libcamera: control_ids: Generate map of all supported controls

In order to deserialise a ControlList, we will need to lookup ControlId
instances based on their numerical ID. Generate a global map from the
controls definitions to support such a lookup.

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

include/libcamera/control_ids.h.in

@@ -24,6 +24,8 @@ ${ids}
 
 ${controls}
 
+extern const ControlIdMap controls;
+
 } /* namespace controls */
 
 } /* namespace libcamera */

include/libcamera/controls.h

@@ -111,6 +111,7 @@ private:
 	ControlValue max_;
 };
 
+using ControlIdMap = std::unordered_map<unsigned int, const ControlId *>;
 using ControlInfoMap = std::unordered_map<const ControlId *, ControlRange>;
 
 class ControlList

src/libcamera/control_ids.cpp.in

@@ -31,6 +31,13 @@ ${controls_doc}
 ${controls_def}
 #endif
 
+/**
+ * \brief List of all supported libcamera controls
+ */
+extern const ControlIdMap controls {
+${controls_map}
+};
+
 } /* namespace controls */
 
 } /* namespace libcamera */

src/libcamera/controls.cpp

@@ -355,6 +355,15 @@ std::string ControlRange::toString() const
 	return ss.str();
 }
 
+/**
+ * \typedef ControlIdMap
+ * \brief A map of numerical control ID to ControlId
+ *
+ * The map is used by ControlList instances to access controls by numerical
+ * IDs. A global map of all libcamera controls is provided by
+ * controls::controls.
+ */
+
 /**
  * \typedef ControlInfoMap
  * \brief A map of ControlId to ControlRange

src/libcamera/gen-controls.py

@@ -25,6 +25,7 @@ ${description}
 
     ctrls_doc = []
     ctrls_def = []
+    ctrls_map = []
 
     for ctrl in controls:
         name, ctrl = ctrl.popitem()
@@ -43,10 +44,12 @@ ${description}
 
         ctrls_doc.append(doc_template.substitute(info))
         ctrls_def.append(def_template.substitute(info))
+        ctrls_map.append('\t{ ' + id_name + ', &' + name + ' },')
 
     return {
         'controls_doc': '\n\n'.join(ctrls_doc),
         'controls_def': '\n'.join(ctrls_def),
+        'controls_map': '\n'.join(ctrls_map),
     }