From b25556c691965c10b61586af8d2679acce6e39dd Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Fri, 17 Oct 2025 21:53:34 +0300
Subject: [PATCH] libcamera: value_node: Add mutable adapters
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The ValueNode class was initially designed to store read-only property
trees. It is useful to also provide mutable access. Add non-const
adapters and iterators and adapters. This allows obtaining a mutable
ValueNode instance when traversing a tree.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Isaac Scott <isaac.scott@ideasonboard.com>
---
 include/libcamera/internal/value_node.h | 32 ++++++++++++++++++-------
 src/libcamera/value_node.cpp            | 10 ++++++++
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/include/libcamera/internal/value_node.h b/include/libcamera/internal/value_node.h
index 16e6660e..b51d2f4b 100644
--- a/include/libcamera/internal/value_node.h
+++ b/include/libcamera/internal/value_node.h
@@ -143,17 +143,31 @@ public:
 		}
 	};
 
-	class DictAdapter : public Adapter<DictIterator<const ValueNode,
-							ValueContainer::const_iterator>,
-					   const ValueContainer>
+	class DictAdapter : public Adapter<DictIterator<ValueNode,
+							ValueContainer::iterator>,
+					   ValueContainer>
 	{
 	public:
 		using key_type = std::string;
 	};
 
-	class ListAdapter : public Adapter<ListIterator<const ValueNode,
-							ValueContainer::const_iterator>,
-					   const ValueContainer>
+	class ListAdapter : public Adapter<ListIterator<ValueNode,
+							ValueContainer::iterator>,
+					   ValueContainer>
+	{
+	};
+
+	class ConstDictAdapter : public Adapter<DictIterator<const ValueNode,
+							     ValueContainer::const_iterator>,
+						const ValueContainer>
+	{
+	public:
+		using key_type = std::string;
+	};
+
+	class ConstListAdapter : public Adapter<ListIterator<const ValueNode,
+							     ValueContainer::const_iterator>,
+						const ValueContainer>
 	{
 	};
 #endif /* __DOXYGEN__ */
@@ -211,8 +225,10 @@ public:
 			.set(*this, std::forward<T>(value));
 	}
 
-	DictAdapter asDict() const { return DictAdapter{ list_ }; }
-	ListAdapter asList() const { return ListAdapter{ list_ }; }
+	DictAdapter asDict() { return DictAdapter{ list_ }; }
+	ListAdapter asList() { return ListAdapter{ list_ }; }
+	ConstDictAdapter asDict() const { return ConstDictAdapter{ list_ }; }
+	ConstListAdapter asList() const { return ConstListAdapter{ list_ }; }
 
 	const ValueNode &operator[](std::size_t index) const;
 
diff --git a/src/libcamera/value_node.cpp b/src/libcamera/value_node.cpp
index cb43fa9c..6221a22a 100644
--- a/src/libcamera/value_node.cpp
+++ b/src/libcamera/value_node.cpp
@@ -337,6 +337,11 @@ template struct ValueNode::Accessor<std::vector<uint32_t>>;
 template struct ValueNode::Accessor<std::vector<std::string>>;
 #endif /* __DOXYGEN__ */
 
+/**
+ * \fn ValueNode::asDict()
+ * \copydoc ValueNode::asDict() const
+ */
+
 /**
  * \fn ValueNode::asDict() const
  * \brief Wrap a dictionary ValueNode in an adapter that exposes iterators
@@ -357,6 +362,11 @@ template struct ValueNode::Accessor<std::vector<std::string>>;
  * \return An adapter of unspecified type compatible with range-based for loops
  */
 
+/**
+ * \fn ValueNode::asList()
+ * \copydoc ValueNode::asList() const
+ */
+
 /**
  * \fn ValueNode::asList() const
  * \brief Wrap a list ValueNode in an adapter that exposes iterators