Clean up node construction API

9 files changed, 323 insertions, 231 deletions

diff --git a/serd/serd.h b/serd/serd.h
index 45e7ea56..b10d9ce9 100644
--- a/serd/serd.h
+++ b/serd/serd.h
@@ -463,18 +463,30 @@ serd_uri_serialise_relative(const SerdURI* uri,
 */
 
 /**
-   Create a new node from `str`.
+   Create a new "simple" node that is just a string.
+
+   This can be used to create blank, CURIE, or URI nodes from an already
+   measured string or slice of a buffer, which avoids a strlen compared to the
+   friendly constructors.  This may not be used for literals since those must
+   be measured to set the SERD_HAS_NEWLINE and SERD_HAS_QUOTE flags.
+*/
+SERD_API
+SerdNode*
+serd_node_new_simple_node(SerdType type, const char* str, size_t len);
+
+/**
+   Create a new plain literal string node from `str`.
 */
 SERD_API
 SerdNode*
-serd_node_new_string(SerdType type, const char* str);
+serd_node_new_string(const char* str);
 
 /**
-   Create a new node from a prefix of `str`.
+   Create a new plain literal string node from a prefix of `str`.
 */
 SERD_API
 SerdNode*
-serd_node_new_substring(SerdType type, const char* str, size_t len);
+serd_node_new_substring(const char* str, size_t len);
 
 /**
    Create a new literal node from `str`.
@@ -490,81 +502,72 @@ serd_node_new_literal(const char*     str,
 
 /**
    Create a new blank node.
-
-   Note this function measures `str`, which is a common bottleneck.
-   Use sord_node_from_serd_node() instead if `str` is already measured.
 */
 SERD_API
 SerdNode*
 serd_node_new_blank(const char* str);
 
 /**
-   Simple wrapper for serd_node_new_uri() to resolve a URI node.
+   Create a new CURIE node.
 */
 SERD_API
 SerdNode*
-serd_node_new_uri_from_node(const SerdNode* uri_node,
-                            const SerdURI*  base,
-                            SerdURI*        out);
+serd_node_new_curie(const char* str);
 
 /**
-   Simple wrapper for serd_node_new_uri() to resolve a URI string.
+   Create a new URI from a string.
 */
 SERD_API
 SerdNode*
-serd_node_new_uri_from_string(const char*    str,
-                              const SerdURI* base,
-                              SerdURI*       out);
+serd_node_new_uri(const char* str);
 
 /**
-   Create a new file URI node from a file system path and optional hostname.
+   Create a new URI from a string, resolved against a base URI.
+*/
+SERD_API
+SerdNode*
+serd_node_new_resolved_uri(const char* str, const SerdNode* base);
 
-   Backslashes in Windows paths will be converted and '%' will always be
-   percent encoded.  If `escape` is true, all other invalid characters will be
-   percent encoded as well.
+/**
+   Resolve `node` against `base`.
 
-   If `path` is relative, `hostname` is ignored.
-   If `out` is not NULL, it will be set to the parsed URI.
+   If `node` is not a relative URI, an equivalent new node is returned.
 */
 SERD_API
 SerdNode*
-serd_node_new_file_uri(const char* path,
-                       const char* hostname,
-                       SerdURI*    out,
-                       bool        escape);
+serd_node_resolve(const SerdNode* node, const SerdNode* base);
 
 /**
-   Create a new node by serialising `uri` into a new string.
-
-   @param uri The URI to serialise.
+   Create a new file URI node from a file system path and optional hostname.
 
-   @param base Base URI to resolve `uri` against (or NULL for no resolution).
+   Backslashes in Windows paths will be converted and '%' will always be
+   percent encoded.  If `escape` is true, all other invalid characters will be
+   percent encoded as well.
 
-   @param out Set to the parsing of the new URI (i.e. points only to
-   memory owned by the new returned node).
+   If `path` is relative, `hostname` is ignored.
 */
 SERD_API
 SerdNode*
-serd_node_new_uri(const SerdURI* uri, const SerdURI* base, SerdURI* out);
+serd_node_new_file_uri(const char* path, const char* hostname, bool escape);
 
 /**
-   Create a new node by serialising `uri` into a new relative URI.
+   Create a new URI from a string, relative to a base URI.
 
-   @param uri The URI to serialise.
+   @param str URI string.
 
-   @param base Base URI to make `uri` relative to, if possible.
+   @param base Base URI to make `str` relative to, if possible.
 
-   @param root Root URI for resolution (see serd_uri_serialise_relative()).
+   @param root Optional root URI for resolution.
 
-   @param out Set to the parsing of the new URI (i.e. points only to
-   memory owned by the new returned node).
+   The URI is made relative iff if it a child of `base` and `root`.  The
+   optional `root` parameter must be a prefix of `base` and can be used keep
+   up-references ("../") within a certain namespace.
 */
 SERD_API
 SerdNode*
-serd_node_new_relative_uri(const SerdURI* uri,
-                           const SerdURI* base,
-                           const SerdURI* root,
-                           SerdURI*       out);
+serd_node_new_relative_uri(const char*     str,
+                           const SerdNode* base,
+                           const SerdNode* root);
 
 /**
    Create a new node by serialising `d` into an xsd:decimal string.
@@ -793,7 +796,7 @@ serd_env_free(SerdEnv* env);
 */
 SERD_API
 const SerdNode*
-serd_env_base_uri(const SerdEnv* env, SerdURI* out);
+serd_env_base_uri(const SerdEnv* env);
 
 /**
    Set the current base URI.
@@ -990,13 +993,12 @@ serd_reader_free(SerdReader* reader);
 */
 SERD_API
 SerdWriter*
-serd_writer_new(SerdWorld*     world,
-                SerdSyntax     syntax,
-                SerdStyle      style,
-                SerdEnv*       env,
-                const SerdURI* base_uri,
-                SerdWriteFunc  ssink,
-                void*          stream);
+serd_writer_new(SerdWorld*      world,
+                SerdSyntax      syntax,
+                SerdStyle       style,
+                SerdEnv*        env,
+                SerdWriteFunc   ssink,
+                void*           stream);
 
 /**
    Free `writer`.
diff --git a/src/env.c b/src/env.c
index c99d2bc4..ea098c1b 100644
--- a/src/env.c
+++ b/src/env.c
@@ -14,6 +14,8 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
+#include "env.h"
+
 #include "node.h"
 
 #include "serd/serd.h"
@@ -61,12 +63,15 @@ serd_env_free(SerdEnv* env)
 	free(env);
 }
 
+const SerdURI*
+serd_env_get_parsed_base_uri(const SerdEnv* env)
+{
+	return &env->base_uri;
+}
+
 const SerdNode*
-serd_env_base_uri(const SerdEnv* env, SerdURI* out)
+serd_env_base_uri(const SerdEnv* env)
 {
-	if (out) {
-		*out = env->base_uri;
-	}
 	return env->base_uri_node;
 }
 
@@ -74,14 +79,16 @@ SerdStatus
 serd_env_set_base_uri(SerdEnv*        env,
                       const SerdNode* uri)
 {
-	if (!env || !uri) {
+	if (!env || !uri || uri->type != SERD_URI) {
 		return SERD_ERR_BAD_ARG;
 	}
 
 	// Resolve base URI and create a new node and URI for it
+	SerdNode* base_uri_node = serd_node_new_resolved_uri_i(
+		serd_node_string(uri), &env->base_uri);
+
 	SerdURI   base_uri;
-	SerdNode* base_uri_node = serd_node_new_uri_from_node(
-		uri, &env->base_uri, &base_uri);
+	serd_uri_parse(serd_node_string(base_uri_node), &base_uri);
 
 	if (base_uri_node) {
 		// Replace the current base URI
@@ -142,13 +149,12 @@ serd_env_set_prefix(SerdEnv*        env,
 		serd_env_add(env, name, uri);
 	} else {
 		// Resolve relative URI and create a new node and URI for it
-		SerdURI   abs_uri;
-		SerdNode* abs_uri_node = serd_node_new_uri_from_node(
-			uri, &env->base_uri, &abs_uri);
+		SerdNode* abs_uri = serd_node_new_resolved_uri_i(
+			serd_node_string(uri), &env->base_uri);
 
 		// Set prefix to resolved (absolute) URI
-		serd_env_add(env, name, abs_uri_node);
-		serd_node_free(abs_uri_node);
+		serd_env_add(env, name, abs_uri);
+		serd_node_free(abs_uri);
 	}
 	return SERD_SUCCESS;
 }
@@ -158,8 +164,8 @@ serd_env_set_prefix_from_strings(SerdEnv*    env,
                                  const char* name,
                                  const char* uri)
 {
-	SerdNode* name_node = serd_node_new_string(SERD_LITERAL, name);
-	SerdNode* uri_node  = serd_node_new_string(SERD_URI, uri);
+	SerdNode* name_node = serd_node_new_string(name);
+	SerdNode* uri_node  = serd_node_new_uri(uri);
 
 	const SerdStatus st = serd_env_set_prefix(env, name_node, uri_node);
 
@@ -222,10 +228,9 @@ serd_env_expand_node(const SerdEnv*  env,
 	switch (node->type) {
 	case SERD_LITERAL:
 		break;
-	case SERD_URI: {
-		SerdURI ignored;
-		return serd_node_new_uri_from_node(node, &env->base_uri, &ignored);
-	}
+	case SERD_URI:
+		return serd_node_new_resolved_uri_i(
+			serd_node_string(node), &env->base_uri);
 	case SERD_CURIE: {
 		SerdStringView prefix;
 		SerdStringView suffix;
diff --git a/src/env.h b/src/env.h
new file mode 100644
index 00000000..d1894613
--- /dev/null
+++ b/src/env.h
@@ -0,0 +1,24 @@
+/*
+  Copyright 2011-2020 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef SERD_ENV_H
+#define SERD_ENV_H
+
+#include "serd/serd.h"
+
+const SerdURI* serd_env_get_parsed_base_uri(const SerdEnv* env);
+
+#endif  // SERD_ENV_H
diff --git a/src/node.c b/src/node.c
index 95a34fac..2bb1d493 100644
--- a/src/node.c
+++ b/src/node.c
@@ -42,6 +42,9 @@
 
 static const size_t serd_node_align = sizeof(SerdNode);
 
+static SerdNode*
+serd_node_new_from_uri(const SerdURI* uri, const SerdURI* base);
+
 static size_t
 serd_node_pad_size(const size_t n_bytes)
 {
@@ -93,7 +96,22 @@ serd_node_set(SerdNode** dst, const SerdNode* src)
 }
 
 SerdNode*
-serd_node_new_string(SerdType type, const char* str)
+serd_node_new_simple_node(SerdType type, const char* str, const size_t len)
+{
+	if (!str) {
+		return NULL;
+	} else if (type != SERD_BLANK && type != SERD_CURIE && type != SERD_URI) {
+		return NULL;
+	}
+
+	SerdNode* node = serd_node_malloc(len, 0, type);
+	memcpy(serd_node_buffer(node), str, len);
+	node->n_bytes = len;
+	return node;
+}
+
+SerdNode*
+serd_node_new_string(const char* str)
 {
 	if (!str) {
 		return NULL;
@@ -101,14 +119,14 @@ serd_node_new_string(SerdType type, const char* str)
 
 	SerdNodeFlags flags   = 0;
 	const size_t  n_bytes = serd_strlen(str, &flags);
-	SerdNode*     node    = serd_node_malloc(n_bytes, flags, type);
+	SerdNode*     node    = serd_node_malloc(n_bytes, flags, SERD_LITERAL);
 	memcpy(serd_node_buffer(node), str, n_bytes);
 	node->n_bytes = n_bytes;
 	return node;
 }
 
 SerdNode*
-serd_node_new_substring(SerdType type, const char* str, const size_t len)
+serd_node_new_substring(const char* str, const size_t len)
 {
 	if (!str) {
 		return NULL;
@@ -116,7 +134,7 @@ serd_node_new_substring(SerdType type, const char* str, const size_t len)
 
 	SerdNodeFlags flags   = 0;
 	const size_t  n_bytes = serd_substrlen(str, len, &flags);
-	SerdNode*     node    = serd_node_malloc(n_bytes, flags, type);
+	SerdNode*     node    = serd_node_malloc(n_bytes, flags, SERD_LITERAL);
 	memcpy(serd_node_buffer(node), str, n_bytes);
 	node->n_bytes = n_bytes;
 	return node;
@@ -172,15 +190,19 @@ serd_node_new_literal(const char*     str,
 SerdNode*
 serd_node_new_blank(const char* str)
 {
-	if (!str) {
-		return NULL;
-	}
+	return str ? serd_node_new_simple_node(SERD_BLANK, str, strlen(str)) : NULL;
+}
 
-	const size_t n_bytes = strlen(str);
-	SerdNode*    node    = serd_node_malloc(n_bytes, 0, SERD_BLANK);
-	memcpy(serd_node_buffer(node), str, n_bytes);
-	node->n_bytes = n_bytes;
-	return node;
+SerdNode*
+serd_node_new_curie(const char* str)
+{
+	return str ? serd_node_new_simple_node(SERD_CURIE, str, strlen(str)) : NULL;
+}
+
+SerdNode*
+serd_node_new_uri(const char* str)
+{
+	return str ? serd_node_new_simple_node(SERD_URI, str, strlen(str)) : NULL;
 }
 
 SerdNode*
@@ -236,29 +258,43 @@ string_sink(const void* buf, size_t size, size_t nmemb, void* stream)
 }
 
 SerdNode*
-serd_node_new_uri_from_node(const SerdNode* uri_node,
-                            const SerdURI*  base,
-                            SerdURI*        out)
+serd_node_new_resolved_uri(const char* str, const SerdNode* base)
 {
-	const char* uri_str = serd_node_string(uri_node);
-	return (uri_node && uri_node->type == SERD_URI && uri_str)
-		? serd_node_new_uri_from_string(uri_str, base, out)
-		: NULL;
+	if (!base || base->type != SERD_URI) {
+		return NULL;
+	}
+
+	SerdURI base_uri;
+	serd_uri_parse(serd_node_string(base), &base_uri);
+	return serd_node_new_resolved_uri_i(str, &base_uri);
+}
+
+SerdNode*
+serd_node_resolve(const SerdNode* node, const SerdNode* base)
+{
+	if (!node || !base || node->type != SERD_URI || base->type != SERD_URI) {
+		return NULL;
+	}
+
+	SerdURI uri;
+	SerdURI base_uri;
+	serd_uri_parse(serd_node_string(node), &uri);
+	serd_uri_parse(serd_node_string(base), &base_uri);
+
+	return serd_node_new_from_uri(&uri, &base_uri);
 }
 
 SerdNode*
-serd_node_new_uri_from_string(const char*    str,
-                              const SerdURI* base,
-                              SerdURI*       out)
+serd_node_new_resolved_uri_i(const char* str, const SerdURI* base)
 {
 	if (!str || str[0] == '\0') {
 		// Empty URI => Base URI, or nothing if no base is given
-		return base ? serd_node_new_uri(base, NULL, out) : NULL;
+		return base ? serd_node_new_from_uri(base, NULL) : NULL;
 	}
 
 	SerdURI uri;
 	serd_uri_parse(str, &uri);
-	return serd_node_new_uri(&uri, base, out);  // Resolve/Serialise
+	return serd_node_new_from_uri(&uri, base);
 }
 
 static inline bool
@@ -281,10 +317,7 @@ is_uri_path_char(const char c)
 }
 
 SerdNode*
-serd_node_new_file_uri(const char* path,
-                       const char* hostname,
-                       SerdURI*    out,
-                       bool        escape)
+serd_node_new_file_uri(const char* path, const char* hostname, bool escape)
 {
 	const size_t path_len     = strlen(path);
 	const size_t hostname_len = hostname ? strlen(hostname) : 0;
@@ -318,18 +351,13 @@ serd_node_new_file_uri(const char* path,
 	}
 	serd_buffer_sink_finish(&buffer);
 
-	SerdNode* node = serd_node_new_substring(
-		SERD_URI, (const char*)buffer.buf, buffer.len);
-	if (out) {
-		serd_uri_parse(serd_node_buffer(node), out);
-	}
-
+	SerdNode* node = serd_node_new_uri((const char*)buffer.buf);
 	free(buffer.buf);
 	return node;
 }
 
-SerdNode*
-serd_node_new_uri(const SerdURI* uri, const SerdURI* base, SerdURI* out)
+static SerdNode*
+serd_node_new_from_uri(const SerdURI* uri, const SerdURI* base)
 {
 	SerdURI abs_uri = *uri;
 	if (base) {
@@ -344,33 +372,36 @@ serd_node_new_uri(const SerdURI* uri, const SerdURI* base, SerdURI* out)
 	serd_node_buffer(node)[actual_len] = '\0';
 	node->n_bytes = actual_len;
 
-	if (out) {
-		serd_uri_parse(serd_node_buffer(node), out);  // TODO: avoid double parse
-	}
-
 	return node;
 }
 
 SerdNode*
-serd_node_new_relative_uri(const SerdURI* uri,
-                           const SerdURI* base,
-                           const SerdURI* root,
-                           SerdURI*       out)
+serd_node_new_relative_uri(const char*     str,
+                           const SerdNode* base,
+                           const SerdNode* root)
 {
-	const size_t uri_len    = serd_uri_string_length(uri);
-	const size_t base_len   = serd_uri_string_length(base);
+	SerdURI uri      = SERD_URI_NULL;
+	SerdURI base_uri = SERD_URI_NULL;
+	SerdURI root_uri = SERD_URI_NULL;
+
+	serd_uri_parse(str, &uri);
+	if (base) {
+		serd_uri_parse(serd_node_string(base), &base_uri);
+	}
+	if (root) {
+		serd_uri_parse(serd_node_string(root), &root_uri);
+	}
+
+	const size_t uri_len    = serd_uri_string_length(&uri);
+	const size_t base_len   = serd_uri_string_length(&base_uri);
 	SerdNode*    node       = serd_node_malloc(uri_len + base_len, 0, SERD_URI);
 	char*        ptr        = serd_node_buffer(node);
 	const size_t actual_len = serd_uri_serialise_relative(
-		uri, base, root, string_sink, &ptr);
+		&uri, &base_uri, root ? &root_uri : NULL, string_sink, &ptr);
 
 	serd_node_buffer(node)[actual_len] = '\0';
 	node->n_bytes = actual_len;
 
-	if (out) {
-		serd_uri_parse(serd_node_buffer(node), out);  // TODO: avoid double parse
-	}
-
 	return node;
 }
 
@@ -499,6 +530,15 @@ serd_node_length(const SerdNode* node)
 	return node ? node->n_bytes : 0;
 }
 
+static const SerdNode*
+serd_node_meta_node(const SerdNode* node)
+{
+	const size_t len = serd_node_pad_size(node->n_bytes);
+	assert((intptr_t)node % serd_node_align == 0);
+	assert(len % serd_node_align == 0);
+	return node + 1 + (len / serd_node_align);
+}
+
 const SerdNode*
 serd_node_datatype(const SerdNode* node)
 {
@@ -506,11 +546,7 @@ serd_node_datatype(const SerdNode* node)
 		return NULL;
 	}
 
-	const size_t len = serd_node_pad_size(node->n_bytes);
-	assert((intptr_t)node % serd_node_align == 0);
-	assert(len % serd_node_align == 0);
-
-	const SerdNode* const datatype = node + 1 + (len / serd_node_align);
+	const SerdNode* const datatype = serd_node_meta_node(node);
 	assert(datatype->type == SERD_URI || datatype->type == SERD_CURIE);
 	return datatype;
 }
@@ -522,11 +558,7 @@ serd_node_language(const SerdNode* node)
 		return NULL;
 	}
 
-	const size_t len = serd_node_pad_size(node->n_bytes);
-	assert((intptr_t)node % serd_node_align == 0);
-	assert(len % serd_node_align == 0);
-
-	const SerdNode* const lang = node + 1 + (len / serd_node_align);
+	const SerdNode* const lang = serd_node_meta_node(node);
 	assert(lang->type == SERD_LITERAL);
 	return lang;
 }
diff --git a/src/node.h b/src/node.h
index f99da1a6..8bc6083e 100644
--- a/src/node.h
+++ b/src/node.h
@@ -41,5 +41,6 @@ serd_node_buffer_c(const SerdNode* node)
 
 SerdNode* serd_node_malloc(size_t n_bytes, SerdNodeFlags flags, SerdType type);
 void      serd_node_set(SerdNode** dst, const SerdNode* src);
+SerdNode* serd_node_new_resolved_uri_i(const char* str, const SerdURI* base);
 
 #endif  // SERD_NODE_H
diff --git a/src/serdi.c b/src/serdi.c
index e9a0299c..ef620c3c 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -224,13 +224,11 @@ main(int argc, char** argv)
 			: SERD_NQUADS);
 	}
 
-	SerdURI   base_uri = SERD_URI_NULL;
-	SerdNode* base     = NULL;
+	SerdNode* base = NULL;
 	if (a < argc) {  // Base URI given on command line
-		base = serd_node_new_uri_from_string(
-			(const char*)argv[a], NULL, &base_uri);
+		base = serd_node_new_uri((const char*)argv[a]);
 	} else if (!from_string && !from_stdin) {  // Use input file URI
-		base = serd_node_new_file_uri(input, NULL, &base_uri, true);
+		base = serd_node_new_file_uri(input, NULL, true);
 	}
 
 	FILE*      out_fd = stdout;
@@ -261,7 +259,6 @@ main(int argc, char** argv)
 	                                     output_syntax,
 	                                     (SerdStyle)output_style,
 	                                     env,
-	                                     &base_uri,
 	                                     (SerdWriteFunc)fwrite,
 	                                     out_fd);
 
@@ -273,7 +270,7 @@ main(int argc, char** argv)
 		serd_world_set_error_sink(world, quiet_error_sink, NULL);
 	}
 
-	SerdNode* root = serd_node_new_string(SERD_URI, root_uri);
+	SerdNode* root = serd_node_new_uri(root_uri);
 	serd_writer_set_root_uri(writer, root);
 	serd_writer_chop_blank_prefix(writer, chop_prefix);
 	serd_reader_add_blank_prefix(reader, add_prefix);
diff --git a/src/writer.c b/src/writer.c
index bbe2a247..9d7a6790 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -15,6 +15,7 @@
 */
 
 #include "byte_sink.h"
+#include "env.h"
 #include "node.h"
 #include "serd_internal.h"
 #include "stack.h"
@@ -100,7 +101,6 @@ struct SerdWriterImpl {
 	SerdEnv*      env;
 	SerdNode*     root_node;
 	SerdURI       root_uri;
-	SerdURI       base_uri;
 	SerdStack     anon_stack;
 	SerdByteSink  byte_sink;
 	SerdErrorSink error_sink;
@@ -528,21 +528,19 @@ write_uri_node(SerdWriter* const        writer,
 
 	write_sep(writer, SEP_URI_BEGIN);
 	if (writer->style & SERD_STYLE_RESOLVED) {
-		SerdURI in_base_uri;
+		const SerdURI* base_uri = serd_env_get_parsed_base_uri(writer->env);
 		SerdURI uri;
 		SerdURI abs_uri;
-		serd_env_base_uri(writer->env, &in_base_uri);
 		serd_uri_parse(node_str, &uri);
-		serd_uri_resolve(&uri, &in_base_uri, &abs_uri);
-		bool rooted = uri_is_under(&writer->base_uri, &writer->root_uri);
-		SerdURI* root = rooted ? &writer->root_uri : & writer->base_uri;
+		serd_uri_resolve(&uri, base_uri, &abs_uri);
+		bool rooted = uri_is_under(base_uri, &writer->root_uri);
+		const SerdURI* root = rooted ? &writer->root_uri : base_uri;
 		if (!uri_is_under(&abs_uri, root) ||
 		    writer->syntax == SERD_NTRIPLES ||
 		    writer->syntax == SERD_NQUADS) {
 			serd_uri_serialise(&abs_uri, uri_sink, writer);
 		} else {
-			serd_uri_serialise_relative(
-				&uri, &writer->base_uri, root, uri_sink, writer);
+			serd_uri_serialise_relative(&uri, base_uri, root, uri_sink, writer);
 		}
 	} else {
 		write_uri_from_node(writer, node);
@@ -867,7 +865,6 @@ serd_writer_new(SerdWorld*     world,
                 SerdSyntax     syntax,
                 SerdStyle      style,
                 SerdEnv*       env,
-                const SerdURI* base_uri,
                 SerdWriteFunc  ssink,
                 void*          stream)
 {
@@ -879,7 +876,6 @@ serd_writer_new(SerdWorld*     world,
 	writer->env          = env;
 	writer->root_node    = NULL;
 	writer->root_uri     = SERD_URI_NULL;
-	writer->base_uri     = base_uri ? *base_uri : SERD_URI_NULL;
 	writer->anon_stack   = serd_stack_new(4 * sizeof(WriteContext));
 	writer->context      = context;
 	writer->list_subj    = NULL;
@@ -915,8 +911,6 @@ serd_writer_set_base_uri(SerdWriter*     writer,
                          const SerdNode* uri)
 {
 	if (!serd_env_set_base_uri(writer->env, uri)) {
-		serd_env_base_uri(writer->env, &writer->base_uri);
-
 		if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) {
 			if (ctx(writer, FIELD_GRAPH) || ctx(writer, FIELD_SUBJECT)) {
 				sink(" .\n\n", 4, writer);
diff --git a/tests/env_test.c b/tests/env_test.c
index 8e0c9205..607b8763 100644
--- a/tests/env_test.c
+++ b/tests/env_test.c
@@ -36,13 +36,21 @@ test_env(void)
 {
 	SerdWorld* world = serd_world_new();
 
-	SerdNode* u   = serd_node_new_string(SERD_URI, "http://example.org/foo");
-	SerdNode* b   = serd_node_new_string(SERD_CURIE, "invalid");
-	SerdNode* c   = serd_node_new_string(SERD_CURIE, "eg.2:b");
-	SerdNode* s   = serd_node_new_string(SERD_LITERAL, "hello");
-	SerdEnv*  env = serd_env_new(NULL);
+	SerdNode* hello = serd_node_new_string("hello\"");
+	SerdNode* u     = serd_node_new_uri("http://example.org/foo");
+	SerdNode* b     = serd_node_new_curie("invalid");
+	SerdNode* c     = serd_node_new_curie("eg.2:b");
+	SerdNode* s     = serd_node_new_string("hello");
+	SerdEnv*  env   = serd_env_new(NULL);
 	serd_env_set_prefix_from_strings(env, "eg.2", "http://example.org/");
 
+	assert(!serd_env_base_uri(env));
+	assert(serd_env_set_base_uri(env, NULL));
+	assert(!serd_env_base_uri(env));
+	assert(serd_env_set_base_uri(env, hello));
+	assert(!serd_env_base_uri(env));
+	serd_node_free(hello);
+
 	SerdStringView prefix;
 	SerdStringView suffix;
 	assert(serd_env_expand(env, b, &prefix, &suffix));
@@ -57,7 +65,7 @@ test_env(void)
 	assert(!strcmp(serd_node_string(xu), "http://example.org/foo"));
 	serd_node_free(xu);
 
-	SerdNode* badpre  = serd_node_new_string(SERD_CURIE, "hm:what");
+	SerdNode* badpre = serd_node_new_curie("hm:what");
 	SerdNode* xbadpre = serd_env_expand_node(env, badpre);
 	assert(!xbadpre);
 
@@ -67,10 +75,10 @@ test_env(void)
 
 	assert(serd_env_set_prefix(env, NULL, NULL));
 
-	SerdNode* lit = serd_node_new_string(SERD_LITERAL, "hello");
+	SerdNode* lit = serd_node_new_string("hello");
 	assert(serd_env_set_prefix(env, b, lit));
 
-	SerdNode* blank = serd_node_new_string(SERD_BLANK, "b1");
+	SerdNode* blank = serd_node_new_blank("b1");
 	assert(!serd_env_expand_node(env, blank));
 	serd_node_free(blank);
 
@@ -79,10 +87,9 @@ test_env(void)
 	serd_env_foreach(env, count_prefixes, &n_prefixes);
 	assert(n_prefixes == 1);
 
-	SerdNode*       shorter_uri = serd_node_new_string(SERD_URI, "urn:foo");
+	SerdNode*       shorter_uri = serd_node_new_uri("urn:foo");
 	const SerdNode* prefix_name = NULL;
 	assert(!serd_env_qualify(env, shorter_uri, &prefix_name, &suffix));
-
 	serd_node_free(shorter_uri);
 	serd_node_free(lit);
 	serd_node_free(badpre);
diff --git a/tests/serd_test.c b/tests/serd_test.c
index 067f5e2e..0a65fbe9 100644
--- a/tests/serd_test.c
+++ b/tests/serd_test.c
@@ -110,8 +110,8 @@ test_file_uri(const char* hostname,
 		expected_path = path;
 	}
 
-	SerdNode*   node     = serd_node_new_file_uri(path, hostname, 0, escape);
-	const char* node_str = serd_node_string(node);
+	SerdNode*   node         = serd_node_new_file_uri(path, hostname, escape);
+	const char* node_str     = serd_node_string(node);
 	char*       out_hostname = NULL;
 	char*       out_path     = serd_file_uri_parse(node_str, &out_hostname);
 	assert(!strcmp(node_str, expected_uri));
@@ -367,17 +367,16 @@ static void
 test_node_equals(void)
 {
 	const uint8_t replacement_char_str[] = { 0xEF, 0xBF, 0xBD, 0 };
-	SerdNode* lhs = serd_node_new_string(SERD_LITERAL, (const char*)replacement_char_str);
-	SerdNode* rhs = serd_node_new_string(SERD_LITERAL, "123");
+	SerdNode* lhs = serd_node_new_string((const char*)replacement_char_str);
+	SerdNode* rhs = serd_node_new_string("123");
 	assert(!serd_node_equals(lhs, rhs));
 
-	SerdNode* qnode = serd_node_new_string(SERD_CURIE, "foo:bar");
+	SerdNode* qnode = serd_node_new_curie("foo:bar");
 	assert(!serd_node_equals(lhs, qnode));
-	assert(serd_node_equals(lhs, lhs));
+	serd_node_free(qnode);
 
 	assert(!serd_node_copy(NULL));
 
-	serd_node_free(qnode);
 	serd_node_free(lhs);
 	serd_node_free(rhs);
 }
@@ -385,34 +384,44 @@ test_node_equals(void)
 static void
 test_node_from_string(void)
 {
-	SerdNode* hello = serd_node_new_string(SERD_LITERAL, "hello\"");
-	assert(serd_node_length(hello) == 6 &&
-	       serd_node_flags(hello) == SERD_HAS_QUOTE &&
-	       !strcmp(serd_node_string(hello), "hello\""));
+	assert(!serd_node_new_string(NULL));
 
-	assert(!serd_node_new_string(SERD_URI, NULL));
+	SerdNode* hello = serd_node_new_string("hello\"");
+	assert(serd_node_length(hello) == 6);
+	assert(serd_node_flags(hello) == SERD_HAS_QUOTE);
+	assert(!strncmp(serd_node_string(hello), "hello\"", 6));
 	serd_node_free(hello);
 }
 
 static void
 test_node_from_substring(void)
 {
-	assert(!serd_node_new_substring(SERD_LITERAL, NULL, 32));
+	assert(!serd_node_new_substring(NULL, 32));
 
-	SerdNode* a_b = serd_node_new_substring(SERD_LITERAL, "a\"bc", 3);
-	assert(serd_node_length(a_b) == 3 &&
-	       serd_node_flags(a_b) == SERD_HAS_QUOTE &&
-	       !strncmp(serd_node_string(a_b), "a\"b", 3));
+	SerdNode* a_b = serd_node_new_substring("a\"bc", 3);
+	assert(serd_node_length(a_b) == 3);
+	assert(serd_node_flags(a_b) == SERD_HAS_QUOTE);
+	assert(strlen(serd_node_string(a_b)) == 3);
+	assert(!strncmp(serd_node_string(a_b), "a\"b", 3));
 
 	serd_node_free(a_b);
-	a_b = serd_node_new_substring(SERD_LITERAL, "a\"bc", 10);
-	assert(serd_node_length(a_b) == 4 &&
-	       serd_node_flags(a_b) == SERD_HAS_QUOTE &&
-	       !strncmp(serd_node_string(a_b), "a\"bc", 4));
+	a_b = serd_node_new_substring("a\"bc", 10);
+	assert(serd_node_length(a_b) == 4);
+	assert(serd_node_flags(a_b) == SERD_HAS_QUOTE);
+	assert(strlen(serd_node_string(a_b)) == 4);
+	assert(!strncmp(serd_node_string(a_b), "a\"bc", 4));
 	serd_node_free(a_b);
 }
 
-static void test_literal(void)
+static void
+test_simple_node(void)
+{
+	assert(!serd_node_new_simple_node(SERD_LITERAL, "Literal", 7));
+	assert(!serd_node_new_simple_node(SERD_URI, NULL, 0));
+}
+
+static void
+test_literal(void)
 {
 	assert(!serd_node_new_literal(NULL, NULL, NULL));
 
@@ -431,9 +440,7 @@ static void test_literal(void)
 	               "en"));
 	serd_node_free(hello_l);
 
-	SerdNode* eg_Thing = serd_node_new_uri_from_string(
-	        "http://example.org/Thing", NULL, NULL);
-
+	SerdNode* eg_Thing = serd_node_new_uri("http://example.org/Thing");
 	SerdNode* hello_dt = serd_node_new_literal("hello_dt\"", eg_Thing, NULL);
 	assert(serd_node_length(hello_dt) == 9);
 	assert(!strcmp(serd_node_string(hello_dt), "hello_dt\""));
@@ -447,58 +454,79 @@ static void test_literal(void)
 static void
 test_uri_from_string(void)
 {
-	assert(!serd_node_new_uri_from_string(NULL, NULL, NULL));
-
-	SerdURI   base_uri;
-	SerdNode* base = serd_node_new_uri_from_string("http://example.org/",
-	                                               NULL, &base_uri);
-	SerdNode* nil  = serd_node_new_uri_from_string(NULL, &base_uri, NULL);
-	SerdNode* nil2 = serd_node_new_uri_from_string("", &base_uri, NULL);
+	assert(!serd_node_new_uri(NULL));
+
+	SerdNode* base      = serd_node_new_uri("http://example.org/a/b/c/");
+	SerdNode* not_a_uri = serd_node_new_string("hello");
+	SerdNode* nil       = serd_node_new_resolved_uri(NULL, base);
+	SerdNode* nil2      = serd_node_new_resolved_uri("", base);
+	assert(!serd_node_new_resolved_uri("", NULL));
+	assert(!serd_node_new_resolved_uri("", not_a_uri));
 	assert(serd_node_type(nil) == SERD_URI);
 	assert(!strcmp(serd_node_string(nil), serd_node_string(base)));
 	assert(serd_node_type(nil2) == SERD_URI);
 	assert(!strcmp(serd_node_string(nil2), serd_node_string(base)));
-	serd_node_free(nil);
 	serd_node_free(nil2);
+	serd_node_free(nil);
+	serd_node_free(not_a_uri);
 	serd_node_free(base);
 }
 
 static void
-test_relative_uri(void)
+check_rel_uri(const char*     uri,
+              const SerdNode* base,
+              const SerdNode* root,
+              const char*     expected)
 {
-	SerdURI   base_uri;
-	SerdNode* base = serd_node_new_uri_from_string("http://example.org/",
-	                                               NULL, &base_uri);
-
-	SerdNode* abs = serd_node_new_string(SERD_URI, "http://example.org/foo/bar");
-	SerdURI   abs_uri;
-	serd_uri_parse(serd_node_string(abs), &abs_uri);
-
-	SerdURI   rel_uri;
-	SerdNode* rel = serd_node_new_relative_uri(&abs_uri, &base_uri, NULL, &rel_uri);
-	assert(!strcmp(serd_node_string(rel), "/foo/bar"));
+	SerdNode* rel = serd_node_new_relative_uri(uri, base, root);
+	const int ret = strcmp(serd_node_string(rel), expected);
+	serd_node_free(rel);
+	assert(!ret);
+}
 
-	SerdNode* up = serd_node_new_relative_uri(&base_uri, &abs_uri, NULL, NULL);
-	assert(!strcmp(serd_node_string(up), "../"));
+static void
+test_relative_uri(void)
+{
+	SerdNode* root = serd_node_new_uri("http://example.org/a/b/");
+	SerdNode* base = serd_node_new_uri("http://example.org/a/b/c/");
 
-	SerdNode* noup = serd_node_new_relative_uri(&base_uri, &abs_uri, &abs_uri, NULL);
-	assert(!strcmp(serd_node_string(noup), "http://example.org/"));
+	check_rel_uri("http://example.org/a/b/c/foo", base, NULL, "foo");
+	check_rel_uri("http://example.org/a/", base, NULL, "../../");
+	check_rel_uri("http://example.org/a/", base, root, "http://example.org/a/");
+	check_rel_uri("http://example.org/", base, NULL, "../../../");
+	check_rel_uri("http://drobilla.net/a", base, NULL, "http://drobilla.net/a");
 
-	SerdNode* x = serd_node_new_string(SERD_URI, "http://example.org/foo/x");
-	SerdURI   x_uri;
-	serd_uri_parse(serd_node_string(x), &x_uri);
+	serd_node_free(base);
+	serd_node_free(root);
+}
 
-	SerdNode* x_rel =
-		serd_node_new_relative_uri(&x_uri, &abs_uri, &abs_uri, NULL);
-	assert(!strcmp(serd_node_string(x_rel), "x"));
+static void
+test_uri_resolution(void)
+{
+	SerdNode* base      = serd_node_new_uri("http://example.org/a/b/c/");
+	SerdNode* nil       = serd_node_new_resolved_uri(NULL, base);
+	SerdNode* nil2      = serd_node_new_resolved_uri("", base);
+	SerdNode* not_a_uri = serd_node_new_string("hello");
+	SerdNode* root      = serd_node_new_uri("http://example.org/a/b/");
+
+	assert(!serd_node_resolve(NULL, base));
+	assert(!serd_node_resolve(nil, NULL));
+	assert(!serd_node_resolve(not_a_uri, base));
+	assert(!serd_node_resolve(nil, not_a_uri));
+
+	SerdNode* rel = serd_node_new_relative_uri(
+		"http://example.org/a/b/c/foo", base, NULL);
+	SerdNode* resolved = serd_node_resolve(rel, base);
+	assert(!strcmp(serd_node_string(resolved),
+	               "http://example.org/a/b/c/foo"));
 
-	serd_node_free(x_rel);
-	serd_node_free(x);
-	serd_node_free(noup);
-	serd_node_free(up);
-	serd_node_free(abs);
+	serd_node_free(nil);
+	serd_node_free(nil2);
+	serd_node_free(not_a_uri);
+	serd_node_free(resolved);
 	serd_node_free(rel);
 	serd_node_free(base);
+	serd_node_free(root);
 }
 
 static void
@@ -526,7 +554,6 @@ test_writer(const char* const path)
 	                                     SERD_TURTLE,
 	                                     (SerdStyle)0,
 	                                     env,
-	                                     NULL,
 	                                     (SerdWriteFunc)fwrite,
 	                                     fd);
 	assert(writer);
@@ -534,7 +561,7 @@ test_writer(const char* const path)
 	serd_writer_chop_blank_prefix(writer, "tmp");
 	serd_writer_chop_blank_prefix(writer, NULL);
 
-	SerdNode* lit = serd_node_new_string(SERD_LITERAL, "hello");
+	SerdNode* lit = serd_node_new_string("hello");
 
 	const SerdSink* iface = serd_writer_get_sink(writer);
 	assert(iface->base(iface->handle, lit));
@@ -543,9 +570,9 @@ test_writer(const char* const path)
 	assert(serd_writer_env(writer) == env);
 
 	uint8_t buf[] = { 0xEF, 0xBF, 0xBD, 0 };
-	SerdNode* s = serd_node_new_string(SERD_URI, "");
-	SerdNode* p = serd_node_new_string(SERD_URI, "http://example.org/pred");
-	SerdNode* o = serd_node_new_string(SERD_LITERAL, (char*)buf);
+	SerdNode* s = serd_node_new_uri("");
+	SerdNode* p = serd_node_new_uri("http://example.org/pred");
+	SerdNode* o = serd_node_new_string((char*)buf);
 
 	// Write 3 invalid statements (should write nothing)
 	const SerdNode* junk[][5] = { { s,    p,    NULL },
@@ -564,7 +591,7 @@ test_writer(const char* const path)
 			       junk[i][0], junk[i][1], junk[i][2]));
 	}
 
-	SerdNode* urn_Type = serd_node_new_uri_from_string("urn:Type", NULL, NULL);
+	SerdNode* urn_Type = serd_node_new_uri("urn:Type");
 
 	SerdNode* t = serd_node_new_literal((char*)buf, urn_Type, NULL);
 	SerdNode* l = serd_node_new_literal((char*)buf, NULL, "en");
@@ -585,16 +612,17 @@ test_writer(const char* const path)
 
 	// Write statements with bad UTF-8 (should be replaced)
 	const char bad_str[] = { (char)0xFF, (char)0x90, 'h', 'i', 0 };
-	SerdNode*  bad_lit   = serd_node_new_string(SERD_LITERAL, bad_str);
-	SerdNode*  bad_uri   = serd_node_new_string(SERD_URI, bad_str);
+	SerdNode*  bad_lit   = serd_node_new_string(bad_str);
+	SerdNode*  bad_uri   = serd_node_new_uri(bad_str);
 	assert(!iface->statement(iface->handle, 0, NULL, s, p, bad_lit));
 	assert(!iface->statement(iface->handle, 0, NULL, s, p, bad_uri));
-	serd_node_free(bad_lit);
+
 	serd_node_free(bad_uri);
+	serd_node_free(bad_lit);
 
 	// Write 1 valid statement
 	serd_node_free(o);
-	o = serd_node_new_string(SERD_LITERAL, "hello");
+	o = serd_node_new_string("hello");
 	assert(!iface->statement(iface->handle, 0, NULL, s, p, o));
 
 	serd_writer_free(writer);
@@ -607,9 +635,9 @@ test_writer(const char* const path)
 	// Test buffer sink
 	SerdBuffer buffer = { NULL, 0 };
 	writer = serd_writer_new(
-		world, SERD_TURTLE, (SerdStyle)0, env, NULL, serd_buffer_sink, &buffer);
+		world, SERD_TURTLE, (SerdStyle)0, env, serd_buffer_sink, &buffer);
 
-	o = serd_node_new_string(SERD_URI, "http://example.org/base");
+	o = serd_node_new_uri("http://example.org/base");
 	assert(!serd_writer_set_base_uri(writer, o));
 
 	serd_node_free(o);
@@ -633,7 +661,7 @@ test_reader(const char* path)
 	SerdReader* reader = serd_reader_new(world, SERD_TURTLE, &sink);
 	assert(reader);
 
-	SerdNode* g = serd_node_new_string(SERD_URI, "http://example.org/");
+	SerdNode* g = serd_node_new_uri("http://example.org/");
 	serd_reader_set_default_graph(reader, g);
 	serd_reader_add_blank_prefix(reader, "tmp");
 	serd_reader_add_blank_prefix(reader, NULL);
@@ -706,9 +734,11 @@ main(void)
 	test_node_equals();
 	test_node_from_string();
 	test_node_from_substring();
+	test_simple_node();
 	test_literal();
 	test_uri_from_string();
 	test_relative_uri();
+	test_uri_resolution();
 	test_blank();
 	test_read_chunks();
 	test_read_string();