fix(linux/pipewire): avoid memory leaks (#5360)

Co-authored-by: Psyke83 <psyke83@users.noreply.github.com>

src/platform/linux/kwingrab.cpp

@@ -248,7 +248,7 @@ namespace kwin {
    * @brief KWin screencast output name and geometry.
    */
   struct output_parameter_t {
-    std::string name = "";  ///< KWin output name.
+    std::string name;  ///< KWin output name.
     int width = 0;  ///< Output width in pixels.
     int height = 0;  ///< Output height in pixels.
     int pos_x = 0;  ///< Output X position in the compositor layout.
@@ -272,6 +272,7 @@ namespace kwin {
     screencast_t &operator=(screencast_t &&) = delete;  // Do not allow to copying
 
     ~screencast_t() {
+      // Release KDE screencast wayland extensions and reset pointers
       if (kde_screencast_stream_v1_) {
         zkde_screencast_stream_unstable_v1_close(kde_screencast_stream_v1_);
         kde_screencast_stream_v1_ = nullptr;
@@ -280,23 +281,30 @@ namespace kwin {
         zkde_screencast_unstable_v1_destroy(kde_screencast_v1_);
         kde_screencast_v1_ = nullptr;
       }
-
       if (kde_output_order) {
         kde_output_order_v1_destroy(kde_output_order);
         kde_output_order = nullptr;
       }
 
+      // Clear output order list
+      output_order.clear();
+      // Clear current output parameters
+      out_params.reset();
+      out_params = nullptr;
+
       // wl_output is owned by the registry, released on disconnect
-      for (const auto &out : outputs | std::views::keys) {
-        wl_output_destroy(out);
+      // also cleanup associated output parameters and clear output list when done
+      for (auto &[output, params] : outputs) {
+        wl_output_destroy(output);
+        params.reset();
       }
       outputs.clear();
 
+      // Release wayland registry, display and reset pointers
       if (wl_registry) {
         wl_registry_destroy(wl_registry);
         wl_registry = nullptr;
       }
-
       if (wl_display) {
         wl_display_disconnect(wl_display);
         wl_display = nullptr;

src/platform/linux/pipewire.cpp

@@ -123,6 +123,18 @@ namespace pipewire {
     int n_modifiers;  ///< Number of entries in `modifiers`.
   };
 
+  /**
+   * @brief Pipewire image assembled for encoding.
+   */
+  struct img_descriptor_t: public egl::img_descriptor_t {
+    ~img_descriptor_t() override {
+      if (data) {
+        delete[] data;
+        data = nullptr;
+      }
+    }
+  };
+
   /**
    * @brief PipeWire core, context, and stream setup used for screencast capture.
    */
@@ -136,34 +148,44 @@ namespace pipewire {
 
     ~pipewire_t() {
       BOOST_LOG(debug) << "[pipewire] Destroying pipewire_t"sv;
-      try {
-        cleanup_stream();
-      } catch (const std::exception &e) {
-        BOOST_LOG(error) << "[pipewire] Standard exception caught in ~pipewire_t cleanup_stream: "sv << e.what();
-      } catch (...) {
-        BOOST_LOG(error) << "[pipewire] Unknown exception caught in ~pipewire_t cleanup_stream"sv;
-      }
-
       pw_thread_loop_lock(loop);
 
+      // Lock the frame mutex to stop fill_img
+      BOOST_LOG(debug) << "[pipewire] Stop fill_img"sv;
+      {
+        std::scoped_lock lock(stream_data.frame_mutex);
+        stream_data.frame_ready = false;
+        stream_data.current_buffer = nullptr;
+      }
+
+      // Release pipewire stream
+      if (stream_data.stream) {
+        BOOST_LOG(debug) << "[pipewire] Disconnect stream"sv;
+        pw_stream_disconnect(stream_data.stream);
+        BOOST_LOG(debug) << "[pipewire] Destroy stream"sv;
+        pw_stream_destroy(stream_data.stream);
+        stream_data.stream = nullptr;
+      }
+      // Release pipewire core
       if (core) {
         BOOST_LOG(debug) << "[pipewire] Disconnect PW core"sv;
         pw_core_disconnect(core);
         core = nullptr;
       }
+      // Release pipewire context
       if (context) {
         BOOST_LOG(debug) << "[pipewire] Destroy PW context"sv;
         pw_context_destroy(context);
         context = nullptr;
       }
-
-      pw_thread_loop_unlock(loop);
-
+      // Release pipewire file descriptor
       if (fd >= 0) {
         BOOST_LOG(debug) << "[pipewire] Close pipewire_fd"sv;
         close(fd);
       }
+      // Release pipewire thread loop
       BOOST_LOG(debug) << "[pipewire] Stop PW thread loop"sv;
+      pw_thread_loop_unlock(loop);
       pw_thread_loop_stop(loop);
       BOOST_LOG(debug) << "[pipewire] Destroy PW thread loop"sv;
       pw_thread_loop_destroy(loop);
@@ -245,34 +267,6 @@ namespace pipewire {
       return 0;
     }
 
-    /**
-     * @brief Release the active PipeWire stream and listener.
-     */
-    void cleanup_stream() {
-      BOOST_LOG(debug) << "[pipewire] Cleaning up stream"sv;
-      if (loop && stream_data.stream) {
-        pw_thread_loop_lock(loop);
-
-        // 1. Lock the frame mutex to stop fill_img
-        BOOST_LOG(debug) << "[pipewire] Stop fill_img"sv;
-        {
-          std::scoped_lock lock(stream_data.frame_mutex);
-          stream_data.frame_ready = false;
-          stream_data.current_buffer = nullptr;
-        }
-
-        if (stream_data.stream) {
-          BOOST_LOG(debug) << "[pipewire] Disconnect stream"sv;
-          pw_stream_disconnect(stream_data.stream);
-          BOOST_LOG(debug) << "[pipewire] Destroy stream"sv;
-          pw_stream_destroy(stream_data.stream);
-          stream_data.stream = nullptr;
-        }
-
-        pw_thread_loop_unlock(loop);
-      }
-    }
-
     /**
      * @brief Create the PipeWire stream if it is not already active.
      *
@@ -934,7 +928,7 @@ namespace pipewire {
      */
     std::shared_ptr<platf::img_t> alloc_img() override {
       // Note: this img_t type is also used for memory buffers
-      auto img = std::make_shared<egl::img_descriptor_t>();
+      auto img = std::make_shared<img_descriptor_t>();
 
       img->width = width;
       img->height = height;
@@ -1067,12 +1061,7 @@ namespace pipewire {
      * @return Capture status reported to the streaming pipeline.
      */
     int dummy_img(platf::img_t *img) override {
-      if (!img) {
-        return -1;
-      }
-
-      img->data = new std::uint8_t[img->height * img->row_pitch];
-      std::fill_n(img->data, img->height * img->row_pitch, 0);
+      // Empty images are recognized as dummies by the zero sequence number
       return 0;
     }