Simplify node construction API

5 files changed, 214 insertions, 184 deletions

diff --git a/src/env.c b/src/env.c
index b4824aae..526e72c5 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"
@@ -36,10 +38,10 @@ struct SerdEnvImpl {
 };
 
 SerdEnv*
-serd_env_new(const SerdNode* const base_uri)
+serd_env_new(const SerdStringView base_uri)
 {
   SerdEnv* env = (SerdEnv*)calloc(1, sizeof(struct SerdEnvImpl));
-  if (env && base_uri) {
+  if (env && base_uri.len) {
     serd_env_set_base_uri(env, base_uri);
   }
 
@@ -62,41 +64,39 @@ serd_env_free(SerdEnv* const env)
   free(env);
 }
 
-const SerdNode*
-serd_env_base_uri(const SerdEnv* const env, SerdURIView* const out)
+SerdURIView
+serd_env_base_uri_view(const SerdEnv* const env)
 {
-  if (out) {
-    *out = env->base_uri;
-  }
+  return env->base_uri;
+}
 
-  return env->base_uri_node;
+const SerdNode*
+serd_env_base_uri(const SerdEnv* const env)
+{
+  return env ? env->base_uri_node : NULL;
 }
 
 SerdStatus
-serd_env_set_base_uri(SerdEnv* const env, const SerdNode* const uri)
+serd_env_set_base_uri(SerdEnv* const env, const SerdStringView uri)
 {
-  if (uri && uri->type != SERD_URI) {
-    return SERD_ERR_BAD_ARG;
-  }
-
-  if (!uri) {
+  if (!uri.len) {
     serd_node_free(env->base_uri_node);
     env->base_uri_node = NULL;
     env->base_uri      = SERD_URI_NULL;
     return SERD_SUCCESS;
   }
 
+  SerdNode* const old_base_uri = env->base_uri_node;
+
   // Resolve the new base against the current base in case it is relative
   const SerdURIView new_base_uri =
-    serd_resolve_uri(serd_parse_uri(serd_node_string(uri)), env->base_uri);
-
-  SerdNode* const new_base_node = serd_new_parsed_uri(new_base_uri);
+    serd_resolve_uri(serd_parse_uri(uri.buf), env->base_uri);
 
   // Replace the current base URI
-  serd_node_free(env->base_uri_node);
-  env->base_uri_node = new_base_node;
+  env->base_uri_node = serd_new_parsed_uri(new_base_uri);
   env->base_uri      = serd_node_uri_view(env->base_uri_node);
 
+  serd_node_free(old_base_uri);
   return SERD_SUCCESS;
 }
 
@@ -118,36 +118,30 @@ serd_env_find(const SerdEnv* const env,
 }
 
 static void
-serd_env_add(SerdEnv* const        env,
-             const SerdNode* const name,
-             const SerdNode* const uri)
+serd_env_add(SerdEnv* const       env,
+             const SerdStringView name,
+             const SerdStringView uri)
 {
-  const char*       name_str = serd_node_string(name);
-  SerdPrefix* const prefix   = serd_env_find(env, name_str, name->length);
+  SerdPrefix* const prefix = serd_env_find(env, name.buf, name.len);
   if (prefix) {
-    if (!serd_node_equals(prefix->uri, uri)) {
-      SerdNode* old_prefix_uri = prefix->uri;
-      prefix->uri              = serd_node_copy(uri);
-      serd_node_free(old_prefix_uri);
+    if (strcmp(serd_node_string(prefix->uri), uri.buf)) {
+      serd_node_free(prefix->uri);
+      prefix->uri = serd_new_uri(uri);
     }
   } else {
     env->prefixes = (SerdPrefix*)realloc(
       env->prefixes, (++env->n_prefixes) * sizeof(SerdPrefix));
-    env->prefixes[env->n_prefixes - 1].name = serd_node_copy(name);
-    env->prefixes[env->n_prefixes - 1].uri  = serd_node_copy(uri);
+    env->prefixes[env->n_prefixes - 1].name = serd_new_string(name);
+    env->prefixes[env->n_prefixes - 1].uri  = serd_new_uri(uri);
   }
 }
 
 SerdStatus
-serd_env_set_prefix(SerdEnv* const        env,
-                    const SerdNode* const name,
-                    const SerdNode* const uri)
+serd_env_set_prefix(SerdEnv* const       env,
+                    const SerdStringView name,
+                    const SerdStringView uri)
 {
-  if (!name || uri->type != SERD_URI) {
-    return SERD_ERR_BAD_ARG;
-  }
-
-  if (serd_uri_string_has_scheme(serd_node_string(uri))) {
+  if (serd_uri_string_has_scheme(uri.buf)) {
     // Set prefix to absolute URI
     serd_env_add(env, name, uri);
     return SERD_SUCCESS;
@@ -158,32 +152,14 @@ serd_env_set_prefix(SerdEnv* const        env,
   }
 
   // Resolve relative URI and create a new node and URI for it
-  SerdNode* const abs_uri =
-    serd_new_resolved_uri(serd_node_string_view(uri), env->base_uri);
+  SerdNode* const abs_uri = serd_new_resolved_uri(uri, env->base_uri);
 
   // Set prefix to resolved (absolute) URI
-  serd_env_add(env, name, abs_uri);
-
+  serd_env_add(env, name, serd_node_string_view(abs_uri));
   serd_node_free(abs_uri);
-
   return SERD_SUCCESS;
 }
 
-SerdStatus
-serd_env_set_prefix_from_strings(SerdEnv* const    env,
-                                 const char* const name,
-                                 const char* const uri)
-{
-  SerdNode* name_node = serd_new_string(SERD_LITERAL, name);
-  SerdNode* uri_node  = serd_new_string(SERD_URI, uri);
-
-  const SerdStatus st = serd_env_set_prefix(env, name_node, uri_node);
-
-  serd_node_free(name_node);
-  serd_node_free(uri_node);
-  return st;
-}
-
 bool
 serd_env_qualify(const SerdEnv* const   env,
                  const SerdNode* const  uri,
diff --git a/src/env.h b/src/env.h
new file mode 100644
index 00000000..1c36b4ee
--- /dev/null
+++ b/src/env.h
@@ -0,0 +1,26 @@
+/*
+  Copyright 2011-2020 David Robillard <d@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"
+
+SERD_CONST_FUNC
+SerdURIView
+serd_env_base_uri_view(const SerdEnv* env);
+
+#endif // SERD_ENV_H
diff --git a/src/node.c b/src/node.c
index edfa28b5..fcec7336 100644
--- a/src/node.c
+++ b/src/node.c
@@ -44,6 +44,9 @@ static const size_t serd_node_align = 2 * sizeof(uint64_t);
 
 static const SerdNodeFlags meta_mask = (SERD_HAS_DATATYPE | SERD_HAS_LANGUAGE);
 
+static SerdNode*
+serd_new_from_uri(SerdURIView uri, SerdURIView base);
+
 static size_t
 serd_uri_string_length(const SerdURIView* const uri)
 {
@@ -136,68 +139,77 @@ serd_node_set(SerdNode** const dst, const SerdNode* const src)
 }
 
 SerdNode*
-serd_new_string(SerdNodeType type, const char* str)
+serd_new_simple_node(const SerdNodeType type, const SerdStringView str)
 {
+  if (type != SERD_BLANK && type != SERD_CURIE && type != SERD_URI) {
+    return NULL;
+  }
+
   SerdNodeFlags flags  = 0;
-  const size_t  length = serd_strlen(str, &flags);
+  const size_t  length = str.buf ? serd_strlen(str.buf, &flags) : 0;
   SerdNode*     node   = serd_node_malloc(length, flags, type);
 
-  memcpy(serd_node_buffer(node), str, length);
-  node->length = length;
+  if (node) {
+    if (str.buf) {
+      memcpy(serd_node_buffer(node), str.buf, length);
+    }
+
+    node->length = length;
+  }
 
   return node;
 }
 
 SerdNode*
-serd_new_substring(const SerdNodeType type,
-                   const char* const  str,
-                   const size_t       len)
+serd_new_string(const SerdStringView str)
 {
   SerdNodeFlags flags  = 0;
-  const size_t  length = serd_substrlen(str, len, &flags);
-  SerdNode*     node   = serd_node_malloc(length, flags, type);
-  memcpy(serd_node_buffer(node), str, length);
+  const size_t  length = serd_substrlen(str.buf, str.len, &flags);
+  SerdNode*     node   = serd_node_malloc(length, flags, SERD_LITERAL);
+
+  memcpy(serd_node_buffer(node), str.buf, str.len);
   node->length = length;
+
   return node;
 }
 
 SerdNode*
-serd_new_literal(const char* const str,
-                 const char* const datatype,
-                 const char* const lang)
+serd_new_literal(const SerdStringView str,
+                 const SerdStringView datatype_uri,
+                 const SerdStringView lang)
 {
   SerdNodeFlags flags  = 0;
-  const size_t  length = serd_strlen(str, &flags);
+  const size_t  length = serd_substrlen(str.buf, str.len, &flags);
   const size_t  len    = serd_node_pad_size(length);
 
   SerdNode* node = NULL;
-  if (lang) {
-    flags |= SERD_HAS_LANGUAGE;
-    const size_t lang_len  = strlen(lang);
-    const size_t total_len = len + sizeof(SerdNode) + lang_len;
-    node                   = serd_node_malloc(total_len, flags, SERD_LITERAL);
-    memcpy(serd_node_buffer(node), str, length);
+  if (lang.len) {
+    const size_t total_len = len + sizeof(SerdNode) + lang.len;
+
+    node = serd_node_malloc(total_len, flags | SERD_HAS_LANGUAGE, SERD_LITERAL);
     node->length = length;
+    memcpy(serd_node_buffer(node), str.buf, length);
 
     SerdNode* lang_node = node + 1 + (len / sizeof(SerdNode));
     lang_node->type     = SERD_LITERAL;
-    lang_node->length   = lang_len;
-    memcpy(serd_node_buffer(lang_node), lang, lang_len);
-  } else if (datatype) {
-    flags |= SERD_HAS_DATATYPE;
-    const size_t datatype_len = strlen(datatype);
-    const size_t total_len    = len + sizeof(SerdNode) + datatype_len;
-    node = serd_node_malloc(total_len, flags, SERD_LITERAL);
-    memcpy(serd_node_buffer(node), str, length);
+    lang_node->length   = lang.len;
+    memcpy(serd_node_buffer(lang_node), lang.buf, lang.len);
+
+  } else if (datatype_uri.len) {
+    const size_t total_len = len + sizeof(SerdNode) + datatype_uri.len;
+
+    node = serd_node_malloc(total_len, flags | SERD_HAS_DATATYPE, SERD_LITERAL);
     node->length = length;
+    memcpy(serd_node_buffer(node), str.buf, length);
 
     SerdNode* datatype_node = node + 1 + (len / sizeof(SerdNode));
     datatype_node->type     = SERD_URI;
-    datatype_node->length   = datatype_len;
-    memcpy(serd_node_buffer(datatype_node), datatype, datatype_len);
+    datatype_node->length   = datatype_uri.len;
+    memcpy(serd_node_buffer(datatype_node), datatype_uri.buf, datatype_uri.len);
+
   } else {
     node = serd_node_malloc(length, flags, SERD_LITERAL);
-    memcpy(serd_node_buffer(node), str, length);
+    memcpy(serd_node_buffer(node), str.buf, length);
     node->length = length;
   }
 
@@ -205,6 +217,18 @@ serd_new_literal(const char* const str,
 }
 
 SerdNode*
+serd_new_blank(const SerdStringView str)
+{
+  return serd_new_simple_node(SERD_BLANK, str);
+}
+
+SerdNode*
+serd_new_curie(const SerdStringView str)
+{
+  return serd_new_simple_node(SERD_CURIE, str);
+}
+
+SerdNode*
 serd_node_copy(const SerdNode* node)
 {
   if (!node) {
@@ -247,13 +271,9 @@ serd_node_equals(const SerdNode* const a, const SerdNode* const b)
 }
 
 SerdNode*
-serd_new_uri(const char* const str)
+serd_new_uri(const SerdStringView str)
 {
-  const size_t length = strlen(str);
-  SerdNode*    node   = serd_node_malloc(length, 0, SERD_URI);
-  memcpy(serd_node_buffer(node), str, length);
-  node->length = length;
-  return node;
+  return serd_new_simple_node(SERD_URI, str);
 }
 
 SerdNode*
@@ -336,52 +356,46 @@ is_uri_path_char(const char c)
 }
 
 SerdNode*
-serd_new_file_uri(const char* const  path,
-                  const char* const  hostname,
-                  SerdURIView* const out)
-{
-  const size_t path_len     = strlen(path);
-  const size_t hostname_len = hostname ? strlen(hostname) : 0;
-  const bool   is_windows   = is_windows_path(path);
-  size_t       uri_len      = 0;
-  char*        uri          = NULL;
-
-  if (path[0] == '/' || is_windows) {
-    uri_len = strlen("file://") + hostname_len + is_windows;
+serd_new_file_uri(const SerdStringView path, const SerdStringView hostname)
+{
+  const bool is_windows = is_windows_path(path.buf);
+  size_t     uri_len    = 0;
+  char*      uri        = NULL;
+
+  if (path.buf[0] == '/' || is_windows) {
+    uri_len = strlen("file://") + hostname.len + is_windows;
     uri     = (char*)calloc(uri_len + 1, 1);
 
     memcpy(uri, "file://", 7);
 
-    if (hostname) {
-      memcpy(uri + 7, hostname, hostname_len + 1);
+    if (hostname.len) {
+      memcpy(uri + 7, hostname.buf, hostname.len + 1);
     }
 
     if (is_windows) {
-      uri[7 + hostname_len] = '/';
+      uri[7 + hostname.len] = '/';
     }
   }
 
   SerdBuffer buffer = {uri, uri_len};
-  for (size_t i = 0; i < path_len; ++i) {
-    if (is_windows && path[i] == '\\') {
+  for (size_t i = 0; i < path.len; ++i) {
+    if (is_windows && path.buf[i] == '\\') {
       serd_buffer_sink("/", 1, &buffer);
-    } else if (path[i] == '%') {
+    } else if (path.buf[i] == '%') {
       serd_buffer_sink("%%", 2, &buffer);
-    } else if (is_uri_path_char(path[i])) {
-      serd_buffer_sink(path + i, 1, &buffer);
+    } else if (is_uri_path_char(path.buf[i])) {
+      serd_buffer_sink(path.buf + i, 1, &buffer);
     } else {
       char escape_str[10] = {'%', 0, 0, 0, 0, 0, 0, 0, 0, 0};
-      snprintf(escape_str + 1, sizeof(escape_str) - 1, "%X", (unsigned)path[i]);
+      snprintf(
+        escape_str + 1, sizeof(escape_str) - 1, "%X", (unsigned)path.buf[i]);
       serd_buffer_sink(escape_str, 3, &buffer);
     }
   }
   serd_buffer_sink_finish(&buffer);
 
   SerdNode* node =
-    serd_new_substring(SERD_URI, (const char*)buffer.buf, buffer.len);
-  if (out) {
-    *out = serd_parse_uri(serd_node_buffer(node));
-  }
+    serd_new_uri(SERD_SUBSTRING((const char*)buffer.buf, buffer.len - 1));
 
   free(buffer.buf);
   return node;
@@ -527,6 +541,14 @@ serd_node_uri_view(const SerdNode* const node)
                                   : SERD_URI_NULL;
 }
 
+SERD_PURE_FUNC
+static const SerdNode*
+serd_node_meta_node(const SerdNode* node)
+{
+  const size_t len = serd_node_pad_size(node->length);
+  return node + 1 + (len / sizeof(SerdNode));
+}
+
 const SerdNode*
 serd_node_datatype(const SerdNode* const node)
 {
@@ -534,8 +556,7 @@ serd_node_datatype(const SerdNode* const node)
     return NULL;
   }
 
-  const size_t          len      = serd_node_pad_size(node->length);
-  const SerdNode* const datatype = node + 1 + (len / sizeof(SerdNode));
+  const SerdNode* const datatype = serd_node_meta_node(node);
   assert(datatype->type == SERD_URI || datatype->type == SERD_CURIE);
   return datatype;
 }
@@ -547,8 +568,7 @@ serd_node_language(const SerdNode* const node)
     return NULL;
   }
 
-  const size_t          len  = serd_node_pad_size(node->length);
-  const SerdNode* const lang = node + 1 + (len / sizeof(SerdNode));
+  const SerdNode* const lang = serd_node_meta_node(node);
   assert(lang->type == SERD_LITERAL);
   return lang;
 }
diff --git a/src/serdi.c b/src/serdi.c
index e86042bb..ed34b0fb 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -316,20 +316,19 @@ main(int argc, char** argv)
   const SerdWriterFlags writer_flags =
     choose_style(input_syntax, output_syntax, ascii, bulk_write, full_uris);
 
-  SerdURIView base_uri = SERD_URI_NULL;
-  SerdNode*   base     = NULL;
+  SerdNode* base = NULL;
   if (a < argc) { // Base URI given on command line
-    base_uri = serd_parse_uri(argv[a]);
-    base     = serd_new_parsed_uri(base_uri);
+    base = serd_new_uri(SERD_STRING((const char*)argv[a]));
   } else if (from_file && in_fd != stdin) { // Use input file URI
-    base = serd_new_file_uri(input, NULL, &base_uri);
+    base = serd_new_file_uri(SERD_STRING(input), SERD_EMPTY_STRING());
   }
 
   FILE* const    out_fd = stdout;
-  SerdEnv* const env    = serd_env_new(base);
+  SerdEnv* const env =
+    serd_env_new(base ? serd_node_string_view(base) : SERD_EMPTY_STRING());
 
-  SerdWriter* const writer = serd_writer_new(
-    output_syntax, writer_flags, env, &base_uri, serd_file_sink, out_fd);
+  SerdWriter* const writer =
+    serd_writer_new(output_syntax, writer_flags, env, serd_file_sink, out_fd);
 
   SerdReader* const reader =
     serd_reader_new(input_syntax,
@@ -346,11 +345,14 @@ main(int argc, char** argv)
     serd_writer_set_error_sink(writer, quiet_error_sink, NULL);
   }
 
-  SerdNode* root = root_uri ? serd_new_string(SERD_URI, root_uri) : NULL;
-  serd_writer_set_root_uri(writer, root);
+  if (root_uri) {
+    SerdNode* const root = serd_new_uri(SERD_STRING(root_uri));
+    serd_writer_set_root_uri(writer, root);
+    serd_node_free(root);
+  }
+
   serd_writer_chop_blank_prefix(writer, chop_prefix);
   serd_reader_add_blank_prefix(reader, add_prefix);
-  serd_node_free(root);
 
   SerdStatus st = SERD_SUCCESS;
   if (!from_file) {
diff --git a/src/writer.c b/src/writer.c
index b4917052..227d516c 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"
@@ -96,7 +97,6 @@ struct SerdWriterImpl {
   SerdEnv*        env;
   SerdNode*       root_node;
   SerdURIView     root_uri;
-  SerdURIView     base_uri;
   SerdStack       anon_stack;
   SerdByteSink    byte_sink;
   SerdErrorFunc   error_func;
@@ -602,7 +602,7 @@ write_uri_node(SerdWriter* const writer,
   }
 
   if (!has_scheme && !supports_uriref(writer) &&
-      !serd_env_base_uri(writer->env, NULL)) {
+      !serd_env_base_uri(writer->env)) {
     w_err(writer,
           SERD_ERR_BAD_ARG,
           "syntax does not support URI reference <%s>\n",
@@ -611,22 +611,18 @@ write_uri_node(SerdWriter* const writer,
   }
 
   write_sep(writer, SEP_URI_BEGIN);
-  if (writer->flags & SERD_WRITE_RESOLVED) {
-    const SerdURIView uri = serd_parse_uri(node_str);
-
-    SerdURIView in_base_uri;
-    serd_env_base_uri(writer->env, &in_base_uri);
-
-    const SerdURIView  abs_uri = serd_resolve_uri(uri, in_base_uri);
-    const bool         rooted  = uri_is_under(&in_base_uri, &writer->root_uri);
-    const SerdURIView* root    = rooted ? &writer->root_uri : &in_base_uri;
+  if ((writer->flags & SERD_WRITE_RESOLVED) && serd_env_base_uri(writer->env)) {
+    const SerdURIView  base_uri = serd_env_base_uri_view(writer->env);
+    SerdURIView        uri      = serd_parse_uri(node_str);
+    SerdURIView        abs_uri  = serd_resolve_uri(uri, base_uri);
+    bool               rooted   = uri_is_under(&base_uri, &writer->root_uri);
+    const SerdURIView* root     = rooted ? &writer->root_uri : &base_uri;
 
     if (writer->syntax == SERD_NTRIPLES || writer->syntax == SERD_NQUADS ||
-        !uri_is_under(&abs_uri, root) ||
-        !uri_is_related(&abs_uri, &in_base_uri)) {
+        !uri_is_under(&abs_uri, root) || !uri_is_related(&abs_uri, &base_uri)) {
       serd_write_uri(abs_uri, uri_sink, writer);
     } else {
-      serd_write_uri(serd_relative_uri(uri, in_base_uri), uri_sink, writer);
+      serd_write_uri(serd_relative_uri(uri, base_uri), uri_sink, writer);
     }
   } else {
     write_uri_from_node(writer, node);
@@ -939,12 +935,11 @@ serd_writer_finish(SerdWriter* writer)
 }
 
 SerdWriter*
-serd_writer_new(SerdSyntax         syntax,
-                SerdWriterFlags    flags,
-                SerdEnv*           env,
-                const SerdURIView* base_uri,
-                SerdSink           ssink,
-                void*              stream)
+serd_writer_new(SerdSyntax      syntax,
+                SerdWriterFlags flags,
+                SerdEnv*        env,
+                SerdSink        ssink,
+                void*           stream)
 {
   const WriteContext context = WRITE_CONTEXT_NULL;
   SerdWriter*        writer  = (SerdWriter*)calloc(1, sizeof(SerdWriter));
@@ -954,7 +949,6 @@ serd_writer_new(SerdSyntax         syntax,
   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;
@@ -992,22 +986,24 @@ serd_writer_chop_blank_prefix(SerdWriter* writer, const char* prefix)
 SerdStatus
 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 (uri->type != SERD_URI) {
+    return SERD_ERR_BAD_ARG;
+  }
 
-    if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) {
-      if (ctx(writer, FIELD_GRAPH) || ctx(writer, FIELD_SUBJECT)) {
-        sink(" .\n\n", 4, writer);
-        reset_context(writer, true);
-      }
-      sink("@base <", 7, writer);
-      sink(serd_node_string(uri), uri->length, writer);
-      sink("> .\n", 4, writer);
+  serd_env_set_base_uri(writer->env, serd_node_string_view(uri));
+
+  if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) {
+    if (ctx(writer, FIELD_GRAPH) || ctx(writer, FIELD_SUBJECT)) {
+      sink(" .\n\n", 4, writer);
+      reset_context(writer, true);
     }
-    writer->indent = 0;
-    return reset_context(writer, true);
+    sink("@base <", 7, writer);
+    sink(serd_node_string(uri), uri->length, writer);
+    sink("> .\n", 4, writer);
   }
-  return SERD_ERR_UNKNOWN;
+
+  writer->indent = 0;
+  return reset_context(writer, true);
 }
 
 SerdStatus
@@ -1019,7 +1015,7 @@ serd_writer_set_root_uri(SerdWriter* writer, const SerdNode* uri)
 
   if (uri) {
     writer->root_node = serd_node_copy(uri);
-    writer->root_uri  = serd_parse_uri(serd_node_string(writer->root_node));
+    writer->root_uri  = serd_node_uri_view(writer->root_node);
   }
 
   return SERD_SUCCESS;
@@ -1030,22 +1026,32 @@ serd_writer_set_prefix(SerdWriter*     writer,
                        const SerdNode* name,
                        const SerdNode* uri)
 {
-  if (!serd_env_set_prefix(writer->env, name, uri)) {
-    if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) {
-      if (ctx(writer, FIELD_GRAPH) || ctx(writer, FIELD_SUBJECT)) {
-        sink(" .\n\n", 4, writer);
-        reset_context(writer, true);
-      }
-      sink("@prefix ", 8, writer);
-      sink(serd_node_string(name), name->length, writer);
-      sink(": <", 3, writer);
-      write_uri_from_node(writer, uri);
-      sink("> .\n", 4, writer);
+  SerdStatus st = SERD_SUCCESS;
+
+  if (name->type != SERD_LITERAL || uri->type != SERD_URI) {
+    return SERD_ERR_BAD_ARG;
+  }
+
+  if ((st = serd_env_set_prefix(writer->env,
+                                serd_node_string_view(name),
+                                serd_node_string_view(uri)))) {
+    return st;
+  }
+
+  if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) {
+    if (ctx(writer, FIELD_GRAPH) || ctx(writer, FIELD_SUBJECT)) {
+      sink(" .\n\n", 4, writer);
+      reset_context(writer, true);
     }
-    writer->indent = 0;
-    return reset_context(writer, true);
+    sink("@prefix ", 8, writer);
+    sink(serd_node_string(name), name->length, writer);
+    sink(": <", 3, writer);
+    write_uri_from_node(writer, uri);
+    sink("> .\n", 4, writer);
   }
-  return SERD_ERR_UNKNOWN;
+
+  writer->indent = 0;
+  return reset_context(writer, true);
 }
 
 void