controls: Add boolean constructors for ControlInfo

It would be convenient to be able to iterate over available boolean
values, for example for controls that designate if some function can be
enabled/disabled. The current min/max/def constructor is insufficient,
as .values() is empty, so the values cannot be easily iterated over, and
creating a Span of booleans does not work for the values constructor.

Add new constructors to ControlInfo that takes a set of booleans (if
both booleans are valid values) plus a default, and another that takes
only one boolean (if only one boolean is a valid value).

Update the ControlInfo test accordingly.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/controls.cpp

@@ -514,6 +514,35 @@ ControlInfo::ControlInfo(Span<const ControlValue> values,
 		values_.push_back(value);
 }
 
+/**
+ * \brief Construct a boolean ControlInfo with both boolean values
+ * \param[in] values The control valid boolean values (both true and false)
+ * \param[in] def The control default boolean value
+ *
+ * Construct a ControlInfo for a boolean control, where both true and false are
+ * valid values. \a values must be { false, true } (the order is irrelevant).
+ * The minimum value will always be false, and the maximum always true. The
+ * default value is \a def.
+ */
+ControlInfo::ControlInfo(std::set<bool> values, bool def)
+	: min_(false), max_(true), def_(def), values_({ false, true })
+{
+	assert(values.count(def) && values.size() == 2);
+}
+
+/**
+ * \brief Construct a boolean ControlInfo with only one valid value
+ * \param[in] value The control valid boolean value
+ *
+ * Construct a ControlInfo for a boolean control, where there is only valid
+ * value. The minimum, maximum, and default values will all be \a value.
+ */
+ControlInfo::ControlInfo(bool value)
+	: min_(value), max_(value), def_(value)
+{
+	values_ = { value };
+}
+
 /**
  * \fn ControlInfo::min()
  * \brief Retrieve the minimum value of the control