如何使用NativeCall缓解Rakudo中的错误？

Question

我希望能够在REPR CStruct/CPointer的类中使用双指针:

typedef struct CipherContext {
          void    *cipher;
    const uint8_t *key;
          size_t   key_len;
    const uint8_t *path;
          size_t   path_len;
          size_t   block_size;
          void    *handle;

          int      (*cipher_init)(void **, const uint8_t *, size_t);
          int      (*cipher_encode)(void *, const uint8_t *, uint8_t *, size_t);
          int      (*cipher_decode)(void *, const uint8_t *, uint8_t *, size_t);
          void     (*cipher_free)(void *);
    const uint8_t *(*cipher_strerror)(int);
} CipherContext;

      int            cipher_context_init(CipherContext **, const uint8_t *, size_t, const uint8_t *, size_t, size_t);
      int            cipher_context_encode(CipherContext *, const uint8_t *, uint8_t *, size_t);
      int            cipher_context_decode(CipherContext *, const uint8_t *, uint8_t *, size_t);
      void           cipher_context_free(CipherContext *);
const uint8_t       *cipher_context_strerror(int);

Perl 6代码:

method new(Blob :$key!, Str :$path!, Int :$block-size!) {
    my Pointer[::?CLASS]     $ptr     .= new;
    my Int                   $err      = cipher_context_init($ptr, $key, $key.elems, $path, $path.codes, $block-size);
    return $ptr.deref unless $err;

    my Str $errstr = cipher_context_strerror($err) || do {
        my &cipher-strerror = nativecast(:(int32 --> Str), $!cipher-strerror);
        cipher-strerror($err)
    };
    die "Failed to initialize cipher context: $errstr";
}

submethod DESTROY() {
    cipher_context_free(self)
}

短杆:

use v6.d;
use Nativecall;

class Foo is repr('CPointer') { 
    my Pointer[::?CLASS] $foo .= nw;
}

由于Rakudo中的一个错误,我无法弄清楚如何做到这一点.有没有更好的方法可以处理代码的C部分中的错误(这就是为什么我这样写它)？

Answer 1

失败的原因与失败相同:

class Foo {...}

BEGIN Foo ~~ Bool; # <------

class Foo{
}

部分问题似乎Foo是Pointer.^parameterize在调用方法时尚未编写.

所以它还不是一个子类型Any.(甚至Mu)

解决方法是.^compose在BEGIN使用之前在移相器中添加呼叫Pointer[::??CLASS].

class Foo is repr('CPointer') {
  BEGIN ::?CLASS.^compose;

  my Pointer[::?CLASS] $foo .= new;
}

我的猜测是真正的解决方案是将Bool.ACCEPTS(Bool:U: \topic)候选人改为Bool.ACCEPTS(Bool:U: Mu \topic).

我认为这是因为这也失败了基本相同的错误:

Mu ~~ Bool