From 3c82d5a919f43aaa314b459e721eed69a76bfdd2 Mon Sep 17 00:00:00 2001
From: Xaver Hugl <xaver.hugl@gmail.com>
Date: Wed, 20 Mar 2024 16:28:05 +0100
Subject: [PATCH] core: introduce DrmDevice

---
 src/CMakeLists.txt     |  2 ++
 src/core/drmdevice.cpp | 76 ++++++++++++++++++++++++++++++++++++++++++
 src/core/drmdevice.h   | 45 +++++++++++++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 src/core/drmdevice.cpp
 create mode 100644 src/core/drmdevice.h

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index fee195f186..f25a88142b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -47,6 +47,7 @@ target_sources(kwin PRIVATE
     core/colorpipelinestage.cpp
     core/colorspace.cpp
     core/colortransformation.cpp
+    core/drmdevice.cpp
     core/gbmgraphicsbufferallocator.cpp
     core/graphicsbuffer.cpp
     core/graphicsbufferallocator.cpp
@@ -549,6 +550,7 @@ install(FILES
     core/colorpipelinestage.h
     core/colorspace.h
     core/colortransformation.h
+    core/drmdevice.h
     core/gbmgraphicsbufferallocator.h
     core/graphicsbuffer.h
     core/graphicsbufferallocator.h
diff --git a/src/core/drmdevice.cpp b/src/core/drmdevice.cpp
new file mode 100644
index 0000000000..95519e1f18
--- /dev/null
+++ b/src/core/drmdevice.cpp
@@ -0,0 +1,76 @@
+/*
+    KWin - the KDE window manager
+    This file is part of the KDE project.
+
+    SPDX-FileCopyrightText: 2024 Xaver Hugl <xaver.hugl@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+#include "drmdevice.h"
+
+#include "gbmgraphicsbufferallocator.h"
+
+#include <fcntl.h>
+#include <gbm.h>
+#include <sys/stat.h>
+
+namespace KWin
+{
+
+DrmDevice::DrmDevice(const QString &path, dev_t id, FileDescriptor &&fd, gbm_device *gbmDevice)
+    : m_path(path)
+    , m_id(id)
+    , m_fd(std::move(fd))
+    , m_gbmDevice(gbmDevice)
+    , m_allocator(std::make_unique<GbmGraphicsBufferAllocator>(gbmDevice))
+{
+}
+
+DrmDevice::~DrmDevice()
+{
+    gbm_device_destroy(m_gbmDevice);
+}
+
+QString DrmDevice::path() const
+{
+    return m_path;
+}
+
+dev_t DrmDevice::deviceId() const
+{
+    return m_id;
+}
+
+gbm_device *DrmDevice::gbmDevice() const
+{
+    return m_gbmDevice;
+}
+
+GraphicsBufferAllocator *DrmDevice::allocator() const
+{
+    return m_allocator.get();
+}
+
+int DrmDevice::fileDescriptor() const
+{
+    return m_fd.get();
+}
+
+std::unique_ptr<DrmDevice> DrmDevice::open(const QString &path)
+{
+    FileDescriptor fd{::open(path.toLocal8Bit(), O_RDWR | O_CLOEXEC)};
+    if (!fd.isValid()) {
+        return nullptr;
+    }
+    struct stat buf;
+    if (fstat(fd.get(), &buf) == -1) {
+        return nullptr;
+    }
+    gbm_device *device = gbm_create_device(fd.get());
+    if (!device) {
+        return nullptr;
+    }
+    return std::unique_ptr<DrmDevice>(new DrmDevice(path, buf.st_rdev, std::move(fd), device));
+}
+
+}
diff --git a/src/core/drmdevice.h b/src/core/drmdevice.h
new file mode 100644
index 0000000000..9f11fd2a88
--- /dev/null
+++ b/src/core/drmdevice.h
@@ -0,0 +1,45 @@
+/*
+    KWin - the KDE window manager
+    This file is part of the KDE project.
+
+    SPDX-FileCopyrightText: 2024 Xaver Hugl <xaver.hugl@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+#pragma once
+
+#include <QString>
+
+#include "graphicsbufferallocator.h"
+#include "kwin_export.h"
+#include "utils/filedescriptor.h"
+
+struct gbm_device;
+
+namespace KWin
+{
+
+class KWIN_EXPORT DrmDevice
+{
+public:
+    ~DrmDevice();
+
+    QString path() const;
+    dev_t deviceId() const;
+    gbm_device *gbmDevice() const;
+    GraphicsBufferAllocator *allocator() const;
+    int fileDescriptor() const;
+
+    static std::unique_ptr<DrmDevice> open(const QString &path);
+
+private:
+    explicit DrmDevice(const QString &path, dev_t id, FileDescriptor &&fd, gbm_device *gbmDevice);
+
+    const QString m_path;
+    const dev_t m_id;
+    const FileDescriptor m_fd;
+    gbm_device *const m_gbmDevice;
+    const std::unique_ptr<GraphicsBufferAllocator> m_allocator;
+};
+
+}