Add first draft version of upmake, tool for updating makefiles.

Start moving away from files.bkl as the primary source for the files -- and
away from bakefile itself as the make/project file generator -- by storing the
list of files in a new build/files file and provide a simple build/upmake
script for updating files.bkl and the manually maintained MSVC10+ projects
from this file contents.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76610 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

build/tools/upmake/lib/Text/Upmake.pm

@@ -0,0 +1,78 @@
+package Text::Upmake;
+
+use strict;
+use warnings;
+use autodie;
+
+use Exporter qw(import);
+
+our @EXPORT = qw(read_files_list upmake);
+
+=head1 NAME
+
+Text::Upmake - Update make files.
+
+=head1 SYNOPSIS
+
+=head1 AUTHOR
+
+Vadim Zeitlin
+
+=cut
+
+# Reads the file containing the file lists definitions and returns a hash ref
+# with variable names as keys and refs to arrays of the file names as values.
+#
+# Takes an (open) file handle as argument.
+sub read_files_list
+{
+    my ($fh) = @_;
+
+    my ($var, %vars);
+    while (<$fh>) {
+        chomp;
+        s/#.*$//;
+        s/^\s+//;
+        s/\s+$//;
+        next if !$_;
+
+        if (/^(\w+)\s*=$/) {
+            $var = $1;
+        } else {
+            die "Unexpected contents outside variable definition at line $.\n"
+                unless defined $var;
+            push @{$vars{$var}}, $_;
+        }
+    }
+
+    return \%vars;
+}
+
+# Update the file with the given name in place using the specified function and
+# passing it the rest of the arguments.
+#
+# This is meant to be used with update_xxx() below.
+sub upmake
+{
+    my ($fname, $updater, @args) = @_;
+
+    my $fname_new = "$fname.upmake.new"; # TODO make it more unique
+
+    open my $in, '<', $fname;
+    open my $out, '>', $fname_new;
+
+    my $changed = $updater->($in, $out, @args);
+
+    close $in;
+    close $out;
+
+    if ($changed) {
+        rename $fname_new, $fname;
+    } else {
+        unlink $fname_new;
+    }
+
+    $changed
+}
+
+1;