Add proof-of-concept stand-alone test binary which just prints Hello World

May it multiply in great numbers and help to stabilize the DOM
implementation.

src/dom/Makefile

@@ -4,4 +4,6 @@ include $(top_builddir)/Makefile.config
 SUBDIRS = css sgml
 OBJS = node.o select.o stack.o scanner.o
 
+SUBDIRS-$(CONFIG_DEBUG) += test
+
 include $(top_srcdir)/Makefile.lib

src/dom/test/Makefile

@@ -0,0 +1,23 @@
+top_builddir=../../..
+include $(top_builddir)/Makefile.config
+
+PROG = sgml-parser
+
+TESTDEPS = \
+ $(top_builddir)/src/dom/lib.o \
+ $(top_builddir)/src/util/error.o \
+ $(top_builddir)/src/osdep/stub.o \
+ $(top_builddir)/src/util/hash.o \
+ $(top_builddir)/src/util/string.o \
+ $(top_builddir)/src/util/memdebug.o \
+ $(top_builddir)/src/util/memory.o
+
+sgml-parser: $(TESTDEPS) sgml-parser.o
+	$(call cmd,link)
+
+test: sgml-parser
+	./sgml-parser
+
+CLEAN += sgml-parser.o
+
+include $(top_srcdir)/Makefile.lib

src/dom/test/sgml-parser.c

@@ -0,0 +1,212 @@
+/* Tool for testing the SGML parser */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "elinks.h"
+
+#include "dom/node.h"
+#include "dom/sgml/parser.h"
+#include "dom/stack.h"
+
+
+/* Compress a string to a single line with newlines etc. replaced with "\\n"
+ * sequence. */
+static inline unsigned char *
+compress_string(unsigned char *string, unsigned int length)
+{
+	struct string buffer;
+	unsigned char escape[2] = "\\";
+
+	if (!init_string(&buffer)) return NULL;
+
+	for (; length > 0; string++, length--) {
+		unsigned char *bytes = string;
+
+		if (*string == '\n' || *string == '\r' || *string == '\t') {
+			bytes	  = escape;
+			escape[1] = *string == '\n' ? 'n'
+				  : (*string == '\r' ? 'r' : 't');
+		}
+
+		add_bytes_to_string(&buffer, bytes, bytes == escape ? 2 : 1);
+	}
+
+	return buffer.source;
+}
+
+/* Set @string to the value of the given @node, however, with strings
+ * compressed and entity references 'expanded'. */
+static void
+set_enhanced_dom_node_value(struct dom_string *string, struct dom_node *node)
+{
+	struct dom_string *value;
+
+	assert(node);
+
+	memset(string, 0, sizeof(*string));
+
+	switch (node->type) {
+	case DOM_NODE_ENTITY_REFERENCE:
+		/* FIXME: Set to the entity value. */
+		string->string = null_or_stracpy(string->string);
+		break;
+
+	default:
+		value = get_dom_node_value(node);
+		if (!value) {
+			set_dom_string(string, NULL, 0);
+			return;
+		}
+
+		string->string = compress_string(value->string, value->length);
+	}
+
+	string->length = string->string ? strlen(string->string) : 0;
+}
+
+static unsigned char indent_string[] =
+	"                                                                    ";
+
+#define get_indent_offset(stack) \
+	((stack)->depth < sizeof(indent_string)/2 ? (stack)->depth * 2 : sizeof(indent_string))
+
+static void
+sgml_parser_test_tree(struct dom_stack *stack, struct dom_node *node, void *data)
+{
+	struct dom_string *value = &node->string;
+	struct dom_string *name = get_dom_node_name(node);
+
+	printf("%.*s %.*s: %.*s\n",
+		get_indent_offset(stack), indent_string,
+		name->length, name->string,
+		value->length, value->string);
+}
+
+static void
+sgml_parser_test_id_leaf(struct dom_stack *stack, struct dom_node *node, void *data)
+{
+	struct dom_string value;
+	struct dom_string *name;
+	struct dom_string *id;
+
+	assert(node);
+
+	name	= get_dom_node_name(node);
+	id	= get_dom_node_type_name(node->type);
+	set_enhanced_dom_node_value(&value, node);
+
+	printf("%.*s %.*s: %.*s -> %.*s\n",
+		get_indent_offset(stack), indent_string,
+		id->length, id->string, name->length, name->string,
+		value.length, value.string);
+
+	if (is_dom_string_set(&value))
+		done_dom_string(&value);
+}
+
+static void
+sgml_parser_test_leaf(struct dom_stack *stack, struct dom_node *node, void *data)
+{
+	struct dom_string *name;
+	struct dom_string value;
+
+	assert(node);
+
+	name	= get_dom_node_name(node);
+	set_enhanced_dom_node_value(&value, node);
+
+	printf("%.*s %.*s: %.*s\n",
+		get_indent_offset(stack), indent_string,
+		name->length, name->string,
+		value.length, value.string);
+
+	if (is_dom_string_set(&value))
+		done_dom_string(&value);
+}
+
+static void
+sgml_parser_test_branch(struct dom_stack *stack, struct dom_node *node, void *data)
+{
+	struct dom_string *name;
+	struct dom_string *id;
+
+	assert(node);
+
+	name	= get_dom_node_name(node);
+	id	= get_dom_node_type_name(node->type);
+
+	printf("%.*s %.*s: %.*s\n",
+		get_indent_offset(stack), indent_string,
+		id->length, id->string, name->length, name->string);
+}
+
+struct dom_stack_context_info sgml_parser_test_context_info = {
+	/* Object size: */			0,
+	/* Push: */
+	{
+		/*				*/ NULL,
+		/* DOM_NODE_ELEMENT		*/ sgml_parser_test_branch,
+		/* DOM_NODE_ATTRIBUTE		*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_TEXT		*/ sgml_parser_test_leaf,
+		/* DOM_NODE_CDATA_SECTION	*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_ENTITY_REFERENCE	*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_ENTITY		*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_PROC_INSTRUCTION	*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_COMMENT		*/ sgml_parser_test_leaf,
+		/* DOM_NODE_DOCUMENT		*/ sgml_parser_test_tree,
+		/* DOM_NODE_DOCUMENT_TYPE	*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_DOCUMENT_FRAGMENT	*/ sgml_parser_test_id_leaf,
+		/* DOM_NODE_NOTATION		*/ sgml_parser_test_id_leaf,
+	},
+	/* Pop: */
+	{
+		/*				*/ NULL,
+		/* DOM_NODE_ELEMENT		*/ NULL,
+		/* DOM_NODE_ATTRIBUTE		*/ NULL,
+		/* DOM_NODE_TEXT		*/ NULL,
+		/* DOM_NODE_CDATA_SECTION	*/ NULL,
+		/* DOM_NODE_ENTITY_REFERENCE	*/ NULL,
+		/* DOM_NODE_ENTITY		*/ NULL,
+		/* DOM_NODE_PROC_INSTRUCTION	*/ NULL,
+		/* DOM_NODE_COMMENT		*/ NULL,
+		/* DOM_NODE_DOCUMENT		*/ NULL,
+		/* DOM_NODE_DOCUMENT_TYPE	*/ NULL,
+		/* DOM_NODE_DOCUMENT_FRAGMENT	*/ NULL,
+		/* DOM_NODE_NOTATION		*/ NULL,
+	}
+};
+
+int
+main(int argc, char *argv[])
+{
+	struct dom_node *root;
+	struct sgml_parser *parser;
+	enum sgml_document_type doctype = SGML_DOCTYPE_HTML;
+	struct dom_string uri = INIT_DOM_STRING("dom://test", -1);
+	struct dom_string buffer = INIT_DOM_STRING("<html><body><p>Hello World!</p></body></html>", -1);
+
+	parser = init_sgml_parser(SGML_PARSER_STREAM, doctype, &uri);
+	if (!parser) return 1;
+
+	add_dom_stack_context(&parser->stack, NULL, &sgml_parser_test_context_info);
+
+	root = parse_sgml(parser, &buffer);
+	if (root) {
+		assert(parser->stack.depth == 1);
+
+		get_dom_stack_top(&parser->stack)->immutable = 0;
+		/* For SGML_PARSER_STREAM this will free the DOM
+		 * root node. */
+		pop_dom_node(&parser->stack);
+	}
+
+	done_sgml_parser(parser);
+
+	return 0;
+}