Gracefully handle NULL reader sinks.

Add serd_strerror.
Fix erroneously equal SERD_ERR_BAD_SYNTAX and SERD_ERR_BAD_ARG.


git-svn-id: http://svn.drobilla.net/serd/trunk@211 490d8e77-9747-427b-9fa3-0b8f29cee8a0

2 files changed, 51 insertions, 11 deletions

diff --git a/src/error.c b/src/error.c
new file mode 100644
index 00000000..cfab5a77
--- /dev/null
+++ b/src/error.c
@@ -0,0 +1,33 @@
+/*
+  Copyright 2011 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.
+*/
+
+#include "serd_internal.h"
+
+SERD_API
+const uint8_t*
+serd_strerror(SerdStatus st)
+{
+	switch (st) {
+	case SERD_SUCCESS:        return (const uint8_t*)"Success";
+	case SERD_FAILURE:        return (const uint8_t*)"Non-fatal failure";
+	case SERD_ERR_UNKNOWN:    return (const uint8_t*)"Unknown error";
+	case SERD_ERR_BAD_SYNTAX: return (const uint8_t*)"Invalid syntax";
+	case SERD_ERR_BAD_ARG:    return (const uint8_t*)"Invalid argument";
+	case SERD_ERR_NOT_FOUND:  return (const uint8_t*)"Not found";
+	}
+	return (const uint8_t*)"Success";  // never reached
+}
+
diff --git a/src/reader.c b/src/reader.c
index 24802164..3cb2e3db 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -15,6 +15,7 @@
 */
 
 #include <assert.h>
+#include <errno.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -316,14 +317,15 @@ emit_statement(SerdReader* reader, SerdStatementFlags* flags,
 	const SerdNode datatype  = public_node(reader, d);
 	const SerdNode lang      = public_node_from_ref(reader, SERD_LITERAL, l);
 	object.flags = f;
-	bool ret = !reader->statement_sink(reader->handle,
-	                                   *flags,
-	                                   &graph,
-	                                   &subject,
-	                                   &predicate,
-	                                   &object,
-	                                   &datatype,
-	                                   &lang);
+	bool ret = !reader->statement_sink
+		|| !reader->statement_sink(reader->handle,
+		                           *flags,
+		                           &graph,
+		                           &subject,
+		                           &predicate,
+		                           &object,
+		                           &datatype,
+		                           &lang);
 	*flags = (*flags & SERD_ANON_CONT) ? SERD_ANON_CONT : 0;
 	return ret;
 }
@@ -1326,7 +1328,9 @@ read_base(SerdReader* reader)
 	Ref uri;
 	TRY_RET(uri = read_uriref(reader));
 	const SerdNode uri_node = public_node_from_ref(reader, SERD_URI, uri);
-	reader->base_sink(reader->handle, &uri_node);
+	if (reader->base_sink) {
+		reader->base_sink(reader->handle, &uri_node);
+	}
 	pop_string(reader, uri);
 	return true;
 }
@@ -1339,7 +1343,7 @@ read_prefixID(SerdReader* reader)
 	// `@' is already eaten in read_directive
 	eat_string(reader, "prefix", 6);
 	TRY_RET(read_ws_plus(reader));
-	bool ret = false;
+	bool ret = true;
 	Ref name = read_prefixName(reader);
 	if (!name) {
 		name = push_string(reader, "", 0);
@@ -1350,7 +1354,9 @@ read_prefixID(SerdReader* reader)
 	TRY_THROW(uri = read_uriref(reader));
 	const SerdNode name_node = public_node_from_ref(reader, SERD_LITERAL, name);
 	const SerdNode uri_node  = public_node_from_ref(reader, SERD_URI, uri);
-	ret = !reader->prefix_sink(reader->handle, &name_node, &uri_node);
+	if (reader->prefix_sink) {
+		ret = !reader->prefix_sink(reader->handle, &name_node, &uri_node);
+	}
 	pop_string(reader, uri);
 except:
 	pop_string(reader, name);
@@ -1503,6 +1509,7 @@ serd_reader_read_file(SerdReader*    reader,
 
 	FILE* fd = fopen((const char*)path, "r");
 	if (!fd) {
+		fprintf(stderr, "Error opening file %s (%s)\n", path, strerror(errno));
 		return SERD_ERR_UNKNOWN;
 	}
 	SerdStatus ret = serd_reader_read_file_handle(reader, fd, path);