[host] linux: add skeleton pipewire capture backend

host/platform/Linux/capture/CMakeLists.txt

@@ -3,7 +3,19 @@ project(capture LANGUAGES C)
 
 include("PreCapture")
 
-add_capture("XCB")
+option(USE_XCB "Enable XSHM Support" ON)
+option(USE_PIPEWIRE "Enable Pipewire Support" OFF)
+
+if (USE_XCB)
+  add_capture("XCB")
+endif()
+
+if (USE_PIPEWIRE)
+  add_capture("pipewire")
+endif()
+
+add_feature_info(USE_XCB USE_XCB "XCB/XSHM capture backend.")
+add_feature_info(USE_PIPEWIRE USE_PIPEWIRE "Pipewire Screencast capture backend.")
 
 include("PostCapture")
 

host/platform/Linux/capture/XCB/src/xcb.c

@@ -48,7 +48,7 @@ struct xcb
   xcb_xfixes_get_cursor_image_cookie_t curC;
 };
 
-struct xcb * this = NULL;
+static struct xcb * this = NULL;
 
 // forwards
 

host/platform/Linux/capture/pipewire/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.0)
+project(capture_pipewire LANGUAGES C)
+
+add_library(capture_pipewire STATIC
+	src/pipewire.c
+)
+
+target_link_libraries(capture_pipewire
+	lg_common
+)
+
+target_include_directories(capture_pipewire
+	PRIVATE
+		src
+)

host/platform/Linux/capture/pipewire/src/pipewire.c

@@ -0,0 +1,99 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2021 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "interface/capture.h"
+#include "interface/platform.h"
+#include "common/debug.h"
+#include <string.h>
+#include <stdlib.h>
+
+struct pipewire
+{
+};
+
+static struct pipewire * this = NULL;
+
+// forwards
+
+static bool pipewire_deinit();
+
+// implementation
+
+static const char * pipewire_getName(void)
+{
+  return "Pipewire";
+}
+
+static bool pipewire_create(CaptureGetPointerBuffer getPointerBufferFn, CapturePostPointerBuffer postPointerBufferFn)
+{
+  DEBUG_ASSERT(!this);
+  this = calloc(1, sizeof(*this));
+  return true;
+}
+
+static bool pipewire_init(void)
+{
+  goto fail;
+fail:
+  pipewire_deinit();
+  return false;
+}
+
+static bool pipewire_deinit(void)
+{
+  return false;
+}
+
+static void pipewire_free(void)
+{
+  free(this);
+  this = NULL;
+}
+
+static CaptureResult pipewire_capture(void)
+{
+  return CAPTURE_RESULT_ERROR;
+}
+
+static CaptureResult pipewire_waitFrame(CaptureFrame * frame,
+    const size_t maxFrameSize)
+{
+  return CAPTURE_RESULT_ERROR;
+}
+
+static CaptureResult pipewire_getFrame(FrameBuffer * frame,
+    const unsigned int height, int frameIndex)
+{
+  return CAPTURE_RESULT_ERROR;
+}
+
+struct CaptureInterface Capture_pipewire =
+{
+  .shortName       = "pipewire",
+  .asyncCapture    = false,
+  .getName         = pipewire_getName,
+  .create          = pipewire_create,
+  .init            = pipewire_init,
+  .deinit          = pipewire_deinit,
+  .free            = pipewire_free,
+  .capture         = pipewire_capture,
+  .waitFrame       = pipewire_waitFrame,
+  .getFrame        = pipewire_getFrame
+};