| use 5.008; |
| package base; |
| |
| use strict 'vars'; |
| use vars qw($VERSION); |
| $VERSION = '2.26'; |
| $VERSION =~ tr/_//d; |
| |
| # simplest way to avoid indexing of the package: no package statement |
| sub base::__inc::unhook { @INC = grep !(ref eq 'CODE' && $_ == $_[0]), @INC } |
| # instance is blessed array of coderefs to be removed from @INC at scope exit |
| sub base::__inc::scope_guard::DESTROY { base::__inc::unhook $_ for @{$_[0]} } |
| |
| # constant.pm is slow |
| sub SUCCESS () { 1 } |
| |
| sub PUBLIC () { 2**0 } |
| sub PRIVATE () { 2**1 } |
| sub INHERITED () { 2**2 } |
| sub PROTECTED () { 2**3 } |
| |
| my $Fattr = \%fields::attr; |
| |
| sub has_fields { |
| my($base) = shift; |
| my $fglob = ${"$base\::"}{FIELDS}; |
| return( ($fglob && 'GLOB' eq ref($fglob) && *$fglob{HASH}) ? 1 : 0 ); |
| } |
| |
| sub has_attr { |
| my($proto) = shift; |
| my($class) = ref $proto || $proto; |
| return exists $Fattr->{$class}; |
| } |
| |
| sub get_attr { |
| $Fattr->{$_[0]} = [1] unless $Fattr->{$_[0]}; |
| return $Fattr->{$_[0]}; |
| } |
| |
| if ($] < 5.009) { |
| *get_fields = sub { |
| # Shut up a possible typo warning. |
| () = \%{$_[0].'::FIELDS'}; |
| my $f = \%{$_[0].'::FIELDS'}; |
| |
| # should be centralized in fields? perhaps |
| # fields::mk_FIELDS_be_OK. Peh. As long as %{ $package . '::FIELDS' } |
| # is used here anyway, it doesn't matter. |
| bless $f, 'pseudohash' if (ref($f) ne 'pseudohash'); |
| |
| return $f; |
| } |
| } |
| else { |
| *get_fields = sub { |
| # Shut up a possible typo warning. |
| () = \%{$_[0].'::FIELDS'}; |
| return \%{$_[0].'::FIELDS'}; |
| } |
| } |
| |
| if ($] < 5.008) { |
| *_module_to_filename = sub { |
| (my $fn = $_[0]) =~ s!::!/!g; |
| $fn .= '.pm'; |
| return $fn; |
| } |
| } |
| else { |
| *_module_to_filename = sub { |
| (my $fn = $_[0]) =~ s!::!/!g; |
| $fn .= '.pm'; |
| utf8::encode($fn); |
| return $fn; |
| } |
| } |
| |
| sub import { |
| my $class = shift; |
| |
| return SUCCESS unless @_; |
| |
| # List of base classes from which we will inherit %FIELDS. |
| my $fields_base; |
| |
| my $inheritor = caller(0); |
| |
| my @bases; |
| foreach my $base (@_) { |
| if ( $inheritor eq $base ) { |
| warn "Class '$inheritor' tried to inherit from itself\n"; |
| } |
| |
| next if grep $_->isa($base), ($inheritor, @bases); |
| |
| # Following blocks help isolate $SIG{__DIE__} and @INC changes |
| { |
| my $sigdie; |
| { |
| local $SIG{__DIE__}; |
| my $fn = _module_to_filename($base); |
| my $dot_hidden; |
| eval { |
| my $guard; |
| if ($INC[-1] eq '.' && %{"$base\::"}) { |
| # So: the package already exists => this an optional load |
| # And: there is a dot at the end of @INC => we want to hide it |
| # However: we only want to hide it during our *own* require() |
| # (i.e. without affecting nested require()s). |
| # So we add a hook to @INC whose job is to hide the dot, but which |
| # first checks checks the callstack depth, because within nested |
| # require()s the callstack is deeper. |
| # Since CORE::GLOBAL::require makes it unknowable in advance what |
| # the exact relevant callstack depth will be, we have to record it |
| # inside a hook. So we put another hook just for that at the front |
| # of @INC, where it's guaranteed to run -- immediately. |
| # The dot-hiding hook does its job by sitting directly in front of |
| # the dot and removing itself from @INC when reached. This causes |
| # the dot to move up one index in @INC, causing the loop inside |
| # pp_require() to skip it. |
| # Loaded coded may disturb this precise arrangement, but that's OK |
| # because the hook is inert by that time. It is only active during |
| # the top-level require(), when @INC is in our control. The only |
| # possible gotcha is if other hooks already in @INC modify @INC in |
| # some way during that initial require(). |
| # Note that this jiggery hookery works just fine recursively: if |
| # a module loaded via base.pm uses base.pm itself, there will be |
| # one pair of hooks in @INC per base::import call frame, but the |
| # pairs from different nestings do not interfere with each other. |
| my $lvl; |
| unshift @INC, sub { return if defined $lvl; 1 while defined caller ++$lvl; () }; |
| splice @INC, -1, 0, sub { return if defined caller $lvl; ++$dot_hidden, &base::__inc::unhook; () }; |
| $guard = bless [ @INC[0,-2] ], 'base::__inc::scope_guard'; |
| } |
| require $fn |
| }; |
| if ($dot_hidden && (my @fn = grep -e && !( -d _ || -b _ ), $fn.'c', $fn)) { |
| require Carp; |
| Carp::croak(<<ERROR); |
| Base class package "$base" is not empty but "$fn[0]" exists in the current directory. |
| To help avoid security issues, base.pm now refuses to load optional modules |
| from the current working directory when it is the last entry in \@INC. |
| If your software worked on previous versions of Perl, the best solution |
| is to use FindBin to detect the path properly and to add that path to |
| \@INC. As a last resort, you can re-enable looking in the current working |
| directory by adding "use lib '.'" to your code. |
| ERROR |
| } |
| # Only ignore "Can't locate" errors from our eval require. |
| # Other fatal errors (syntax etc) must be reported. |
| # |
| # changing the check here is fragile - if the check |
| # here isn't catching every error you want, you should |
| # probably be using parent.pm, which doesn't try to |
| # guess whether require is needed or failed, |
| # see [perl #118561] |
| die if $@ && $@ !~ /^Can't locate \Q$fn\E .*? at .* line [0-9]+(?:, <[^>]*> (?:line|chunk) [0-9]+)?\.\n\z/s |
| || $@ =~ /Compilation failed in require at .* line [0-9]+(?:, <[^>]*> (?:line|chunk) [0-9]+)?\.\n\z/; |
| unless (%{"$base\::"}) { |
| require Carp; |
| local $" = " "; |
| Carp::croak(<<ERROR); |
| Base class package "$base" is empty. |
| (Perhaps you need to 'use' the module which defines that package first, |
| or make that module available in \@INC (\@INC contains: @INC). |
| ERROR |
| } |
| $sigdie = $SIG{__DIE__} || undef; |
| } |
| # Make sure a global $SIG{__DIE__} makes it out of the localization. |
| $SIG{__DIE__} = $sigdie if defined $sigdie; |
| } |
| push @bases, $base; |
| |
| if ( has_fields($base) || has_attr($base) ) { |
| # No multiple fields inheritance *suck* |
| if ($fields_base) { |
| require Carp; |
| Carp::croak("Can't multiply inherit fields"); |
| } else { |
| $fields_base = $base; |
| } |
| } |
| } |
| # Save this until the end so it's all or nothing if the above loop croaks. |
| push @{"$inheritor\::ISA"}, @bases; |
| |
| if( defined $fields_base ) { |
| inherit_fields($inheritor, $fields_base); |
| } |
| } |
| |
| sub inherit_fields { |
| my($derived, $base) = @_; |
| |
| return SUCCESS unless $base; |
| |
| my $battr = get_attr($base); |
| my $dattr = get_attr($derived); |
| my $dfields = get_fields($derived); |
| my $bfields = get_fields($base); |
| |
| $dattr->[0] = @$battr; |
| |
| if( keys %$dfields ) { |
| warn <<"END"; |
| $derived is inheriting from $base but already has its own fields! |
| This will cause problems. Be sure you use base BEFORE declaring fields. |
| END |
| |
| } |
| |
| # Iterate through the base's fields adding all the non-private |
| # ones to the derived class. Hang on to the original attribute |
| # (Public, Private, etc...) and add Inherited. |
| # This is all too complicated to do efficiently with add_fields(). |
| while (my($k,$v) = each %$bfields) { |
| my $fno; |
| if ($fno = $dfields->{$k} and $fno != $v) { |
| require Carp; |
| Carp::croak ("Inherited fields can't override existing fields"); |
| } |
| |
| if( $battr->[$v] & PRIVATE ) { |
| $dattr->[$v] = PRIVATE | INHERITED; |
| } |
| else { |
| $dattr->[$v] = INHERITED | $battr->[$v]; |
| $dfields->{$k} = $v; |
| } |
| } |
| |
| foreach my $idx (1..$#{$battr}) { |
| next if defined $dattr->[$idx]; |
| $dattr->[$idx] = $battr->[$idx] & INHERITED; |
| } |
| } |
| |
| 1; |
| |
| __END__ |
| |