# HG changeset patch
# User Michael Goffioul <michael.goffioul@gmail.com>
# Date 1322925582 0
# Node ID 43cc49c7abd19d256c3baa06fa00e54a78157260
# Parent  1126c29078787c0b4842cd3a94e145fa4a5e7713
Use thread-safe atomic reference counting (GCC and MSVC).

* configure.ac: New --enable-atomic-refcount argument.
(octave_allocator): Fix USE_OCTAVE_ALLOCATOR variable assignment.
(OCTAVE_CONFIG_INCLUDED): New macro in config.h.

* oct-refcount.h (OCTREFCOUNT_ATOMIC_INCREMENT,
OCTREFCOUNT_ATOMIC_INCREMENT_POST, OCTREFCOUNT_ATOMIC_DECREMENT,
OCTREFCOUNT_ATOMIC_DECREMENT_POST): New macro, defined for MSVC and GCC
when USE_ATOMIC_REFCOUNT is defined.
(octave_refcount:operator++, octave_refcount::operator--): Use them.
(octave_refcount::operator count_type): Cast returned value to volatile.
(octave_refcount::direct): Remove unsafe member.
* Array.h (Array::make_unique): Delete rep if refcount reaches 0.
* Sparse.h (Sparse::make_unique): Delete rep if refcount reaches 0.
* Array.h (Array:~Array, Array::operator=): Delete rep only when refcount is
excatly 0.
* Array.cc (Array::clear): Likewise.
* Sparse.cc (Sparse::~Sparse, Sparse::operator=): Likewise.
* SparseCmplxQR.h (SparseCmplxQR::~SparseCmplxQR, SparseCmplxQR::operator=):
Likewise.
* SparseQR.h (SparseQR::~SparseQR, SparseQR::operator=): Likewise.
* sparse-base-chol.h (sparse_base_chol::~sparse_base_chol,
sparse_base_chol::operator): Likewise.
* dim-vector.h (oct-refcount.h): New included header.
(dim_vector::make_unique, dim_vector::resize): Use OCTREFCOUNT_ATOMIC_DECREMENT
macro and delete rep when refcount reaches 0.
(dim_vector::dim_vector): Use OCTREFCOUNT_ATOMIC_INCREMENT.
(dim_vector::operator=): Use OCTREFCOUNT_ATOMIC_INCREMENT and
OCTREFCOUNT_ATOMIC_DECREMENT.
(dim_vector::~dim_vector): Use OCTREFCOUNT_ATOMIC_DECREMENT.
* oct-mutex.h (oct-refcount.h): New included header.
(octave_base_mutex::count): Use octave_refcount class.

* gl-render.cc (oct-refcount.h): New included header.
* graphics.h.in (oct-refcount.h): Likewise.
(base_property::count, base_graphics_toolkit::count,
base_graphics_object::count, base_graphics_event::count): Use octave_refcount.
(property::~property, property::operator=): Delete rep only when refcountn is
excatly 0.
* oct-map.h (octave_fields::make_unique): Delete rep when refcount reaches 0.
* oct-stream.h (oct-refcount.h): New included header.
(octave_base_stream::count): Use octave_refcount class.
* ov.h (octave_value::make_unique): Delete rep when refcount reaches 0.
* symtab.h (oct-refcount.h): New included header.
(symbol_record_rep::count, fcn_info_rep::count): Use octave_refcount class.

* DLD-FUNCTIONS/urlwrite.cc (oct-refcount.h): New included header.
(curl_handle_rep::count): Use octave_refcount class.

diff -r 1126c2907878 -r 43cc49c7abd1 configure.ac
--- a/configure.ac	Sat Dec 03 05:23:52 2011 -0500
+++ b/configure.ac	Sat Dec 03 15:19:42 2011 +0000
@@ -171,11 +171,20 @@
 AC_ARG_ENABLE(octave-allocator,
   [AS_HELP_STRING([--enable-octave-allocator],
      [use the obsolete octave_allocator class for many of Octave's objects (mostly octave_value types).  You probably do NOT want to enable this feature.  (default is no)])],
-  [if test "$enableval" = yes; then USE_ALLOCATOR=true; fi], [])
+  [if test "$enableval" = yes; then USE_OCTAVE_ALLOCATOR=true; fi], [])
 if $USE_OCTAVE_ALLOCATOR; then
   AC_DEFINE(USE_OCTAVE_ALLOCATOR, 1, [Define to use octave_allocator class.])
 fi
 
+USE_ATOMIC_REFCOUNT=false
+AC_ARG_ENABLE(atomic-refcount,
+  [AS_HELP_STRING([--enable-atomic-refcount],
+     [use atomic operations for internal reference counting. This is required for thread-safe behavior.  (default is no)])],
+  [if test "$enableval" = yes; then USE_ATOMIC_REFCOUNT=true; fi], [])
+if $USE_ATOMIC_REFCOUNT; then
+  AC_DEFINE(USE_ATOMIC_REFCOUNT, 1, [Define to use atomic operations for reference counting.])
+fi
+
 ### Make it possible to disable running Make in the doc directory.
 ### Useful for building on systems without TeX, for example.
 DOCDIR=doc
@@ -2089,6 +2098,9 @@
 typedef OCTAVE_IDX_TYPE octave_idx_type;
 
 #include <stdint.h>
+
+/* Tag indicating octave config.h has been included */
+#define OCTAVE_CONFIG_INCLUDED 1
 ])
 
 ### Do the substitutions in all the Makefiles.
@@ -2465,6 +2477,22 @@
   warn_msg_printed=true
 fi
 
+if $USE_ATOMIC_REFCOUNT; then
+  AC_MSG_WARN([])
+  AC_MSG_WARN([Using atomic reference counting.])
+  AC_MSG_WARN([This feature allows to access octave data safely from])
+  AC_MSG_WARN([another thread, for instance from a GUI. However this])
+  AC_MSG_WARN([results in a small performance penalty in the octave])
+  AC_MSG_WARN([interpreter.])
+  AC_MSG_WARN([])
+  if $USE_OCTAVE_ALLOCATOR; then
+    AC_MSG_WARN([Thread-safe behavior is not guaranteed unless you also])
+    AC_MSG_WARN([disable the use of the octave_allocator class.])
+    AC_MSG_WARN([])
+  fi
+  warn_msg_printed=true
+fi
+
 if $warn_msg_printed; then
   AC_MSG_NOTICE([])
   AC_MSG_NOTICE([NOTE: libraries may be skipped if a library is not found OR])
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/Array.cc
--- a/liboctave/Array.cc	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/Array.cc	Sat Dec 03 15:19:42 2011 +0000
@@ -84,7 +84,7 @@
 void
 Array<T>::clear (void)
 {
-  if (--rep->count <= 0)
+  if (--rep->count == 0)
     delete rep;
 
   rep = nil_rep ();
@@ -99,7 +99,7 @@
 void
 Array<T>::clear (const dim_vector& dv)
 {
-  if (--rep->count <= 0)
+  if (--rep->count == 0)
     delete rep;
 
   rep = new ArrayRep (dv.safe_numel ());
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/Array.h
--- a/liboctave/Array.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/Array.h	Sat Dec 03 15:19:42 2011 +0000
@@ -110,8 +110,12 @@
     {
       if (rep->count > 1)
         {
-          --rep->count;
-          rep = new ArrayRep (slice_data, slice_len);
+          ArrayRep *r = new ArrayRep (slice_data, slice_len);
+
+          if (--rep->count == 0)
+            delete rep;
+          
+          rep = r;
           slice_data = rep->data;
         }
     }
@@ -225,7 +229,7 @@
 
   ~Array (void)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
         delete rep;
     }
 
@@ -233,7 +237,7 @@
     {
       if (this != &a)
         {
-          if (--rep->count <= 0)
+          if (--rep->count == 0)
             delete rep;
 
           rep = a.rep;
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/Sparse.cc
--- a/liboctave/Sparse.cc	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/Sparse.cc	Sat Dec 03 15:19:42 2011 +0000
@@ -667,7 +667,7 @@
 template <class T>
 Sparse<T>::~Sparse (void)
 {
-  if (--rep->count <= 0)
+  if (--rep->count == 0)
     delete rep;
 }
 
@@ -677,7 +677,7 @@
 {
   if (this != &a)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
         delete rep;
 
       rep = a.rep;
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/Sparse.h
--- a/liboctave/Sparse.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/Sparse.h	Sat Dec 03 15:19:42 2011 +0000
@@ -147,8 +147,12 @@
     {
       if (rep->count > 1)
         {
-          --rep->count;
-          rep = new SparseRep (*rep);
+          SparseRep *r = new SparseRep (*rep);
+
+          if (--rep->count == 0)
+            delete rep;
+
+          rep = r;
         }
     }
 
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/SparseCmplxQR.h
--- a/liboctave/SparseCmplxQR.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/SparseCmplxQR.h	Sat Dec 03 15:19:42 2011 +0000
@@ -96,7 +96,7 @@
 
   ~SparseComplexQR (void)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
         delete rep;
     }
 
@@ -104,7 +104,7 @@
     {
       if (this != &a)
         {
-          if (--rep->count <= 0)
+          if (--rep->count == 0)
             delete rep;
 
           rep = a.rep;
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/SparseQR.h
--- a/liboctave/SparseQR.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/SparseQR.h	Sat Dec 03 15:19:42 2011 +0000
@@ -98,7 +98,7 @@
 
   ~SparseQR (void)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
         delete rep;
     }
 
@@ -106,7 +106,7 @@
     {
       if (this != &a)
         {
-          if (--rep->count <= 0)
+          if (--rep->count == 0)
             delete rep;
 
           rep = a.rep;
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/dim-vector.h
--- a/liboctave/dim-vector.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/dim-vector.h	Sat Dec 03 15:19:42 2011 +0000
@@ -32,6 +32,7 @@
 
 #include "lo-error.h"
 #include "lo-macros.h"
+#include "oct-refcount.h"
 
 // Rationale: This implementation is more tricky than Array, but the
 // big plus is that dim_vector requires only one allocation instead of
@@ -128,8 +129,12 @@
   {
     if (count () > 1)
       {
-        --count();
-        rep = clonerep ();
+	octave_idx_type *new_rep = clonerep ();
+
+	if (OCTREFCOUNT_ATOMIC_DECREMENT(&(count())) == 0)
+	  freerep ();
+
+        rep = new_rep;
       }
   }
 
@@ -222,9 +227,11 @@
 
   static octave_idx_type dim_max (void);
 
-  explicit dim_vector (void) : rep (nil_rep ()) { count()++; }
+  explicit dim_vector (void) : rep (nil_rep ())
+  { OCTREFCOUNT_ATOMIC_INCREMENT (&(count())); }
 
-  dim_vector (const dim_vector& dv) : rep (dv.rep) { count()++; }
+  dim_vector (const dim_vector& dv) : rep (dv.rep)
+  { OCTREFCOUNT_ATOMIC_INCREMENT (&(count())); }
 
   static dim_vector alloc (int n)
   {
@@ -235,11 +242,11 @@
   {
     if (&dv != this)
       {
-        if (--count() <= 0)
+        if (OCTREFCOUNT_ATOMIC_DECREMENT (&(count())) == 0)
           freerep ();
 
         rep = dv.rep;
-        count()++;
+        OCTREFCOUNT_ATOMIC_INCREMENT (&(count()));
       }
 
     return *this;
@@ -247,7 +254,7 @@
 
   ~dim_vector (void)
   {
-    if (--count() <= 0)
+    if (OCTREFCOUNT_ATOMIC_DECREMENT (&(count())) == 0)
       freerep ();
   }
 
@@ -265,7 +272,7 @@
       {
         octave_idx_type *r = resizerep (n, fill_value);
 
-        if (--count() <= 0)
+        if (OCTREFCOUNT_ATOMIC_DECREMENT (&(count())) == 0)
           freerep ();
 
         rep = r;
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/oct-mutex.h
--- a/liboctave/oct-mutex.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/oct-mutex.h	Sat Dec 03 15:19:42 2011 +0000
@@ -23,6 +23,8 @@
 #if !defined (octave_octave_mutex_h)
 #define octave_octave_mutex_h 1
 
+#include "oct-refcount.h"
+
 class octave_mutex;
 
 class
@@ -42,7 +44,7 @@
   virtual bool try_lock (void);
 
 private:
-  int count;
+  octave_refcount<int> count;
 };
 
 class
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/oct-refcount.h
--- a/liboctave/oct-refcount.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/oct-refcount.h	Sat Dec 03 15:19:42 2011 +0000
@@ -23,6 +23,30 @@
 #if !defined (octave_refcount_h)
 #define octave_refcount_h 1
 
+#ifndef OCTAVE_CONFIG_INCLUDED
+# error "The file <octave/config.h> must be included before oct-refcount.h."
+#endif
+
+#if defined (USE_ATOMIC_REFCOUNT) && (defined (_MSC_VER) || defined (__GNUC__))
+# if defined (_MSC_VER)
+#  include <intrin.h>
+#  define OCTREFCOUNT_ATOMIC_INCREMENT(x) _InterlockedIncrement((long*)x)
+#  define OCTREFCOUNT_ATOMIC_DECREMENT(x) _InterlockedDecrement((long*)x)
+#  define OCTREFCOUNT_ATOMIC_INCREMENT_POST(x) _InterlockedExchangeAdd((long*)x,  1)
+#  define OCTREFCOUNT_ATOMIC_DECREMENT_POST(x) _InterlockedExchangeAdd((long*)x, -1)
+# elif defined (__GNUC__)
+#  define OCTREFCOUNT_ATOMIC_INCREMENT(x) __sync_add_and_fetch(x,  1)
+#  define OCTREFCOUNT_ATOMIC_DECREMENT(x) __sync_add_and_fetch(x, -1)
+#  define OCTREFCOUNT_ATOMIC_INCREMENT_POST(x) __sync_fetch_and_add(x,  1)
+#  define OCTREFCOUNT_ATOMIC_DECREMENT_POST(x) __sync_fetch_and_add(x, -1)
+# endif
+#else // Generic non-locking versions
+# define OCTREFCOUNT_ATOMIC_INCREMENT(x) ++(*(x))
+# define OCTREFCOUNT_ATOMIC_DECREMENT(x) --(*(x))
+# define OCTREFCOUNT_ATOMIC_INCREMENT_POST(x) (*(x))++
+# define OCTREFCOUNT_ATOMIC_DECREMENT_POST(x) (*(x))--
+#endif
+
 // Encapsulates a reference counter.
 template <class T>
 class octave_refcount
@@ -35,28 +59,28 @@
   // Increment/Decrement. int is postfix.
   count_type operator++(void)
     {
-      return ++count;
+      return OCTREFCOUNT_ATOMIC_INCREMENT (&count);
     }
 
   count_type operator++(int)
     {
-      return count++;
+      return OCTREFCOUNT_ATOMIC_INCREMENT_POST (&count);
     }
 
   count_type operator--(void)
     {
-      return --count;
+      return OCTREFCOUNT_ATOMIC_DECREMENT (&count);
     }
 
   count_type operator--(int)
     {
-      return count--;
+      return OCTREFCOUNT_ATOMIC_DECREMENT_POST (&count);
     }
 
-  operator count_type (void) const { return count; }
-
-  // For low-level optimizations only.
-  count_type& direct (void) const { return count; }
+  operator count_type (void) const
+    {
+      return static_cast<count_type const volatile&> (count);
+    }
 
 private:
   count_type count;
diff -r 1126c2907878 -r 43cc49c7abd1 liboctave/sparse-base-chol.h
--- a/liboctave/sparse-base-chol.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/liboctave/sparse-base-chol.h	Sat Dec 03 15:19:42 2011 +0000
@@ -178,7 +178,7 @@
 
   virtual ~sparse_base_chol (void)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
         delete rep;
     }
 
@@ -186,7 +186,7 @@
     {
       if (this != &a)
         {
-          if (--rep->count <= 0)
+          if (--rep->count == 0)
             delete rep;
 
           rep = a.rep;
diff -r 1126c2907878 -r 43cc49c7abd1 src/DLD-FUNCTIONS/urlwrite.cc
--- a/src/DLD-FUNCTIONS/urlwrite.cc	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/DLD-FUNCTIONS/urlwrite.cc	Sat Dec 03 15:19:42 2011 +0000
@@ -46,6 +46,7 @@
 #include "ov-cell.h"
 #include "pager.h"
 #include "oct-map.h"
+#include "oct-refcount.h"
 #include "unwind-prot.h"
 
 #ifdef HAVE_CURL
@@ -141,7 +142,7 @@
         return !ascii;
       }
 
-    size_t count;
+    octave_refcount<size_t> count;
     std::string host;
     bool valid;
     bool ascii;
diff -r 1126c2907878 -r 43cc49c7abd1 src/gl-render.cc
--- a/src/gl-render.cc	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/gl-render.cc	Sat Dec 03 15:19:42 2011 +0000
@@ -30,6 +30,7 @@
 
 #include <lo-mappers.h>
 #include "oct-locbuf.h"
+#include "oct-refcount.h"
 #include "gl-render.h"
 #include "txt-eng.h"
 #include "txt-eng-ft.h"
diff -r 1126c2907878 -r 43cc49c7abd1 src/graphics.h.in
--- a/src/graphics.h.in	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/graphics.h.in	Sat Dec 03 15:19:42 2011 +0000
@@ -42,6 +42,7 @@
 #include "gripes.h"
 #include "oct-map.h"
 #include "oct-mutex.h"
+#include "oct-refcount.h"
 #include "ov.h"
 #include "txt-eng-ft.h"
 
@@ -482,7 +483,7 @@
 
 private:
   int id;
-  int count;
+  octave_refcount<int> count;
   std::string name;
   graphics_handle parent;
   bool hidden;
@@ -1910,7 +1911,7 @@
 
   ~property (void)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
         delete rep;
     }
 
@@ -1965,7 +1966,7 @@
 
   property& operator = (const property& p)
     {
-      if (rep && --rep->count <= 0)
+      if (rep && --rep->count == 0)
         delete rep;
 
       rep = p.rep;
@@ -2133,7 +2134,7 @@
 
 private:
   std::string name;
-  int count;
+  octave_refcount<int> count;
 
 private:
   void gripe_invalid (const std::string& fname) const
@@ -2739,7 +2740,7 @@
 
 protected:
   // A reference count.
-  int count;
+  octave_refcount<int> count;
 
   // A flag telling whether this object is a valid object
   // in the backend context.
@@ -5097,7 +5098,7 @@
   virtual void execute (void) = 0;
 
 private:
-  int count;
+  octave_refcount<int> count;
 };
 
 class
diff -r 1126c2907878 -r 43cc49c7abd1 src/oct-map.h
--- a/src/oct-map.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/oct-map.h	Sat Dec 03 15:19:42 2011 +0000
@@ -73,8 +73,12 @@
     {
       if (rep->count > 1)
         {
-          --rep->count;
-          rep = new fields_rep (*rep);
+          fields_rep *r = new fields_rep (*rep);
+
+          if (--rep->count == 0)
+            delete rep;
+
+          rep = r;
         }
     }
 
diff -r 1126c2907878 -r 43cc49c7abd1 src/oct-stream.h
--- a/src/oct-stream.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/oct-stream.h	Sat Dec 03 15:19:42 2011 +0000
@@ -37,6 +37,7 @@
 #include "data-conv.h"
 #include "lo-utils.h"
 #include "mach-info.h"
+#include "oct-refcount.h"
 
 class
 OCTINTERP_API
@@ -427,7 +428,7 @@
 private:
 
   // A reference count.
-  octave_idx_type count;
+  octave_refcount<octave_idx_type> count;
 
   // The permission bits for the file.  Should be some combination of
   // std::ios::open_mode bits.
diff -r 1126c2907878 -r 43cc49c7abd1 src/ov.h
--- a/src/ov.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/ov.h	Sat Dec 03 15:19:42 2011 +0000
@@ -315,8 +315,12 @@
     {
       if (rep->count > 1)
         {
-          --rep->count;
-          rep = rep->unique_clone ();
+	  octave_base_value *r = rep->unique_clone ();
+
+          if (--rep->count == 0)
+            delete rep;
+
+          rep = r;
         }
     }
 
@@ -327,8 +331,12 @@
     {
       if (rep->count > obsolete_copies + 1)
         {
-          --rep->count;
-          rep = rep->unique_clone ();
+          octave_base_value *r = rep->unique_clone ();
+
+          if (--rep->count == 0)
+            delete rep;
+
+          rep = r;
         }
     }
 
diff -r 1126c2907878 -r 43cc49c7abd1 src/symtab.h
--- a/src/symtab.h	Sat Dec 03 05:23:52 2011 -0500
+++ b/src/symtab.h	Sat Dec 03 15:19:42 2011 +0000
@@ -37,6 +37,7 @@
 class octave_user_function;
 
 #include "oct-obj.h"
+#include "oct-refcount.h"
 #include "ov.h"
 
 class
@@ -387,7 +388,7 @@
 
       fcn_info *finfo;
 
-      size_t count;
+      octave_refcount<size_t> count;
 
     private:
 
@@ -728,7 +729,7 @@
 
       octave_value built_in_function;
 
-      size_t count;
+      octave_refcount<size_t> count;
 
     private: