[libcamera-devel,v2,2/6] libcamera: Provide a V4L2Base class

1383 diff mbox series

diff --git a/src/libcamera/include/v4l2_base.h b/src/libcamera/include/v4l2_base.h
new file mode 100644
index 000000000000..2fda81a960d2
--- /dev/null
+++ b/src/libcamera/include/v4l2_base.h
@@ -0,0 +1,31 @@ 
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * v4l2_base.h - Common base for V4L2 devices and subdevices
+ */
+#ifndef __LIBCAMERA_V4L2_BASE__
+#define __LIBCAMERA_V4L2_BASE__
+
+#include <vector>
+
+namespace libcamera {
+
+class V4L2Base
+{
+public:
+	virtual ~V4L2Base()
+	{
+	}
+
+	virtual int open() = 0;
+	virtual void close() = 0;
+	bool isOpen() const;
+
+protected:
+	int fd_;
+};
+
+}; /* namespace libcamera */
+
+#endif /* __LIBCAMERA_V4L2_BASE__ */
diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
index bdecc087fe5a..d9bcdb921b8c 100644
--- a/src/libcamera/include/v4l2_device.h
+++ b/src/libcamera/include/v4l2_device.h
@@ -17,6 +17,7 @@ 
 #include <libcamera/signal.h>
 
 #include "log.h"
+#include "v4l2_base.h"
 
 namespace libcamera {
 
@@ -111,7 +112,7 @@  public:
 	const std::string toString() const;
 };
 
-class V4L2Device : protected Loggable
+class V4L2Device : public V4L2Base, protected Loggable
 {
 public:
 	explicit V4L2Device(const std::string &deviceNode);
@@ -121,9 +122,8 @@  public:
 
 	V4L2Device &operator=(const V4L2Device &) = delete;
 
-	int open();
-	bool isOpen() const;
-	void close();
+	int open() override;
+	void close() override;
 
 	const char *driverName() const { return caps_.driver(); }
 	const char *deviceName() const { return caps_.card(); }
@@ -167,7 +167,6 @@  private:
 	void bufferAvailable(EventNotifier *notifier);
 
 	std::string deviceNode_;
-	int fd_;
 	V4L2Capability caps_;
 
 	enum v4l2_buf_type bufferType_;
diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index 3e4e5107aebe..bdef3e69dd8c 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -16,6 +16,7 @@ 
 #include "formats.h"
 #include "log.h"
 #include "media_object.h"
+#include "v4l2_base.h"
 
 namespace libcamera {
 
@@ -28,7 +29,7 @@  struct V4L2SubdeviceFormat {
 	const std::string toString() const;
 };
 
-class V4L2Subdevice : protected Loggable
+class V4L2Subdevice : public V4L2Base, protected Loggable
 {
 public:
 	explicit V4L2Subdevice(const MediaEntity *entity);
@@ -36,9 +37,8 @@  public:
 	V4L2Subdevice &operator=(const V4L2Subdevice &) = delete;
 	~V4L2Subdevice();
 
-	int open();
-	bool isOpen() const;
-	void close();
+	int open() override;
+	void close() override;
 
 	const MediaEntity *entity() const { return entity_; }
 
@@ -64,7 +64,6 @@  private:
 			 Rectangle *rect);
 
 	const MediaEntity *entity_;
-	int fd_;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
index 6a73580d71f5..6d858a22531e 100644
--- a/src/libcamera/meson.build
+++ b/src/libcamera/meson.build
@@ -21,6 +21,7 @@  libcamera_sources = files([
     'stream.cpp',
     'timer.cpp',
     'utils.cpp',
+    'v4l2_base.cpp',
     'v4l2_device.cpp',
     'v4l2_subdevice.cpp',
 ])
@@ -38,6 +39,7 @@  libcamera_headers = files([
     'include/media_object.h',
     'include/pipeline_handler.h',
     'include/utils.h',
+    'include/v4l2_base.h',
     'include/v4l2_device.h',
     'include/v4l2_subdevice.h',
 ])
diff --git a/src/libcamera/v4l2_base.cpp b/src/libcamera/v4l2_base.cpp
new file mode 100644
index 000000000000..7d05a3c82e4d
--- /dev/null
+++ b/src/libcamera/v4l2_base.cpp
@@ -0,0 +1,64 @@ 
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * v4l2_base.cpp - Common base for V4L2 devices and subdevices
+ */
+
+#include "v4l2_base.h"
+
+/**
+ * \file v4l2_base.h
+ * \brief Common base for V4L2 devices and subdevices
+ */
+
+namespace libcamera {
+
+/**
+ * \class V4L2Base
+ * \brief Base class for V4L2Device and V4L2Subdevice
+ *
+ * The V4L2Base class groups together the methods and fields common to
+ * both V4L2Device and V4L2Subdevice, and provide a base abstract class which
+ * defines a streamlined interface that both the derived class have to implement.
+ *
+ * The interface defined by V4L2Base only requires derived classes to implement
+ * methods that modifies the status of the file descriptor associated with
+ * the video device or subdevice, such as \a open() and \a close().
+ *
+ * Methods common to V4L2Device and V4L2Subdevice, such as V4L2 controls
+ * support are implemented in the base class to maximize code re-use.
+ */
+
+/**
+ * \brief Open a V4L2 device or subdevice
+ *
+ * Pure virtual method to be implemented by the derived classes.
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+
+/**
+ * \brief Close the device or subdevice
+ *
+ * Pure virtual method to be implemented by the derived classes.
+ */
+
+/**
+ * \brief Check if the V4L2 device or subdevice is open
+ * \return True if the V4L2 device or subdevice is open, false otherwise
+ */
+bool V4L2Base::isOpen() const
+{
+	return fd_ != -1;
+}
+
+/**
+ * \var V4L2Base::fd_
+ * \brief The V4L2 device or subdevice device node file descriptor
+ *
+ * The file descriptor is initialized to -1 and reset to this value once
+ * the device or subdevice gets closed.
+ */
+
+}; /* namespace libcamera */
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 0821bd75fb42..64533e88a512 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -270,9 +270,11 @@  const std::string V4L2DeviceFormat::toString() const
  * \param[in] deviceNode The file-system path to the video device node
  */
 V4L2Device::V4L2Device(const std::string &deviceNode)
-	: deviceNode_(deviceNode), fd_(-1), bufferPool_(nullptr),
+	: deviceNode_(deviceNode), bufferPool_(nullptr),
 	  queuedBuffersCount_(0), fdEvent_(nullptr)
 {
+	fd_ = -1;
+
 	/*
 	 * We default to an MMAP based CAPTURE device, however this will be
 	 * updated based upon the device capabilities.
@@ -368,15 +370,6 @@  int V4L2Device::open()
 	return 0;
 }
 
-/**
- * \brief Check if device is successfully opened
- * \return True if the device is open, false otherwise
- */
-bool V4L2Device::isOpen() const
-{
-	return fd_ != -1;
-}
-
 /**
  * \brief Close the device, releasing any resources acquired by open()
  */
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index fceee33156e9..3a053fadb3f6 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -102,8 +102,9 @@  const std::string V4L2SubdeviceFormat::toString() const
  * path
  */
 V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
-	: entity_(entity), fd_(-1)
+	: entity_(entity)
 {
+	fd_ = -1;
 }
 
 V4L2Subdevice::~V4L2Subdevice()
@@ -137,15 +138,6 @@  int V4L2Subdevice::open()
 	return 0;
 }
 
-/**
- * \brief Check if the subdevice is open
- * \return True if the subdevice is open, false otherwise
- */
-bool V4L2Subdevice::isOpen() const
-{
-	return fd_ != -1;
-}
-
 /**
  * \brief Close the subdevice, releasing any resources acquired by open()
  */