From: Vincent Pit <vince@profvince.com>
Date: Fri, 1 May 2009 18:54:03 +0000 (+0200)
Subject: Enhance thread safety
X-Git-Tag: v0.06~1
X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FLexical-Types.git;a=commitdiff_plain;h=b56734d8bae611bf89f0c65a084de7079d119d96

Enhance thread safety
---

diff --git a/Types.xs b/Types.xs
index 60f499c..0644b00 100644
--- a/Types.xs
+++ b/Types.xs
@@ -31,9 +31,149 @@
 # define HvNAMELEN_get(H) strlen(HvNAME_get(H))
 #endif
 
+#ifndef SvIS_FREED
+# define SvIS_FREED(sv) ((sv)->sv_flags == SVTYPEMASK)
+#endif
+
+/* ... Thread safety and multiplicity ...................................... */
+
+#ifndef LT_MULTIPLICITY
+# if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
+#  define LT_MULTIPLICITY 1
+# else
+#  define LT_MULTIPLICITY 0
+# endif
+#endif
+#if LT_MULTIPLICITY && !defined(tTHX)
+# define tTHX PerlInterpreter*
+#endif
+
+#if LT_MULTIPLICITY && defined(USE_ITHREADS) && defined(dMY_CXT) && defined(MY_CXT) && defined(START_MY_CXT) && defined(MY_CXT_INIT) && (defined(MY_CXT_CLONE) || defined(dMY_CXT_SV))
+# define LT_THREADSAFE 1
+# ifndef MY_CXT_CLONE
+#  define MY_CXT_CLONE \
+    dMY_CXT_SV;                                                      \
+    my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1)); \
+    Copy(INT2PTR(my_cxt_t*, SvUV(my_cxt_sv)), my_cxtp, 1, my_cxt_t); \
+    sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))
+# endif
+#else
+# define LT_THREADSAFE 0
+#endif
+
 /* --- Helpers ------------------------------------------------------------- */
 
-/* ... Hints ............................................................... */
+/* ... Thread-safe hints ................................................... */
+
+#if LT_THREADSAFE
+
+#define PTABLE_NAME        ptable_hints
+#define PTABLE_VAL_FREE(V) if ((V) && !SvIS_FREED((SV *) (V))) SvREFCNT_dec(V)
+
+#define pPTBL  pTHX
+#define pPTBL_ pTHX_
+#define aPTBL  aTHX
+#define aPTBL_ aTHX_
+
+#include "ptable.h"
+
+#define MY_CXT_KEY __PACKAGE__ "::_guts" XS_VERSION
+
+typedef struct {
+ ptable *tbl;
+ tTHX    owner;
+} my_cxt_t;
+
+START_MY_CXT
+
+STATIC void lt_ptable_hints_clone(pTHX_ ptable_ent *ent, void *ud_) {
+ my_cxt_t *ud  = ud_;
+ SV       *val = ent->val;
+
+ if (ud->owner != aTHX) {
+  CLONE_PARAMS param;
+  AV *stashes = (SvTYPE(val) == SVt_PVHV && HvNAME_get(val)) ? newAV() : NULL;
+  param.stashes    = stashes;
+  param.flags      = 0;
+  param.proto_perl = ud->owner;
+  val = sv_dup(val, &param);
+  if (stashes) {
+   av_undef(stashes);
+   SvREFCNT_dec(stashes);
+  }
+ }
+
+ ptable_hints_store(aPTBL_ ud->tbl, ent->key, val);
+ SvREFCNT_inc(val);
+}
+
+STATIC void lt_thread_cleanup(pTHX_ void *);
+
+STATIC void lt_thread_cleanup(pTHX_ void *ud) {
+ int *level = ud;
+ SV  *id;
+
+ if (*level) {
+  *level = 0;
+  LEAVE;
+  SAVEDESTRUCTOR_X(lt_thread_cleanup, level);
+  ENTER;
+ } else {
+  dMY_CXT;
+  PerlMemShared_free(level);
+  ptable_hints_free(aPTBL_ MY_CXT.tbl);
+ }
+}
+
+STATIC SV *lt_tag(pPTBL_ SV *value) {
+#define lt_tag(V) lt_tag(aPTBL_ (V))
+ dMY_CXT;
+
+ value = SvOK(value) && SvROK(value) ? SvRV(value) : NULL;
+ /* We only need for the key to be an unique tag for looking up the value later.
+  * Allocated memory provides convenient unique identifiers, so that's why we
+  * use the value pointer as the key itself. */
+ ptable_hints_store(aPTBL_ MY_CXT.tbl, value, value);
+ SvREFCNT_inc(value);
+
+ return newSVuv(PTR2UV(value));
+}
+
+STATIC SV *lt_detag(pTHX_ const SV *hint) {
+#define lt_detag(H) lt_detag(aTHX_ (H))
+ void *tag;
+ SV   *value;
+
+ if (!hint || !SvOK(hint) || !SvIOK(hint))
+  croak("Wrong hint");
+
+ tag = INT2PTR(void *, SvIVX(hint));
+ {
+  dMY_CXT;
+  value = ptable_fetch(MY_CXT.tbl, tag);
+ }
+
+ return value;
+}
+
+#else
+
+STATIC SV *lt_tag(pTHX_ SV *value) {
+#define lt_tag(V) lt_tag(aTHX_ (V))
+ UV tag = 0;
+
+ if (SvOK(value) && SvROK(value)) {
+  value = SvRV(value);
+  SvREFCNT_inc(value);
+  tag = PTR2UV(value);
+ }
+
+ return newSVuv(tag);
+}
+
+#define lt_detag(H) INT2PTR(SV *, SvUVX(H))
+
+#endif /* LT_THREADSAFE */
 
 STATIC U32 lt_hash = 0;
 
@@ -74,8 +214,8 @@ typedef struct {
  OP *(*pp_padsv)(pTHX);
 } lt_op_info;
 
-STATIC void lt_map_store(pPTABLE_ const OP *o, SV *orig_pkg, SV *type_pkg, SV *type_meth, OP *(*pp_padsv)(pTHX)) {
-#define lt_map_store(O, OP, TP, TM, PP) lt_map_store(aPTABLE_ (O), (OP), (TP), (TM), (PP))
+STATIC void lt_map_store(pPTBL_ const OP *o, SV *orig_pkg, SV *type_pkg, SV *type_meth, OP *(*pp_padsv)(pTHX)) {
+#define lt_map_store(O, OP, TP, TM, PP) lt_map_store(aPTBL_ (O), (OP), (TP), (TM), (PP))
  lt_op_info *oi;
 
 #ifdef USE_ITHREADS
@@ -84,7 +224,7 @@ STATIC void lt_map_store(pPTABLE_ const OP *o, SV *orig_pkg, SV *type_pkg, SV *t
 
  if (!(oi = ptable_fetch(lt_op_map, o))) {
   oi = PerlMemShared_malloc(sizeof *oi);
-  ptable_store(lt_op_map, o, oi);
+  ptable_store(aPTBL_ lt_op_map, o, oi);
  }
 
  oi->orig_pkg  = orig_pkg;
@@ -215,7 +355,7 @@ STATIC OP *lt_ck_padany(pTHX_ OP *o) {
   SV *orig_meth = lt_default_meth;
   SV *type_pkg  = NULL;
   SV *type_meth = NULL;
-  SV *code      = INT2PTR(SV *, SvUVX(hint));
+  SV *code      = lt_detag(hint);
 
   SvREADONLY_on(orig_pkg);
 
@@ -294,11 +434,18 @@ STATIC U32 lt_initialized = 0;
 
 MODULE = Lexical::Types      PACKAGE = Lexical::Types
 
-PROTOTYPES: DISABLE
+PROTOTYPES: ENABLE
 
 BOOT: 
 {                                    
  if (!lt_initialized++) {
+  HV *stash;
+#if LT_THREADSAFE
+  MY_CXT_INIT;
+  MY_CXT.tbl   = ptable_new();
+  MY_CXT.owner = aTHX;
+#endif
+
   lt_op_map = ptable_new();
 #ifdef USE_ITHREADS
   MUTEX_INIT(&lt_op_map_mutex);
@@ -313,20 +460,47 @@ BOOT:
   PL_check[OP_PADANY] = MEMBER_TO_FPTR(lt_ck_padany);
   lt_old_ck_padsv     = PL_check[OP_PADSV];
   PL_check[OP_PADSV]  = MEMBER_TO_FPTR(lt_ck_padsv);
+
+  stash = gv_stashpvn(__PACKAGE__, __PACKAGE_LEN__, 1);
+  newCONSTSUB(stash, "LT_THREADSAFE", newSVuv(LT_THREADSAFE));
  }
 }
 
-SV *_tag(SV *ref)
+#if LT_THREADSAFE
+
+void
+CLONE(...)
+PROTOTYPE: DISABLE
 PREINIT:
- SV *ret;
+ ptable *t;
+ int    *level;
 CODE:
- if (SvOK(ref) && SvROK(ref)) {
-  SV *sv = SvRV(ref);
-  SvREFCNT_inc(sv);
-  ret = newSVuv(PTR2UV(sv));
- } else {
-  ret = newSVuv(0);
+ {
+  my_cxt_t ud;
+  dMY_CXT;
+  ud.tbl   = t = ptable_new();
+  ud.owner = MY_CXT.owner;
+  ptable_walk(MY_CXT.tbl, lt_ptable_hints_clone, &ud);
+ }
+ {
+  MY_CXT_CLONE;
+  MY_CXT.tbl   = t;
+  MY_CXT.owner = aTHX;
  }
- RETVAL = ret;
+ {
+  level = PerlMemShared_malloc(sizeof *level);
+  *level = 1;
+  LEAVE;
+  SAVEDESTRUCTOR_X(lt_thread_cleanup, level);
+  ENTER;
+ }
+
+#endif
+
+SV *
+_tag(SV *value)
+PROTOTYPE: $
+CODE:
+ RETVAL = lt_tag(value);
 OUTPUT:
  RETVAL
diff --git a/lib/Lexical/Types.pm b/lib/Lexical/Types.pm
index 0ac794a..2999a76 100644
--- a/lib/Lexical/Types.pm
+++ b/lib/Lexical/Types.pm
@@ -245,6 +245,12 @@ If you prefer to use constants rather than creating empty packages, you can repl
 
     sub new { ... }
 
+=head1 CONSTANTS
+
+=head2 C<LT_THREADSAFE>
+
+True iff the module could have been built when thread-safety features.
+
 =head1 CAVEATS
 
 The restrictions on the type (being either a defined package name or a constant) apply even if you use the C<'as'> option to redirect to another package, and are unlikely to find a workaround as this happens deep inside the lexer - far from the reach of an extension.
diff --git a/ptable.h b/ptable.h
index a279736..fc50652 100644
--- a/ptable.h
+++ b/ptable.h
@@ -6,47 +6,95 @@
  * shared across threads.
  * Copyright goes to the original authors, bug reports to me. */
 
+/* This header is designed to be included several times with different
+ * definitions for PTABLE_NAME and PTABLE_VAL_FREE(). */
+
+#undef pPTBLMS
+#undef pPTBLMS_
+#undef aPTBLMS
+#undef aPTBLMS_
+
+/* Context for PerlMemShared_* functions */
+
 #ifdef PERL_IMPLICIT_SYS
-# define pPTABLE  pTHX
-# define pPTABLE_ pTHX_
-# define aPTABLE  aTHX
-# define aPTABLE_ aTHX_
+# define pPTBLMS  pTHX
+# define pPTBLMS_ pTHX_
+# define aPTBLMS  aTHX
+# define aPTBLMS_ aTHX_
 #else
-# define pPTABLE
-# define pPTABLE_
-# define aPTABLE
-# define aPTABLE_
+# define pPTBLMS
+# define pPTBLMS_
+# define aPTBLMS
+# define aPTBLMS_
+#endif
+
+#ifndef pPTBL
+# define pPTBL  pPTBLMS
+#endif
+#ifndef pPTBL_
+# define pPTBL_ pPTBLMS_
+#endif
+#ifndef aPTBL
+# define aPTBL  aPTBLMS
+#endif
+#ifndef aPTBL_
+# define aPTBL_ aPTBLMS_
+#endif
+
+#ifndef PTABLE_NAME
+# define PTABLE_NAME ptable
+#endif
+
+#ifndef PTABLE_VAL_FREE
+# define PTABLE_VAL_FREE(V)
+#endif
+
+#ifndef PTABLE_JOIN
+# define PTABLE_PASTE(A, B) A ## B
+# define PTABLE_JOIN(A, B)  PTABLE_PASTE(A, B)
 #endif
 
+#ifndef PTABLE_PREFIX
+# define PTABLE_PREFIX(X) PTABLE_JOIN(PTABLE_NAME, X)
+#endif
+
+#ifndef ptable_ent
 typedef struct ptable_ent {
  struct ptable_ent *next;
  const void *       key;
  void *             val;
 } ptable_ent;
+#define ptable_ent ptable_ent
+#endif /* !ptable_ent */
 
+#ifndef ptable
 typedef struct ptable {
  ptable_ent **ary;
  UV           max;
  UV           items;
 } ptable;
+#define ptable ptable
+#endif /* !ptable */
 
-#ifndef PTABLE_VAL_FREE
-# define PTABLE_VAL_FREE(V)
-#endif
-
-STATIC ptable *ptable_new(pPTABLE) {
-#define ptable_new() ptable_new(aPTABLE)
+#ifndef ptable_new
+STATIC ptable *ptable_new(pPTBLMS) {
+#define ptable_new() ptable_new(aPTBLMS)
  ptable *t = PerlMemShared_malloc(sizeof *t);
  t->max   = 127;
  t->items = 0;
  t->ary   = PerlMemShared_calloc(t->max + 1, sizeof *t->ary);
  return t;
 }
+#endif /* !ptable_new */
 
-#define PTABLE_HASH(ptr) \
-  ((PTR2UV(ptr) >> 3) ^ (PTR2UV(ptr) >> (3 + 7)) ^ (PTR2UV(ptr) >> (3 + 17)))
+#ifndef PTABLE_HASH
+# define PTABLE_HASH(ptr) \
+     ((PTR2UV(ptr) >> 3) ^ (PTR2UV(ptr) >> (3 + 7)) ^ (PTR2UV(ptr) >> (3 + 17)))
+#endif
 
+#ifndef ptable_find
 STATIC ptable_ent *ptable_find(const ptable * const t, const void * const key) {
+#define ptable_find ptable_find
  ptable_ent *ent;
  const UV hash = PTABLE_HASH(key);
 
@@ -58,15 +106,20 @@ STATIC ptable_ent *ptable_find(const ptable * const t, const void * const key) {
 
  return NULL;
 }
+#endif /* !ptable_find */
 
+#ifndef ptable_fetch
 STATIC void *ptable_fetch(const ptable * const t, const void * const key) {
+#define ptable_fetch ptable_fetch
  const ptable_ent *const ent = ptable_find(t, key);
 
  return ent ? ent->val : NULL;
 }
+#endif /* !ptable_fetch */
 
-STATIC void ptable_split(pPTABLE_ ptable * const t) {
-#define ptable_split(T) ptable_split(aPTABLE_ (T))
+#ifndef ptable_split
+STATIC void ptable_split(pPTBLMS_ ptable * const t) {
+#define ptable_split(T) ptable_split(aPTBLMS_ (T))
  ptable_ent **ary = t->ary;
  const UV oldsize = t->max + 1;
  UV newsize = oldsize * 2;
@@ -93,9 +146,9 @@ STATIC void ptable_split(pPTABLE_ ptable * const t) {
   }
  }
 }
+#endif /* !ptable_split */
 
-STATIC void ptable_store(pPTABLE_ ptable * const t, const void * const key, void * const val) {
-#define ptable_store(T, K, V) ptable_store(aPTABLE_ (T), (K), (V))
+STATIC void PTABLE_PREFIX(_store)(pPTBL_ ptable * const t, const void * const key, void * const val) {
  ptable_ent *ent = ptable_find(t, key);
 
  if (ent) {
@@ -115,10 +168,22 @@ STATIC void ptable_store(pPTABLE_ ptable * const t, const void * const key, void
  }
 }
 
-#if 0
+#ifndef ptable_walk
+STATIC void ptable_walk(pTHX_ ptable * const t, void (*cb)(pTHX_ ptable_ent *ent, void *userdata), void *userdata) {
+#define ptable_walk(T, CB, UD) ptable_walk(aTHX_ (T), (CB), (UD))
+ if (t && t->items) {
+  register ptable_ent ** const array = t->ary;
+  UV i = t->max;
+  do {
+   ptable_ent *entry;
+   for (entry = array[i]; entry; entry = entry->next)
+    cb(aTHX_ entry, userdata);
+  } while (i--);
+ }
+}
+#endif /* !ptable_walk */
 
-STATIC void ptable_clear(pPTABLE_ ptable * const t) {
-#define ptable_clear(T) ptable_clear(aPTABLE_ (T))
+STATIC void PTABLE_PREFIX(_clear)(pPTBL_ ptable * const t) {
  if (t && t->items) {
   register ptable_ent ** const array = t->ary;
   UV i = t->max;
@@ -130,7 +195,7 @@ STATIC void ptable_clear(pPTABLE_ ptable * const t) {
     void *val = oentry->val;
     entry = entry->next;
     PTABLE_VAL_FREE(val);
-    PerlMemShared_free(entry);
+    PerlMemShared_free(oentry);
    }
    array[i] = NULL;
   } while (i--);
@@ -139,13 +204,13 @@ STATIC void ptable_clear(pPTABLE_ ptable * const t) {
  }
 }
 
-STATIC void ptable_free(pPTABLE_ ptable * const t) {
-#define ptable_free(T) ptable_free(aPTABLE_ (T))
+STATIC void PTABLE_PREFIX(_free)(pPTBL_ ptable * const t) {
  if (!t)
   return;
- ptable_clear(t);
+ PTABLE_PREFIX(_clear)(aPTBL_ t);
  PerlMemShared_free(t->ary);
  PerlMemShared_free(t);
 }
 
-#endif
+#undef PTABLE_NAME
+#undef PTABLE_VAL_FREE
diff --git a/t/30-threads.t b/t/30-threads.t
index c3db6c1..3f46124 100644
--- a/t/30-threads.t
+++ b/t/30-threads.t
@@ -15,9 +15,17 @@ BEGIN {
 
 use threads;
 
-use Test::More tests => 10 * 2 * 2 * (1 + 2);
+use Test::More;
 
-defined and diag "Using threads $_" for $threads::VERSION;
+BEGIN {
+ require Lexical::Types;
+ if (Lexical::Types::LT_THREADSAFE()) {
+  plan tests => 10 * 2 * 3 * (1 + 2);
+  defined and diag "Using threads $_" for $threads::VERSION;
+ } else {
+  plan skip_all => 'This Lexical::Types isn\'t thread safe';
+ }
+}
 
 {
  package Lexical::Types::Test::Tag;
@@ -50,6 +58,16 @@ sub try {
    is $t2, $tid, "typed lexical correctly initialized in eval at run $_ in thread $tid";
 EVALD
   diag $@ if $@;
+
+SKIP:
+  {
+   skip 'Hints aren\'t propagated into eval STRING below perl 5.10' => 3
+                                                             unless $] >= 5.010;
+   eval <<'EVALD';
+    my Tag $t3;
+    is $t3, $tid, "typed lexical correctly initialized in eval (propagated) at run $_ in thread $tid"
+EVALD
+  }
  }
 }