[libcamera-devel] [RFC PATCH v2 5/9] libcamera: Implement a ControlList

[Niklas Söderlund]

Hi Kieran,

Thanks for your patch.

On 2019-06-21 17:13:57 +0100, Kieran Bingham wrote:
> Define a ControlList which wraps the STL std::unordered_map to contain
> a list of associative pairs of ControlInfo and Value items.
> 
> A ControlInfo (or represented by its ControlId) together with a Value
> provide a control item which can be interpreted by the internal IPA and
> PipelineHandler components.
> 
> To pass a set of controls around, a ControlList  can be added to a
> Request or stored locally to establish a set of default values for later
> reuse.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
>  include/libcamera/controls.h |  41 +++++++++++
>  src/libcamera/controls.cpp   | 128 +++++++++++++++++++++++++++++++++++
>  2 files changed, 169 insertions(+)
> 
> diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
> index 95198d41c4cf..5835b840a31b 100644
> --- a/include/libcamera/controls.h
> +++ b/include/libcamera/controls.h
> @@ -4,6 +4,9 @@
>   *
>   * controls.h - Control handling
>   */
> +
> +#include <unordered_map>
> +
>  #ifndef __LIBCAMERA_CONTROLS_H__
>  #define __LIBCAMERA_CONTROLS_H__
>  
> @@ -53,6 +56,44 @@ private:
>  
>  std::ostream &operator<<(std::ostream &stream, const ControlInfo &value);
>  
> +class ControlList
> +{
> +private:
> +	struct ControlInfoHasher {
> +		std::size_t operator()(const ControlInfo &ci) const
> +		{
> +			return std::hash<int>()(ci.id());
> +		}
> +	};
> +
> +	typedef std::unordered_map<ControlInfo, Value, ControlInfoHasher> ControlListMap;

Is this needed to go first or can it be moved down to the other private 
section?

> +
> +public:
> +	ControlList();
> +
> +	using iterator = ControlListMap::iterator;
> +	using const_iterator = ControlListMap::const_iterator;
> +
> +	iterator begin() { return controls_.begin(); }
> +	iterator end() { return controls_.end(); }
> +	const_iterator begin() const { return controls_.begin(); }
> +	const_iterator end() const { return controls_.end(); }
> +
> +	bool contains(ControlId id) const { return controls_.count(id); };

Would not return controls_.find(id) != controls_.end() be better?

> +	bool empty() const { return controls_.empty(); }
> +	size_t size() const { return controls_.size(); }
> +	void reset() { controls_.clear(); }
> +
> +	Value &operator[](ControlId id) { return controls_[id]; }
> +
> +	void update(const ControlList &list);
> +	void update(enum ControlId id, const Value &value);
> +	void update(const ControlInfo &info, const Value &value);
> +
> +private:
> +	ControlListMap controls_;
> +};
> +
>  } /* namespace libcamera */
>  
>  #endif /* __LIBCAMERA_CONTROLS_H__ */
> diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> index b1be46ddb55e..7c55afffe4ca 100644
> --- a/src/libcamera/controls.cpp
> +++ b/src/libcamera/controls.cpp
> @@ -157,4 +157,132 @@ std::ostream &operator<<(std::ostream &stream, const ControlInfo &info)
>  	return stream << info.toString();
>  }
>  
> +/**
> + * \class ControlList
> + * \brief Associates a list of ControlIds with their values.
> + *
> + * The ControlList stores a pair of ControlInfo and Value classes as an
> + * unordered map. Entries can be updated using array syntax such as
> + *   myControlList[MyControlId] = myValue;
> + * or
> + *   myNewValue = myControlList[MyControlId];

I don't think this will update the value.

I think you can drop the examples and the last sentence from the 
documentation.

With these issues addressed,

Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

> + */
> +
> +/**
> + * \brief Construct a ControlList
> + */
> +ControlList::ControlList()
> +{
> +}
> +
> +/**
> + * \typedef ControlList::iterator
> + * \brief Iterator for the controls contained within the list.
> + */
> +
> +/**
> + * \typedef ControlList::const_iterator
> + * \brief Const iterator for the controls contained within the list.
> + */
> +
> +/**
> + * \fn iterator ControlList::begin()
> + * \brief Retrieve an iterator to the first Control in the list
> + * \return An iterator to the first Control in the list
> + */
> +
> +/**
> + * \fn iterator ControlList::end()
> + * \brief Retrieve an iterator to the next element after the last controls in
> + * the instance.
> + * \return An iterator to the element following the last control in the instance
> + */
> +
> +/**
> + * \fn const_iterator ControlList::begin() const
> + * \brief Retrieve a const_iterator to the first Control in the list
> + * \return A const_iterator to the first Control in the list
> + */
> +
> +/**
> + * \fn const_iterator ControlList::end() const
> + * \brief Retrieve a constant iterator pointing to an empty element after the
> + * \return A const iterator to the element following the last control in the
> + * instance
> + */
> +
> +/**
> + * \fn ControlList::contains()
> + * \brief Identify if the List contains a control with the specified ControlId
> + * \return True if the list contains a matching control, false otherwise
> + */
> +
> +/**
> + * \fn ControlList::empty()
> + * \brief Identify if the list is empty
> + * \return True if the list does not contain any control, false otherwise
> + */
> +
> +/**
> + * \fn ControlList::size()
> + * \brief Retrieve the number of controls in the list
> + * \return The number of Control entries stored in the list
> + */
> +
> +/**
> + * \fn ControlList::reset()
> + * \brief Removes all controls from the list
> + */
> +
> +/**
> + * \fn ControlList::operator[]()
> + * \brief Access the control with the given Id
> + * \param id The id of the control to access
> + * \return The Value of the control with a ControlId of \a Id
> + */
> +
> +/**
> + * \brief Update all Control values with the value from the given \a list
> + * \param list The list of controls to update or append to this list
> + *
> + * Update all controls in the ControlList, by the values given by \a list
> + * If the list already contains a control of this ID then it will be overwritten
> + */
> +void ControlList::update(const ControlList &list)
> +{
> +	for (auto it : list) {
> +		const ControlInfo &info = it.first;
> +		const Value &value = it.second;
> +
> +		controls_[info] = value;
> +	}
> +}
> +
> +/**
> + * \brief Update a control value in the list
> + * \param id The ControlId of the control to update
> + * \param value The new value for the updated control
> + *
> + * Set the Control value in the list to the appropriate value
> + * If the list already contains a control of this ID then it will be overwritten
> + */
> +void ControlList::update(enum ControlId id, const Value &value)
> +{
> +	controls_[id] = value;
> +}
> +
> +/**
> + * \brief Update a control value in the list.
> + * \param info The ControlInfo of the control to update
> + * \param value The new value for the updated control
> + *
> + * Set the Control value in the list to the appropriate value.
> + * If the list already contains a control of the Id matching the ControlInfo
> + * then it will be overwritten.
> + */
> +void ControlList::update(const ControlInfo &info, const Value &value)
> +{
> +	controls_[info] = value;
> +}
> +
>  } /* namespace libcamera */
> -- 
> 2.20.1
> 
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-- 
Regards,
Niklas Söderlund