[PATCH v2 3/4] libcamera: controls: Add support for querying direction information

Paul Elder paul.elder at ideasonboard.com
Wed Nov 27 09:50:16 CET 2024


Add support to ControlId for querying direction information. This allows
applications to query whether a ControlId is meant for being set in
controls or to be returned in metadata or both. This also has a side
effect of properly encoding this information, as previously it was only
mentioned losely and inconsistently in the control id definition.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
Changes in v2:
- simplify code
---
 include/libcamera/controls.h     | 20 ++++++++++++++-
 src/libcamera/control_ids.cpp.in |  4 +--
 src/libcamera/controls.cpp       | 43 ++++++++++++++++++++++++++++++--
 3 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
index 3cfe2de5973c..74a566a05db4 100644
--- a/include/libcamera/controls.h
+++ b/include/libcamera/controls.h
@@ -17,6 +17,7 @@
 #include <vector>
 
 #include <libcamera/base/class.h>
+#include <libcamera/base/flags.h>
 #include <libcamera/base/span.h>
 
 #include <libcamera/geometry.h>
@@ -235,8 +236,18 @@ private:
 class ControlId
 {
 public:
+	enum class Direction {
+		In = (1 << 0),
+		Out = (1 << 1),
+	};
+
+	using DirectionFlags = Flags<Direction>;
+
 	ControlId(unsigned int id, const std::string &name, const std::string &vendor,
 		  ControlType type, std::size_t size = 0,
+		  DirectionFlags direction =
+			  static_cast<DirectionFlags>(Direction::In) |
+			  static_cast<DirectionFlags>(Direction::Out),
 		  const std::map<std::string, int32_t> &enumStrMap = {});
 
 	unsigned int id() const { return id_; }
@@ -245,6 +256,8 @@ public:
 	ControlType type() const { return type_; }
 	bool isArray() const { return size_ > 0; }
 	std::size_t size() const { return size_; }
+	bool isInput() const { return !!(direction_ & Direction::In); }
+	bool isOutput() const { return !!(direction_ & Direction::Out); }
 	const std::map<int32_t, std::string> &enumerators() const { return reverseMap_; }
 
 private:
@@ -255,10 +268,13 @@ private:
 	std::string vendor_;
 	ControlType type_;
 	std::size_t size_;
+	DirectionFlags direction_;
 	std::map<std::string, int32_t> enumStrMap_;
 	std::map<int32_t, std::string> reverseMap_;
 };
 
+LIBCAMERA_FLAGS_ENABLE_OPERATORS(ControlId::Direction)
+
 static inline bool operator==(unsigned int lhs, const ControlId &rhs)
 {
 	return lhs == rhs.id();
@@ -286,9 +302,11 @@ public:
 	using type = T;
 
 	Control(unsigned int id, const char *name, const char *vendor,
+		ControlId::DirectionFlags direction = ControlId::Direction::In
+						    | ControlId::Direction::Out,
 		const std::map<std::string, int32_t> &enumStrMap = {})
 		: ControlId(id, name, vendor, details::control_type<std::remove_cv_t<T>>::value,
-			    details::control_type<std::remove_cv_t<T>>::size, enumStrMap)
+			    details::control_type<std::remove_cv_t<T>>::size, direction, enumStrMap)
 	{
 	}
 
diff --git a/src/libcamera/control_ids.cpp.in b/src/libcamera/control_ids.cpp.in
index afe9e2c96610..65668d486dbc 100644
--- a/src/libcamera/control_ids.cpp.in
+++ b/src/libcamera/control_ids.cpp.in
@@ -89,9 +89,9 @@ extern const std::map<std::string, {{ctrl.type}}> {{ctrl.name}}NameValueMap = {
 	{ "{{enum.name}}", {{enum.name}} },
 {%- endfor %}
 };
-extern const Control<{{ctrl.type}}> {{ctrl.name}}({{ctrl.name|snake_case|upper}}, "{{ctrl.name}}", "{{vendor}}", {{ctrl.name}}NameValueMap);
+extern const Control<{{ctrl.type}}> {{ctrl.name}}({{ctrl.name|snake_case|upper}}, "{{ctrl.name}}", "{{vendor}}", {{ctrl.direction}}, {{ctrl.name}}NameValueMap);
 {% else -%}
-extern const Control<{{ctrl.type}}> {{ctrl.name}}({{ctrl.name|snake_case|upper}}, "{{ctrl.name}}", "{{vendor}}");
+extern const Control<{{ctrl.type}}> {{ctrl.name}}({{ctrl.name|snake_case|upper}}, "{{ctrl.name}}", "{{vendor}}", {{ctrl.direction}});
 {% endif -%}
 {%- endfor %}
 
diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
index 2efecf0fc52b..f221a7e621ab 100644
--- a/src/libcamera/controls.cpp
+++ b/src/libcamera/controls.cpp
@@ -397,14 +397,15 @@ void ControlValue::reserve(ControlType type, bool isArray, std::size_t numElemen
  * \param[in] vendor The vendor name
  * \param[in] type The control data type
  * \param[in] size The size of the array control, or 0 if scalar control
+ * \param[in] direction The direction of the control, if it can be used in Controls or Metadata
  * \param[in] enumStrMap The map from enum names to values (optional)
  */
 ControlId::ControlId(unsigned int id, const std::string &name,
 		     const std::string &vendor, ControlType type,
-		     std::size_t size,
+		     std::size_t size, DirectionFlags direction,
 		     const std::map<std::string, int32_t> &enumStrMap)
 	: id_(id), name_(name), vendor_(vendor), type_(type), size_(size),
-	  enumStrMap_(enumStrMap)
+	  direction_(direction), enumStrMap_(enumStrMap)
 {
 	for (const auto &pair : enumStrMap_)
 		reverseMap_[pair.second] = pair.first;
@@ -440,6 +441,26 @@ ControlId::ControlId(unsigned int id, const std::string &name,
  * \return True if the control is an array control, false otherwise
  */
 
+/**
+ * \fn bool ControlId::isInput() const
+ * \brief Determine if the control is available to be used as an input control
+ *
+ * Controls can be used either as input as a control, or as output in metadata.
+ * This function checks if the control is allowed to be used as the former.
+ *
+ * \return True if the control can be used as an input control, false otherwise
+ */
+
+/**
+ * \fn bool ControlId::isOutput() const
+ * \brief Determine if the control is available to be used in output metadata
+ *
+ * Controls can be used either as input as a control, or as output in metadata.
+ * This function checks if the control is allowed to be used as the latter.
+ *
+ * \return True if the control can be returned in output metadata, false otherwise
+ */
+
 /**
  * \fn std::size_t ControlId::size() const
  * \brief Retrieve the size of the control if it is an array control
@@ -471,6 +492,22 @@ ControlId::ControlId(unsigned int id, const std::string &name,
  * \return True if \a lhs.id() is equal to \a rhs, false otherwise
  */
 
+/**
+ * \enum ControlId::Direction
+ * \brief The direction that a control of the ControlId is capable of being passed from/to
+ *
+ * \var ControlId::Direction::In
+ * \brief The control can be passed as input in controls
+ *
+ * \var ControlId::Direction::Out
+ * \brief The control can be returned as output in metadata
+ */
+
+/**
+ * \typedef ControlId::DirectionFlags
+ * \brief A wrapper for ControlId::Direction so that it can be used as flags
+ */
+
 /**
  * \class Control
  * \brief Describe a control and its intrinsic properties
@@ -504,6 +541,8 @@ ControlId::ControlId(unsigned int id, const std::string &name,
  * \param[in] id The control numerical ID
  * \param[in] name The control name
  * \param[in] vendor The vendor name
+ * \param[in] direction The direction of the control, if it can be used in
+ * Controls or Metadata
  * \param[in] enumStrMap The map from enum names to values (optional)
  *
  * The control data type is automatically deduced from the template type T.
-- 
2.39.2



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