Added the ability to disable hooks (#326)

* Added the ability to disable hooks

Generic fix for issue #236

* Moved HooksDisabled-check to the top

* Updated documentation for hooks_disabled context manager

Author: Ayuto

addons/source-python/packages/source-python/memory/hooks.py

@@ -5,11 +5,16 @@
 # =============================================================================
 # >> IMPORTS
 # =============================================================================
+# Python
+from contextlib import contextmanager
+
 # Source.Python Imports
 #   Core
 from core import AutoUnload
 #   Memory
 from _memory import HookType
+from _memory import set_hooks_disabled
+from _memory import get_hooks_disabled
 from memory import Function
 
 
@@ -19,6 +24,9 @@
 __all__ = ('HookType',
            'PostHook',
            'PreHook',
+           'set_hooks_disabled',
+           'get_hooks_disabled',
+           'hooks_disabled'
            )
 
 
@@ -73,3 +81,44 @@ class PostHook(_Hook):
     """Decorator class used to create post hooks that auto unload."""
 
     hook_type = HookType.POST
+
+
+# =============================================================================
+# >> FUNCTIONS
+# =============================================================================
+@contextmanager
+def hooks_disabled(disabled=True):
+    """Temporarily disable or enable all hook callbacks. By default hooks are
+    enabled. Thus, this context manager is mainly used to temporarily disable
+    hook callbacks. If the context ends, the original value is restored. This
+    can be used e. g. to avoid recursive calls when damaging a player in a
+    ``on_take_damage`` hook or ``player_hurt`` event.
+
+    .. note::
+
+        This would only disable hooks created with Source.Python. Hooks that
+        have been created by other server plugins will still be called.
+
+    Example:
+
+    .. code:: python
+
+        from players.entity import Player
+        from memory.hooks import hooks_disabled
+
+        # Get a Player instance of the player with index 1
+        player = Player(1)
+
+        # Damage the player. This would call e. g. on_take_damage hooks
+        player.take_damage(5)
+
+        # To avoid calling the on_take_damage hooks, use the following:
+        with hooks_disabled()
+            player.take_damage(5)
+    """
+    old = get_hooks_disabled()
+    set_hooks_disabled(disabled)
+    try:
+        yield
+    finally:
+        set_hooks_disabled(old)

src/core/modules/memory/memory_hooks.cpp

@@ -44,6 +44,8 @@ using namespace boost::python;
 // g_mapCallbacks[<CHook *>][<HookType_t>] -> [<object>, <object>, ...]
 std::map<CHook *, std::map<HookType_t, std::list<object> > > g_mapCallbacks;
 
+bool g_HooksDisabled;
+
 
 // ============================================================================
 // >> HELPER FUNCTIONS
@@ -80,6 +82,9 @@ object GetArgument(CHook* pHook, int iIndex)
 // ============================================================================
 bool SP_HookHandler(HookType_t eHookType, CHook* pHook)
 {
+	if (g_HooksDisabled)
+		return false;
+
 	std::list<object> callbacks = g_mapCallbacks[pHook][eHookType];
 
 	// No need to do all this stuff, if there is no callback registered

src/core/modules/memory/memory_hooks.h

@@ -76,4 +76,16 @@ class CStackData
 //---------------------------------------------------------------------------------
 bool SP_HookHandler(HookType_t eHookType, CHook* pHook);
 
+extern bool g_HooksDisabled;
+
+inline void SetHooksDisabled(bool value)
+{
+	g_HooksDisabled = value;
+}
+
+inline bool GetHooksDisabled()
+{
+	return g_HooksDisabled;
+}
+
 #endif // MEMORY_HOOKS_H

src/core/modules/memory/memory_wrap.cpp

@@ -68,6 +68,8 @@ void export_protection(scope);
 // ============================================================================
 DECLARE_SP_MODULE(_memory)
 {
+	SetHooksDisabled(false);
+
 	export_function_info(_memory);
 	export_binary_file(_memory);
 	export_pointer(_memory);
@@ -956,6 +958,18 @@ void export_functions(scope _memory)
 		":param DataType data_type: The data type you would like to get the size of.\n"
 		":param int alignment: The alignment that should be used."
 	);
+
+	def("get_hooks_disabled",
+		&GetHooksDisabled,
+		"Return whether or not hook callbacks are disabled.\n"
+		"\n"
+		":rtype: bool");
+
+	def("set_hooks_disabled",
+		&SetHooksDisabled,
+		"Set whether or not hook callbacks are disabled.\n"
+		"\n"
+		":param bool disabled: If ``True``, hook callbacks are disabled.");
 }