MAXVOL = ZERO;

#---------------------------------------------------------------------

# If you'd like to run the main executable from a  specific directory,
# set $PATH_RUNDIR equal to an absolute path for the directory. Other-
# wise, set this parameter equal to an empty string.

my $PATH_RUNDIR = "__META_PREFIX__/program";

#---------------------------------------------------------------------
#                            main routine
#---------------------------------------------------------------------

sub Main
{
    my $data;                   # Data buffer
    my $str;                    # Scratch

#---------------------------------------------------------------------
# Initial setup.

    select STDERR; $| = ONE;    # Set flush-on-write mode
    select STDOUT; $| = ONE;    # Ditto [note: this line must be last]

#---------------------------------------------------------------------
# Handle multiple-instances test (if enabled).

    &VerifyNotRunning
    (
        -icon_path    => $ALERT_ICON_PATH ,
        -name         => $PROGNAME        ,

        -pattern_this =>
            ':\d\d\s(perl |)(\S+/|)' . $PROGNAME . '(|\.wrapper)\s' ,
        -pattern_next =>
            ':\d\d\s(perl |)(\S+/|)' . $PROGNAME . '\.bin\s'
    )
        if $FLAG_PROHIBIT_MULTI_INSTANCE;

#---------------------------------------------------------------------
# Handle VNC test (if enabled).

    &AbortIfVNC
    (
        -icon_path => $ALERT_ICON_PATH ,
        -name      => $PROGNAME
    )
        if $FLAG_PROHIBIT_VNC;

#---------------------------------------------------------------------
# Handle direct-rendering test (if enabled).

    &AbortUnlessDRI
    (
        -icon_path => $ALERT_ICON_PATH ,
        -name      => $PROGNAME
    )
        if $FLAG_REQUIRE_DIRECT_RENDERING;

#---------------------------------------------------------------------
# Handle available-memory test (if enabled).

    &CheckAvailableMemory
    (
        -icon_path => $ALERT_ICON_PATH ,
        -min_free  => $MIN_FREE_KB     ,
        -name      => $PROGNAME
    )
        if defined ($MIN_FREE_KB) && ($MIN_FREE_KB =~ m@^[1-9]\d*\z@);

#---------------------------------------------------------------------
# Set SDL_MOUSE_RELATIVE, if necessary.

    if (defined ($SDL_MOUSE_RELATIVE) &&
        ($SDL_MOUSE_RELATIVE =~ m@^\d+\z@))
    {
        $ENV {SDL_MOUSE_RELATIVE} = $SDL_MOUSE_RELATIVE;
    }

#---------------------------------------------------------------------
# Adjust LD_LIBRARY_PATH, if necessary.

    if (defined ($EXTRA_LIBPATHS) && length ($EXTRA_LIBPATHS))
    {
        $str =  $ENV {LD_LIBRARY_PATH};
        $str =  "" unless defined $str;
        $str =  "$EXTRA_LIBPATHS:$str";
        $str =~ s@^:+@@;
        $str =~ s@:+\z@@;
        $str =~ y/:/:/s;
        $ENV {LD_LIBRARY_PATH} = $str;
    }

#---------------------------------------------------------------------
# Adjust initial volume (if necessary).

# Note:  This code runs "resetpcmvol"  whether or not  minimum  and/or
# maximum volume levels are specified. Reasons:  a. "resetpcmvol"  may
# correct certain problems either way. b. This simplifies  the cleanup
# code at the end of the wrapper.

    $str =  '__META_LACUTIL__/resetpcmvol --show';

    $str .= " --min=$MINVOL" if defined ($MINVOL) &&
        ($MINVOL =~ m@^\d+\z@) &&
        ($MINVOL > ZERO) && ($MINVOL <= 100);

    $str .= " --max=$MAXVOL" if defined ($MAXVOL) &&
        ($MAXVOL =~ m@^\d+\z@) &&
        ($MAXVOL > ZERO) && ($MAXVOL <= 100);

    $str =  `$str 2>&1`;
    $str =  "" unless defined ($str) && ($str =~ m@^\d+\s*\z@);
    $str =~ s@\s+\z@@s;
    my $OrigVolume = $str;

#---------------------------------------------------------------------
# Get initial display dimensions (if possible).

    my $X11DIM;

    $str =  `__META_LACUTIL__/getx11dim 2>&1`;
    $str =  "" unless defined $str;
    $str =~ s@\s+\z@@s;

    $X11DIM = $str if $str =~ m@^\d+x\d+\z@;

#---------------------------------------------------------------------
# Go to appropriate directory.

                                # Use a specified directory?
    if (!defined ($PATH_RUNDIR) || !length ($PATH_RUNDIR) ||
        (!-d $PATH_RUNDIR) || !chdir ($PATH_RUNDIR))
    {                           # No  - Use home directory instead
        my $HOME = $ENV {HOME};
        $HOME = '/' unless defined $HOME;
        chdir $HOME;
    }

#---------------------------------------------------------------------
# Run the target program.

    system $TARGET_EXE;

#---------------------------------------------------------------------
# Fix resulting display problems (if necessary).

    if (defined ($X11DIM))
    {
        $str =  `__META_LACUTIL__/getx11dim 2>&1`;
        $str =  "" unless defined $str;
        $str =~ s@\s+\z@@s;

        system "__META_LACUTIL__/setx11dim --fast $X11DIM"
            unless $str eq $X11DIM;
    }

#---------------------------------------------------------------------
# Restore original volume (if possible).

                                # Do we know the original volume?
    if ($OrigVolume =~ m@^\d+\z@)
    {                           # Yes - Restore it
        system "__META_LACUTIL__/resetpcmvol --set=$OrigVolume";
    }

    undef;
}

#---------------------------------------------------------------------
#                            main program
#---------------------------------------------------------------------

&Main();                        # Call the main routine
exit ZERO;                      # Normal exit