Make statement sink take a statement rather than nodes

This makes the interface more extensible, towards associating more information
with statements.  The serd_sink_write_nodes wrapper remains so that user code
does not need to allocate in order to write statement.

3 files changed, 19 insertions, 16 deletions

diff --git a/src/reader.c b/src/reader.c
index ee27a2fb..40c48a41 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -21,6 +21,7 @@
 #include "serd/serd.h"
 #include "serd_internal.h"
 #include "stack.h"
+#include "statement.h"
 #include "system.h"
 #include "world.h"
 
@@ -125,9 +126,12 @@ emit_statement(SerdReader* reader, ReadContext ctx, SerdNode* o)
 	   (subject and predicate) were already zeroed by subsequent pushes. */
 	serd_node_zero_pad(o);
 
+	const SerdStatement statement = {
+		{ ctx.subject, ctx.predicate, o, graph }
+	};
+
 	const SerdStatus st = reader->sink->statement(
-		reader->sink->handle, *ctx.flags, graph,
-		ctx.subject, ctx.predicate, o);
+		reader->sink->handle, *ctx.flags, &statement);
 	*ctx.flags &= SERD_ANON_CONT|SERD_LIST_CONT;  // Preserve only cont flags
 	return st;
 }
diff --git a/src/sink.c b/src/sink.c
index eb31bbf6..1c5c500f 100644
--- a/src/sink.c
+++ b/src/sink.c
@@ -16,6 +16,8 @@
 
 #include "serd/serd.h"
 
+#include "statement.h"
+
 SerdStatus
 serd_sink_write_base(const SerdSink* sink, const SerdNode* uri)
 {
@@ -35,12 +37,7 @@ serd_sink_write_statement(const SerdSink*          sink,
                           const SerdStatementFlags flags,
                           const SerdStatement*     statement)
 {
-	return sink->statement(sink->handle,
-	                       flags,
-	                       serd_statement_get_graph(statement),
-	                       serd_statement_get_subject(statement),
-	                       serd_statement_get_predicate(statement),
-	                       serd_statement_get_object(statement));
+	return sink->statement(sink->handle, flags, statement);
 }
 
 SerdStatus
@@ -51,8 +48,8 @@ serd_sink_write(const SerdSink*          sink,
                 const SerdNode*          object,
                 const SerdNode*          graph)
 {
-	return sink->statement(
-	        sink->handle, flags, graph, subject, predicate, object);
+	const SerdStatement statement = { { subject, predicate, object, graph } };
+	return sink->statement(sink->handle, flags, &statement);
 }
 
 SerdStatus
diff --git a/src/writer.c b/src/writer.c
index b58260a1..692139a6 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -685,13 +685,15 @@ write_list_obj(SerdWriter*        writer,
 }
 
 static SerdStatus
-serd_writer_write_statement(SerdWriter*        writer,
-                            SerdStatementFlags flags,
-                            const SerdNode*    graph,
-                            const SerdNode*    subject,
-                            const SerdNode*    predicate,
-                            const SerdNode*    object)
+serd_writer_write_statement(SerdWriter*          writer,
+                            SerdStatementFlags   flags,
+                            const SerdStatement* statement)
 {
+	const SerdNode* const subject   = serd_statement_get_subject(statement);
+	const SerdNode* const predicate = serd_statement_get_predicate(statement);
+	const SerdNode* const object    = serd_statement_get_object(statement);
+	const SerdNode* const graph     = serd_statement_get_graph(statement);
+
 	if (!subject || !predicate || !object ||
 	    !is_resource(subject) || !is_resource(predicate)) {
 		return SERD_ERR_BAD_ARG;