As suggested by Arthur: the threads and threads::shared
[p5sagit/p5-mst-13.2.git] / ext / threads / shared / shared.xs
index 56ac88d..2680bbf 100644 (file)
@@ -5,10 +5,6 @@
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
  *
- */
-
-/*
- *
  * "Hand any two wizards a piece of rope and they would instinctively pull in
  * opposite directions."
  *                         --Sourcery
@@ -22,6 +18,8 @@
 #include "perl.h"
 #include "XSUB.h"
 
+#ifdef USE_ITHREADS
+
 #define SHAREDSvPTR(a)      ((a)->sv)
 
 /*
@@ -40,32 +38,92 @@ PerlInterpreter *PL_sharedsv_space;             /* The shared sv space */
 /*
  * Only one thread at a time is allowed to mess with shared space.
  */
-perl_mutex       PL_sharedsv_space_mutex;       /* Mutex protecting the shared sv space */
-PerlInterpreter  *PL_shared_owner;              /* For locking assertions */
 
-#define SHARED_LOCK         STMT_START { \
-                             MUTEX_LOCK(&PL_sharedsv_space_mutex);      \
-                             PL_shared_owner = aTHX;                    \
-                            } STMT_END
+typedef struct
+{
+ perl_mutex             mutex;
+ PerlInterpreter       *owner;
+ I32                    locks;
+ perl_cond              cond;
+#ifdef DEBUG_LOCKS
+ char *                         file;
+ int                    line;
+#endif
+} recursive_lock_t;
+
+recursive_lock_t PL_sharedsv_lock;       /* Mutex protecting the shared sv space */
+
+void
+recursive_lock_init(pTHX_ recursive_lock_t *lock)
+{
+    Zero(lock,1,recursive_lock_t);
+    MUTEX_INIT(&lock->mutex);
+    COND_INIT(&lock->cond);
+}
+
+void
+recursive_lock_release(pTHX_ recursive_lock_t *lock)
+{
+    MUTEX_LOCK(&lock->mutex);
+    if (lock->owner != aTHX) {
+       MUTEX_UNLOCK(&lock->mutex);
+    }
+    else {
+       if (--lock->locks == 0) {
+           lock->owner = NULL;
+           COND_SIGNAL(&lock->cond);
+       }
+    }
+    MUTEX_UNLOCK(&lock->mutex);
+}
+
+void
+recursive_lock_acquire(pTHX_ recursive_lock_t *lock,char *file,int line)
+{
+    assert(aTHX);
+    MUTEX_LOCK(&lock->mutex);
+    if (lock->owner == aTHX) {
+       lock->locks++;
+    }
+    else {
+       while (lock->owner) {
+#ifdef DEBUG_LOCKS
+           Perl_warn(aTHX_ " %p waiting - owned by %p %s:%d\n",
+                     aTHX, lock->owner, lock->file, lock->line);
+#endif
+           COND_WAIT(&lock->cond,&lock->mutex);
+        }
+       lock->locks = 1;
+       lock->owner = aTHX;
+#ifdef DEBUG_LOCKS
+       lock->file  = file;
+       lock->line  = line;
+#endif
+    }
+    MUTEX_UNLOCK(&lock->mutex);
+    SAVEDESTRUCTOR_X(recursive_lock_release,lock);
+}
 
-#define SHARED_UNLOCK       STMT_START { \
-                             PL_shared_owner = NULL;                    \
-                             MUTEX_UNLOCK(&PL_sharedsv_space_mutex);    \
+#define ENTER_LOCK         STMT_START { \
+                             ENTER; \
+                             recursive_lock_acquire(aTHX_ &PL_sharedsv_lock, __FILE__, __LINE__);   \
                             } STMT_END
 
+#define LEAVE_LOCK       LEAVE
+
 
 /* A common idiom is to acquire access and switch in ... */
 #define SHARED_EDIT        STMT_START {        \
-                               SHARED_LOCK;    \
+                               ENTER_LOCK;     \
                                SHARED_CONTEXT; \
                            } STMT_END
 
 /* then switch out and release access. */
 #define SHARED_RELEASE     STMT_START {        \
                                CALLER_CONTEXT; \
-                               SHARED_UNLOCK;  \
+                               LEAVE_LOCK;     \
                            } STMT_END
-                       
+
 
 /*
 
@@ -81,11 +139,8 @@ PerlInterpreter  *PL_shared_owner;              /* For locking assertions */
 
 typedef struct {
     SV                 *sv;             /* The actual SV - in shared space */
-    perl_mutex          mutex;          /* Our mutex */
-    perl_cond           cond;           /* Our condition variable */
+    recursive_lock_t    lock;
     perl_cond           user_cond;      /* For user-level conditions */
-    IV                  locks;          /* Number of locks held */
-    PerlInterpreter    *owner;          /* Who owns the lock? */
 } shared_sv;
 
 /* The SV in shared-space has a back-pointer to the shared_sv
@@ -100,15 +155,14 @@ int
 sharedsv_shared_mg_free(pTHX_ SV *sv, MAGIC *mg)
 {
     shared_sv *shared = (shared_sv *) mg->mg_ptr;
+    assert( aTHX == PL_sharedsv_space );
     if (shared) {
-       PerlIO_debug(__FUNCTION__ "Free %p\n",shared);
        PerlMemShared_free(shared);
        mg->mg_ptr = NULL;
     }
     return 0;
 }
 
-
 MGVTBL sharedsv_shared_vtbl = {
  0,                            /* get */
  0,                            /* set */
@@ -135,9 +189,22 @@ MGVTBL sharedsv_elem_vtbl;      /* elements of hashes and arrays have this
    the sharedsv_scalar_vtbl associates it with the value
  */
 
+
+/* Accessor to convert threads::shared::tie objects back shared_sv * */
+shared_sv *
+SV_to_sharedsv(pTHX_ SV *sv)
+{
+    shared_sv *shared = 0;
+    if (SvROK(sv))
+     {
+      shared = INT2PTR(shared_sv *, SvIV(SvRV(sv)));
+     }
+    return shared;
+}
+
 =for apidoc sharedsv_find
 
-Given a private side SV tries to find if a given SV has a shared backend,
+Given a private side SV tries to find if the SV has a shared backend,
 by looking for the magic.
 
 =cut
@@ -156,13 +223,20 @@ Perl_sharedsv_find(pTHX_ SV *sv)
            }
            break;
        default:
+           /* This should work for elements as well as they
+            * have scalar magic as well as their element magic
+            */
            if ((mg = mg_find(sv, PERL_MAGIC_shared_scalar))
                && mg->mg_virtual == &sharedsv_scalar_vtbl) {
                return (shared_sv *) mg->mg_ptr;
-               }
+           }
            break;
        }
     }
+    /* Just for tidyness of API also handle tie objects */
+    if (SvROK(sv) && sv_derived_from(sv, "threads::shared::tie")) {
+       return SV_to_sharedsv(aTHX_ sv);
+    }
     return NULL;
 }
 
@@ -174,18 +248,17 @@ Perl_sharedsv_find(pTHX_ SV *sv)
 shared_sv *
 Perl_sharedsv_associate(pTHX_ SV **psv, SV *ssv, shared_sv *data)
 {
-    /* First try and get global data structure */
     dTHXc;
     MAGIC *mg = 0;
-    SV *sv;
+    SV *sv    = (psv) ? *psv : Nullsv;
 
     /* If we are asked for an private ops we need a thread */
     assert ( aTHX !=  PL_sharedsv_space );
 
     /* To avoid need for recursive locks require caller to hold lock */
-    if ( PL_shared_owner != aTHX )
-     abort();
-    assert ( PL_shared_owner == aTHX );
+    assert ( PL_sharedsv_lock.owner == aTHX );
+
+    /* First try and get existing global data structure */
 
     /* Try shared SV as 1st choice */
     if (!data && ssv && SvTYPE(ssv) >= SVt_PVMG) {
@@ -193,79 +266,86 @@ Perl_sharedsv_associate(pTHX_ SV **psv, SV *ssv, shared_sv *data)
            data = (shared_sv *) mg->mg_ptr;
        }
     }
-    /* Next try private SV */
-    if (!data && psv && *psv) {
-       data = Perl_sharedsv_find(aTHX,*psv);
+
+    /* Next see if private SV is associated with something */
+    if (!data && sv) {
+       data = Perl_sharedsv_find(aTHX_ sv);
     }
+
     /* If neither of those then create a new one */
     if (!data) {
+           SHARED_CONTEXT;
+           if (!ssv)
+               ssv = newSV(0);
            data = PerlMemShared_malloc(sizeof(shared_sv));
            Zero(data,1,shared_sv);
-           MUTEX_INIT(&data->mutex);
-           COND_INIT(&data->cond);
+           SHAREDSvPTR(data) = ssv;
+           /* Tag shared side SV with data pointer */
+           sv_magicext(ssv, ssv, PERL_MAGIC_ext, &sharedsv_shared_vtbl,
+                  (char *)data, 0);
+           recursive_lock_init(aTHX_ &data->lock);
            COND_INIT(&data->user_cond);
-           data->owner = 0;
-           data->locks = 0;
+           CALLER_CONTEXT;
     }
 
     if (!ssv)
        ssv = SHAREDSvPTR(data);
-       
-    /* If we know type allocate shared side SV */
-    if (psv && *psv && !ssv) {
+    if (!SHAREDSvPTR(data))
+       SHAREDSvPTR(data) = ssv;
+
+    /* If we know type upgrade shared side SV */
+    if (sv && SvTYPE(ssv) < SvTYPE(sv)) {
        SHARED_CONTEXT;
-       ssv = newSV(0);
        sv_upgrade(ssv, SvTYPE(*psv));
-       /* Tag shared side SV with data pointer */
-       sv_magicext(ssv, ssv, PERL_MAGIC_ext, &sharedsv_shared_vtbl,
-                  (char *)data, 0);
        CALLER_CONTEXT;
     }
 
-    if (!SHAREDSvPTR(data))
-       SHAREDSvPTR(data) = ssv;
-
     /* Now if requested allocate private SV */
-    if (psv && !*psv && ssv) {
-       sv = newSV(0);
-       sv_upgrade(sv, SvTYPE(SHAREDSvPTR(data)));
-       *psv = sv;
+    if (psv && !sv) {
+       *psv = sv = newSV(0);
     }
 
     /* Finally if private SV exists check and add magic */
-    if (psv && (sv = *psv)) {
+    if (sv) {
        MAGIC *mg = 0;
+       if (SvTYPE(sv) < SvTYPE(ssv)) {
+           sv_upgrade(sv, SvTYPE(ssv));
+       }
        switch(SvTYPE(sv)) {
        case SVt_PVAV:
        case SVt_PVHV:
            if (!(mg = mg_find(sv, PERL_MAGIC_tied))
-               || mg->mg_virtual != &sharedsv_array_vtbl) {
+               || mg->mg_virtual != &sharedsv_array_vtbl
+               || (shared_sv *) mg->mg_ptr != data) {
                SV *obj = newSV(0);
                sv_setref_iv(obj, "threads::shared::tie",PTR2IV(data));
-               if (mg)
+               if (mg) {
                    sv_unmagic(sv, PERL_MAGIC_tied);
+               }
                mg = sv_magicext(sv, obj, PERL_MAGIC_tied, &sharedsv_array_vtbl,
                                (char *) data, 0);
                mg->mg_flags |= (MGf_COPY|MGf_DUP);
-               SvREFCNT_inc(SHAREDSvPTR(data));
-               PerlIO_debug(__FUNCTION__ " %p %d\n",data,SvREFCNT(SHAREDSvPTR(data)));
+               SvREFCNT_inc(ssv);
                SvREFCNT_dec(obj);
            }
            break;
 
        default:
-           if (SvTYPE(sv) < SVt_PVMG || !(mg = mg_find(sv, PERL_MAGIC_shared_scalar)) ||
-               mg->mg_virtual != &sharedsv_scalar_vtbl) {
-               if (mg)
+           if ((SvTYPE(sv) < SVt_PVMG)
+               || !(mg = mg_find(sv, PERL_MAGIC_shared_scalar))
+               || mg->mg_virtual != &sharedsv_scalar_vtbl
+               || (shared_sv *) mg->mg_ptr != data) {
+               if (mg) {
                    sv_unmagic(sv, PERL_MAGIC_shared_scalar);
+               }
                mg = sv_magicext(sv, Nullsv, PERL_MAGIC_shared_scalar,
                                &sharedsv_scalar_vtbl, (char *)data, 0);
                mg->mg_flags |= (MGf_COPY|MGf_DUP);
-               SvREFCNT_inc(SHAREDSvPTR(data));
-               PerlIO_debug(__FUNCTION__ " %p %d\n",data,SvREFCNT(SHAREDSvPTR(data)));
+               SvREFCNT_inc(ssv);
            }
            break;
        }
+       assert ( Perl_sharedsv_find(aTHX_ *psv) == data );
     }
     return data;
 }
@@ -292,11 +372,11 @@ Perl_sharedsv_share(pTHX_ SV *sv)
     case SVt_PVCV:
        Perl_croak(aTHX_ "Cannot share subs yet");
        break;
-       
+
     default:
-       SHARED_LOCK;
+       ENTER_LOCK;
        Perl_sharedsv_associate(aTHX_ &sv, 0, 0);
-       SHARED_UNLOCK;
+       LEAVE_LOCK;
        SvSETMAGIC(sv);
        break;
     }
@@ -308,8 +388,9 @@ int
 sharedsv_scalar_mg_get(pTHX_ SV *sv, MAGIC *mg)
 {
     shared_sv *shared = (shared_sv *) mg->mg_ptr;
+    assert(shared);
 
-    SHARED_LOCK;
+    ENTER_LOCK;
     if (SHAREDSvPTR(shared)) {
        if (SvROK(SHAREDSvPTR(shared))) {
            SV *obj = Nullsv;
@@ -322,19 +403,15 @@ sharedsv_scalar_mg_get(pTHX_ SV *sv, MAGIC *mg)
            sv_setsv_nomg(sv, SHAREDSvPTR(shared));
        }
     }
-    SHARED_UNLOCK;
+    LEAVE_LOCK;
     return 0;
 }
 
-int
-sharedsv_scalar_mg_set(pTHX_ SV *sv, MAGIC *mg)
+void
+sharedsv_scalar_store(pTHX_ SV *sv, shared_sv *shared)
 {
     dTHXc;
-    shared_sv *shared;
     bool allowed = TRUE;
-    SHARED_LOCK;
-    shared = Perl_sharedsv_associate(aTHX_ &sv, Nullsv, (shared_sv *) mg->mg_ptr);
-
     if (SvROK(sv)) {
        shared_sv* target = Perl_sharedsv_find(aTHX_ SvRV(sv));
        if (target) {
@@ -350,15 +427,26 @@ sharedsv_scalar_mg_set(pTHX_ SV *sv, MAGIC *mg)
        }
     }
     else {
+               SvTEMP_off(sv);
        SHARED_CONTEXT;
        sv_setsv_nomg(SHAREDSvPTR(shared), sv);
        CALLER_CONTEXT;
     }
-    SHARED_RELEASE;
-
     if (!allowed) {
        Perl_croak(aTHX_ "Invalid value for shared scalar");
     }
+}
+
+int
+sharedsv_scalar_mg_set(pTHX_ SV *sv, MAGIC *mg)
+{
+    shared_sv *shared;
+    ENTER_LOCK;
+    /* We call associate to potentially upgrade shared side SV */
+    shared = Perl_sharedsv_associate(aTHX_ &sv, Nullsv, (shared_sv *) mg->mg_ptr);
+    assert(shared);
+    sharedsv_scalar_store(aTHX_ sv, shared);
+    LEAVE_LOCK;
     return 0;
 }
 
@@ -366,8 +454,9 @@ int
 sharedsv_scalar_mg_free(pTHX_ SV *sv, MAGIC *mg)
 {
     shared_sv *shared = (shared_sv *) mg->mg_ptr;
-    PerlIO_debug(__FUNCTION__ " %p %d\n",shared,SvREFCNT(SHAREDSvPTR(shared))-1);
+#if 0
     assert (SvREFCNT(SHAREDSvPTR(shared)) < 1000);
+#endif
     Perl_sharedsv_free(aTHX_ shared);
     return 0;
 }
@@ -375,8 +464,6 @@ sharedsv_scalar_mg_free(pTHX_ SV *sv, MAGIC *mg)
 int
 sharedsv_scalar_mg_clear(pTHX_ SV *sv, MAGIC *mg)
 {
-    shared_sv *shared = (shared_sv *) mg->mg_ptr;
-    PerlIO_debug(__FUNCTION__ " %p %d\n",shared,SvREFCNT(SHAREDSvPTR(shared)));
     return 0;
 }
 
@@ -390,7 +477,6 @@ sharedsv_scalar_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
     if (shared) {
        SvREFCNT_inc(SHAREDSvPTR(shared));
     }
-    PerlIO_debug(__FUNCTION__ " %p %d\n",shared,SvREFCNT(SHAREDSvPTR(shared)));
     return 0;
 }
 
@@ -405,51 +491,45 @@ MGVTBL sharedsv_scalar_vtbl = {
 };
 
 /* Now the arrays/hashes stuff */
-
 int
 sharedsv_elem_mg_FETCH(pTHX_ SV *sv, MAGIC *mg)
 {
     dTHXc;
-    shared_sv *shared = Perl_sharedsv_find(aTHX_ mg->mg_obj);
+    shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
     shared_sv *target = Perl_sharedsv_find(aTHX_ sv);
     SV** svp;
 
     assert ( shared );
     assert ( SHAREDSvPTR(shared) );
 
-    SHARED_EDIT;
+    ENTER_LOCK;
+
     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
        assert ( mg->mg_ptr == 0 );
+       SHARED_CONTEXT;
        svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 0);
     }
     else {
+       char *key = mg->mg_ptr;
+       STRLEN len = mg->mg_len;
        assert ( mg->mg_ptr != 0 );
-       svp = hv_fetch((HV*) SHAREDSvPTR(shared), mg->mg_ptr, mg->mg_len, 0);
+       if (mg->mg_len == HEf_SVKEY) {
+          key = SvPV((SV *) mg->mg_ptr, len);
+       }
+       SHARED_CONTEXT;
+       svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 0);
     }
-
+    CALLER_CONTEXT;
     if (svp) {
-       if (target) {
-           if (SHAREDSvPTR(target) != *svp) {
-               if (SHAREDSvPTR(target)) {
-                   PerlIO_debug(__FUNCTION__ " %p %d\n",shared,SvREFCNT(SHAREDSvPTR(shared)));
-                   SvREFCNT_dec(SHAREDSvPTR(target));
-               }
-               SHAREDSvPTR(target) = SvREFCNT_inc(*svp);
-           }
-       }
-       else {
-           CALLER_CONTEXT;
-           Perl_sharedsv_associate(aTHX_ &sv, *svp, 0);
-           SHARED_CONTEXT;
-       }
+       /* Exists in the array */
+       target = Perl_sharedsv_associate(aTHX_ &sv, *svp, target);
+       sv_setsv(sv, *svp);
     }
-    else if (target) {
-       if (SHAREDSvPTR(target)) {
-           SvREFCNT_dec(SHAREDSvPTR(target));
-       }
-       SHAREDSvPTR(target) = Nullsv;
+    else {
+       /* Not in the array */
+       sv_setsv(sv, &PL_sv_undef);
     }
-    SHARED_RELEASE;
+    LEAVE_LOCK;
     return 0;
 }
 
@@ -457,25 +537,34 @@ int
 sharedsv_elem_mg_STORE(pTHX_ SV *sv, MAGIC *mg)
 {
     dTHXc;
-    shared_sv *shared = Perl_sharedsv_find(aTHX_ mg->mg_obj);
+    shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
     shared_sv *target;
-    SV *val;
+    SV **svp;
     /* Theory - SV itself is magically shared - and we have ordered the
        magic such that by the time we get here it has been stored
        to its shared counterpart
      */
-    SHARED_LOCK;
-    target = Perl_sharedsv_associate(aTHX_ &sv, Nullsv, 0);
-    SHARED_CONTEXT;
-    val = SHAREDSvPTR(target);
+    ENTER_LOCK;
+    assert(shared);
+    assert(SHAREDSvPTR(shared));
     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
-       av_store((AV*) SHAREDSvPTR(shared), mg->mg_len, SvREFCNT_inc(val));
+       assert ( mg->mg_ptr == 0 );
+       SHARED_CONTEXT;
+       svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 1);
     }
     else {
-       hv_store((HV*) SHAREDSvPTR(shared), mg->mg_ptr, mg->mg_len,
-                      SvREFCNT_inc(val), 0);
+       char *key = mg->mg_ptr;
+       STRLEN len = mg->mg_len;
+       assert ( mg->mg_ptr != 0 );
+       if (mg->mg_len == HEf_SVKEY)
+          key = SvPV((SV *) mg->mg_ptr, len);
+       SHARED_CONTEXT;
+       svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 1);
     }
-    SHARED_RELEASE;
+    CALLER_CONTEXT;
+    target = Perl_sharedsv_associate(aTHX_ &sv, *svp, 0);
+    sharedsv_scalar_store(aTHX_ sv, target);
+    LEAVE_LOCK;
     return 0;
 }
 
@@ -483,36 +572,39 @@ int
 sharedsv_elem_mg_DELETE(pTHX_ SV *sv, MAGIC *mg)
 {
     dTHXc;
-    shared_sv *shared = Perl_sharedsv_find(aTHX_ mg->mg_obj);
-    SV* ssv;
-    SHARED_EDIT;
+    shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
+    ENTER_LOCK;
+    sharedsv_elem_mg_FETCH(aTHX_ sv, mg);
     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
-       ssv = av_delete((AV*) SHAREDSvPTR(shared), mg->mg_len, 0);
+       SHARED_CONTEXT;
+       av_delete((AV*) SHAREDSvPTR(shared), mg->mg_len, G_DISCARD);
     }
     else {
-       ssv = hv_delete((HV*) SHAREDSvPTR(shared), mg->mg_ptr, mg->mg_len, 0);
+       char *key = mg->mg_ptr;
+       STRLEN len = mg->mg_len;
+       assert ( mg->mg_ptr != 0 );
+       if (mg->mg_len == HEf_SVKEY)
+          key = SvPV((SV *) mg->mg_ptr, len);
+       SHARED_CONTEXT;
+       hv_delete((HV*) SHAREDSvPTR(shared), key, len, G_DISCARD);
     }
-    SHARED_RELEASE;
-    /* It is no longer in the array - so remove that magic */
-    sv_unmagic(sv, PERL_MAGIC_tiedelem);
-    Perl_sharedsv_associate(aTHX_ &sv, ssv, 0);
+    CALLER_CONTEXT;
+    LEAVE_LOCK;
     return 0;
 }
 
-
 int
 sharedsv_elem_mg_free(pTHX_ SV *sv, MAGIC *mg)
 {
-    Perl_sharedsv_free(aTHX_ Perl_sharedsv_find(aTHX_ mg->mg_obj));
+    Perl_sharedsv_free(aTHX_ SV_to_sharedsv(aTHX_ mg->mg_obj));
     return 0;
 }
 
 int
 sharedsv_elem_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 {
-    shared_sv *shared = Perl_sharedsv_find(aTHX_ mg->mg_obj);
+    shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
     SvREFCNT_inc(SHAREDSvPTR(shared));
-    PerlIO_debug(__FUNCTION__ " %p %d\n",shared,SvREFCNT(SHAREDSvPTR(shared)));
     mg->mg_flags |= MGf_DUP;
     return 0;
 }
@@ -582,10 +674,6 @@ sharedsv_array_mg_copy(pTHX_ SV *sv, MAGIC* mg,
                            name, namlen);
     SvREFCNT_inc(SHAREDSvPTR(shared));
     nmg->mg_flags |= MGf_DUP;
-#if 0
-    /* Maybe do this to associate shared value immediately ? */
-    sharedsv_elem_FIND(aTHX_ nsv, nmg);
-#endif
     return 1;
 }
 
@@ -594,7 +682,6 @@ sharedsv_array_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 {
     shared_sv *shared = (shared_sv *) mg->mg_ptr;
     SvREFCNT_inc(SHAREDSvPTR(shared));
-    PerlIO_debug(__FUNCTION__ " %p %d\n",shared,SvREFCNT(SHAREDSvPTR(shared)));
     mg->mg_flags |= MGf_DUP;
     return 0;
 }
@@ -618,32 +705,7 @@ Recursively unlocks a shared sv.
 void
 Perl_sharedsv_unlock(pTHX_ shared_sv* ssv)
 {
-    MUTEX_LOCK(&ssv->mutex);
-    if (ssv->owner != aTHX) {
-       Perl_croak(aTHX_ "panic: Perl_sharedsv_unlock unlocking mutex that we don't own");
-       MUTEX_UNLOCK(&ssv->mutex);
-       return;
-    }
-
-    if (--ssv->locks == 0) {
-       ssv->owner = NULL;
-       COND_SIGNAL(&ssv->cond);
-    }
-    MUTEX_UNLOCK(&ssv->mutex);
- }
-
-void
-Perl_sharedsv_unlock_scope(pTHX_ shared_sv* ssv)
-{
-    MUTEX_LOCK(&ssv->mutex);
-    if (ssv->owner != aTHX) {
-       MUTEX_UNLOCK(&ssv->mutex);
-       return;
-    }
-    ssv->locks = 0;
-    ssv->owner = NULL;
-    COND_SIGNAL(&ssv->cond);
-    MUTEX_UNLOCK(&ssv->mutex);
+    recursive_lock_release(aTHX_ &ssv->lock);
 }
 
 =for apidoc sharedsv_lock
@@ -658,19 +720,7 @@ Perl_sharedsv_lock(pTHX_ shared_sv* ssv)
 {
     if (!ssv)
        return;
-    MUTEX_LOCK(&ssv->mutex);
-    if (ssv->owner && ssv->owner == aTHX) {
-       ssv->locks++;
-       MUTEX_UNLOCK(&ssv->mutex);
-       return;
-    }
-    while (ssv->owner)
-      COND_WAIT(&ssv->cond,&ssv->mutex);
-    ssv->locks++;
-    ssv->owner = aTHX;
-    if (ssv->locks == 1)
-       SAVEDESTRUCTOR_X(Perl_sharedsv_unlock_scope,ssv);
-    MUTEX_UNLOCK(&ssv->mutex);
+    recursive_lock_acquire(aTHX_ &ssv->lock, __FILE__, __LINE__);
 }
 
 void
@@ -696,27 +746,19 @@ Perl_sharedsv_init(pTHX)
   PL_sharedsv_space = perl_alloc();
   perl_construct(PL_sharedsv_space);
   CALLER_CONTEXT;
-  MUTEX_INIT(&PL_sharedsv_space_mutex);
+  recursive_lock_init(aTHX_ &PL_sharedsv_lock);
   PL_lockhook = &Perl_sharedsv_locksv;
   PL_sharehook = &Perl_sharedsv_share;
 }
 
-/* Accessor to convert threads::shared::tie objects back shared_sv * */
-shared_sv *
-SV_to_sharedsv(pTHX_ SV *sv)
-{
-    shared_sv *shared = 0;
-    if (SvROK(sv))
-     {
-      shared = INT2PTR(shared_sv *, SvIV(SvRV(sv)));
-     }
-    return shared;
-}
+#endif /* USE_ITHREADS */
 
 MODULE = threads::shared       PACKAGE = threads::shared::tie
 
 PROTOTYPES: DISABLE
 
+#ifdef USE_ITHREADS
+
 void
 PUSH(shared_sv *shared, ...)
 CODE:
@@ -725,8 +767,9 @@ CODE:
        for(i = 1; i < items; i++) {
            SV* tmp = newSVsv(ST(i));
            shared_sv *target;
-           SHARED_LOCK;
+           ENTER_LOCK;
            target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
+           sharedsv_scalar_store(aTHX_ tmp, target);
            SHARED_CONTEXT;
            av_push((AV*) SHAREDSvPTR(shared), SHAREDSvPTR(target));
            SHARED_RELEASE;
@@ -738,32 +781,33 @@ UNSHIFT(shared_sv *shared, ...)
 CODE:
        dTHXc;
        int i;
-       SHARED_LOCK;
+       ENTER_LOCK;
        SHARED_CONTEXT;
        av_unshift((AV*)SHAREDSvPTR(shared), items - 1);
        CALLER_CONTEXT;
        for(i = 1; i < items; i++) {
            SV* tmp = newSVsv(ST(i));
            shared_sv *target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
+           sharedsv_scalar_store(aTHX_ tmp, target);
            SHARED_CONTEXT;
            av_store((AV*) SHAREDSvPTR(shared), i - 1, SHAREDSvPTR(target));
            CALLER_CONTEXT;
            SvREFCNT_dec(tmp);
        }
-       SHARED_UNLOCK;
+       LEAVE_LOCK;
 
 void
 POP(shared_sv *shared)
 CODE:
        dTHXc;
        SV* sv;
-       SHARED_LOCK;
+       ENTER_LOCK;
        SHARED_CONTEXT;
        sv = av_pop((AV*)SHAREDSvPTR(shared));
        CALLER_CONTEXT;
        ST(0) = Nullsv;
        Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
-       SHARED_UNLOCK;
+       LEAVE_LOCK;
        XSRETURN(1);
 
 void
@@ -771,13 +815,13 @@ SHIFT(shared_sv *shared)
 CODE:
        dTHXc;
        SV* sv;
-       SHARED_LOCK;
+       ENTER_LOCK;
        SHARED_CONTEXT;
        sv = av_shift((AV*)SHAREDSvPTR(shared));
        CALLER_CONTEXT;
        ST(0) = Nullsv;
        Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
-       SHARED_UNLOCK;
+       LEAVE_LOCK;
        XSRETURN(1);
 
 void
@@ -789,6 +833,17 @@ CODE:
        SHARED_RELEASE;
 
 void
+STORESIZE(shared_sv *shared,IV count)
+CODE:
+       dTHXc;
+       SHARED_EDIT;
+       av_fill((AV*) SHAREDSvPTR(shared), count);
+       SHARED_RELEASE;
+
+
+
+
+void
 EXISTS(shared_sv *shared, SV *index)
 CODE:
        dTHXc;
@@ -798,19 +853,14 @@ CODE:
            exists = av_exists((AV*) SHAREDSvPTR(shared), SvIV(index));
        }
        else {
-           exists = hv_exists_ent((HV*) SHAREDSvPTR(shared), index, 0);
+           STRLEN len;
+           char *key = SvPV(index,len);
+           exists = hv_exists((HV*) SHAREDSvPTR(shared), key, len);
        }
        SHARED_RELEASE;
        ST(0) = (exists) ? &PL_sv_yes : &PL_sv_no;
        XSRETURN(1);
 
-void
-STORESIZE(shared_sv *shared,IV count)
-CODE:
-       dTHXc;
-       SHARED_EDIT;
-       av_fill((AV*) SHAREDSvPTR(shared), count);
-       SHARED_RELEASE;
 
 void
 FIRSTKEY(shared_sv *shared)
@@ -819,7 +869,7 @@ CODE:
        char* key = NULL;
        I32 len = 0;
        HE* entry;
-       SHARED_LOCK;
+       ENTER_LOCK;
        SHARED_CONTEXT;
        hv_iterinit((HV*) SHAREDSvPTR(shared));
        entry = hv_iternext((HV*) SHAREDSvPTR(shared));
@@ -831,7 +881,7 @@ CODE:
             CALLER_CONTEXT;
             ST(0) = &PL_sv_undef;
        }
-       SHARED_UNLOCK;
+       LEAVE_LOCK;
        XSRETURN(1);
 
 void
@@ -841,10 +891,10 @@ CODE:
        char* key = NULL;
        I32 len = 0;
        HE* entry;
-       SHARED_LOCK;
+       ENTER_LOCK;
        SHARED_CONTEXT;
        entry = hv_iternext((HV*) SHAREDSvPTR(shared));
-       if(entry) {
+       if (entry) {
                key = hv_iterkey(entry,&len);
                CALLER_CONTEXT;
                ST(0) = sv_2mortal(newSVpv(key, len));
@@ -852,7 +902,7 @@ CODE:
             CALLER_CONTEXT;
             ST(0) = &PL_sv_undef;
        }
-       SHARED_UNLOCK;
+       LEAVE_LOCK;
        XSRETURN(1);
 
 MODULE = threads::shared                PACKAGE = threads::shared
@@ -860,7 +910,21 @@ MODULE = threads::shared                PACKAGE = threads::shared
 PROTOTYPES: ENABLE
 
 void
-_thrcnt(SV *ref)
+_id(SV *ref)
+       PROTOTYPE: \[$@%]
+CODE:
+       shared_sv *shared;
+       if(SvROK(ref))
+           ref = SvRV(ref);
+       if (shared = Perl_sharedsv_find(aTHX_ ref)) {
+           ST(0) = sv_2mortal(newSViv(PTR2IV(shared)));
+           XSRETURN(1);
+       }
+       XSRETURN_UNDEF;
+
+
+void
+_refcnt(SV *ref)
        PROTOTYPE: \[$@%]
 CODE:
        shared_sv *shared;
@@ -911,15 +975,16 @@ cond_wait_enabled(SV *ref)
        shared = Perl_sharedsv_find(aTHX_ ref);
        if(!shared)
            croak("cond_wait can only be used on shared values");
-       if(shared->owner != aTHX)
+       if(shared->lock.owner != aTHX)
            croak("You need a lock before you can cond_wait");
-       MUTEX_LOCK(&shared->mutex);
-       shared->owner = NULL;
-       locks = shared->locks = 0;
-       COND_WAIT(&shared->user_cond, &shared->mutex);
-       shared->owner = aTHX;
-       shared->locks = locks;
-       MUTEX_UNLOCK(&shared->mutex);
+       /* Stealing the members of the lock object worries me - NI-S */
+       MUTEX_LOCK(&shared->lock.mutex);
+       shared->lock.owner = NULL;
+       locks = shared->lock.locks = 0;
+       COND_WAIT(&shared->user_cond, &shared->lock.mutex);
+       shared->lock.owner = aTHX;
+       shared->lock.locks = locks;
+       MUTEX_UNLOCK(&shared->lock.mutex);
 
 void
 cond_signal_enabled(SV *ref)
@@ -945,7 +1010,14 @@ cond_broadcast_enabled(SV *ref)
            croak("cond_broadcast can only be used on shared values");
        COND_BROADCAST(&shared->user_cond);
 
+#endif /* USE_ITHREADS */
+
 BOOT:
 {
+#ifdef USE_ITHREADS
      Perl_sharedsv_init(aTHX);
+#endif /* USE_ITHREADS */
 }
+
+
+