[libcamera-devel] [PATCH 2/9] libcamera: controls: Support getting and setting controls by ControlId

[Laurent Pinchart]

The ControlList class has template get() and set() methods to get and
set control values. The methods require a reference to a Control
instance, which is only available when calling them with a hardcoded
control. In order to support serialisation and deserialisation of
ControlList, we need a way to get and set control values based on a
ControlId. Add new get() and set() overload methods to do so.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 include/libcamera/controls.h |  3 +++
 src/libcamera/controls.cpp   | 46 ++++++++++++++++++++++++++++++++++--
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
index 90426753f40f..49ff1a6f747f 100644
--- a/include/libcamera/controls.h
+++ b/include/libcamera/controls.h
@@ -156,6 +156,9 @@ public:
 		val->set<T>(value);
 	}
 
+	const ControlValue &get(const ControlId &id) const;
+	void set(const ControlId &id, const ControlValue &value);
+
 private:
 	const ControlValue *find(const ControlId &id) const;
 	ControlValue *find(const ControlId &id);
diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
index f3260edce0bc..f862a09adef9 100644
--- a/src/libcamera/controls.cpp
+++ b/src/libcamera/controls.cpp
@@ -445,7 +445,7 @@ bool ControlList::contains(const ControlId &id) const
  */
 
 /**
- * \fn template<typename T> const T &ControlList::get() const
+ * \fn template<typename T> const T &ControlList::get(const Control<T> &ctrl) const
  * \brief Get the value of a control
  * \param[in] ctrl The control
  *
@@ -460,7 +460,7 @@ bool ControlList::contains(const ControlId &id) const
  */
 
 /**
- * \fn template<typename T> void ControlList::set()
+ * \fn template<typename T> void ControlList::set(const Control< T > &ctrl, const T &value)
  * \brief Set the control value to \a value
  * \param[in] ctrl The control
  * \param[in] value The control value
@@ -473,6 +473,48 @@ bool ControlList::contains(const ControlId &id) const
  * camera that the list refers to.
  */
 
+/**
+ * \brief Get the value of control \a id
+ * \param[in] id The control ID
+ *
+ * The behaviour is undefined if the control \a id is not present in the list.
+ * Use ControlList::contains() to test for the presence of a control in the
+ * list before retrieving its value.
+ *
+ * \return The control value
+ */
+const ControlValue &ControlList::get(const ControlId &id) const
+{
+	const ControlValue *val = find(id);
+	if (!val) {
+		static ControlValue zero;
+		return zero;
+	}
+
+	return *val;
+}
+
+/**
+ * \brief Set the value of control \a id to \a value
+ * \param[in] id The control ID
+ * \param[in] value The control value
+ *
+ * This method sets the value of a control in the control list. If the control
+ * is already present in the list, its value is updated, otherwise it is added
+ * to the list.
+ *
+ * The behaviour is undefined if the control \a ctrl is not supported by the
+ * camera that the list refers to.
+ */
+void ControlList::set(const ControlId &id, const ControlValue &value)
+{
+	ControlValue *val = find(id);
+	if (!val)
+		return;
+
+	*val = value;
+}
+
 const ControlValue *ControlList::find(const ControlId &id) const
 {
 	const auto iter = controls_.find(&id);
-- 
Regards,

Laurent Pinchart