🔧 Remove paint-target signal

src/ShaderFactory.js

@@ -19,44 +19,71 @@ const ExtensionUtils = imports.misc.extensionUtils;
 const Me             = imports.misc.extensionUtils.getCurrentExtension();
 
 //////////////////////////////////////////////////////////////////////////////////////////
-// This is the base class for all effects of Burn-My-Windows. It provides the logic     //
-// required for creating shader instances and reusing them as much as possible.         //
+// Each effect of Burn-My-Windows owns an instance of this class. It is used to created //
+// shaders whenever a new one is required. It tries to re-use old shaders as much as    //
+// possible in order to avoid memory leaks.                                             //
 //////////////////////////////////////////////////////////////////////////////////////////
 
 var ShaderFactory = class ShaderFactory {
 
-  // The _freeShaders array contains previously created shaders which are not currently in
-  // use.
+  // Creates a new ShaderFactory. Requires the nick of the effect and a callback function
+  // which will be called whenever a new shader is created.
   constructor(nick, setupFunc) {
+    // The _freeShaders array contains previously created shaders which are not currently
+    // in use.
     this._freeShaders = [];
-    this._nick        = nick;
-    this._setupFunc   = setupFunc;
+
+    // The nick of the effect is required when creating new shaders as it's part of the
+    // GLSL source code file name.
+    this._nick = nick;
+
+    // Store the setup callback.
+    this._setupFunc = setupFunc;
   }
 
   // ---------------------------------------------------------------- API for extension.js
 
-  // This is called from extension.js whenever a window is opened or closed with this
-  // effect. It returns an instance of the shader class, trying to reuse previously
-  // created shaders. If a new shader instance is required, it calls this.createShader().
-  // This method must be defined be the derived class!
+  // This is called from extension.js whenever a window is opened or closed. It returns an
+  // instance of the shader class, trying to reuse previously created shaders. If a new
+  // shader instance is required, it calls creates a new one and calls the setupFunc
+  // thereafter.
   getShader() {
     let shader;
 
+    // If there are currently no free shaders, we have to create a new one.
     if (this._freeShaders.length == 0) {
 
+      // Since Shell.GLSLEffect caches the shader source per class (not per instance), we
+      // have to derive a new shader type for each effect. The type name contains the nick
+      // of the effect to make it unique.
       const typeName = `BurnMyWindowsShader_${this._nick}`;
 
+      // Only try to register the new type once.
       if (GObject.type_from_name(typeName) == null) {
+        const outerThis = this;
         GObject.registerClass({GTypeName: typeName},
-                              class Shader extends Me.imports.src.Shader.Shader {});
+                              class Shader extends Me.imports.src.Shader.Shader {
+          // This will actually load the GLSL source code from the resources.
+          _init() {
+            super._init(outerThis._nick);
+          }
+
+          // This can be called to mark this instance to be re-usable.
+          returnToFactory() {
+            outerThis._freeShaders.push(this);
+          }
+        });
       }
 
-      shader = GObject.Object.new(GObject.type_from_name(typeName), {'nick': this._nick});
-
-      shader.returnToFactory = () => {
-        this._freeShaders.push(shader);
-      };
+      // Now create a niew instance of the newly registered shader type.
+      // GObject.Object.new is only available with newer versions of GJS.
+      if (GObject.Object.new) {
+        shader = GObject.Object.new(GObject.type_from_name(typeName), {});
+      } else {
+        shader = GObject.Object.newv(GObject.type_from_name(typeName), []);
+      }
 
+      // Call the provided setup callback.
       this._setupFunc(shader);
 
     } else {