added a quick experimental system for overriding core natives

--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401695

core/systems/ExtensionSys.cpp

@@ -285,7 +285,22 @@ void CExtension::RemovePlugin(IPlugin *pPlugin)
 		if ((*iter).pl == pPlugin)
 		{
 			iter = m_WeakNatives.erase(iter);
-		} else {
+		}
+		else
+		{
+			iter++;
+		}
+	}
+
+	iter = m_ReplacedNatives.begin();
+	while (iter != m_ReplacedNatives.end())
+	{
+		if ((*iter).pl == pPlugin)
+		{
+			iter = m_ReplacedNatives.erase(iter);
+		}
+		else
+		{
 			iter++;
 		}
 	}
@@ -703,6 +718,7 @@ void CExtensionManager::BindAllNativesToPlugin(IPlugin *pPlugin)
 	uint32_t natives = pContext->GetNativesNum();
 	sp_native_t *native;
 	sm_extnative_t *x_native;
+	sm_repnative_t *r_native;
 	for (uint32_t i=0; i<natives; i++)
 	{
 		/* Make sure the native is valid */
@@ -710,11 +726,26 @@ void CExtensionManager::BindAllNativesToPlugin(IPlugin *pPlugin)
 		{
 			continue;
 		}
+
 		/* Make sure the native is not already bound */
 		if (native->status == SP_NATIVE_BOUND)
+		{
+			/* If it is bound, see if there is a replacement. */
+			if ((r_native = m_RepNatives.retrieve(native->name)) == NULL)
 			{
 				continue;
 			}
+
+			/* Rewrite the address.  Whee! */
+			native->pfn = r_native->info.func;
+
+			/* Make sure this will unload safely */
+			WeakNative wn((CPlugin *)pPlugin, i);
+			r_native->owner->m_ReplacedNatives.push_back(wn);
+
+			continue;
+		}
+
 		/* See if we've got this native in our cache */
 		if ((x_native = m_ExtNatives.retrieve(native->name)) == NULL)
 		{
@@ -789,7 +820,7 @@ bool CExtensionManager::UnloadExtension(IExtension *_pExt)
 			g_PluginSys.OnLibraryAction((*s_iter).c_str(), false, true);
 		}
 
-		/* Unbound weak natives */
+		/* Unbind weak natives */
 		List<WeakNative>::iterator wkn_iter;
 		for (wkn_iter=pExt->m_WeakNatives.begin(); wkn_iter!=pExt->m_WeakNatives.end(); wkn_iter++)
 		{
@@ -798,6 +829,21 @@ bool CExtensionManager::UnloadExtension(IExtension *_pExt)
 			ctx->natives[wkn.idx].status = SP_NATIVE_UNBOUND;
 		}
 
+		/* Unbind replacement natives, link them back to their originals */
+		for (wkn_iter = pExt->m_ReplacedNatives.begin();
+			 wkn_iter != pExt->m_ReplacedNatives.end();
+			 wkn_iter++)
+		{
+			WeakNative & wkn = (*wkn_iter);
+			sp_context_t *ctx = wkn.pl->GetContext();
+			sm_repnative_t *r_native = m_RepNatives.retrieve(ctx->natives[wkn.idx].name);
+			if (r_native == NULL || ctx->natives[wkn.idx].pfn != r_native->info.func)
+			{
+				continue;
+			}
+			ctx->natives[wkn.idx].pfn = r_native->original;
+		}
+
 		/* Notify and/or unload all dependencies */
 		List<CExtension *>::iterator c_iter;
 		CExtension *pDep;
@@ -871,6 +917,22 @@ bool CExtensionManager::UnloadExtension(IExtension *_pExt)
 			}
 		}
 
+		/* Unbind our replacement natives */
+		List<sm_repnative_t>::iterator rep_iter = m_RepNativeList.begin();
+		while (rep_iter != m_RepNativeList.end())
+		{
+			sm_repnative_t & r_native = (*rep_iter);
+			if (r_native.owner == pExt)
+			{
+				m_RepNatives.remove(r_native.info.name);
+				rep_iter = m_RepNativeList.erase(rep_iter);
+			}
+			else
+			{
+				rep_iter++;
+			}
+		}
+
 		/* Tell it to unload */
 		pAPI = pExt->GetAPI();
 		pAPI->OnExtensionUnload();
@@ -919,6 +981,25 @@ void CExtensionManager::AddNatives(IExtension *pOwner, const sp_nativeinfo_t *na
 	}
 }
 
+void CExtensionManager::OverrideNatives(IExtension *myself, const sp_nativeinfo_t *natives)
+{
+	SPVM_NATIVE_FUNC orig;
+
+	for (unsigned int i = 0; natives[i].func != NULL && natives[i].name != NULL; i++)
+	{
+		if ((orig = g_PluginSys.FindCoreNative(natives[i].name)) == NULL)
+		{
+			continue;
+		}
+		sm_repnative_t rep;
+		rep.info = natives[i];
+		rep.owner = (CExtension *)myself;
+		rep.original = orig;
+		m_RepNativeList.push_back(rep);
+		m_RepNatives.insert(natives[i].name, rep);
+	}
+}
+
 void CExtensionManager::MarkAllLoaded()
 {
 	List<CExtension *>::iterator iter;

core/systems/ExtensionSys.h

@@ -55,6 +55,14 @@ struct sm_extnative_t
 	const sp_nativeinfo_t *info;
 };
 
+/* Replacement native */
+struct sm_repnative_t
+{
+	CExtension *owner;
+	sp_nativeinfo_t info;
+	SPVM_NATIVE_FUNC original;
+};
+
 class CExtension : public IExtension
 {
 	friend class CExtensionManager;
@@ -98,6 +106,7 @@ protected:
 	List<IPlugin *> m_Plugins;
 	List<const sp_nativeinfo_t *> m_Natives;
 	List<WeakNative> m_WeakNatives;
+	List<WeakNative> m_ReplacedNatives;
 	List<String> m_Libraries;
 	unsigned int unload_code;
 	bool m_bFullyLoaded;
@@ -168,6 +177,7 @@ public:
 	void TryAutoload();
 	void AddLibrary(IExtension *pSource, const char *library);
 	bool LibraryExists(const char *library);
+	void OverrideNatives(IExtension *myself, const sp_nativeinfo_t *natives);
 public:
 	CExtension *GetExtensionFromIdent(IdentityToken_t *ptr);
 	void Shutdown();
@@ -175,6 +185,8 @@ private:
 	CExtension *FindByOrder(unsigned int num);
 private:
 	List<CExtension *> m_Libs;
+	List<sm_repnative_t> m_RepNativeList;
+	KTrie<sm_repnative_t> m_RepNatives;
 	KTrie<sm_extnative_t> m_ExtNatives;
 };
 

core/systems/PluginSys.cpp

@@ -1440,6 +1440,18 @@ void CPluginManager::AddCoreNativesToPlugin(CPlugin *pPlugin)
 	}
 }
 
+SPVM_NATIVE_FUNC CPluginManager::FindCoreNative(const char *name)
+{
+	SPVM_NATIVE_FUNC pfn;
+
+	if (!sm_trie_retrieve(m_pCoreNatives, name, (void **)&pfn))
+	{
+		return NULL;
+	}
+
+	return pfn;
+}
+
 void CPluginManager::TryRefreshDependencies(CPlugin *pPlugin)
 {
 	assert(pPlugin->GetBaseContext() != NULL);

core/systems/PluginSys.h

@@ -489,6 +489,7 @@ public:
 	}
 public:
 	bool AddFakeNative(IPluginFunction *pFunction, const char *name, SPVM_FAKENATIVE_FUNC func);
+	SPVM_NATIVE_FUNC FindCoreNative(const char *name);
 private:
 	void AddFakeNativesToPlugin(CPlugin *pPlugin);
 	void TryRefreshDependencies(CPlugin *pOther);

core/systems/ShareSys.cpp

@@ -243,3 +243,8 @@ void ShareSystem::RegisterLibrary(IExtension *myself, const char *name)
 {
 	g_Extensions.AddLibrary(myself, name);
 }
+
+void ShareSystem::OverrideNatives(IExtension *myself, const sp_nativeinfo_t *natives)
+{
+	g_Extensions.OverrideNatives(myself, natives);
+}

core/systems/ShareSys.h

@@ -81,6 +81,7 @@ public: //IShareSys
 	void DestroyIdentity(IdentityToken_t *identity);
 	void AddDependency(IExtension *myself, const char *filename, bool require, bool autoload);
 	void RegisterLibrary(IExtension *myself, const char *name);
+	void OverrideNatives(IExtension *myself, const sp_nativeinfo_t *natives);
 public: //SMGlobalClass
 	/* Pre-empt in case anything tries to register idents early */
 	void OnSourceModStartup(bool late);

public/IExtensionSys.h

@@ -127,8 +127,11 @@ namespace SourceMod
 
 	/**
 	 * @brief Version code of the IExtensionInterface API itself.
+	 *
+	 * Note: This is bumped when IShareSys is changed, because IShareSys 
+	 * itself is not versioned.
 	 */
-	#define SMINTERFACE_EXTENSIONAPI_VERSION	2
+	#define SMINTERFACE_EXTENSIONAPI_VERSION	3
 
 	/**
 	 * @brief The interface an extension must expose.

public/IShareSys.h

@@ -200,6 +200,29 @@ namespace SourceMod
 		 * @param name			Library name.
 		 */
 		virtual void RegisterLibrary(IExtension *myself, const char *name) =0;
+
+		/**
+		 * @brief Adds a list of natives to the global native pool, to be 
+		 * bound on plugin load.
+		 *
+		 * Unlike AddNatives(), this function implements natives that are 
+		 * ALWAYS bound, regardless of whether a previous function is bound. 
+		 * That means extensions can override Core natives.
+		 *
+		 * A Core version of each native must exist.  If one does not, then 
+		 * Core will simply ignore that entry.
+		 *
+		 * Override natives represent a weak coupling.  If the extension is 
+		 * unloaded, the native will be re-bound to the Core version.
+		 * 
+		 * @param myself		Identity token of parent object.
+		 * @param natives		Array of natives to add.  The last entry in 
+		 *						the array must be filled with NULLs to 
+		 *						terminate the array.  The array must be static 
+		 *						as Core will cache the pointer for the 
+		 *						lifetime of the extension.
+		 */
+		virtual void OverrideNatives(IExtension *myself, const sp_nativeinfo_t *natives) =0;
 	};
 }