libcamera: Add ControlValidator

The new abstract ControlValidator class defines an interface that will
be used by the ControlList class to validate controls. This will allow
controls to the validated against different object types, such as Camera
and V4L2Device.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

4 files changed, 74 insertions, 0 deletions

diff --git a/src/libcamera/control_validator.cpp b/src/libcamera/control_validator.cpp
new file mode 100644
index 00000000..8e5cf3c3
--- /dev/null
+++ b/src/libcamera/control_validator.cpp
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * control_validator.cpp - Control validator
+ */
+
+#include "control_validator.h"
+
+/**
+ * \file control_validator.h
+ * \brief Abstract control validator
+ */
+
+namespace libcamera {
+
+/**
+ * \class ControlValidator
+ * \brief Interface for the control validator
+ *
+ * The ControlValidator class is used by the ControlList class to validate
+ * controls added to the list. It is an abstract class providing an interface
+ * for object-specific control validation, such a Camera controls and V4L2
+ * controls.
+ */
+
+/**
+ * \fn ControlValidator::name()
+ * \brief Retrieve the name of the object associated with the validator
+ * \return The name of the object associated with the validator
+ */
+
+/**
+ * \fn ControlValidator::validate()
+ * \brief Validate a control
+ * \param[in] id The control ID
+ *
+ * This method validates the control \a id against the object corresponding to
+ * the validator. It shall at least validate that the control is applicable to
+ * the object instance, and may perform additional checks.
+ *
+ * \return True if the control is valid, false otherwise
+ */
+
+} /* namespace libcamera */
diff --git a/src/libcamera/include/control_validator.h b/src/libcamera/include/control_validator.h
new file mode 100644
index 00000000..3598b18f
--- /dev/null
+++ b/src/libcamera/include/control_validator.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * control_validator.h - Control validator
+ */
+#ifndef __LIBCAMERA_CONTROL_VALIDATOR_H__
+#define __LIBCAMERA_CONTROL_VALIDATOR_H__
+
+#include <string>
+
+namespace libcamera {
+
+class ControlId;
+
+class ControlValidator
+{
+public:
+	virtual ~ControlValidator() {}
+
+	virtual const std::string &name() const = 0;
+	virtual bool validate(const ControlId &id) const = 0;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_CONTROL_VALIDATOR_H__ */
diff --git a/src/libcamera/include/meson.build b/src/libcamera/include/meson.build
index 933be854..1cf47204 100644
--- a/src/libcamera/include/meson.build
+++ b/src/libcamera/include/meson.build
@@ -1,5 +1,6 @@
 libcamera_headers = files([
     'camera_sensor.h',
+    'control_validator.h',
     'device_enumerator.h',
     'device_enumerator_sysfs.h',
     'device_enumerator_udev.h',
diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
index f0795bbd..be845b48 100644
--- a/src/libcamera/meson.build
+++ b/src/libcamera/meson.build
@@ -5,6 +5,7 @@ libcamera_sources = files([
     'camera_manager.cpp',
     'camera_sensor.cpp',
     'controls.cpp',
+    'control_validator.cpp',
     'device_enumerator.cpp',
     'device_enumerator_sysfs.cpp',
     'event_dispatcher.cpp',