Add model and serd-sort utility

With all the new functionality, the complexity of the serd-pipe command-line
interface is starting to push the limits of available flags. So, instead of
grafting on further options to control a model, this commit adds a new tool,
serd-sort, which acts somewhat like a stripped-down serd-pipe that stores
statements in a model in memory.

This keeps the complexity (including the user-facing complexity) of any one
tool down, since other more focused tools can be used for streaming tasks in a
pipeline.

In other words, abandon Swissarmyknifeism, take a page from the Unix
philosophy, and try to expose the model functionality to the command-line in a
dedicated focused tool.  The model implementation is tested by using this tool
to run a subset of the usual test suites, and a special suite to test statement
sorting.

1 files changed, 44 insertions, 0 deletions

diff --git a/include/serd/inserter.h b/include/serd/inserter.h
new file mode 100644
index 00000000..482bff5b
--- /dev/null
+++ b/include/serd/inserter.h
@@ -0,0 +1,44 @@
+// Copyright 2011-2022 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#ifndef SERD_INSERTER_H
+#define SERD_INSERTER_H
+
+#include "serd/attributes.h"
+#include "serd/model.h"
+#include "serd/node.h"
+#include "serd/sink.h"
+#include "zix/attributes.h"
+
+SERD_BEGIN_DECLS
+
+/**
+   @defgroup serd_inserter Inserter
+   @ingroup serd_storage
+   @{
+*/
+
+/**
+   Create an inserter for writing statements to a model.
+
+   Once created, an inserter is just a sink with no additional interface.
+
+   @param model The model to insert received statements into.
+
+   @param default_graph Optional default graph, which will be set on received
+   statements that have no graph.  This allows, for example, loading a Turtle
+   document into an isolated graph in the model.
+
+   @return A newly allocated sink which must be freed with serd_sink_free().
+*/
+SERD_API SerdSink* ZIX_ALLOCATED
+serd_inserter_new(SerdModel* ZIX_NONNULL       model,
+                  const SerdNode* ZIX_NULLABLE default_graph);
+
+/**
+   @}
+*/
+
+SERD_END_DECLS
+
+#endif // SERD_INSERTER_H