X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FSub-Op.git;a=blobdiff_plain;f=lib%2FSub%2FOp.pm;h=44b3e9b671d5379b1374f63496e3df64958ed899;hp=877cf3123c4a64ec15272a76b3ae29773155f60b;hb=159088ccddecdea45fdae8093319b41c097adc86;hpb=6a7b5fad65453cfc8742554cef515b1d7c84443a

diff --git a/lib/Sub/Op.pm b/lib/Sub/Op.pm
index 877cf31..44b3e9b 100644
--- a/lib/Sub/Op.pm
+++ b/lib/Sub/Op.pm
@@ -11,7 +11,7 @@ Sub::Op - Install subroutines as opcodes.
 
 =head1 VERSION
 
-Version 0.01
+Version 0.02
 
 =cut
 
@@ -20,7 +20,7 @@ our ($VERSION, @ISA);
 sub dl_load_flags { 0x01 }
 
 BEGIN {
- $VERSION = '0.01';
+ $VERSION = '0.02';
  require DynaLoader;
  push @ISA, 'DynaLoader';
  __PACKAGE__->bootstrap($VERSION);
@@ -50,12 +50,13 @@ In your XS file :
     BOOT:
     {
      sub_op_config_t c;
-     c.name  = "reftype";
-     c.len   = sizeof("reftype")-1;
-     c.pp    = scalar_util_reftype;
-     c.check = 0;
-     c.ud    = NULL;
-     sub_op_register(aTHX_ &c);
+     sub_op_init(&c);
+     c.name    = "reftype";
+     c.namelen = sizeof("reftype")-1;
+     c.pp      = scalar_util_reftype;
+     c.check   = 0;
+     c.ud      = NULL;
+     sub_op_register(aTHX_ &c, 0);
     }
 
 In your Perl module file :
@@ -93,8 +94,33 @@ In your F<Makefile.PL> :
      ...
     );
 
+=head1 DESCRIPTION
+
+This module provides a C and Perl API for replacing subroutine calls by custom opcodes.
+This has two main advantages :
+
+=over 4
+
+=item *
+
+it gets rid of the overhead of a normal subroutine call ;
+
+=item *
+
+there's no symbol table entry defined for the subroutine.
+
+=back
+
+Subroutine calls with and without parenthesis are handled.
+Ampersand calls are B<not> replaced, and as such will still allow to call a subroutine with same name defined earlier.
+This may or may not be considered as a bug, but it gives the same semantics as Perl keywords, so I believe it's reasonable.
+
+When L<B> and L<B::Deparse> are loaded, they get automatically monkeypatched so that introspecting modules like L<B::Concise> and L<B::Deparse> still produce a valid output.
+
 =cut
 
+use Scalar::Util;
+
 use B::Hooks::EndOfScope;
 use Variable::Magic 0.08;
 
@@ -117,13 +143,30 @@ my $sw = Variable::Magic::wizard(
   my $pkg = $data->{pkg};
   my $fqn = join '::', $pkg, $name;
 
-  no strict 'refs';
-  *$fqn = $placeholder unless exists &$fqn;
+  {
+   local $SIG{__WARN__} = sub {
+    CORE::warn(@_) unless $_[0] =~ /^Constant subroutine.*redefined/;
+   } if _constant_sub(do { no strict 'refs'; \&$fqn });
+   no strict 'refs';
+   no warnings 'redefine';
+   *$fqn = $placeholder;
+  }
 
   return;
  },
 );
 
+sub _tag {
+ my ($pkg, $name) = @_;
+
+ my $fqn = join '::', $pkg, $name;
+
+ return {
+  old   => _defined_sub($fqn) ? \&$fqn : undef,
+  proto => prototype($fqn),
+ };
+}
+
 sub _map {
  my ($pkg) = @_;
 
@@ -138,8 +181,14 @@ sub _map {
 sub _cast {
  my ($pkg, $name) = @_;
 
- no strict 'refs';
- Variable::Magic::cast(%{"${pkg}::"}, $sw, $pkg, { $name => 1 });
+ my $map = { $name => _tag(@_) };
+
+ {
+  no strict 'refs';
+  Variable::Magic::cast(%{"${pkg}::"}, $sw, $pkg, $map);
+ }
+
+ return $map;
 }
 
 sub _dispell {
@@ -149,18 +198,102 @@ sub _dispell {
  Variable::Magic::dispell(%{"${pkg}::"}, $sw);
 }
 
+=head1 C API
+
+=head2 C<sub_op_config_t>
+
+A typedef'd struct that configures how L<Sub::Op> should handle a given subroutine name.
+It has the following members :
+
+=over 4
+
+=item *
+
+C<const char *name>
+
+The name of the subroutine you want to replace.
+Allowed to be static.
+
+=item *
+
+C<STRLEN namelen>
+
+C<name>'s length, in bytes.
+
+=item *
+
+C<Perl_ppaddr_t pp>
+
+The pp function that will be called instead of the subroutine.
+C<Perl_ppaddr_t> is a typedef'd function pointer defined by perl as :
+
+    typedef OP *(*Perl_ppaddr_t)(pTHX);
+
+=item *
+
+C<sub_op_check_t check>
+
+An optional callback that will be called each time a call to C<name> is replaced.
+You can use it to attach extra info to those ops (e.g. with a pointer table) or to perform more optimizations to the optree.
+C<sub_op_check_t> is a typedef'd function pointer defined by :
+
+    typedef OP *(*sub_op_check_t)(pTHX_ OP *, void *);
+
+=item *
+
+C<void *ud>
+
+An optional user data passed to the C<check> callback.
+
+=back
+
+=head2 C<void sub_op_init(sub_op_config_t *c)>
+
+Initializes the fields of the C<sub_op_config_t> object.
+For future compatibility, it is required to call this function with your config object before storing your actual values.
+It will store safe defaults for members you won't set.
+
+=head2 C<void sub_op_register(pTHX_ const sub_op_config_t *c, U32 flags)>
+
+Registers a name and its configuration into L<Sub::Op>.
+The caller is responsible for allocating and freeing the C<sub_op_config_t> object.
+No pointer to it or to its members is kept, except if you pass the flag C<SUB_OP_REGISTER_STEAL> in which case the configuration object will be stolen to be stored into L<Sub::Op>'s internal datastructure.
+
+=head2 C<sub_op_config_t *sub_op_dup(pTHX_ const sub_op_config_t *orig)>
+
+Deeply clones the specified C<sub_op_config_t> object.
+
+=head2 C<void sub_op_free(pTHX_ sub_op_config_t *c)>
+
+Free the memory associated with the specified C<sub_op_config_t> object.
+
+=head1 PERL API
+
+=head2 C<enable $name, [ $pkg ]>
+
+Enable the replacement with a custom opcode of calls to the C<$name> subroutine of the C<$pkg> package in the current lexical scope.
+A pp callback must have been registered for C<$name> by calling the C function C<sub_op_register> in the XS section of your module.
+
+When C<$pkg> is not set, it defaults to the caller package.
+
+=cut
+
 sub enable {
  my $name = shift;
 
  my $pkg = @_ > 0 ? $_[0] : caller;
- my $fqn = "${pkg}::$name";
-
  my $map = _map($pkg);
 
  if (defined $map) {
-  $map->{$name} = 1;
+  $map->{$name} = _tag($pkg, $name);
  } else {
-  _cast($pkg, $name);
+  $map = _cast($pkg, $name);
+ }
+
+ my $proto = $map->{$name}->{proto};
+ if (defined $proto) {
+  no strict 'refs';
+  Scalar::Util::set_prototype(\&{"${pkg}::$name"}, undef);
  }
 
  $^H |= 0x00020000;
@@ -171,15 +304,38 @@ sub enable {
  return;
 }
 
+=head2 C<disable $name, [ $pkg ]>
+
+Disable the replacement for calls to C<$name> in the package C<$pkg>.
+
+When C<$pkg> is not set, it defaults to the caller package.
+
+=cut
+
 sub disable {
  my $name = shift;
 
  my $pkg = @_ > 0 ? $_[0] : caller;
- my $fqn = "${pkg}::$name";
-
  my $map = _map($pkg);
 
+ my $fqn = join '::', $pkg, $name;
+
  if (defined $map) {
+  my $tag = $map->{$name};
+
+  my $old = $tag->{old};
+  if (defined $old) {
+   no strict 'refs';
+   no warnings 'redefine';
+   *$fqn = $old;
+  }
+
+  my $proto = $tag->{proto};
+  if (defined $proto) {
+   no strict 'refs';
+   Scalar::Util::set_prototype(\&$fqn, $proto);
+  }
+
   delete $map->{$name};
   unless (keys %$map) {
    _dispell($pkg);
@@ -201,6 +357,18 @@ sub _inject {
  }
 }
 
+sub _defined_sub {
+ my ($fqn) = @_;
+ my @parts = split /::/, $fqn;
+ my $name  = pop @parts;
+ my $pkg   = '';
+ for (@parts) {
+  $pkg .= $_ . '::';
+  return 0 unless do { no strict 'refs'; %$pkg };
+ }
+ return do { no strict 'refs'; defined &{"$pkg$name"} };
+}
+
 {
  my $injector;
  BEGIN {
@@ -234,15 +402,16 @@ sub _inject {
   $B_OP_inject{can} = sub {
    my ($obj, $meth) = @_;
    if ($meth eq 'first') {
-    return undef unless defined _custom_name($obj);
+    return undef unless $obj->isa('B::UNOP') or defined _custom_name($obj);
    }
    $obj->SUPER::can($meth);
   };
 
-  if (%B:: and %B::OP:: and *B::OP::type{CODE}) {
+  if (_defined_sub('B::OP::type')) {
    _inject('B::OP', \%B_OP_inject);
   } else {
-   Variable::Magic::cast %B::OP::, $injector, 'B::OP', \%B_OP_inject;
+   no strict 'refs';
+   Variable::Magic::cast %{'B::OP::'}, $injector, 'B::OP', \%B_OP_inject;
   }
 
   my $B_Deparse_inject = {
@@ -250,12 +419,13 @@ sub _inject {
     my ($self, $op, $cx) = @_;
     my $name = _custom_name($op);
     die 'unhandled custom op' unless defined $name;
-    if ($op->flags & B::OPf_STACKED()) {
+    if ($op->flags & do { no strict 'refs'; &{'B::OPf_STACKED'}() }) {
      my $kid = $op->first;
      $kid = $kid->first->sibling; # skip ex-list, pushmark
      my @exprs;
-     for (; not B::Deparse::null($kid); $kid = $kid->sibling) {
+     while (not do { no strict 'refs'; &{'B::Deparse::null'}($kid) }) {
       push @exprs, $self->deparse($kid, 6);
+      $kid = $kid->sibling;
      }
      my $args = join(", ", @exprs);
      return "$name($args)";
@@ -265,16 +435,29 @@ sub _inject {
    },
   };
 
-  if (%B:: and %B::Deparse:: and *B::Deparse::pp_entersub{CODE}) {
+  if (_defined_sub('B::Deparse::pp_entersub')) {
    _inject('B::Deparse', $B_Deparse_inject);
   } else {
-   Variable::Magic::cast %B::Deparse::, $injector, 'B::Deparse', $B_Deparse_inject;
+   no strict 'refs';
+   Variable::Magic::cast %{'B::Deparse::'}, $injector, 'B::Deparse', $B_Deparse_inject;
   }
  }
 }
 
 BEGIN { _monkeypatch() }
 
+=head1 EXAMPLES
+
+See the F<t/Sub-Op-LexicalSub> directory that implements a complete example.
+
+=head1 CAVEATS
+
+Preexistent definitions of a sub whose name is handled by L<Sub::Op> are restored at the end of the lexical scope in which the module is used.
+But if you define a sub in the scope of action of L<Sub::Op> with a name that is currently being replaced, the new declaration will be obliterated at the scope end.
+
+Function calls without parenthesis inside an C<eval STRING> in the scope of the pragma won't be replaced.
+I know a few ways of fixing this, but I've not yet decided on which.
+
 =head1 DEPENDENCIES
 
 L<perl> 5.10.
@@ -287,6 +470,10 @@ L<ExtUtils::Depends>.
 
 L<subs::auto>.
 
+L<B::Hooks::XSUB::CallAsOp> provides a C API to declare XSUBs that effectively call a specific PP function.
+Thus, it allows you to write XSUBs with the PP stack conventions used for implementing perl core keywords.
+There's no opcode replacement and no parsing hacks.
+
 L<B::Hooks::OP::Check::EntersubForCV>.
 
 =head1 AUTHOR