Ensure that all free methods tolerate NULL

3 files changed, 12 insertions, 0 deletions

diff --git a/src/env.c b/src/env.c
index e5cb954a..e67b42c0 100644
--- a/src/env.c
+++ b/src/env.c
@@ -47,6 +47,10 @@ serd_env_new(const SerdNode* base_uri)
 void
 serd_env_free(SerdEnv* env)
 {
+	if (!env) {
+		return;
+	}
+
 	for (size_t i = 0; i < env->n_prefixes; ++i) {
 		serd_node_free(&env->prefixes[i].name);
 		serd_node_free(&env->prefixes[i].uri);
diff --git a/src/reader.c b/src/reader.c
index 4710caac..5d33e45d 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -218,6 +218,10 @@ serd_reader_set_error_sink(SerdReader*   reader,
 void
 serd_reader_free(SerdReader* reader)
 {
+	if (!reader) {
+		return;
+	}
+
 	pop_node(reader, reader->rdf_nil);
 	pop_node(reader, reader->rdf_rest);
 	pop_node(reader, reader->rdf_first);
diff --git a/src/writer.c b/src/writer.c
index 81e0a845..5f312c30 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -978,6 +978,10 @@ serd_writer_set_prefix(SerdWriter*     writer,
 void
 serd_writer_free(SerdWriter* writer)
 {
+	if (!writer) {
+		return;
+	}
+
 	serd_writer_finish(writer);
 	serd_stack_free(&writer->anon_stack);
 	free(writer->bprefix);