Plugin reload <plugin_name> feature (#4942)

+ Add `reload <pluginname>`
* Fixes #365

Co-authored-by: Alexander Harkness <me@bearbin.net>
Co-authored-by: pwnOrbitals <c.de-claverie@pm.me>
Co-authored-by: Tiger Wang <ziwei.tiger@outlook.com>

CONTRIBUTORS

@@ -37,10 +37,10 @@ lkolbly
 LogicParrot
 Luksor
 M10360
-maxluchterhand1
 marmot21
 Masy98
 mathiascode
+maxluchterhand1
 MaxwellScroggs
 mborland
 mBornand
@@ -53,6 +53,7 @@ nesco
 NiLSPACE (formerly STR_Warrior)
 p-mcgowan
 pokechu22
+pwnOrbitals
 rs2k
 SamJBarney
 Schwertspize
@@ -64,8 +65,8 @@ structinf (xdot)
 sweetgiorni
 Sxw1212
 Taugeshtu
-tigerw (Tiger Wang)
 theophriene
+tigerw (Tiger Wang)
 tonibm19
 TooAngel
 UltraCoderRU

Server/Plugins/APIDump/Classes/Plugins.lua

@@ -675,6 +675,17 @@ cPluginManager.AddHook(cPluginManager.HOOK_CHAT, OnChatMessage);
 				},
 				Notes = "Queues the specified plugin to be unloaded. To avoid deadlocks, the unloading happens in the main tick thread asynchronously.",
 			},
+			ReloadPlugin =
+			{
+				Params =
+				{
+					{
+						Name = "PluginName",
+						Type = "string",
+					},
+				},
+				Notes = "Queues the specified plugin to be reloaded. To avoid deadlocks, the reloading happens in the main tick thread asynchronously.",
+			}
 		},
 		Constants =
 		{

src/Bindings/Plugin.cpp

@@ -45,7 +45,7 @@ void cPlugin::Unload(void)
 
 AString cPlugin::GetLocalFolder(void) const
 {
-	return std::string("Plugins/") + m_FolderName;
+	return "Plugins" + cFile::GetPathSeparator() + m_FolderName;
 }
 
 

src/Bindings/PluginManager.cpp

@@ -165,35 +165,54 @@ void cPluginManager::InsertDefaultPlugins(cSettingsRepositoryInterface & a_Setti
 
 void cPluginManager::Tick(float a_Dt)
 {
-	// Unload plugins that have been scheduled for unloading:
+	decltype(m_PluginsNeedAction) PluginsNeedAction;
-	AStringVector PluginsToUnload;
 	{
-		cCSLock Lock(m_CSPluginsToUnload);
+		cCSLock Lock(m_CSPluginsNeedAction);
-		std::swap(m_PluginsToUnload, PluginsToUnload);
+		std::swap(m_PluginsNeedAction, PluginsNeedAction);
 	}
-	for (auto & folder: PluginsToUnload)
+
+	// Process deferred actions:
+	for (auto & CurrentPlugin : PluginsNeedAction)
 	{
-		bool HasUnloaded = false;
+		auto & Action = CurrentPlugin.first;
-		bool HasFound = false;
+		auto & Folder = CurrentPlugin.second;
-		for (auto & plugin: m_Plugins)
+
+		bool WasLoaded = false;
+		bool WasFound = false;
+		for (auto & Plugin: m_Plugins)
 		{
-			if (plugin->GetFolderName() == folder)
+			if (Plugin->GetFolderName() == Folder)
 			{
-				HasFound = true;
+				WasFound = true;
-				if (plugin->IsLoaded())
+				if (Plugin->IsLoaded())
 				{
-					plugin->Unload();
+					switch (Action)
-					HasUnloaded = true;
+					{
+						case PluginAction::Reload :
+						{
+							// Reload plugins by unloading, then loading:
+							Plugin->Unload();
+							Plugin->Load();
+							break;
+						}
+						case PluginAction::Unload :
+						{
+							// Unload plugins that have been scheduled for unloading:
+							Plugin->Unload();
+							break;
+						}
+					}
+					WasLoaded = true;
 				}
 			}
 		}
-		if (!HasFound)
+		if (!WasFound)
 		{
-			LOG("Cannot unload plugin in folder \"%s\", there's no such plugin folder", folder.c_str());
+			LOG("Cannot act on plugin in folder \"%s\", there's no such plugin folder", Folder.c_str());
 		}
-		else if (!HasUnloaded)
+		else if (!WasLoaded)
 		{
-			LOG("Cannot unload plugin in folder \"%s\", it has not been loaded.", folder.c_str());
+			LOG("Cannot act on plugin in folder \"%s\", it has not been loaded.", Folder.c_str());
 		}
 	}  // for plugin - m_Plugins[]
 
@@ -1317,8 +1336,18 @@ void cPluginManager::UnloadPluginsNow()
 
 void cPluginManager::UnloadPlugin(const AString & a_PluginFolder)
 {
-	cCSLock Lock(m_CSPluginsToUnload);
+	cCSLock Lock(m_CSPluginsNeedAction);
-	m_PluginsToUnload.push_back(a_PluginFolder);
+	m_PluginsNeedAction.emplace_back(PluginAction::Unload, a_PluginFolder);
+}
+
+
+
+
+
+void cPluginManager::ReloadPlugin(const AString & a_PluginFolder)
+{
+	cCSLock Lock(m_CSPluginsNeedAction);
+	m_PluginsNeedAction.emplace_back(PluginAction::Reload, a_PluginFolder);
 }
 
 

src/Bindings/PluginManager.h

@@ -162,6 +162,14 @@ public:
 	} ;  // tolua_export
 
 
+	/** Defines the deferred actions needed for a plugin */
+	enum class PluginAction
+	{
+		Reload,
+		Unload
+	};
+
+
 	/** Used as a callback for enumerating bound commands */
 	class cCommandEnumCallback
 	{
@@ -303,6 +311,10 @@ public:
 	Note that this function returns before the plugin is unloaded, to avoid deadlocks. */
 	void UnloadPlugin(const AString & a_PluginFolder);  // tolua_export
 
+	/** Queues the specified plugin to be reloaded in the next call to Tick().
+	Note that this function returns before the plugin is unloaded, to avoid deadlocks. */
+	void ReloadPlugin(const AString & a_PluginFolder);  // tolua_export
+
 	/** Loads the plugin from the specified plugin folder.
 	Returns true if the plugin was loaded successfully or was already loaded before, false otherwise. */
 	bool LoadPlugin(const AString & a_PluginFolder);  // tolua_export
@@ -408,13 +420,13 @@ private:
 	typedef std::map<AString, cCommandReg> CommandMap;
 
 
-	/** FolderNames of plugins that should be unloaded.
+	/** FolderNames of plugins that need an action (unload, reload, ...).
-	The plugins will be unloaded within the next call to Tick(), to avoid multithreading issues.
+	The plugins will be acted upon within the next call to Tick(), to avoid multithreading issues.
-	Protected against multithreaded access by m_CSPluginsToUnload. */
+	Protected against multithreaded access by m_CSPluginsNeedAction. */
-	AStringVector m_PluginsToUnload;
+	std::vector<std::pair<PluginAction, AString>> m_PluginsNeedAction;
 
 	/** Protects m_PluginsToUnload against multithreaded access. */
-	mutable cCriticalSection m_CSPluginsToUnload;
+	mutable cCriticalSection m_CSPluginsNeedAction;
 
 	/** All plugins that have been found in the Plugins folder. */
 	cPluginPtrs m_Plugins;

src/Server.cpp

@@ -463,7 +463,15 @@ void cServer::ExecuteConsoleCommand(const AString & a_Cmd, cCommandOutputCallbac
 	}
 	else if (split[0] == "reload")
 	{
-		cPluginManager::Get()->ReloadPlugins();
+		if (split.size() > 1)
+		{
+			cPluginManager::Get()->ReloadPlugin(split[1]);
+			a_Output.Out("Plugin reload scheduled");
+		}
+		else
+		{
+			cPluginManager::Get()->ReloadPlugins();
+		}
 		a_Output.Finished();
 		return;
 	}