desktop_capturer: Utils for scoped instantiation of pointers/data

Moves the `Scoped` template (meant for clearing up the references) into
separate utils so as to allow for reuse in future. Other portal instances
e.g. remote desktop portal will benefit from this later.

Bug: chromium:1291247
Change-Id: Ie36415573edcbe4f697cf97b568243f09f26915d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/249400
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mark Foltz <mfoltz@chromium.org>
Commit-Queue: Salman Malik <salmanmalik@google.com>
Cr-Commit-Position: refs/heads/main@{#35916}

modules/desktop_capture/BUILD.gn

@@ -565,6 +565,8 @@ rtc_library("desktop_capture_generic") {
       "linux/wayland/base_capturer_pipewire.h",
       "linux/wayland/egl_dmabuf.cc",
       "linux/wayland/egl_dmabuf.h",
+      "linux/wayland/scoped_glib.cc",
+      "linux/wayland/scoped_glib.h",
       "linux/wayland/screencast_portal.cc",
       "linux/wayland/screencast_portal.h",
       "linux/wayland/shared_screencast_stream.cc",

modules/desktop_capture/linux/wayland/scoped_glib.cc

@@ -0,0 +1,59 @@
+/*
+ *  Copyright 2022 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/desktop_capture/linux/wayland/scoped_glib.h"
+
+#include <gio/gio.h>
+
+namespace webrtc {
+
+template <>
+Scoped<GError>::~Scoped() {
+  if (ptr_) {
+    g_error_free(ptr_);
+  }
+}
+
+template <>
+Scoped<char>::~Scoped() {
+  if (ptr_) {
+    g_free(ptr_);
+  }
+}
+
+template <>
+Scoped<GVariant>::~Scoped() {
+  if (ptr_) {
+    g_variant_unref(ptr_);
+  }
+}
+
+template <>
+Scoped<GVariantIter>::~Scoped() {
+  if (ptr_) {
+    g_variant_iter_free(ptr_);
+  }
+}
+
+template <>
+Scoped<GDBusMessage>::~Scoped() {
+  if (ptr_) {
+    g_object_unref(ptr_);
+  }
+}
+
+template <>
+Scoped<GUnixFDList>::~Scoped() {
+  if (ptr_) {
+    g_object_unref(ptr_);
+  }
+}
+
+}  // namespace webrtc

modules/desktop_capture/linux/wayland/scoped_glib.h

@@ -0,0 +1,50 @@
+/*
+ *  Copyright 2022 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef MODULES_DESKTOP_CAPTURE_LINUX_WAYLAND_SCOPED_GLIB_H_
+#define MODULES_DESKTOP_CAPTURE_LINUX_WAYLAND_SCOPED_GLIB_H_
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+template <class T>
+class Scoped {
+ public:
+  Scoped() {}
+  explicit Scoped(T* val) { ptr_ = val; }
+  ~Scoped() { RTC_DCHECK_NOTREACHED(); }
+
+  T* operator->() const { return ptr_; }
+
+  explicit operator bool() const { return ptr_ != nullptr; }
+
+  bool operator!() const { return ptr_ == nullptr; }
+
+  T* get() const { return ptr_; }
+
+  T** receive() {
+    RTC_CHECK(!ptr_);
+    return &ptr_;
+  }
+
+  Scoped& operator=(T* val) {
+    RTC_DCHECK(val);
+    ptr_ = val;
+    return *this;
+  }
+
+ protected:
+  T* ptr_ = nullptr;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_DESKTOP_CAPTURE_LINUX_WAYLAND_SCOPED_GLIB_H_

modules/desktop_capture/linux/wayland/screencast_portal.cc

@@ -13,6 +13,7 @@
 #include <gio/gunixfdlist.h>
 #include <glib-object.h>
 
+#include "modules/desktop_capture/linux/wayland/scoped_glib.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
 
@@ -26,75 +27,6 @@ const char kSessionInterfaceName[] = "org.freedesktop.portal.Session";
 const char kRequestInterfaceName[] = "org.freedesktop.portal.Request";
 const char kScreenCastInterfaceName[] = "org.freedesktop.portal.ScreenCast";
 
-template <class T>
-class Scoped {
- public:
-  Scoped() {}
-  explicit Scoped(T* val) { ptr_ = val; }
-  ~Scoped() { RTC_DCHECK_NOTREACHED(); }
-
-  T* operator->() { return ptr_; }
-
-  bool operator!() { return ptr_ == nullptr; }
-
-  T* get() { return ptr_; }
-
-  T** receive() {
-    RTC_CHECK(!ptr_);
-    return &ptr_;
-  }
-
-  Scoped& operator=(T* val) {
-    ptr_ = val;
-    return *this;
-  }
-
- protected:
-  T* ptr_ = nullptr;
-};
-
-template <>
-Scoped<GError>::~Scoped() {
-  if (ptr_) {
-    g_error_free(ptr_);
-  }
-}
-
-template <>
-Scoped<char>::~Scoped() {
-  if (ptr_) {
-    g_free(ptr_);
-  }
-}
-
-template <>
-Scoped<GVariant>::~Scoped() {
-  if (ptr_) {
-    g_variant_unref(ptr_);
-  }
-}
-
-template <>
-Scoped<GVariantIter>::~Scoped() {
-  if (ptr_) {
-    g_variant_iter_free(ptr_);
-  }
-}
-
-template <>
-Scoped<GDBusMessage>::~Scoped() {
-  if (ptr_) {
-    g_object_unref(ptr_);
-  }
-}
-
-template <>
-Scoped<GUnixFDList>::~Scoped() {
-  if (ptr_) {
-    g_object_unref(ptr_);
-  }
-}
-
 ScreenCastPortal::ScreenCastPortal(CaptureSourceType source_type,
                                    PortalNotifier* notifier)
     : notifier_(notifier), capture_source_type_(source_type) {}