Clean up node construction API

9 files changed, 279 insertions, 252 deletions

diff --git a/serd/serd.h b/serd/serd.h
index 0f937b24..89f612a3 100644
--- a/serd/serd.h
+++ b/serd/serd.h
@@ -439,18 +439,11 @@ serd_uri_serialise_relative(const SerdURI* uri,
 */
 
 /**
-   Create a new node from `str`.
+   Create a new plain literal string node from `str`.
 */
 SERD_API
 SerdNode*
-serd_node_new_string(SerdType type, const char* str);
-
-/**
-   Create a new node from a prefix of `str`.
-*/
-SERD_API
-SerdNode*
-serd_node_new_substring(SerdType type, const char* str, size_t len);
+serd_node_new_string(const char* str);
 
 /**
    Create a new literal node from `str`.
@@ -466,15 +459,19 @@ 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);
 
 /**
+   Create a new CURIE node.
+*/
+SERD_API
+SerdNode*
+serd_node_new_curie(const char* str);
+
+/**
    Return a deep copy of `node`.
 */
 SERD_API
@@ -489,72 +486,60 @@ bool
 serd_node_equals(const SerdNode* a, const SerdNode* b);
 
 /**
-   Simple wrapper for serd_node_new_uri() to resolve a URI node.
+   Create a new URI from a string.
 */
 SERD_API
 SerdNode*
-serd_node_new_uri_from_node(const SerdNode* uri_node,
-                            const SerdURI*  base,
-                            SerdURI*        out);
+serd_node_new_uri(const char* str);
 
 /**
-   Simple wrapper for serd_node_new_uri() to resolve a URI string.
+   Create a new URI from a string, resolved against a base URI.
 */
 SERD_API
 SerdNode*
-serd_node_new_uri_from_string(const char*    str,
-                              const SerdURI* base,
-                              SerdURI*       out);
+serd_node_new_resolved_uri(const char* str, const SerdNode* base);
 
 /**
-   Create a new file URI node from a file system path and optional hostname.
+   Resolve `node` against `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.
-
-   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.
+   If `out` is not NULL, it will be set to the parsed URI.
 */
 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.
@@ -772,8 +757,7 @@ serd_env_free(SerdEnv* env);
 */
 SERD_API
 const SerdNode*
-serd_env_get_base_uri(const SerdEnv* env,
-                      SerdURI*       out);
+serd_env_get_base_uri(const SerdEnv* env);
 
 /**
    Set the current base URI.
@@ -986,13 +970,12 @@ serd_reader_free(SerdReader* reader);
 */
 SERD_API
 SerdWriter*
-serd_writer_new(SerdWorld*     world,
-                SerdSyntax     syntax,
-                SerdStyle      style,
-                SerdEnv*       env,
-                const SerdURI* base_uri,
-                SerdSink       ssink,
-                void*          stream);
+serd_writer_new(SerdWorld*      world,
+                SerdSyntax      syntax,
+                SerdStyle       style,
+                SerdEnv*        env,
+                SerdSink        ssink,
+                void*           stream);
 
 /**
    Free `writer`.
diff --git a/src/env.c b/src/env.c
index c81b62b0..7723c70d 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"
@@ -57,13 +59,15 @@ 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_get_base_uri(const SerdEnv* env,
-                      SerdURI*       out)
+serd_env_get_base_uri(const SerdEnv* env)
 {
-	if (out) {
-		*out = env->base_uri;
-	}
 	return env->base_uri_node;
 }
 
@@ -71,14 +75,16 @@ 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_get_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_get_string(base_uri_node), &base_uri);
 
 	if (base_uri_node) {
 		// Replace the current base URI
@@ -137,13 +143,12 @@ 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_get_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;
 }
@@ -153,8 +158,8 @@ 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);
 
@@ -228,10 +233,9 @@ serd_env_expand_node(const SerdEnv*  env,
 		ret->n_bytes = len;
 		return ret;
 	}
-	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_get_string(node), &env->base_uri);
 	default:
 		return NULL;
 	}
diff --git a/src/env.h b/src/env.h
new file mode 100644
index 00000000..ecb6cc15
--- /dev/null
+++ b/src/env.h
@@ -0,0 +1,24 @@
+/*
+  Copyright 2011-2018 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 fcea6bea..7f124f13 100644
--- a/src/node.c
+++ b/src/node.c
@@ -38,6 +38,9 @@
 
 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)
 {
@@ -84,31 +87,30 @@ serd_node_set(SerdNode** dst, const SerdNode* src)
 	}
 }
 
-SerdNode*
-serd_node_new_string(SerdType type, const char* str)
+static SerdNode*
+serd_node_new_simple(SerdType type, const char* str)
 {
 	if (!str) {
 		return NULL;
 	}
 
-	uint32_t     flags   = 0;
-	const size_t n_bytes = serd_strlen(str, &flags);
-	SerdNode*    node    = serd_node_malloc(n_bytes, flags, type);
+	const size_t n_bytes = strlen(str);
+	SerdNode*    node    = serd_node_malloc(n_bytes, 0, type);
 	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_string(const char* str)
 {
 	if (!str) {
 		return NULL;
 	}
 
 	uint32_t     flags   = 0;
-	const size_t n_bytes = serd_substrlen(str, len, &flags);
-	SerdNode*    node    = serd_node_malloc(n_bytes, flags, type);
+	const size_t n_bytes = serd_strlen(str, &flags);
+	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;
@@ -164,15 +166,19 @@ serd_node_new_literal(const char*     str,
 SerdNode*
 serd_node_new_blank(const char* str)
 {
-	if (!str) {
-		return NULL;
-	}
+	return serd_node_new_simple(SERD_BLANK, str);
+}
 
-	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 serd_node_new_simple(SERD_CURIE, str);
+}
+
+SerdNode*
+serd_node_new_uri(const char* str)
+{
+	return serd_node_new_simple(SERD_URI, str);
 }
 
 SERD_API
@@ -232,29 +238,43 @@ string_sink(const void* buf, size_t len, 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_get_string(uri_node);
-	return (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_get_string(base), &base_uri);
+	return serd_node_new_resolved_uri_i(str, &base_uri);
 }
 
 SerdNode*
-serd_node_new_uri_from_string(const char*    str,
-                              const SerdURI* base,
-                              SerdURI*       out)
+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_get_string(node), &uri);
+	serd_uri_parse(serd_node_get_string(base), &base_uri);
+
+	return serd_node_new_from_uri(&uri, &base_uri);
+}
+
+SerdNode*
+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
@@ -277,10 +297,7 @@ 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;
@@ -311,18 +328,13 @@ 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) {
@@ -337,33 +349,36 @@ 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_get_string(base), &base_uri);
+	}
+	if (root) {
+		serd_uri_parse(serd_node_get_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;
 }
 
@@ -516,6 +531,15 @@ serd_node_get_length(const SerdNode* node)
 	return node ? node->n_bytes : 0;
 }
 
+static const SerdNode*
+serd_node_get_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_get_datatype(const SerdNode* node)
 {
@@ -523,11 +547,7 @@ serd_node_get_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_get_meta_node(node);
 	assert(datatype->type == SERD_URI || datatype->type == SERD_CURIE);
 	return datatype;
 }
@@ -539,11 +559,7 @@ serd_node_get_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_get_meta_node(node);
 	assert(lang->type == SERD_LITERAL);
 	return lang;
 }
diff --git a/src/node.h b/src/node.h
index 025e29de..91202db1 100644
--- a/src/node.h
+++ b/src/node.h
@@ -43,5 +43,6 @@ 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);
 size_t    serd_node_total_size(const SerdNode* node);
+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 ad52de3d..6efce26e 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -212,13 +212,11 @@ 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;
@@ -247,7 +245,7 @@ main(int argc, char** argv)
 
 	SerdWriter* writer = serd_writer_new(
 		world, output_syntax, (SerdStyle)output_style,
-		env, &base_uri, serd_file_sink, out_fd);
+		env, serd_file_sink, out_fd);
 
 	SerdReader* reader = serd_reader_new(
 		world, input_syntax, serd_writer_get_sink_interface(writer));
@@ -257,7 +255,7 @@ 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/string_utils.h b/src/string_utils.h
index ab6ece0e..5f0dec01 100644
--- a/src/string_utils.h
+++ b/src/string_utils.h
@@ -102,22 +102,6 @@ serd_update_flags(const uint8_t c, SerdNodeFlags* const flags)
 	}
 }
 
-static inline size_t
-serd_substrlen(const char* const    str,
-               const size_t         len,
-               SerdNodeFlags* const flags)
-{
-	if (flags) {
-		size_t i = 0;
-		*flags = 0;
-		for (; i < len && str[i]; ++i) {
-			serd_update_flags(str[i], flags);
-		}
-		return i;
-	}
-	return strlen(str);
-}
-
 static inline int
 serd_strncasecmp(const char* s1, const char* s2, size_t n)
 {
diff --git a/src/writer.c b/src/writer.c
index 2ee3412a..2f17d86d 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"
@@ -99,7 +100,6 @@ struct SerdWriterImpl {
 	SerdEnv*          env;
 	SerdNode*         root_node;
 	SerdURI           root_uri;
-	SerdURI           base_uri;
 	SerdStack         anon_stack;
 	SerdByteSink      byte_sink;
 	SerdErrorSink     error_sink;
@@ -527,19 +527,18 @@ write_uri_node(SerdWriter* const        writer,
 
 	write_sep(writer, SEP_URI_BEGIN);
 	if (writer->style & SERD_STYLE_RESOLVED) {
-		SerdURI in_base_uri, uri, abs_uri;
-		serd_env_get_base_uri(writer->env, &in_base_uri);
+		const SerdURI* base_uri = serd_env_get_parsed_base_uri(writer->env);
+		SerdURI uri, abs_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);
@@ -863,13 +862,12 @@ serd_writer_finish(SerdWriter* writer)
 }
 
 SerdWriter*
-serd_writer_new(SerdWorld*     world,
-                SerdSyntax     syntax,
-                SerdStyle      style,
-                SerdEnv*       env,
-                const SerdURI* base_uri,
-                SerdSink       ssink,
-                void*          stream)
+serd_writer_new(SerdWorld*      world,
+                SerdSyntax      syntax,
+                SerdStyle       style,
+                SerdEnv*        env,
+                SerdSink        ssink,
+                void*           stream)
 {
 	const WriteContext context = WRITE_CONTEXT_NULL;
 	SerdWriter*        writer  = (SerdWriter*)calloc(1, sizeof(SerdWriter));
@@ -879,7 +877,6 @@ 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 +912,6 @@ serd_writer_set_base_uri(SerdWriter*     writer,
                          const SerdNode* uri)
 {
 	if (!serd_env_set_base_uri(writer->env, uri)) {
-		serd_env_get_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/serd_test.c b/tests/serd_test.c
index 9d203a15..01f1e60b 100644
--- a/tests/serd_test.c
+++ b/tests/serd_test.c
@@ -91,7 +91,7 @@ check_file_uri(const char* hostname,
 		expected_path = path;
 	}
 
-	SerdNode*   node         = serd_node_new_file_uri(path, hostname, 0, escape);
+	SerdNode*   node         = serd_node_new_file_uri(path, hostname, escape);
 	const char* node_str     = serd_node_get_string(node);
 	char*       out_hostname = NULL;
 	char*       out_path     = serd_file_uri_parse(node_str, &out_hostname);
@@ -113,6 +113,23 @@ check_file_uri(const char* hostname,
 	return ret;
 }
 
+static int
+check_rel_uri(const char*     uri,
+              const SerdNode* base,
+              const SerdNode* root,
+              const char*     expected)
+{
+	SerdNode* rel = serd_node_new_relative_uri(uri, base, root);
+	const int ret = strcmp(serd_node_get_string(rel), expected);
+	serd_node_free(rel);
+	if (ret) {
+		FAILF("Bad relative URI `%s' (expected `%s')\n",
+		      serd_node_get_string(rel),
+		      expected);
+	}
+	return ret;
+}
+
 int
 main(void)
 {
@@ -273,14 +290,14 @@ main(void)
 	// Test serd_node_equals
 
 	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");
 	if (serd_node_equals(lhs, rhs)) {
 		FAILF("%s == %s\n",
 		      serd_node_get_string(lhs), serd_node_get_string(rhs));
 	}
 
-	SerdNode* qnode = serd_node_new_string(SERD_CURIE, "foo:bar");
+	SerdNode* qnode = serd_node_new_curie("foo:bar");
 	if (serd_node_equals(lhs, qnode)) {
 		FAILF("%s == %s\n",
 		      serd_node_get_string(lhs), serd_node_get_string(qnode));
@@ -301,39 +318,17 @@ main(void)
 
 	// Test serd_node_new_string
 
-	SerdNode* hello = serd_node_new_string(SERD_LITERAL, "hello\"");
+	SerdNode* hello = serd_node_new_string("hello\"");
 	if (serd_node_get_length(hello) != 6 ||
 	    serd_node_get_flags(hello) != SERD_HAS_QUOTE ||
 	    strcmp(serd_node_get_string(hello), "hello\"")) {
 		FAILF("Bad node %s\n", serd_node_get_string(hello));
 	}
 
-	if (serd_node_new_string(SERD_URI, NULL)) {
+	if (serd_node_new_string(NULL)) {
 		FAIL("Successfully created node from NULL string\n");
 	}
 
-	// Test serd_node_new_substring
-
-	if (serd_node_new_substring(SERD_LITERAL, NULL, 32)) {
-		FAIL("Successfully created node from NULL substring\n");
-	}
-
-	SerdNode* a_b = serd_node_new_substring(SERD_LITERAL, "a\"bc", 3);
-	if (serd_node_get_length(a_b) != 3 ||
-	    serd_node_get_flags(a_b) != SERD_HAS_QUOTE ||
-	    strncmp(serd_node_get_string(a_b), "a\"b", 3)) {
-		FAILF("Bad node %s\n", serd_node_get_string(a_b));
-	}
-
-	serd_node_free(a_b);
-	a_b = serd_node_new_substring(SERD_LITERAL, "a\"bc", 10);
-	if (serd_node_get_length(a_b) != 4 ||
-	    serd_node_get_flags(a_b) != SERD_HAS_QUOTE ||
-	    strncmp(serd_node_get_string(a_b), "a\"bc", 4)) {
-		FAILF("Bad node %s\n", serd_node_get_string(a_b));
-	}
-	serd_node_free(a_b);
-
 	// Test serd_node_new_literal
 
 	if (serd_node_new_literal(NULL, NULL, NULL)) {
@@ -357,8 +352,7 @@ main(void)
 	}
 	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);
@@ -372,43 +366,71 @@ main(void)
 	serd_node_free(hello_dt);
 	serd_node_free(eg_Thing);
 
-	// Test serd_node_new_uri_from_string
+	// Test absolute URI creation
 
-	if (serd_node_new_uri_from_string(NULL, NULL, NULL)) {
+	if (serd_node_new_uri(NULL)) {
 		FAIL("Successfully created NULL URI\n");
 	}
 
-	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);
-	if (serd_node_get_type(nil) != SERD_URI ||
-	    strcmp(serd_node_get_string(nil), serd_node_get_string(base)) ||
-	    serd_node_get_type(nil2) != SERD_URI ||
-	    strcmp(serd_node_get_string(nil2), serd_node_get_string(base))) {
+	SerdNode* not_a_uri = serd_node_new_string("hello");
+	SerdNode* root      = serd_node_new_uri("http://example.org/a/b/");
+	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);
+	if (serd_node_new_resolved_uri("", NULL)) {
+		FAIL("Successfully created URI resolved against NULL\n");
+	} else if (serd_node_new_resolved_uri("", not_a_uri)) {
+		FAIL("Successfully created URI resolved against non-URI\n");
+	} else if (serd_node_get_type(nil) != SERD_URI ||
+	           strcmp(serd_node_get_string(nil), serd_node_get_string(base)) ||
+	           serd_node_get_type(nil2) != SERD_URI ||
+	           strcmp(serd_node_get_string(nil2), serd_node_get_string(base))) {
 		FAILF("URI %s != base %s\n",
 		      serd_node_get_string(nil),
 		      serd_node_get_string(base));
 	}
 
-	// Test serd_node_new_relative_uri
-	SerdNode* abs = serd_node_new_string(SERD_URI, "http://example.org/foo/bar");
-	SerdURI   abs_uri;
-	serd_uri_parse(serd_node_get_string(abs), &abs_uri);
+	// Test relative URI creation
+
+	if (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,
+	                  "http://example.org/") ||
+	    check_rel_uri("http://drobilla.net/a", base, NULL,
+	                  "http://drobilla.net/a")) {
+		return 1;
+	}
+
+	// Test URI resolution
+
+	if (serd_node_resolve(NULL, base)) {
+		FAIL("Successfully resolved null URI\n");
+	} else if (serd_node_resolve(nil, NULL)) {
+		FAIL("Successfully resolved against null URI\n");
+	} else if (serd_node_resolve(not_a_uri, base)) {
+		FAIL("Successfully resolved a non-URI\n");
+	} else if (serd_node_resolve(nil, not_a_uri)) {
+		FAIL("Successfully resolved against a non-URI\n");
+	}
 
-	SerdURI   rel_uri;
-	SerdNode* rel = serd_node_new_relative_uri(&abs_uri, &base_uri, NULL, &rel_uri);
-	if (strcmp(serd_node_get_string(rel), "/foo/bar")) {
-		FAILF("Bad relative URI %s (expected '/foo/bar')\n",
-		      serd_node_get_string(rel));
+	SerdNode* rel = serd_node_new_relative_uri(
+		"http://example.org/a/b/c/foo", base, NULL);
+	SerdNode* resolved = serd_node_resolve(rel, base);
+	if (strcmp(serd_node_get_string(resolved),
+	           "http://example.org/a/b/c/foo")) {
+		FAILF("Bad resolved URI %s (expected 'http://example.org/a/b/c/foo'\n",
+		      serd_node_get_string(resolved));
 	}
 
-	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);
 
 	// Test serd_node_new_blank
 
@@ -428,13 +450,13 @@ main(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* 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");
 	SerdEnv*  env = serd_env_new(NULL);
 	serd_env_set_prefix_from_strings(env, "eg.2", "http://example.org/");
 
-	if (serd_env_get_base_uri(env, NULL)) {
+	if (serd_env_get_base_uri(env)) {
 		FAIL("Unexpected initial base URI\n");
 	}
 
@@ -446,7 +468,7 @@ main(void)
 		FAILF("Set base URI to %s\n", serd_node_get_string(hello));
 	}
 
-	if (serd_env_get_base_uri(env, NULL)) {
+	if (serd_env_get_base_uri(env)) {
 		FAIL("Unexpected base URI\n");
 	}
 
@@ -468,7 +490,7 @@ main(void)
 	}
 	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);
 	if (xbadpre) {
 		FAILF("Expanded invalid curie %s\n", serd_node_get_string(badpre));
@@ -486,7 +508,7 @@ main(void)
 		FAIL("Set NULL prefix\n");
 	}
 
-	SerdNode* lit = serd_node_new_string(SERD_LITERAL, "hello");
+	SerdNode* lit = serd_node_new_string("hello");
 	if (!serd_env_set_prefix(env, b, lit)) {
 		FAIL("Set prefix to literal\n");
 	}
@@ -498,7 +520,7 @@ main(void)
 		FAILF("Bad prefix count %d\n", n_prefixes);
 	}
 
-	SerdNode* shorter_uri = serd_node_new_string(SERD_URI, "urn:foo");
+	SerdNode* shorter_uri = serd_node_new_uri("urn:foo");
 	const SerdNode* prefix_name;
 	if (serd_env_qualify(env, shorter_uri, &prefix_name, &suffix)) {
 		FAILF("Qualified %s\n", serd_node_get_string(shorter_uri));
@@ -517,7 +539,7 @@ main(void)
 	}
 
 	SerdWriter* writer = serd_writer_new(
-		world, SERD_TURTLE, (SerdStyle)0, env, NULL, serd_file_sink, fd);
+		world, SERD_TURTLE, (SerdStyle)0, env, serd_file_sink, fd);
 	if (!writer) {
 		FAIL("Failed to create writer\n");
 	}
@@ -538,9 +560,9 @@ main(void)
 	}
 
 	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 },
@@ -561,7 +583,7 @@ main(void)
 		}
 	}
 
-	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");
@@ -584,8 +606,8 @@ main(void)
 
 	// 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);
 	if (iface->statement(iface->handle, 0, NULL, s, p, bad_lit)) {
 		FAIL("Failed to write junk UTF-8 literal\n");
 	} else if (iface->statement(iface->handle, 0, NULL, s, p, bad_uri)) {
@@ -596,7 +618,7 @@ main(void)
 
 	// Write 1 valid statement
 	serd_node_free(o);
-	o = serd_node_new_string(SERD_LITERAL, "hello");
+	o = serd_node_new_string("hello");
 	if (iface->statement(iface->handle, 0, NULL, s, p, o)) {
 		FAIL("Failed to write valid statement\n");
 	}
@@ -613,9 +635,9 @@ main(void)
 	// 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");
 	if (serd_writer_set_base_uri(writer, o)) {
 		FAIL("Failed to write to chunk sink\n");
 	}
@@ -640,7 +662,7 @@ main(void)
 		FAIL("Failed to create reader\n");
 	}
 
-	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);