thread.mutex

5 files changed, 107 insertions, 1 deletions

diff --git a/library/lullaby/thread.lua b/library/lullaby/thread.lua
index 1b0e89d..d4efe2d 100644
--- a/library/lullaby/thread.lua
+++ b/library/lullaby/thread.lua
@@ -64,4 +64,26 @@ function thread.unlock(tid) end
 ---@deprecated
 function thread.testcopy() end
 
+---@class mutex-table
+local mutex = {}
+
+---locks the mutex
+---@param T mutex-table
+---@return nil
+function mutex.lock(T) end
+
+---unlocks the mutex
+---@param T mutex-table
+---@return nil
+function mutex.unlock(T) end
+
+---frees the mutex, automatically called by __gc
+---@param T mutex-table
+---@return nil
+function mutex.free(T) end
+
+---returns a mutex object, useful for solving race conditions in multi-threaded environments
+---@return mutex-table
+function thread.mutex() end
+
 return thread
diff --git a/src/thread.c b/src/thread.c
index a5eb892..6d4540d 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -85,6 +85,65 @@ int l_tunlock(lua_State* L){
     return 0;

 }

 

+int _mutex_lock(lua_State* L){

+  lua_pushstring(L, "_");

+  lua_gettable(L, 1);

+  pthread_mutex_t *lock = lua_touserdata(L, -1);

+

+  pthread_mutex_lock(lock);

+

+  return 0;

+}

+

+int _mutex_unlock(lua_State* L){

+  lua_pushstring(L, "_");

+  lua_gettable(L, 1);

+  pthread_mutex_t *lock = lua_touserdata(L, -1);

+

+  pthread_mutex_unlock(lock);

+

+  return 0;

+}

+

+int _mutex_free(lua_State* L){

+  lua_pushstring(L, "_");

+  lua_gettable(L, 1);

+  pthread_mutex_t *lock = lua_touserdata(L, -1);

+

+  if(lock != NULL){

+    pthread_mutex_destroy(&*lock);

+    free(lock);

+

+    luaI_tsetlud(L, 1, "_", NULL);

+  }

+

+  return 0;

+}

+

+int l_mutex(lua_State* L){

+  pthread_mutex_t *lock = malloc(sizeof * lock);

+

+  if(pthread_mutex_init(&*lock, NULL) != 0)

+    luaI_error(L, -1, "mutex init failed");

+

+  lua_newtable(L);

+  int idx = lua_gettop(L);

+  luaI_tsetlud(L, idx, "_", lock);

+  luaI_tsetcf(L, idx, "lock", _mutex_lock);

+  luaI_tsetcf(L, idx, "unlock", _mutex_unlock);

+  luaI_tsetcf(L, idx, "free", _mutex_free);

+

+  lua_newtable(L);

+  int midx = lua_gettop(L);

+  luaI_tsetcf(L, midx, "__gc", _mutex_free);

+

+  lua_pushvalue(L, midx);

+  lua_setmetatable(L, idx);

+  lua_pushvalue(L, idx);

+

+  return 1;

+}

+

 int l_res(lua_State* L){

     int return_count = lua_gettop(L) - 1;

     lua_pushstring(L, "_");

diff --git a/src/thread.h b/src/thread.h
index be9cadd..0b3a27d 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -6,6 +6,7 @@ int l_tlock(lua_State*);
 int l_tunlock(lua_State*);

 int l_buffer(lua_State*);

 int l_testcopy(lua_State*);

+int l_mutex(lua_State*);

 

 void lib_thread_clean();

 

@@ -17,6 +18,7 @@ static const luaL_Reg thread_function_list [] = {
   {"unlock",l_tunlock},

   {"buffer",l_buffer},

   {"testcopy",l_testcopy},

+  {"mutex", l_mutex},

   {NULL,NULL}

 };

 

diff --git a/src/util.h b/src/util.h
index 62cf80d..99f127c 100644
--- a/src/util.h
+++ b/src/util.h
@@ -38,4 +38,4 @@ void _p_fatal(const char*, int, const char*, const char*);
 void p_error(const char*);
 char* strnstr(const char*, const char*, size_t);
 
-#endif //__UTIL_H
\ No newline at end of file
+#endif //__UTIL_H
diff --git a/tests/mutex.lua b/tests/mutex.lua
new file mode 100644
index 0000000..2e5ce4b
--- /dev/null
+++ b/tests/mutex.lua
@@ -0,0 +1,23 @@
+local llby = require"lullaby"
+
+
+local mutex = llby.thread.mutex()
+
+llby.io.print_meta = 1
+llby.io.pprint(mutex)
+
+local th = llby.thread.async(function(res)
+  mutex:lock()
+  os.execute("sleep 5")
+  print("thread")
+  mutex:unlock()
+end)
+
+os.execute("sleep 1")
+mutex:lock()
+print("main")
+mutex:unlock()
+mutex:free()
+--
+th:await()
+