From 800f2d0d4960061a1739a36d8b608a13896b321e Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Sun, 28 Oct 2018 14:00:47 +0100
Subject: Add SerdNodes class for storing a cache of nodes

---
 include/serd/serd.h | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

(limited to 'include/serd/serd.h')

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;
 
@@ -1337,6 +1340,63 @@ SERD_API
 SerdStatus
 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
-- 
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