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/Bakefile0.pm

@@ -0,0 +1,97 @@
+package Text::Upmake::Bakefile0;
+
+use Exporter qw(import);
+our @EXPORT = qw(update_bakefile_0);
+
+=head1 NAME
+
+Text::Upmake::Bakefile0 - Update bakefile-0.x files list.
+
+=head1 SYNOPSIS
+
+This is used exclusively to update wxWidgets C<files.bkl> and is probably not
+useful outside of wxWidgets project.
+
+    use Text::Upmake::Bakefile0;
+    Text::Upmake::upmake('bakefiles/files.bkl', \&update_bakefile_0, $vars);
+
+=head1 SEE ALSO
+
+Text::Upmake
+
+=head1 AUTHOR
+
+Vadim Zeitlin
+
+=cut
+
+# Update file with variable definitions in bakefile-0 format with the data
+# from the hash ref containing all the file lists.
+#
+# Takes the (open) file handles of the files to read and to write and the file
+# lists hash ref as arguments.
+#
+# Returns 1 if any changes were made.
+#
+# The caller must take care of actually renaming the second file to the first
+# one.
+sub update_bakefile_0
+{
+    my ($in, $out, $vars) = @_;
+
+    # Variable whose contents is being currently replaced.
+    my $var;
+
+    # Hash with files defined for the specified variable as keys and 0 or 1
+    # depending on whether we have seen them in the input file as values.
+    my %files;
+
+    # Set to 1 if we made any changes.
+    my $changed = 0;
+    while (<$in>) {
+        chomp;
+
+        if (/<set var="(\w+)" hints="files">/ && exists $vars->{$1}) {
+            $var = $1;
+            %files = map { $_ => 0 } @{$vars->{$var}};
+        } elsif (defined $var) {
+            local $_ = $_;
+            s/<!-- .* -->//;
+            s/^\s+//;
+            s/\s+$//;
+            if (m{</set>}) {
+                # Check if we have any new files.
+                #
+                # TODO Insert them in alphabetical order.
+                while (my ($file, $seen) = each(%files)) {
+                    if (!$seen) {
+                        # This file was wasn't present in the input, add it.
+                        # TODO Use proper indentation.
+                        print $out "    $file\n";
+
+                        $changed = 1;
+                    }
+                }
+
+                undef $var;
+            } elsif ($_) {
+                if (not exists $files{$_}) {
+                    # This file was removed.
+                    $changed = 1;
+                    next;
+                }
+
+                if ($files{$_}) {
+                    warn qq{Duplicate file "$_" in the definition of the } .
+                         qq{variable "$var" at line $.\n}
+                } else {
+                    $files{$_} = 1;
+                }
+            }
+        }
+
+        print $out "$_\n";
+    }
+
+    $changed
+}