Make node qualify and expand functions tolerate a null Env

This is convenient in places where you don't necessarily need an Env, since
these methods will work the same as with an empty Env.

3 files changed, 20 insertions, 3 deletions

diff --git a/include/serd/serd.h b/include/serd/serd.h
index 68443304..fcba2ddf 100644
--- a/include/serd/serd.h
+++ b/include/serd/serd.h
@@ -684,7 +684,7 @@ serd_env_set_prefix_from_strings(SerdEnv* SERD_NONNULL       env,
 /// Qualify `uri` into a CURIE if possible
 SERD_API
 bool
-serd_env_qualify(const SerdEnv* SERD_NONNULL  env,
+serd_env_qualify(const SerdEnv* SERD_NULLABLE env,
                  const SerdNode* SERD_NONNULL uri,
                  SerdNode* SERD_NONNULL       prefix,
                  SerdChunk* SERD_NONNULL      suffix);
@@ -697,7 +697,7 @@ serd_env_qualify(const SerdEnv* SERD_NONNULL  env,
 */
 SERD_API
 SerdStatus
-serd_env_expand(const SerdEnv* SERD_NONNULL  env,
+serd_env_expand(const SerdEnv* SERD_NULLABLE env,
                 const SerdNode* SERD_NONNULL curie,
                 SerdChunk* SERD_NONNULL      uri_prefix,
                 SerdChunk* SERD_NONNULL      uri_suffix);
@@ -709,7 +709,7 @@ serd_env_expand(const SerdEnv* SERD_NONNULL  env,
 */
 SERD_API
 SerdNode
-serd_env_expand_node(const SerdEnv* SERD_NONNULL  env,
+serd_env_expand_node(const SerdEnv* SERD_NULLABLE env,
                      const SerdNode* SERD_NONNULL node);
 
 /// Call `func` for each prefix defined in `env`
diff --git a/src/env.c b/src/env.c
index ad0252fb..385ab2f6 100644
--- a/src/env.c
+++ b/src/env.c
@@ -179,6 +179,10 @@ serd_env_qualify(const SerdEnv* const  env,
                  SerdNode* const       prefix,
                  SerdChunk* const      suffix)
 {
+  if (!env) {
+    return false;
+  }
+
   for (size_t i = 0; i < env->n_prefixes; ++i) {
     const SerdNode* const prefix_uri = &env->prefixes[i].uri;
     if (uri->n_bytes >= prefix_uri->n_bytes) {
@@ -201,6 +205,10 @@ serd_env_expand(const SerdEnv* const  env,
                 SerdChunk* const      uri_prefix,
                 SerdChunk* const      uri_suffix)
 {
+  if (!env) {
+    return SERD_ERR_BAD_CURIE;
+  }
+
   const uint8_t* const colon =
     (const uint8_t*)memchr(curie->buf, ':', curie->n_bytes + 1);
   if (curie->type != SERD_CURIE || !colon) {
@@ -222,6 +230,10 @@ serd_env_expand(const SerdEnv* const  env,
 SerdNode
 serd_env_expand_node(const SerdEnv* const env, const SerdNode* const node)
 {
+  if (!env) {
+    return SERD_NODE_NULL;
+  }
+
   switch (node->type) {
   case SERD_NOTHING:
   case SERD_LITERAL:
diff --git a/test/test_env.c b/test/test_env.c
index b25bd9e2..48bc6c9b 100644
--- a/test/test_env.c
+++ b/test/test_env.c
@@ -50,8 +50,13 @@ test_env(void)
 
   SerdChunk prefix;
   SerdChunk suffix;
+  assert(!serd_env_qualify(NULL, &u, &u, &suffix));
+  assert(serd_env_expand(NULL, &c, &prefix, &suffix));
   assert(serd_env_expand(env, &b, &prefix, &suffix));
 
+  SerdNode nxnode = serd_env_expand_node(NULL, &c);
+  assert(serd_node_equals(&nxnode, &SERD_NODE_NULL));
+
   SerdNode xnode = serd_env_expand_node(env, &SERD_NODE_NULL);
   assert(serd_node_equals(&xnode, &SERD_NODE_NULL));