[python, ruby] Add Director guard file with C++ 11 std::mutex (#2870)

* Improve mutex for director use:
- Use C++ 11 mutex and lock classes.
  Most compilers support C++ 11 by default.
  Leave Win32 and POSIX support for older compiler.
- Use a single file for Python and Ruby.
- Use macro also for guard definition instead of using '#ifdef'.
- Rename old '__THREAD__' to 'SWIG_THREADS' to
  avoid collide with other libraries.
- Remove the use of '__PTHREAD__' as it may collide with other libraries.
- Remove mutex from OCaml, as it is not used in Director class.

Signed-off-by: Erez Geva <ErezGeva2@gmail.com>

* Fixes follow @wsfulton.

Improve description of director_guard.swg.
Remove duplicate line.
Change to SWIG_GUARD_DEFINITION and SWIG_GUARD_DECLARATION
 as full English words are much more easily understood
 than abbreviations.

Signed-off-by: Erez Geva <ErezGeva2@gmail.com>

---------

Signed-off-by: Erez Geva <ErezGeva2@gmail.com>

Lib/director_guard.swg

@@ -0,0 +1,104 @@
+/* -----------------------------------------------------------------------------
+ * director_guard.swg
+ *
+ * Generic Mutex implementation
+ *
+ * Before calling the file, you may choose the following:
+ * - SWIG_THREADS:
+ *   If set than we use mutexs.
+ *   If not set we do not use mutexs.
+ * - SWIG_HAVE_MUTEX:
+ *   If you have a language defined 'Mutex' class, set this flag.
+ *     The language 'Mutex' class need to be a Basic Lockable.
+ *     It must have public 'void lock()' and 'void unlock()' methods.
+ *     See: https://en.cppreference.com/w/cpp/named_req/BasicLockable
+ *   If the flag is unset, use one of the following in that order:
+ *   - C++ 11 or above, use std::mutex.
+ *   - Win32 use CRITICAL_SECTION.
+ *   - Use POSIX Pthread mutex.
+ *
+ * ----------------------------------------------------------------------------- */
+
+#ifdef SWIG_THREADS
+
+#if __cplusplus >= 201103L
+/*
+ * C++ 11 or above
+ * std::mutex        https://en.cppreference.com/w/cpp/thread/mutex
+ * std::unique_lock  https://en.cppreference.com/w/cpp/thread/unique_lock
+ */
+#include <mutex>
+#ifdef SWIG_HAVE_MUTEX
+/* Use Language defined Mutex class */
+#define SWIG_GUARD(_mutex) std::unique_lock<Mutex> _guard(_mutex)
+#define SWIG_GUARD_DEFINITION(_cls, _mutex) Mutex _cls::_mutex
+#define SWIG_GUARD_DECLARATION(_mutex) static Mutex _mutex
+#else
+#define SWIG_GUARD(_mutex) std::unique_lock<std::mutex> _guard(_mutex)
+#define SWIG_GUARD_DEFINITION(_cls, _mutex) std::mutex _cls::_mutex
+#define SWIG_GUARD_DECLARATION(_mutex) static std::mutex _mutex
+#endif
+
+#else /* __cplusplus */
+
+#ifdef SWIG_HAVE_MUTEX
+/* Use Language defined Mutex class */
+
+#elif defined(_WIN32)
+/*
+ * Windows Critical Section Objects
+ * https://learn.microsoft.com/en-us/windows/win32/Sync/critical-section-objects
+ */
+#include <windows.h>
+#include <synchapi.h>
+namespace Swig {
+    class Mutex {
+        CRITICAL_SECTION mutex_;
+    public:
+        Mutex() { InitializeCriticalSection(&mutex_); }
+        ~Mutex() { DeleteCriticalSection(&mutex_); }
+        void lock() { EnterCriticalSection(&mutex_); }
+        void unlock() { LeaveCriticalSection(&mutex_); }
+    };
+}
+
+#else /* _WIN32 */
+/*
+ * POSIX Thread mutex
+ * https://pubs.opengroup.org/onlinepubs/7908799/xsh/pthread.h.html
+ */
+#include <pthread.h>
+namespace Swig {
+    class Mutex {
+        pthread_mutex_t mutex_;
+    public:
+        Mutex() { pthread_mutex_init(&mutex_, NULL); }
+        ~Mutex() { pthread_mutex_destroy(&mutex_); }
+        void lock() { pthread_mutex_lock(&mutex_); }
+        void unlock() { pthread_mutex_unlock(&mutex_); }
+    };
+}
+
+#endif /* _WIN32 */
+
+namespace Swig {
+    class Unique_lock {
+        Mutex &mutex_;
+    public:
+        Unique_lock(Mutex &_mutex) : mutex_(_mutex) { mutex_.lock(); }
+        ~Unique_lock() { mutex_.unlock(); }
+    };
+}
+#define SWIG_GUARD(_mutex) Unique_lock _guard(_mutex)
+#define SWIG_GUARD_DEFINITION(_cls, _mutex) Mutex _cls::_mutex
+#define SWIG_GUARD_DECLARATION(_mutex) static Mutex _mutex
+
+#endif /* __cplusplus */
+
+#else /* SWIG_THREADS */
+
+#define SWIG_GUARD(_mutex)
+#define SWIG_GUARD_DEFINITION(_cls, _mutex)
+#define SWIG_GUARD_DECLARATION(_mutex)
+
+#endif /* SWIG_THREADS */

Lib/ocaml/director.swg

@@ -49,20 +49,6 @@ namespace Swig {
       }
   };
 
-  /* simple thread abstraction for pthreads on win32 */
-#ifdef __THREAD__
-#define __PTHREAD__
-#if defined(_WIN32) || defined(__WIN32__)
-#define pthread_mutex_lock EnterCriticalSection
-#define pthread_mutex_unlock LeaveCriticalSection
-#define pthread_mutex_t CRITICAL_SECTION
-#define MUTEX_INIT(var) CRITICAL_SECTION var
-#else
-#include <pthread.h>
-#define MUTEX_INIT(var) pthread_mutex_t var = PTHREAD_MUTEX_INITIALIZER
-#endif
-#endif
-
   /* director base class */
   class Director {
     private:

Lib/python/director.swg

@@ -14,25 +14,6 @@
 #include <vector>
 #include <map>
 
-#if defined(SWIG_PYTHON_THREADS)
-/*  __THREAD__ is the old macro to activate some thread support */
-# if !defined(__THREAD__)
-#   define __THREAD__ 1
-# endif
-#endif
-
-#ifdef __THREAD__
-#ifndef Py_LIMITED_API
-# include "pythread.h"
-#else
-# if defined(_WIN32)
-#   include <windows.h>
-# else
-#   include <pthread.h>
-# endif
-#endif
-#endif
-
 /*
   Use -DSWIG_PYTHON_DIRECTOR_NO_VTABLE if you don't want to generate a 'virtual
   table', and avoid multiple GetAttr calls to retrieve the python
@@ -262,95 +243,6 @@ namespace Swig {
   };
 
 
-#ifdef __THREAD__
-#ifndef Py_LIMITED_API
-   class Mutex
-   {
-   public:
-       Mutex() {
-           mutex_ = PyThread_allocate_lock();
-       }
-
-       ~Mutex() {
-           PyThread_release_lock(mutex_);
-       }
-
-   private:
-       void Lock() {
-           PyThread_acquire_lock(mutex_, WAIT_LOCK);
-       }
-
-       void Unlock() {
-           PyThread_free_lock(mutex_);
-       }
-
-       PyThread_type_lock mutex_;
-
-       friend class Guard;
-   };
-#elif defined(_WIN32)
-    class Mutex : private CRITICAL_SECTION {
-    public:
-        Mutex() {
-            InitializeCriticalSection(this);
-        }
-
-        ~Mutex() {
-            DeleteCriticalSection(this);
-        }
-
-    private:
-        void Lock() {
-            EnterCriticalSection(this);
-        }
-
-        void Unlock() {
-            LeaveCriticalSection(this);
-        }
-
-        friend class Guard;
-    };
-#else
-    class Mutex {
-    public:
-        Mutex() {
-            pthread_mutex_init(&mutex_, NULL);
-        }
-
-        ~Mutex() {
-            pthread_mutex_destroy(&mutex_);
-        }
-
-    private:
-        void Lock() {
-            pthread_mutex_lock(&mutex_);
-        }
-
-        void Unlock() {
-            pthread_mutex_unlock(&mutex_);
-        }
-
-        friend class Guard;
-
-        pthread_mutex_t mutex_;
-    };
-#endif
-  class Guard {
-    Mutex &mutex_;
-
-  public:
-    Guard(Mutex & mutex) : mutex_(mutex) {
-      mutex_.Lock();
-    }
-
-    ~Guard() {
-      mutex_.Unlock();
-    }
-  };
-# define SWIG_GUARD(mutex) Guard _guard(mutex)
-#else
-# define SWIG_GUARD(mutex)
-#endif
 
   /* director base class */
   class Director {
@@ -411,9 +303,7 @@ namespace Swig {
   private:
     typedef std::map<void *, GCItem_var> swig_ownership_map;
     mutable swig_ownership_map swig_owner;
-#ifdef __THREAD__
-    static Mutex swig_mutex_own;
-#endif
+    SWIG_GUARD_DECLARATION(swig_mutex_own);
 
   public:
     template <typename Type>
@@ -463,9 +353,7 @@ namespace Swig {
     }
   };
 
-#ifdef __THREAD__
-  Mutex Director::swig_mutex_own;
-#endif
+  SWIG_GUARD_DEFINITION(Director, swig_mutex_own);
 }
 
 #endif

Lib/python/director_py_mutex.swg

@@ -0,0 +1,24 @@
+/* -----------------------------------------------------------------------------
+ * director_py_mutex.swg
+ *
+ * contains python mutex for threads
+ * ----------------------------------------------------------------------------- */
+
+#if defined(SWIG_PYTHON_THREADS) && !defined(SWIG_THREADS)
+#define SWIG_THREADS 1
+#endif
+#if defined(SWIG_THREADS) && !defined(Py_LIMITED_API)
+#include "pythread.h"
+#define SWIG_HAVE_MUTEX
+namespace Swig {
+   class Mutex
+   {
+       PyThread_type_lock mutex_;
+   public:
+       Mutex() : mutex_(PyThread_allocate_lock()) {}
+       ~Mutex() { PyThread_release_lock(mutex_); }
+       void lock() { PyThread_acquire_lock(mutex_, WAIT_LOCK); }
+       void unlock() { PyThread_free_lock(mutex_); }
+   };
+}
+#endif

Lib/ruby/director.swg

@@ -202,37 +202,6 @@ namespace Swig {
     }
   };
 
-  /* Simple thread abstraction for pthreads on win32 */
-#ifdef __THREAD__
-# define __PTHREAD__
-# if defined(_WIN32) || defined(__WIN32__)
-#  define pthread_mutex_lock EnterCriticalSection
-#  define pthread_mutex_unlock LeaveCriticalSection
-#  define pthread_mutex_t CRITICAL_SECTION
-#  define SWIG_MUTEX_INIT(var) var
-# else
-#  include <pthread.h>
-#  define SWIG_MUTEX_INIT(var) var = PTHREAD_MUTEX_INITIALIZER
-# endif
-#endif
-
-#ifdef  __PTHREAD__
-  struct Guard {
-    pthread_mutex_t *_mutex;
-
-    Guard(pthread_mutex_t &mutex) : _mutex(&mutex) {
-      pthread_mutex_lock(_mutex);
-    }
-
-    ~Guard() {
-      pthread_mutex_unlock(_mutex);
-    }
-  };
-# define SWIG_GUARD(mutex) Guard _guard(mutex)
-#else
-# define SWIG_GUARD(mutex)
-#endif
-
   /* director base class */
   class Director {
   private:
@@ -266,9 +235,7 @@ namespace Swig {
   private:
     typedef std::map<void *, GCItem_var> swig_ownership_map;
     mutable swig_ownership_map swig_owner;
-#ifdef __PTHREAD__
-    static pthread_mutex_t swig_mutex_own;
-#endif
+    SWIG_GUARD_DECLARATION(swig_mutex_own);
 
   public:
     template <typename Type>
@@ -307,5 +274,6 @@ namespace Swig {
       return own;
     }
   };
+  SWIG_GUARD_DEFINITION(Director, swig_mutex_own);
 }
 

Source/Modules/python.cxx

@@ -808,6 +808,8 @@ public:
     if (Swig_directors_enabled()) {
       // Insert director runtime into the f_runtime file (make it occur before %header section)
       Swig_insert_file("director_common.swg", f_runtime);
+      Swig_insert_file("director_py_mutex.swg", f_runtime);
+      Swig_insert_file("director_guard.swg", f_runtime);
       Swig_insert_file("director.swg", f_runtime);
     }
 

Source/Modules/ruby.cxx

@@ -1155,6 +1155,7 @@ public:
     if (Swig_directors_enabled()) {
       // Insert director runtime into the f_runtime file (make it occur before %header section)
       Swig_insert_file("director_common.swg", f_runtime);
+      Swig_insert_file("director_guard.swg", f_runtime);
       Swig_insert_file("director.swg", f_runtime);
     }