libcamera: v4l2_device: Replace V4L2ControlList with ControlList

The V4L2Device class uses V4L2ControlList as a controls container for
the getControls() and setControls() operations. Having a distinct
container from ControlList will makes the IPA API more complex, as it
needs to explicitly transport both types of lists. This will become even
more painful when implementing serialisation and deserialisation.

To simplify the IPA API and ease the implementation of serialisation and
deserialisation, replace usage of V4L2ControlList with ControlList in
the V4L2Device (and thus CameraSensor) API. The V4L2ControlList class
becomes a thin wrapper around ControlList that slightly simplifies the
creation of control lists for V4L2 controls, and may be removed in the
future.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

1 files changed, 22 insertions, 174 deletions

diff --git a/src/libcamera/v4l2_controls.cpp b/src/libcamera/v4l2_controls.cpp
index 3be21997..c45d3fda 100644
--- a/src/libcamera/v4l2_controls.cpp
+++ b/src/libcamera/v4l2_controls.cpp
@@ -40,7 +40,7 @@
  * sizes.
  *
  * The libcamera V4L2 Controls framework operates on lists of controls, wrapped
- * by the V4L2ControlList class, to match the V4L2 extended controls API. The
+ * by the ControlList class, to match the V4L2 extended controls API. The
  * interface to set and get control is implemented by the V4L2Device class, and
  * this file only provides the data type definitions.
  *
@@ -175,194 +175,42 @@ V4L2ControlInfoMap &V4L2ControlInfoMap::operator=(std::map<unsigned int, V4L2Con
 {
 	std::map<unsigned int, V4L2ControlInfo>::operator=(std::move(info));
 
+	idmap_.clear();
+	for (const auto &ctrl : *this)
+		idmap_[ctrl.first] = &ctrl.second.id();
+
 	return *this;
 }
 
 /**
- * \class V4L2Control
- * \brief A V4L2 control value
- *
- * The V4L2Control class represent the value of a V4L2 control. The class
- * stores values that have been read from or will be applied to a V4L2 device.
- *
- * The value stored in the class instances does not reflect what is actually
- * applied to the hardware but is a pure software cache optionally initialized
- * at control creation time and modified by a control read or write operation.
+ * \fn const ControlIdMap &V4L2ControlInfoMap::idmap() const
+ * \brief Retrieve the ControlId map
  *
- * The write and read controls the V4L2Control class instances are not meant
- * to be directly used but are instead intended to be grouped in
- * V4L2ControlList instances, which are then passed as parameters to
- * V4L2Device::setControls() and V4L2Device::getControls() operations.
- */
-
-/**
- * \fn V4L2Control::V4L2Control
- * \brief Construct a V4L2 control with \a id and \a value
- * \param id The V4L2 control ID
- * \param value The control value
- */
-
-/**
- * \fn V4L2Control::value() const
- * \brief Retrieve the value of the control
+ * Constructing ControlList instances for V4L2 controls requires a ControlIdMap
+ * for the V4L2 device that the control list targets. This helper method
+ * returns a suitable idmap for that purpose.
  *
- * This method is a const version of V4L2Control::value(), returning a const
- * reference to the value.
- *
- * \return The V4L2 control value
- */
-
-/**
- * \fn V4L2Control::value()
- * \brief Retrieve the value of the control
- *
- * This method returns the cached control value, initially set by
- * V4L2ControlList::add() and then updated when the controls are read or
- * written with V4L2Device::getControls() and V4L2Device::setControls().
- *
- * \return The V4L2 control value
- */
-
-/**
- * \fn V4L2Control::id()
- * \brief Retrieve the control ID this instance refers to
- * \return The V4L2Control ID
+ * \return The ControlId map
  */
 
 /**
  * \class V4L2ControlList
- * \brief Container of V4L2Control instances
- *
- * The V4L2ControlList class works as a container for a list of V4L2Control
- * instances. The class provides operations to add a new control to the list,
- * get back a control value, and reset the list of controls it contains.
- *
- * In order to set and get controls, user of the libcamera V4L2 control
- * framework should operate on instances of the V4L2ControlList class, and use
- * them as argument for the V4L2Device::setControls() and
- * V4L2Device::getControls() operations, which write and read a list of
- * controls to or from a V4L2 device (a video device or a subdevice).
- *
- * Controls are added to a V4L2ControlList instance with the add() method, with
- * or without a value.
- *
- * To write controls to a device, the controls of interest shall be added with
- * an initial value by calling V4L2ControlList::add(unsigned int id, int64_t
- * value) to prepare for a write operation. Once the values of all controls of
- * interest have been added, the V4L2ControlList instance is passed to the
- * V4L2Device::setControls(), which sets the controls on the device.
+ * \brief A list of controls for a V4L2 device
  *
- * To read controls from a device, the desired controls are added with
- * V4L2ControlList::add(unsigned int id) to prepare for a read operation. The
- * V4L2ControlList instance is then passed to V4L2Device::getControls(), which
- * reads the controls from the device and updates the values stored in
- * V4L2ControlList.
+ * This class specialises the ControList class for use with V4L2 devices. It
+ * offers a convenience API to create a ControlList from a V4L2ControlInfoMap.
  *
- * V4L2ControlList instances can be reset to remove all controls they contain
- * and prepare to be re-used for a new control write/read sequence.
- */
-
-/**
- * \typedef V4L2ControlList::iterator
- * \brief Iterator on the V4L2 controls contained in the instance
- */
-
-/**
- * \typedef V4L2ControlList::const_iterator
- * \brief Const iterator on the V4L2 controls contained in the instance
- */
-
-/**
- * \fn iterator V4L2ControlList::begin()
- * \brief Retrieve an iterator to the first V4L2Control in the instance
- * \return An iterator to the first V4L2 control
- */
-
-/**
- * \fn const_iterator V4L2ControlList::begin() const
- * \brief Retrieve a constant iterator to the first V4L2Control in the instance
- * \return A constant iterator to the first V4L2 control
+ * V4L2ControlList allows easy construction of a ControlList containing V4L2
+ * controls for a device. It can be used to construct the list of controls
+ * passed to the V4L2Device::getControls() and V4L2Device::setControls()
+ * methods. The class should however not be used in place of ControlList in
+ * APIs.
  */
 
 /**
- * \fn iterator V4L2ControlList::end()
- * \brief Retrieve an iterator pointing to the past-the-end V4L2Control in the
- * instance
- * \return An iterator to the element following the last V4L2 control in the
- * instance
+ * \fn V4L2ControlList::V4L2ControlList(const V4L2ControlInfoMap &info)
+ * \brief Construct a V4L2ControlList associated with a V4L2 device
+ * \param[in] info The V4L2 device control info map
  */
 
-/**
- * \fn const_iterator V4L2ControlList::end() const
- * \brief Retrieve a constant iterator pointing to the past-the-end V4L2Control
- * in the instance
- * \return A constant iterator to the element following the last V4L2 control
- * in the instance
- */
-
-/**
- * \fn V4L2ControlList::empty()
- * \brief Verify if the instance does not contain any control
- * \return True if the instance does not contain any control, false otherwise
- */
-
-/**
- * \fn V4L2ControlList::size()
- * \brief Retrieve the number on controls in the instance
- * \return The number of V4L2Control stored in the instance
- */
-
-/**
- * \fn V4L2ControlList::clear()
- * \brief Remove all controls in the instance
- */
-
-/**
- * \brief Add control with \a id and optional \a value to the instance
- * \param id The V4L2 control ID (V4L2_CID_*)
- * \param value The V4L2 control value
- *
- * This method adds a new V4L2 control to the V4L2ControlList. The newly
- * inserted control shall not already be present in the control lists, otherwise
- * this method, and further use of the control list lead to undefined behaviour.
- */
-void V4L2ControlList::add(unsigned int id, int64_t value)
-{
-	controls_.emplace_back(id, value);
-}
-
-/**
- * \brief Retrieve the control at \a index
- * \param[in] index The control index
- *
- * Controls are stored in a V4L2ControlList in order of insertion and this
- * method retrieves the control at \a index.
- *
- * \return A pointer to the V4L2Control at \a index or nullptr if the
- * index is larger than the number of controls
- */
-V4L2Control *V4L2ControlList::getByIndex(unsigned int index)
-{
-	if (index >= controls_.size())
-		return nullptr;
-
-	return &controls_[index];
-}
-
-/**
- * \brief Retrieve the control with \a id
- * \param[in] id The V4L2 control ID (V4L2_CID_xx)
- * \return A pointer to the V4L2Control with \a id or nullptr if the
- * control ID is not part of this instance.
- */
-V4L2Control *V4L2ControlList::operator[](unsigned int id)
-{
-	for (V4L2Control &ctrl : controls_) {
-		if (ctrl.id() == id)
-			return &ctrl;
-	}
-
-	return nullptr;
-}
-
 } /* namespace libcamera */