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/se3-unattended/var/se3/unattended/install/linuxaux/opt/perl/lib/5.10.0/i586-linux-thread-multi/CORE/ -> cv.h (source)

   1  /*    cv.h
   2   *
   3   *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000,
   4   *    2001, 2002, 2003, 2004, 2005, 2006, 2007, by Larry Wall and others
   5   *
   6   *    You may distribute under the terms of either the GNU General Public
   7   *    License or the Artistic License, as specified in the README file.
   8   *
   9   */
  10  
  11  /* This structure must the beginning of XPVFM in sv.h  */
  12  
  13  struct xpvcv {
  14      union {
  15      NV    xnv_nv;        /* numeric value, if any */
  16      HV *    xgv_stash;
  17      struct {
  18          U32    xlow;
  19          U32    xhigh;
  20      }    xpad_cop_seq;    /* used by pad.c for cop_sequence */
  21      struct {
  22          U32 xbm_previous;    /* how many characters in string before rare? */
  23          U8    xbm_flags;
  24          U8    xbm_rare;    /* rarest character in string */
  25      }    xbm_s;        /* fields from PVBM */
  26      }        xnv_u;
  27      STRLEN    xpv_cur;    /* length of xp_pv as a C string */
  28      STRLEN    xpv_len;    /* allocated size */
  29      union {
  30      IV    xivu_iv;
  31      UV    xivu_uv;
  32      void *    xivu_p1;
  33      I32    xivu_i32;    /* depth, >= 2 indicates recursive call */
  34      HEK *    xivu_namehek;
  35      }        xiv_u;
  36      union {
  37      MAGIC*    xmg_magic;    /* linked list of magicalness */
  38      HV*    xmg_ourstash;    /* Stash for our (when SvPAD_OUR is true) */
  39      } xmg_u;
  40      HV*        xmg_stash;    /* class package */
  41  
  42      HV *    xcv_stash;
  43      union {
  44      OP *    xcv_start;
  45      ANY    xcv_xsubany;
  46      }        xcv_start_u;
  47      union {
  48      OP *    xcv_root;
  49      void    (*xcv_xsub) (pTHX_ CV*);
  50      }        xcv_root_u;
  51      GV *    xcv_gv;
  52      char *    xcv_file;
  53      PADLIST *    xcv_padlist;
  54      CV *    xcv_outside;
  55      U32        xcv_outside_seq; /* the COP sequence (at the point of our
  56                    * compilation) in the lexically enclosing
  57                    * sub */
  58      cv_flags_t    xcv_flags;
  59  };
  60  
  61  typedef struct {
  62      STRLEN    xpv_cur;    /* length of xp_pv as a C string */
  63      STRLEN    xpv_len;    /* allocated size */
  64      union {
  65      IV    xivu_iv;
  66      UV    xivu_uv;
  67      void *    xivu_p1;
  68      I32    xivu_i32;    /* depth, >= 2 indicates recursive call */
  69      HEK *    xivu_namehek;
  70      }        xiv_u;
  71      union {
  72      MAGIC*    xmg_magic;    /* linked list of magicalness */
  73      HV*    xmg_ourstash;    /* Stash for our (when SvPAD_OUR is true) */
  74      } xmg_u;
  75      HV*        xmg_stash;    /* class package */
  76  
  77      HV *    xcv_stash;
  78      union {
  79      OP *    xcv_start;
  80      ANY    xcv_xsubany;
  81      }        xcv_start_u;
  82      union {
  83      OP *    xcv_root;
  84      void    (*xcv_xsub) (pTHX_ CV*);
  85      }        xcv_root_u;
  86      GV *    xcv_gv;
  87      char *    xcv_file;
  88      PADLIST *    xcv_padlist;
  89      CV *    xcv_outside;
  90      U32        xcv_outside_seq; /* the COP sequence (at the point of our
  91                    * compilation) in the lexically enclosing
  92                    * sub */
  93      cv_flags_t    xcv_flags;
  94  } xpvcv_allocated;
  95  
  96  /*
  97  =head1 Handy Values
  98  
  99  =for apidoc AmU||Nullcv
 100  Null CV pointer.
 101  
 102  =head1 CV Manipulation Functions
 103  
 104  =for apidoc Am|HV*|CvSTASH|CV* cv
 105  Returns the stash of the CV.
 106  
 107  =cut
 108  */
 109  
 110  #define Nullcv Null(CV*)
 111  
 112  #define CvSTASH(sv)    ((XPVCV*)SvANY(sv))->xcv_stash
 113  #define CvSTART(sv)    ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_start
 114  #define CvROOT(sv)    ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_root
 115  #define CvXSUB(sv)    ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_xsub
 116  #define CvXSUBANY(sv)    ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_xsubany
 117  #define CvGV(sv)    ((XPVCV*)SvANY(sv))->xcv_gv
 118  #define CvFILE(sv)    ((XPVCV*)SvANY(sv))->xcv_file
 119  #ifdef USE_ITHREADS
 120  #  define CvFILE_set_from_cop(sv, cop)    (CvFILE(sv) = savepv(CopFILE(cop)))
 121  #else
 122  #  define CvFILE_set_from_cop(sv, cop)    (CvFILE(sv) = CopFILE(cop))
 123  #endif
 124  #define CvFILEGV(sv)    (gv_fetchfile(CvFILE(sv)))
 125  #if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
 126  #  define CvDEPTH(sv) (*({const CV *_cv = (CV *)sv; \
 127                assert(SvTYPE(_cv) == SVt_PVCV ||     \
 128                   SvTYPE(_cv) == SVt_PVFM);     \
 129                &((XPVCV*)SvANY(_cv))->xiv_u.xivu_i32; \
 130              }))
 131  #else
 132  #  define CvDEPTH(sv)    ((XPVCV*)SvANY(sv))->xiv_u.xivu_i32
 133  #endif
 134  #define CvPADLIST(sv)    ((XPVCV*)SvANY(sv))->xcv_padlist
 135  #define CvOUTSIDE(sv)    ((XPVCV*)SvANY(sv))->xcv_outside
 136  #define CvFLAGS(sv)    ((XPVCV*)SvANY(sv))->xcv_flags
 137  #define CvOUTSIDE_SEQ(sv) ((XPVCV*)SvANY(sv))->xcv_outside_seq
 138  
 139  #define CVf_METHOD    0x0001    /* CV is explicitly marked as a method */
 140  #define CVf_LOCKED    0x0002    /* CV locks itself or first arg on entry */
 141  #define CVf_LVALUE    0x0004  /* CV return value can be used as lvalue */
 142  
 143  #define CVf_WEAKOUTSIDE    0x0010  /* CvOUTSIDE isn't ref counted */
 144  #define CVf_CLONE    0x0020    /* anon CV uses external lexicals */
 145  #define CVf_CLONED    0x0040    /* a clone of one of those */
 146  #define CVf_ANON    0x0080    /* CvGV() can't be trusted */
 147  #define CVf_UNIQUE    0x0100    /* sub is only called once (eg PL_main_cv,
 148                   * require, eval). */
 149  #define CVf_NODEBUG    0x0200    /* no DB::sub indirection for this CV
 150                     (esp. useful for special XSUBs) */
 151  #define CVf_CONST    0x0400  /* inlinable sub */
 152  #define CVf_ISXSUB    0x0800    /* CV is an XSUB, not pure perl.  */
 153  
 154  /* This symbol for optimised communication between toke.c and op.c: */
 155  #define CVf_BUILTIN_ATTRS    (CVf_METHOD|CVf_LOCKED|CVf_LVALUE)
 156  
 157  #define CvCLONE(cv)        (CvFLAGS(cv) & CVf_CLONE)
 158  #define CvCLONE_on(cv)        (CvFLAGS(cv) |= CVf_CLONE)
 159  #define CvCLONE_off(cv)        (CvFLAGS(cv) &= ~CVf_CLONE)
 160  
 161  #define CvCLONED(cv)        (CvFLAGS(cv) & CVf_CLONED)
 162  #define CvCLONED_on(cv)        (CvFLAGS(cv) |= CVf_CLONED)
 163  #define CvCLONED_off(cv)    (CvFLAGS(cv) &= ~CVf_CLONED)
 164  
 165  #define CvANON(cv)        (CvFLAGS(cv) & CVf_ANON)
 166  #define CvANON_on(cv)        (CvFLAGS(cv) |= CVf_ANON)
 167  #define CvANON_off(cv)        (CvFLAGS(cv) &= ~CVf_ANON)
 168  
 169  #define CvUNIQUE(cv)        (CvFLAGS(cv) & CVf_UNIQUE)
 170  #define CvUNIQUE_on(cv)        (CvFLAGS(cv) |= CVf_UNIQUE)
 171  #define CvUNIQUE_off(cv)    (CvFLAGS(cv) &= ~CVf_UNIQUE)
 172  
 173  #define CvNODEBUG(cv)        (CvFLAGS(cv) & CVf_NODEBUG)
 174  #define CvNODEBUG_on(cv)    (CvFLAGS(cv) |= CVf_NODEBUG)
 175  #define CvNODEBUG_off(cv)    (CvFLAGS(cv) &= ~CVf_NODEBUG)
 176  
 177  #define CvMETHOD(cv)        (CvFLAGS(cv) & CVf_METHOD)
 178  #define CvMETHOD_on(cv)        (CvFLAGS(cv) |= CVf_METHOD)
 179  #define CvMETHOD_off(cv)    (CvFLAGS(cv) &= ~CVf_METHOD)
 180  
 181  #define CvLOCKED(cv)        (CvFLAGS(cv) & CVf_LOCKED)
 182  #define CvLOCKED_on(cv)        (CvFLAGS(cv) |= CVf_LOCKED)
 183  #define CvLOCKED_off(cv)    (CvFLAGS(cv) &= ~CVf_LOCKED)
 184  
 185  #define CvLVALUE(cv)        (CvFLAGS(cv) & CVf_LVALUE)
 186  #define CvLVALUE_on(cv)        (CvFLAGS(cv) |= CVf_LVALUE)
 187  #define CvLVALUE_off(cv)    (CvFLAGS(cv) &= ~CVf_LVALUE)
 188  
 189  #define CvEVAL(cv)        (CvUNIQUE(cv) && !SvFAKE(cv))
 190  #define CvEVAL_on(cv)        (CvUNIQUE_on(cv),SvFAKE_off(cv))
 191  #define CvEVAL_off(cv)        CvUNIQUE_off(cv)
 192  
 193  /* BEGIN|CHECK|INIT|UNITCHECK|END */
 194  #define CvSPECIAL(cv)        (CvUNIQUE(cv) && SvFAKE(cv))
 195  #define CvSPECIAL_on(cv)    (CvUNIQUE_on(cv),SvFAKE_on(cv))
 196  #define CvSPECIAL_off(cv)    (CvUNIQUE_off(cv),SvFAKE_off(cv))
 197  
 198  #define CvCONST(cv)        (CvFLAGS(cv) & CVf_CONST)
 199  #define CvCONST_on(cv)        (CvFLAGS(cv) |= CVf_CONST)
 200  #define CvCONST_off(cv)        (CvFLAGS(cv) &= ~CVf_CONST)
 201  
 202  #define CvWEAKOUTSIDE(cv)    (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
 203  #define CvWEAKOUTSIDE_on(cv)    (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
 204  #define CvWEAKOUTSIDE_off(cv)    (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
 205  
 206  #define CvISXSUB(cv)        (CvFLAGS(cv) & CVf_ISXSUB)
 207  #define CvISXSUB_on(cv)        (CvFLAGS(cv) |= CVf_ISXSUB)
 208  #define CvISXSUB_off(cv)    (CvFLAGS(cv) &= ~CVf_ISXSUB)
 209  
 210  /* Flags for newXS_flags  */
 211  #define XS_DYNAMIC_FILENAME    0x01    /* The filename isn't static  */
 212  
 213  /*
 214  =head1 CV reference counts and CvOUTSIDE
 215  
 216  =for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
 217  
 218  Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
 219  CV (if any). Because pointers to anonymous sub prototypes are
 220  stored in C<&> pad slots, it is a possible to get a circular reference,
 221  with the parent pointing to the child and vice-versa. To avoid the
 222  ensuing memory leak, we do not increment the reference count of the CV
 223  pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
 224  has a C<&> pad slot pointing back to us. In this case, we set the
 225  C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
 226  circumstances we should decrement the refcount of the parent when freeing
 227  the child.
 228  
 229  There is a further complication with non-closure anonymous subs (i.e. those
 230  that do not refer to any lexicals outside that sub). In this case, the
 231  anonymous prototype is shared rather than being cloned. This has the
 232  consequence that the parent may be freed while there are still active
 233  children, eg
 234  
 235      BEGIN { $a = sub { eval '$x' } }
 236  
 237  In this case, the BEGIN is freed immediately after execution since there
 238  are no active references to it: the anon sub prototype has
 239  C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
 240  CV, so it doesn't contribute to BEGIN's refcount either.  When $a is
 241  executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
 242  and the freed BEGIN is accessed.
 243  
 244  To avoid this, whenever a CV and its associated pad is freed, any
 245  C<&> entries in the pad are explicitly removed from the pad, and if the
 246  refcount of the pointed-to anon sub is still positive, then that
 247  child's C<CvOUTSIDE> is set to point to its grandparent. This will only
 248  occur in the single specific case of a non-closure anon prototype
 249  having one or more active references (such as C<$a> above).
 250  
 251  One other thing to consider is that a CV may be merely undefined
 252  rather than freed, eg C<undef &foo>. In this case, its refcount may
 253  not have reached zero, but we still delete its pad and its C<CvROOT> etc.
 254  Since various children may still have their C<CvOUTSIDE> pointing at this
 255  undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
 256  the chain of lexical scopes is unbroken. For example, the following
 257  should print 123:
 258  
 259      my $x = 123;
 260      sub tmp { sub { eval '$x' } }
 261      my $a = tmp();
 262      undef &tmp;
 263      print  $a->();
 264  
 265  =cut
 266  */
 267  
 268  /*
 269   * Local variables:
 270   * c-indentation-style: bsd
 271   * c-basic-offset: 4
 272   * indent-tabs-mode: t
 273   * End:
 274   *
 275   * ex: set ts=8 sts=4 sw=4 noet:
 276   */


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