Add SerdNodes class for storing a cache of nodes

1 files changed, 60 insertions, 0 deletions

diff --git a/include/serd/serd.h b/include/serd/serd.h
index 09017175..7c1ff057 100644
--- a/include/serd/serd.h
+++ b/include/serd/serd.h
@@ -84,6 +84,9 @@ extern "C" {
 /// Global library state
 typedef struct SerdWorldImpl SerdWorld;
 
+/// Hashing node container for interning and simplified memory management
+typedef struct SerdNodesImpl SerdNodes;
+
 /// A subject, predicate, and object, with optional graph context
 typedef struct SerdStatementImpl SerdStatement;
 
@@ -1339,6 +1342,63 @@ serd_writer_finish(SerdWriter* SERD_NONNULL writer);
 
 /**
    @}
+   @defgroup serd_nodes Nodes
+   @{
+*/
+
+/// Create a new node set
+SERD_API
+SerdNodes* SERD_ALLOCATED
+serd_nodes_new(void);
+
+/**
+   Free `nodes` and all nodes that are stored in it.
+
+   Note that this invalidates any pointers previously returned from
+   `serd_nodes_intern()` or `serd_nodes_manage()` calls on `nodes`.
+*/
+SERD_API
+void
+serd_nodes_free(SerdNodes* SERD_NULLABLE nodes);
+
+/**
+   Intern `node`.
+
+   Multiple calls with equivalent nodes will return the same pointer.
+
+   @return A node that is different than, but equivalent to, `node`.
+*/
+SERD_API
+const SerdNode* SERD_ALLOCATED
+serd_nodes_intern(SerdNodes* SERD_NONNULL       nodes,
+                  const SerdNode* SERD_NULLABLE node);
+
+/**
+   Manage `node`.
+
+   Like `serd_nodes_intern`, but takes ownership of `node`, freeing it and
+   returning a previously interned/managed equivalent node if necessary.
+
+   @return A node that is equivalent to `node`.
+*/
+SERD_API
+const SerdNode* SERD_ALLOCATED
+serd_nodes_manage(SerdNodes* SERD_NONNULL nodes, SerdNode* SERD_NULLABLE node);
+
+/**
+   Dereference `node`.
+
+   Decrements the reference count of `node`, and frees the internally stored
+   equivalent node if this was the last reference.  Does nothing if no node
+   equivalent to `node` is stored in `nodes`.
+*/
+SERD_API
+void
+serd_nodes_deref(SerdNodes* SERD_NONNULL      nodes,
+                 const SerdNode* SERD_NONNULL node);
+
+/**
+   @}
    @defgroup serd_statement Statement
    @{
 */