/*
 * This file is part of LibCSS.
 * Licensed under the MIT License,
 *		  http://www.opensource.org/licenses/mit-license.php
 * Copyright 2008 John-Mark Bell <jmb@netsurf-browser.org>
 */

#include <assert.h>
#include <string.h>

#include <parserutils/utils/stack.h>

#include "stylesheet.h"
#include "lex/lex.h"
#include "parse/font_face.h"
#include "parse/important.h"
#include "parse/language.h"
#include "parse/parse.h"
#include "parse/propstrings.h"
#include "parse/properties/properties.h"
#include "parse/properties/utils.h"

#include "utils/parserutilserror.h"
#include "utils/utils.h"

typedef struct context_entry {
	css_parser_event type;		/**< Type of entry */
	void *data;			/**< Data for context */
} context_entry;

/* Event handlers */
static css_error language_handle_event(css_parser_event type, 
		const parserutils_vector *tokens, void *pw);
static css_error handleStartStylesheet(css_language *c, 
		const parserutils_vector *vector);
static css_error handleEndStylesheet(css_language *c, 
		const parserutils_vector *vector);
static css_error handleStartRuleset(css_language *c, 
		const parserutils_vector *vector);
static css_error handleEndRuleset(css_language *c, 
		const parserutils_vector *vector);
static css_error handleStartAtRule(css_language *c, 
		const parserutils_vector *vector);
static css_error handleEndAtRule(css_language *c, 
		const parserutils_vector *vector);
static css_error handleStartBlock(css_language *c, 
		const parserutils_vector *vector);
static css_error handleEndBlock(css_language *c, 
		const parserutils_vector *vector);
static css_error handleBlockContent(css_language *c, 
		const parserutils_vector *vector);
static css_error handleDeclaration(css_language *c, 
		const parserutils_vector *vector);

/* At-rule parsing */
static css_error parseMediaList(css_language *c,
		const parserutils_vector *vector, int *ctx,
		uint64_t *media);
static css_error addNamespace(css_language *c, 
		lwc_string *prefix, lwc_string *uri);
static css_error lookupNamespace(css_language *c, 
		lwc_string *prefix, lwc_string **uri);

/* Selector list parsing */
static css_error parseClass(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_selector_detail *specific);
static css_error parseAttrib(css_language *c, 
		const parserutils_vector *vector, int *ctx,
		css_selector_detail *specific);
static css_error parseNth(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_selector_detail_value *value);
static css_error parsePseudo(css_language *c,
		const parserutils_vector *vector, int *ctx,
		bool in_not, css_selector_detail *specific);
static css_error parseSpecific(css_language *c,
		const parserutils_vector *vector, int *ctx,
		bool in_not, css_selector_detail *specific);
static css_error parseAppendSpecific(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_selector **parent);
static css_error parseSelectorSpecifics(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_selector **parent);
static css_error parseTypeSelector(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_qname *qname);
static css_error parseSimpleSelector(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_selector **result);
static css_error parseCombinator(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_combinator *result);
static css_error parseSelector(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_selector **result);
static css_error parseSelectorList(css_language *c, 
		const parserutils_vector *vector, css_rule *rule);

/* Declaration parsing */
static css_error parseProperty(css_language *c,
		const css_token *property, const parserutils_vector *vector,
		int *ctx, css_rule *rule);

/**
 * Create a CSS language parser
 *
 * \param sheet	    The stylesheet object to parse for
 * \param parser    The core parser object to use
 * \param alloc	    Memory (de)allocation function
 * \param pw	    Pointer to client-specific private data
 * \param language  Pointer to location to receive parser object
 * \return CSS_OK on success,
 *	   CSS_BADPARM on bad parameters,
 *	   CSS_NOMEM on memory exhaustion
 */
css_error css__language_create(css_stylesheet *sheet, css_parser *parser,
		css_allocator_fn alloc, void *pw, void **language)
{
	css_language *c;
	css_parser_optparams params;
	parserutils_error perror;
	css_error error;

	if (sheet == NULL || parser == NULL || alloc == NULL || 
			language == NULL)
		return CSS_BADPARM;

	c = alloc(NULL, sizeof(css_language), pw);
	if (c == NULL)
		return CSS_NOMEM;

	perror = parserutils_stack_create(sizeof(context_entry), 
			STACK_CHUNK, (parserutils_alloc) alloc, pw, 
			&c->context);
	if (perror != PARSERUTILS_OK) {
		alloc(c, 0, pw);
		return css_error_from_parserutils_error(perror);
	}

	params.event_handler.handler = language_handle_event;
	params.event_handler.pw = c;
	error = css__parser_setopt(parser, CSS_PARSER_EVENT_HANDLER, &params);
	if (error != CSS_OK) {
		parserutils_stack_destroy(c->context);
		alloc(c, 0, pw);
		return error;
	}

	c->sheet = sheet;
	c->state = CHARSET_PERMITTED;
	c->default_namespace = NULL;
	c->namespaces = NULL;
	c->num_namespaces = 0;
	c->strings = sheet->propstrings;
	c->alloc = alloc;
	c->pw = pw;

	*language = c;

	return CSS_OK;
}

/**
 * Destroy a CSS language parser
 *
 * \param language  The parser to destroy
 * \return CSS_OK on success, appropriate error otherwise
 */
css_error css__language_destroy(css_language *language)
{
	uint32_t i;
	
	if (language == NULL)
		return CSS_BADPARM;

	if (language->default_namespace != NULL)
		lwc_string_unref(language->default_namespace);

	if (language->namespaces != NULL) {
		for (i = 0; i < language->num_namespaces; i++) {
			lwc_string_unref(language->namespaces[i].prefix);
			lwc_string_unref(language->namespaces[i].uri);
		}

		language->alloc(language->namespaces, 0, language->pw);
	}

	parserutils_stack_destroy(language->context);
	
	language->alloc(language, 0, language->pw);

	return CSS_OK;
}

/**
 * Handler for core parser events
 *
 * \param type	  The event type
 * \param tokens  Vector of tokens read since last event, or NULL
 * \param pw	  Pointer to handler context
 * \return CSS_OK on success, CSS_INVALID to indicate parse error, 
 *	   appropriate error otherwise.
 */
css_error language_handle_event(css_parser_event type, 
		const parserutils_vector *tokens, void *pw)
{
	css_language *language = (css_language *) pw;

	switch (type) {
	case CSS_PARSER_START_STYLESHEET:
		return handleStartStylesheet(language, tokens);
	case CSS_PARSER_END_STYLESHEET:
		return handleEndStylesheet(language, tokens);
	case CSS_PARSER_START_RULESET:
		return handleStartRuleset(language, tokens);
	case CSS_PARSER_END_RULESET:
		return handleEndRuleset(language, tokens);
	case CSS_PARSER_START_ATRULE:
		return handleStartAtRule(language, tokens);
	case CSS_PARSER_END_ATRULE:
		return handleEndAtRule(language, tokens);
	case CSS_PARSER_START_BLOCK:
		return handleStartBlock(language, tokens);
	case CSS_PARSER_END_BLOCK:
		return handleEndBlock(language, tokens);
	case CSS_PARSER_BLOCK_CONTENT:
		return handleBlockContent(language, tokens);
	case CSS_PARSER_DECLARATION:
		return handleDeclaration(language, tokens);
	}

	return CSS_OK;
}

/******************************************************************************
 * Parser stages							      *
 ******************************************************************************/

css_error handleStartStylesheet(css_language *c, 
		const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry entry = { CSS_PARSER_START_STYLESHEET, NULL };

	UNUSED(vector);

	assert(c != NULL);

	perror = parserutils_stack_push(c->context, (void *) &entry);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	return CSS_OK;
}

css_error handleEndStylesheet(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry *entry;

	UNUSED(vector);

	assert(c != NULL);

	entry = parserutils_stack_get_current(c->context);
	if (entry == NULL || entry->type != CSS_PARSER_START_STYLESHEET)
		return CSS_INVALID;

	perror = parserutils_stack_pop(c->context, NULL);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	return CSS_OK;
}

css_error handleStartRuleset(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	css_error error;
	context_entry entry = { CSS_PARSER_START_RULESET, NULL };
	context_entry *cur;
	css_rule *parent_rule = NULL;
	css_rule *rule = NULL;

	assert(c != NULL);

	/* Retrieve parent rule from stack, if any */
	cur = parserutils_stack_get_current(c->context);
	if (cur != NULL && cur->type != CSS_PARSER_START_STYLESHEET)
		parent_rule = cur->data;

	error = css__stylesheet_rule_create(c->sheet, CSS_RULE_SELECTOR, &rule);
	if (error != CSS_OK)
		return error;

	if (vector != NULL) {
		/* Parse selectors, if there are any */
		error = parseSelectorList(c, vector, rule);
		if (error != CSS_OK) {
			css__stylesheet_rule_destroy(c->sheet, rule);
			return error;
		}
	}

	entry.data = rule;

	perror = parserutils_stack_push(c->context, (void *) &entry);
	if (perror != PARSERUTILS_OK) {
		css__stylesheet_rule_destroy(c->sheet, rule);
		return css_error_from_parserutils_error(perror);
	}

	error = css__stylesheet_add_rule(c->sheet, rule, parent_rule);
	if (error != CSS_OK) {
		parserutils_stack_pop(c->context, NULL);
		css__stylesheet_rule_destroy(c->sheet, rule);
		return error;
	}

	/* Flag that we've had a valid rule, so @import/@namespace/@charset 
	 * have no effect. */
	c->state = HAD_RULE;

	/* Rule is now owned by the sheet, so no need to destroy it */

	return CSS_OK;
}

css_error handleEndRuleset(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry *entry;

	UNUSED(vector);

	assert(c != NULL);

	entry = parserutils_stack_get_current(c->context);
	if (entry == NULL || entry->type != CSS_PARSER_START_RULESET)
		return CSS_INVALID;

	perror = parserutils_stack_pop(c->context, NULL);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	return CSS_OK;
}

css_error handleStartAtRule(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry entry = { CSS_PARSER_START_ATRULE, NULL };
	const css_token *token = NULL;
	const css_token *atkeyword = NULL;
	int32_t ctx = 0;
	bool match = false;
	css_rule *rule;
	css_error error;

	/* vector contains: ATKEYWORD ws any0 */

	assert(c != NULL);

	atkeyword = parserutils_vector_iterate(vector, &ctx);

	consumeWhitespace(vector, &ctx);

	/* We now have an ATKEYWORD and the context for the start of any0, if 
	 * there is one */
	assert(atkeyword != NULL && atkeyword->type == CSS_TOKEN_ATKEYWORD);

	if (lwc_string_caseless_isequal(atkeyword->idata, c->strings[CHARSET], 
			&match) == lwc_error_ok && match) {
		if (c->state == CHARSET_PERMITTED) {
			const css_token *charset;

			/* any0 = STRING */
			if (ctx == 0)
				return CSS_INVALID;

			charset = parserutils_vector_iterate(vector, &ctx);
			if (charset == NULL || 
					charset->type != CSS_TOKEN_STRING)
				return CSS_INVALID;

			token = parserutils_vector_iterate(vector, &ctx);
			if (token != NULL)
				return CSS_INVALID;

			error = css__stylesheet_rule_create(c->sheet, 
					CSS_RULE_CHARSET, &rule);
			if (error != CSS_OK)
				return error;

			error = css__stylesheet_rule_set_charset(c->sheet, rule,
					charset->idata);
			if (error != CSS_OK) {
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}

			error = css__stylesheet_add_rule(c->sheet, rule, NULL);
			if (error != CSS_OK) {
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}

			/* Rule is now owned by the sheet, 
			 * so no need to destroy it */

			c->state = IMPORT_PERMITTED;
		} else {
			return CSS_INVALID;
		}
	} else if (lwc_string_caseless_isequal(atkeyword->idata, 
			c->strings[LIBCSS_IMPORT], &match) == lwc_error_ok && 
			match) {
		if (c->state <= IMPORT_PERMITTED) {
			lwc_string *url;
			uint64_t media = 0;

			/* any0 = (STRING | URI) ws 
			 *	  (IDENT ws (',' ws IDENT ws)* )? */
			const css_token *uri = 
				parserutils_vector_iterate(vector, &ctx);
			if (uri == NULL || (uri->type != CSS_TOKEN_STRING && 
					uri->type != CSS_TOKEN_URI))
				return CSS_INVALID;

			consumeWhitespace(vector, &ctx);

			/* Parse media list */
			error = parseMediaList(c, vector, &ctx, &media);
			if (error != CSS_OK)
				return error;

			/* Create rule */
			error = css__stylesheet_rule_create(c->sheet, 
					CSS_RULE_IMPORT, &rule);
			if (error != CSS_OK)
				return error;

			/* Resolve import URI */
			error = c->sheet->resolve(c->sheet->resolve_pw,
					c->sheet->url,
					uri->idata, &url);
			if (error != CSS_OK) {
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}

			/* Inform rule of it */
			error = css__stylesheet_rule_set_nascent_import(c->sheet,
					rule, url, media);
			if (error != CSS_OK) {
				lwc_string_unref(url);
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}

			/* Inform client of need for import */
			if (c->sheet->import != NULL) {
				error = c->sheet->import(c->sheet->import_pw,
						c->sheet, url, media);
				if (error != CSS_OK) {
					lwc_string_unref(url);
					css__stylesheet_rule_destroy(c->sheet, 
							rule);
					return error;
				}
			}

			/* No longer care about url */
			lwc_string_unref(url);

			/* Add rule to sheet */
			error = css__stylesheet_add_rule(c->sheet, rule, NULL);
			if (error != CSS_OK) {
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}

			/* Rule is now owned by the sheet, 
			 * so no need to destroy it */

			c->state = IMPORT_PERMITTED;
		} else {
			return CSS_INVALID;
		}
	} else if (lwc_string_caseless_isequal(atkeyword->idata, 
			c->strings[NAMESPACE], &match) == lwc_error_ok && 
			match) {
		if (c->state <= NAMESPACE_PERMITTED) {
			lwc_string *prefix = NULL;

			/* any0 = (IDENT ws)? (STRING | URI) ws */

			token = parserutils_vector_iterate(vector, &ctx);
			if (token == NULL)
				return CSS_INVALID;

			if (token->type == CSS_TOKEN_IDENT) {
				prefix = token->idata;

				consumeWhitespace(vector, &ctx);

				token = parserutils_vector_iterate(vector, 
						&ctx);
			}

			if (token == NULL || (token->type != CSS_TOKEN_STRING &&
					token->type != CSS_TOKEN_URI)) {
				return CSS_INVALID;
			}

			consumeWhitespace(vector, &ctx);

			error = addNamespace(c, prefix, token->idata);
			if (error != CSS_OK)
				return error;

			c->state = NAMESPACE_PERMITTED;
		} else {
			return CSS_INVALID;
		}
	} else if (lwc_string_caseless_isequal(atkeyword->idata, c->strings[MEDIA], 
			&match) == lwc_error_ok && match) {
		uint64_t media = 0;

		/* any0 = IDENT ws (',' ws IDENT ws)* */

		error = parseMediaList(c, vector, &ctx, &media);
		if (error != CSS_OK)
			return error;

		error = css__stylesheet_rule_create(c->sheet, 
				CSS_RULE_MEDIA, &rule);
		if (error != CSS_OK)
			return error;

		error = css__stylesheet_rule_set_media(c->sheet, rule, media);
		if (error != CSS_OK) {
			css__stylesheet_rule_destroy(c->sheet, rule);
			return error;
		}

		error = css__stylesheet_add_rule(c->sheet, rule, NULL);
		if (error != CSS_OK) {
			css__stylesheet_rule_destroy(c->sheet, rule);
			return error;
		}

		/* Rule is now owned by the sheet, 
		 * so no need to destroy it */

		c->state = HAD_RULE;
	} else if (lwc_string_caseless_isequal(atkeyword->idata, 
			c->strings[FONT_FACE], &match) == lwc_error_ok && 
			match) {
		error = css__stylesheet_rule_create(c->sheet,
				CSS_RULE_FONT_FACE, &rule);
		if (error != CSS_OK)
			return error;
		
		consumeWhitespace(vector, &ctx);

		error = css__stylesheet_add_rule(c->sheet, rule, NULL);
		if (error != CSS_OK) {
			css__stylesheet_rule_destroy(c->sheet, rule);
			return error;
		}

		/* Rule is now owned by the sheet, 
		 * so no need to destroy it */

		c->state = HAD_RULE;
	} else if (lwc_string_caseless_isequal(atkeyword->idata, c->strings[PAGE], 
			&match) == lwc_error_ok && match) {
		const css_token *token;

		/* any0 = (':' IDENT)? ws */

		error = css__stylesheet_rule_create(c->sheet,
				CSS_RULE_PAGE, &rule);
		if (error != CSS_OK)
			return error;

		consumeWhitespace(vector, &ctx);

		token = parserutils_vector_peek(vector, ctx);
		if (token != NULL) {
			css_selector *sel = NULL;

			error = parseSelector(c, vector, &ctx, &sel);
			if (error != CSS_OK) {
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}

			error = css__stylesheet_rule_set_page_selector(c->sheet,
					rule, sel);
			if (error != CSS_OK) {
				css__stylesheet_selector_destroy(c->sheet, sel);
				css__stylesheet_rule_destroy(c->sheet, rule);
				return error;
			}
		}

		error = css__stylesheet_add_rule(c->sheet, rule, NULL);
		if (error != CSS_OK) {
			css__stylesheet_rule_destroy(c->sheet, rule);
			return error;
		}

		/* Rule is now owned by the sheet, 
		 * so no need to destroy it */

		c->state = HAD_RULE;
	} else {
		return CSS_INVALID;
	}

	entry.data = rule;

	perror = parserutils_stack_push(c->context, (void *) &entry);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	return CSS_OK;
}

css_error handleEndAtRule(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry *entry;

	UNUSED(vector);

	assert(c != NULL);

	entry = parserutils_stack_get_current(c->context);
	if (entry == NULL || entry->type != CSS_PARSER_START_ATRULE)
		return CSS_INVALID;

	perror = parserutils_stack_pop(c->context, NULL);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	return CSS_OK;
}

css_error handleStartBlock(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry entry = { CSS_PARSER_START_BLOCK, NULL };
	context_entry *cur;

	UNUSED(vector);

	/* If the current item on the stack isn't a block, 
	 * then clone its data field. This ensures that the relevant rule
	 * is available when parsing the block contents. */
	cur = parserutils_stack_get_current(c->context);
	if (cur != NULL && cur->type != CSS_PARSER_START_BLOCK)
		entry.data = cur->data;

	perror = parserutils_stack_push(c->context, (void *) &entry);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	return CSS_OK;
}

css_error handleEndBlock(css_language *c, const parserutils_vector *vector)
{
	parserutils_error perror;
	context_entry *entry;
	css_rule *rule;

	UNUSED(vector);

	entry = parserutils_stack_get_current(c->context);
	if (entry == NULL || entry->type != CSS_PARSER_START_BLOCK)
		return CSS_INVALID;

	rule = entry->data;

	perror = parserutils_stack_pop(c->context, NULL);
	if (perror != PARSERUTILS_OK) {
		return css_error_from_parserutils_error(perror);
	}

	/* If the block we just popped off the stack was associated with a 
	 * non-block stack entry, and that entry is not a top-level statement,
	 * then report the end of that entry, too. */
	if (rule != NULL && rule->ptype != CSS_RULE_PARENT_STYLESHEET) {
		if (rule->type == CSS_RULE_SELECTOR)
			return handleEndRuleset(c, vector);
	}

	return CSS_OK;
}

css_error handleBlockContent(css_language *c, const parserutils_vector *vector)
{
	context_entry *entry;
	css_rule *rule;

	/* Block content comprises either declarations (if the current block is
	 * associated with @page, @font-face or a selector), or rulesets (if the
	 * current block is associated with @media). */

	entry = parserutils_stack_get_current(c->context);
	if (entry == NULL || entry->data == NULL)
		return CSS_INVALID;

	rule = entry->data;
	if (rule == NULL || (rule->type != CSS_RULE_SELECTOR && 
			rule->type != CSS_RULE_PAGE &&
			rule->type != CSS_RULE_MEDIA && 
			rule->type != CSS_RULE_FONT_FACE))
		return CSS_INVALID;

	if (rule->type == CSS_RULE_MEDIA) {
		/* Expect rulesets */
		return handleStartRuleset(c, vector);
	} else {
		/* Expect declarations */
		return handleDeclaration(c, vector);
	}

	return CSS_OK;
}

css_error handleDeclaration(css_language *c, const parserutils_vector *vector)
{
	css_error error;
	const css_token *token, *ident;
	int ctx = 0;
	context_entry *entry;
	css_rule *rule;

	/* Locations where declarations are permitted:
	 *
	 * + In @page
	 * + In @font-face
	 * + In ruleset
	 */
	entry = parserutils_stack_get_current(c->context);
	if (entry == NULL || entry->data == NULL)
		return CSS_INVALID;

	rule = entry->data;
	if (rule == NULL || (rule->type != CSS_RULE_SELECTOR && 
				rule->type != CSS_RULE_PAGE && 
				rule->type != CSS_RULE_FONT_FACE))
		return CSS_INVALID;

	/* Strip any leading whitespace (can happen if in nested block) */
	consumeWhitespace(vector, &ctx);

	/* IDENT ws ':' ws value 
	 * 
	 * In CSS 2.1, value is any1, so '{' or ATKEYWORD => parse error
	 */
	ident = parserutils_vector_iterate(vector, &ctx);
	if (ident == NULL || ident->type != CSS_TOKEN_IDENT)
		return CSS_INVALID;

	consumeWhitespace(vector, &ctx);

	token = parserutils_vector_iterate(vector, &ctx);
	if (token == NULL || tokenIsChar(token, ':') == false)
		return CSS_INVALID;

	consumeWhitespace(vector, &ctx);

	if (rule->type == CSS_RULE_FONT_FACE) {
		css_rule_font_face * ff_rule = (css_rule_font_face *) rule;
		error = css__parse_font_descriptor(
				c, ident, vector, &ctx, ff_rule);
	} else {
		error = parseProperty(c, ident, vector, &ctx, rule);
	}
	if (error != CSS_OK)
		return error;

	return CSS_OK;
}

/******************************************************************************
 * At-rule parsing functions						      *
 ******************************************************************************/

css_error parseMediaList(css_language *c,
		const parserutils_vector *vector, int *ctx,
		uint64_t *media)
{
	uint64_t ret = 0;
	bool match = false;
	const css_token *token;

	token = parserutils_vector_iterate(vector, ctx);

	while (token != NULL) {
		if (token->type != CSS_TOKEN_IDENT)
			return CSS_INVALID;

		if (lwc_string_caseless_isequal(token->idata, c->strings[AURAL], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_AURAL;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[BRAILLE], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_BRAILLE;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[EMBOSSED], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_EMBOSSED;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[HANDHELD], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_HANDHELD;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[PRINT], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_PRINT;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[PROJECTION], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_PROJECTION;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[SCREEN], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_SCREEN;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[SPEECH], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_SPEECH;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[TTY], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_TTY;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[TV], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_TV;
		} else if (lwc_string_caseless_isequal(
				token->idata, c->strings[ALL], 
				&match) == lwc_error_ok && match) {
			ret |= CSS_MEDIA_ALL;
		} else
			return CSS_INVALID;

		consumeWhitespace(vector, ctx);

		token = parserutils_vector_iterate(vector, ctx);
		if (token != NULL && tokenIsChar(token, ',') == false)
			return CSS_INVALID;

		consumeWhitespace(vector, ctx);
	}

	/* If, after parsing the media list, we still have no media, 
	 * then it must be ALL. */
	if (ret == 0)
		ret = CSS_MEDIA_ALL;

	*media = ret;

	return CSS_OK;
}

/**
 * Add a namespace mapping
 *
 * \param c       Parsing context to add to
 * \param prefix  Namespace prefix, or NULL for default namespace
 * \param uri     Namespace URI
 * \return CSS_OK on success, CSS_NOMEM on memory exhaustion.
 */
css_error addNamespace(css_language *c, lwc_string *prefix, lwc_string *uri)
{
	if (prefix == NULL) {
		/* Replace default namespace */
		if (c->default_namespace != NULL)
			lwc_string_unref(c->default_namespace);

		/* Special case: if new namespace uri is "", use NULL */
		if (lwc_string_length(uri) == 0)
			c->default_namespace = NULL;
		else
			c->default_namespace = lwc_string_ref(uri);
	} else {
		/* Replace, or add mapping */
		bool match;
		uint32_t idx;

		for (idx = 0; idx < c->num_namespaces; idx++) {
			if (lwc_string_isequal(c->namespaces[idx].prefix,
					prefix, &match) == lwc_error_ok &&
					match)
				break;
		}

		if (idx == c->num_namespaces) {
			/* Not found, create a new mapping */
			css_namespace *ns = c->alloc(c->namespaces, 
					sizeof(css_namespace) * 
						(c->num_namespaces + 1), 
					c->pw);

			if (ns == NULL)
				return CSS_NOMEM;

			ns[idx].prefix = lwc_string_ref(prefix);
			ns[idx].uri = NULL;

			c->namespaces = ns;
			c->num_namespaces++;
		}

		/* Replace namespace URI */
		if (c->namespaces[idx].uri != NULL)
			lwc_string_unref(c->namespaces[idx].uri);

		/* Special case: if new namespace uri is "", use NULL */
		if (lwc_string_length(uri) == 0)
			c->namespaces[idx].uri = NULL;
		else
			c->namespaces[idx].uri = lwc_string_ref(uri);
	}

	return CSS_OK;
}

/**
 * Look up a namespace prefix
 *
 * \param c       Language parser context
 * \param prefix  Namespace prefix to find, or NULL for none
 * \param uri     Pointer to location to receive namespace URI
 * \return CSS_OK on success, CSS_INVALID if prefix is not found
 */
css_error lookupNamespace(css_language *c, lwc_string *prefix, lwc_string **uri)
{
	uint32_t idx;
	bool match;

	if (prefix == NULL) {
		*uri = NULL;
	} else {
		for (idx = 0; idx < c->num_namespaces; idx++) {
			if (lwc_string_isequal(c->namespaces[idx].prefix,
					prefix, &match) == lwc_error_ok &&
					match)
				break;
		}

		if (idx == c->num_namespaces)
			return CSS_INVALID;

		*uri = c->namespaces[idx].uri;
	}

	return CSS_OK;
}

/******************************************************************************
 * Selector list parsing functions					      *
 ******************************************************************************/

css_error parseClass(css_language *c, const parserutils_vector *vector, 
		int *ctx, css_selector_detail *specific)
{
	css_qname qname;
	css_selector_detail_value detail_value;
	const css_token *token;

	/* class     -> '.' IDENT */
	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL || tokenIsChar(token, '.') == false)
		return CSS_INVALID;

	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL || token->type != CSS_TOKEN_IDENT)
		return CSS_INVALID;

	detail_value.string = NULL;

	qname.ns = NULL;
	qname.name = token->idata;

	return css__stylesheet_selector_detail_init(c->sheet, 
			CSS_SELECTOR_CLASS, &qname, detail_value,
			CSS_SELECTOR_DETAIL_VALUE_STRING, false, specific);
}

css_error parseAttrib(css_language *c, const parserutils_vector *vector, 
		int *ctx, css_selector_detail *specific)
{
	css_qname qname;
	css_selector_detail_value detail_value;
	const css_token *token, *value = NULL;
	css_selector_type type = CSS_SELECTOR_ATTRIBUTE;
	css_error error;
	lwc_string *prefix = NULL;

	/* attrib    -> '[' ws namespace_prefix? IDENT ws [
	 *		       [ '=' | 
	 *		         INCLUDES | 
	 *		         DASHMATCH | 
	 *		         PREFIXMATCH |
	 *		         SUFFIXMATCH | 
	 *		         SUBSTRINGMATCH 
	 *		       ] ws
	 *		       [ IDENT | STRING ] ws ]? ']'
	 * namespace_prefix -> [ IDENT | '*' ]? '|'
	 */
	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL || tokenIsChar(token, '[') == false)
		return CSS_INVALID;

	consumeWhitespace(vector, ctx);

	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL || (token->type != CSS_TOKEN_IDENT &&
			tokenIsChar(token, '*') == false &&
			tokenIsChar(token, '|') == false))
		return CSS_INVALID;

	if (tokenIsChar(token, '|')) {
		token = parserutils_vector_iterate(vector, ctx);
	} else {
		const css_token *temp;

		temp = parserutils_vector_peek(vector, *ctx);
		if (temp != NULL && tokenIsChar(temp, '|')) {
			prefix = token->idata;

			parserutils_vector_iterate(vector, ctx);

			token = parserutils_vector_iterate(vector, ctx);
		}
	}

	if (token == NULL || token->type != CSS_TOKEN_IDENT)
		return CSS_INVALID;

	error = lookupNamespace(c, prefix, &qname.ns);
	if (error != CSS_OK)
		return error;

	qname.name = token->idata;

	consumeWhitespace(vector, ctx);

	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL)
		return CSS_INVALID;

	if (tokenIsChar(token, ']') == false) {
		if (tokenIsChar(token, '='))
			type = CSS_SELECTOR_ATTRIBUTE_EQUAL;
		else if (token->type == CSS_TOKEN_INCLUDES)
			type = CSS_SELECTOR_ATTRIBUTE_INCLUDES;
		else if (token->type == CSS_TOKEN_DASHMATCH)
			type = CSS_SELECTOR_ATTRIBUTE_DASHMATCH;
		else if (token->type == CSS_TOKEN_PREFIXMATCH)
			type = CSS_SELECTOR_ATTRIBUTE_PREFIX;
		else if (token->type == CSS_TOKEN_SUFFIXMATCH)
			type = CSS_SELECTOR_ATTRIBUTE_SUFFIX;
		else if (token->type == CSS_TOKEN_SUBSTRINGMATCH)
			type = CSS_SELECTOR_ATTRIBUTE_SUBSTRING;
		else
			return CSS_INVALID;

		consumeWhitespace(vector, ctx);

		token = parserutils_vector_iterate(vector, ctx);
		if (token == NULL || (token->type != CSS_TOKEN_IDENT &&
				token->type != CSS_TOKEN_STRING))
			return CSS_INVALID;

		value = token;

		consumeWhitespace(vector, ctx);

		token = parserutils_vector_iterate(vector, ctx);
		if (token == NULL || tokenIsChar(token, ']') == false)
			return CSS_INVALID;
	}

	detail_value.string = value != NULL ? value->idata : NULL;

	return css__stylesheet_selector_detail_init(c->sheet, type, 
			&qname, detail_value, 
			CSS_SELECTOR_DETAIL_VALUE_STRING, false, specific);
}

css_error parseNth(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_selector_detail_value *value)
{
	const css_token *token;
	bool match;

	/* nth -> [ DIMENSION | IDENT ] ws [ [ CHAR ws ]? NUMBER ws ]?
	 *        (e.g. DIMENSION: 2n-1, 2n- 1, 2n -1, 2n - 1)
	 *        (e.g. IDENT: -n-1, -n- 1, -n -1, -n - 1)
	 *     -> NUMBER ws
	 *     -> IDENT(odd) ws
	 *     -> IDENT(even) ws
	 */

	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL || (token->type != CSS_TOKEN_IDENT &&
			token->type != CSS_TOKEN_NUMBER &&
			token->type != CSS_TOKEN_DIMENSION))
		return CSS_INVALID;

	if (token->type == CSS_TOKEN_IDENT &&
			lwc_string_caseless_isequal(token->idata,
				c->strings[ODD], &match) == lwc_error_ok &&
			match) {
		/* Odd */
		value->nth.a = 2;
		value->nth.b = 1;
	} else if (token->type == CSS_TOKEN_IDENT &&
			lwc_string_caseless_isequal(token->idata,
				c->strings[EVEN], &match) == lwc_error_ok &&
			match) {
		/* Even */
		value->nth.a = 2;
		value->nth.b = 0;
	} else if (token->type == CSS_TOKEN_NUMBER) {
		size_t consumed = 0;
		css_fixed val = 0;

		val = css__number_from_lwc_string(token->idata,
				true, &consumed);
		if (consumed != lwc_string_length(token->idata))
			return CSS_INVALID;

		value->nth.a = 0;
		value->nth.b = FIXTOINT(val);
	} else {
		/* [ DIMENSION | IDENT ] ws [ [ CHAR ws ]? NUMBER ws ]?
		 *
		 * (e.g. DIMENSION: 2n-1, 2n- 1, 2n -1, 2n - 1)
		 * (e.g. IDENT: n, -n-1, -n- 1, -n -1, -n - 1)
		 */
		size_t consumed = 0, len;
		const char *data;
		css_fixed a = 0, b = 0;
		int sign = 1;
		bool had_sign = false, had_b = false;

		len = lwc_string_length(token->idata);
		data = lwc_string_data(token->idata);

		/* Compute a */
		if (token->type == CSS_TOKEN_IDENT) {
			if (len < 2) {
				if (data[0] != 'n' && data[0] != 'N')
					return CSS_INVALID;

				/* n */
				a = INTTOFIX(1);

				data += 1;
				len -= 1;
			} else {
				if (data[0] != '-' || 
					(data[1] != 'n' && data[1] != 'N'))
					return CSS_INVALID;

				/* -n */
				a = INTTOFIX(-1);

				data += 2;
				len -= 2;
			}

			if (len > 0) {
				if (data[0] != '-')
					return CSS_INVALID;

				/* -n- */
				sign = -1;
				had_sign = true;

				if (len > 1) {
					/* Reject additional sign */
					if (data[1] == '-' || data[1] == '+')
						return CSS_INVALID;

					/* -n-b */
					b = css__number_from_string(
						(const uint8_t *) data + 1, 
						len - 1,
						true,
						&consumed);
					if (consumed != len - 1)
						return CSS_INVALID;

					had_b = true;
				}
			}
		} else {
			/* 2n */
			a = css__number_from_lwc_string(token->idata, 
					true, &consumed);
			if (consumed == 0 || (data[consumed] != 'n' &&
					data[consumed] != 'N'))
				return CSS_INVALID;

			if (len - (++consumed) > 0) {
				if (data[consumed] != '-')
					return CSS_INVALID;

				/* 2n- */
				sign = -1;
				had_sign = true;

				if (len - (++consumed) > 0) {
					size_t bstart;

					/* Reject additional sign */
					if (data[consumed] == '-' ||
							data[consumed] == '+')
						return CSS_INVALID;

					/* 2n-b */
					bstart = consumed;

					b = css__number_from_string(
						(const uint8_t *) data + bstart,
						len - bstart,
						true,
						&consumed);
					if (consumed != len - bstart)
						return CSS_INVALID;

					had_b = true;
				}
			}
		}

		if (had_b == false) {
			consumeWhitespace(vector, ctx);

			/* Look for optional b : [ [ CHAR ws ]? NUMBER ws ]? */
			token = parserutils_vector_peek(vector, *ctx);

			if (had_sign == false && token != NULL &&
					(tokenIsChar(token, '-') ||
					tokenIsChar(token, '+'))) {
				parserutils_vector_iterate(vector, ctx);

				had_sign = true;

				if (tokenIsChar(token, '-'))
					sign = -1;

				consumeWhitespace(vector, ctx);

				token = parserutils_vector_peek(vector, *ctx);
			}

			/* Expect NUMBER */
			if (token != NULL && token->type == CSS_TOKEN_NUMBER) {
				parserutils_vector_iterate(vector, ctx);

				/* If we've already seen a sign, ensure one
				 * does not occur at the start of this token
				 */
				if (had_sign && lwc_string_length(
						token->idata) > 0) {
					data = lwc_string_data(token->idata);

					if (data[0] == '-' || data[0] == '+')
						return CSS_INVALID;
				}

				b = css__number_from_lwc_string(token->idata,
						true, &consumed);
				if (consumed != lwc_string_length(token->idata))
					return CSS_INVALID;
			}
		}

		value->nth.a = FIXTOINT(a);
		value->nth.b = FIXTOINT(b) * sign;
	}

	consumeWhitespace(vector, ctx);

	return CSS_OK;
}

css_error parsePseudo(css_language *c, const parserutils_vector *vector, 
		int *ctx, bool in_not, css_selector_detail *specific)
{
	static const struct
	{
		int index;
		css_selector_type type;
	} pseudo_lut[] = {
		{ FIRST_CHILD, CSS_SELECTOR_PSEUDO_CLASS },
		{ LINK, CSS_SELECTOR_PSEUDO_CLASS },
		{ VISITED, CSS_SELECTOR_PSEUDO_CLASS },
		{ HOVER, CSS_SELECTOR_PSEUDO_CLASS },
		{ ACTIVE, CSS_SELECTOR_PSEUDO_CLASS },
		{ FOCUS, CSS_SELECTOR_PSEUDO_CLASS },
		{ LANG, CSS_SELECTOR_PSEUDO_CLASS },
		{ LEFT, CSS_SELECTOR_PSEUDO_CLASS },
		{ RIGHT, CSS_SELECTOR_PSEUDO_CLASS },
		{ FIRST, CSS_SELECTOR_PSEUDO_CLASS },
		{ ROOT, CSS_SELECTOR_PSEUDO_CLASS },
		{ NTH_CHILD, CSS_SELECTOR_PSEUDO_CLASS },
		{ NTH_LAST_CHILD, CSS_SELECTOR_PSEUDO_CLASS },
		{ NTH_OF_TYPE, CSS_SELECTOR_PSEUDO_CLASS },
		{ NTH_LAST_OF_TYPE, CSS_SELECTOR_PSEUDO_CLASS },
		{ LAST_CHILD, CSS_SELECTOR_PSEUDO_CLASS },
		{ FIRST_OF_TYPE, CSS_SELECTOR_PSEUDO_CLASS },
		{ LAST_OF_TYPE, CSS_SELECTOR_PSEUDO_CLASS },
		{ ONLY_CHILD, CSS_SELECTOR_PSEUDO_CLASS },
		{ ONLY_OF_TYPE, CSS_SELECTOR_PSEUDO_CLASS },
		{ EMPTY, CSS_SELECTOR_PSEUDO_CLASS },
		{ TARGET, CSS_SELECTOR_PSEUDO_CLASS },
		{ ENABLED, CSS_SELECTOR_PSEUDO_CLASS },
		{ DISABLED, CSS_SELECTOR_PSEUDO_CLASS },
		{ CHECKED, CSS_SELECTOR_PSEUDO_CLASS },
		{ NOT, CSS_SELECTOR_PSEUDO_CLASS },

		{ FIRST_LINE, CSS_SELECTOR_PSEUDO_ELEMENT },
		{ FIRST_LETTER, CSS_SELECTOR_PSEUDO_ELEMENT },
		{ BEFORE, CSS_SELECTOR_PSEUDO_ELEMENT },
		{ AFTER, CSS_SELECTOR_PSEUDO_ELEMENT }
	};
	css_selector_detail_value detail_value;
	css_selector_detail_value_type value_type = 
			CSS_SELECTOR_DETAIL_VALUE_STRING;
	css_qname qname;
	const css_token *token;
	bool match = false, require_element = false, negate = false;
	uint32_t lut_idx;
	css_selector_type type = CSS_SELECTOR_PSEUDO_CLASS;/* GCC's braindead */
	css_error error;

	/* pseudo    -> ':' ':'? [ IDENT | FUNCTION ws any1 ws ')' ] */

	detail_value.string = NULL;

	token = parserutils_vector_iterate(vector, ctx);
	if (token == NULL || tokenIsChar(token, ':') == false)
		return CSS_INVALID;

	/* Optional second colon before pseudo element names */
	token = parserutils_vector_iterate(vector, ctx);
	if (token != NULL && tokenIsChar(token, ':')) {
		/* If present, we require a pseudo element */
		require_element = true;

		/* Consume subsequent token */
		token = parserutils_vector_iterate(vector, ctx);
	}

	/* Expect IDENT or FUNCTION */
	if (token == NULL || (token->type != CSS_TOKEN_IDENT && 
			token->type != CSS_TOKEN_FUNCTION))
		return CSS_INVALID;

	qname.ns = NULL;
	qname.name = token->idata;

	/* Search lut for selector type */
	for (lut_idx = 0; lut_idx < N_ELEMENTS(pseudo_lut); lut_idx++) {
		if ((lwc_string_caseless_isequal(qname.name, 
				c->strings[pseudo_lut[lut_idx].index],
				&match) == lwc_error_ok) && match) {
			type = pseudo_lut[lut_idx].type;
			break;
		}
	}

	/* Not found: invalid */
	if (lut_idx == N_ELEMENTS(pseudo_lut))
		return CSS_INVALID;

	/* Required a pseudo element, but didn't find one: invalid */
	if (require_element && type != CSS_SELECTOR_PSEUDO_ELEMENT)
		return CSS_INVALID;

	/* :not() and pseudo elements are not permitted in :not() */
	if (in_not && (type == CSS_SELECTOR_PSEUDO_ELEMENT || 
			pseudo_lut[lut_idx].index == NOT))
		return CSS_INVALID;

	if (token->type == CSS_TOKEN_FUNCTION) {
		int fun_type = pseudo_lut[lut_idx].index;

		consumeWhitespace(vector, ctx);

		if (fun_type == LANG) {
			/* IDENT */
			token = parserutils_vector_iterate(vector, ctx);
			if (token == NULL || token->type != CSS_TOKEN_IDENT)
				return CSS_INVALID;

			detail_value.string = token->idata;
			value_type = CSS_SELECTOR_DETAIL_VALUE_STRING;

			consumeWhitespace(vector, ctx);
		} else if (fun_type == NTH_CHILD || 
				fun_type == NTH_LAST_CHILD || 
				fun_type == NTH_OF_TYPE || 
				fun_type == NTH_LAST_OF_TYPE) {
			/* an + b */
			error = parseNth(c, vector, ctx, &detail_value);
			if (error != CSS_OK)
				return error;

			value_type = CSS_SELECTOR_DETAIL_VALUE_NTH;
		} else if (fun_type == NOT) {
			/* type_selector | specific */
			token = parserutils_vector_peek(vector, *ctx);
			if (token == NULL)
				return CSS_INVALID;

			if (token->type == CSS_TOKEN_IDENT || 
					tokenIsChar(token, '*') ||
					tokenIsChar(token, '|')) {
				/* Have type selector */
				error = parseTypeSelector(c, vector, ctx, 
						&qname);
				if (error != CSS_OK)
					return error;

				type = CSS_SELECTOR_ELEMENT;

				detail_value.string = NULL;
				value_type = CSS_SELECTOR_DETAIL_VALUE_STRING;
			} else {
				/* specific */
				css_selector_detail det;

				error = parseSpecific(c, vector, ctx, true, 
						&det);
				if (error != CSS_OK)
					return error;

				qname = det.qname;
				type = det.type;
				detail_value = det.value;
				value_type = det.value_type;
			}

			negate = true;

			consumeWhitespace(vector, ctx);
		}

		token = parserutils_vector_iterate(vector, ctx);
		if (token == NULL || tokenIsChar(token, ')') == false)
			return CSS_INVALID;
	}

	return css__stylesheet_selector_detail_init(c->sheet, 
			type, &qname, detail_value, value_type, 
			negate, specific);
}

css_error parseSpecific(css_language *c,
		const parserutils_vector *vector, int *ctx,
		bool in_not, css_selector_detail *specific)
{
	css_error error;
	const css_token *token;

	/* specific  -> [ HASH | class | attrib | pseudo ] */

	token = parserutils_vector_peek(vector, *ctx);
	if (token == NULL)
		return CSS_INVALID;

	if (token->type == CSS_TOKEN_HASH) {
		css_qname qname;
		css_selector_detail_value detail_value;

		detail_value.string = NULL;

		qname.ns = NULL;
		qname.name = token->idata;

		error = css__stylesheet_selector_detail_init(c->sheet,
				CSS_SELECTOR_ID, &qname, detail_value,
				CSS_SELECTOR_DETAIL_VALUE_STRING, false, 
				specific);
		if (error != CSS_OK)
			return error;

		parserutils_vector_iterate(vector, ctx);
	} else if (tokenIsChar(token, '.')) {
		error = parseClass(c, vector, ctx, specific);
		if (error != CSS_OK)
			return error;
	} else if (tokenIsChar(token, '[')) {
		error = parseAttrib(c, vector, ctx, specific);
		if (error != CSS_OK)
			return error;
	} else if (tokenIsChar(token, ':')) {
		error = parsePseudo(c, vector, ctx, in_not, specific);
		if (error != CSS_OK)
			return error;
	} else {
		return CSS_INVALID;
	}

	return CSS_OK;
}

css_error parseAppendSpecific(css_language *c, 
		const parserutils_vector *vector, int *ctx,
		css_selector **parent)
{
	css_error error;
	css_selector_detail specific;

	error = parseSpecific(c, vector, ctx, false, &specific);
	if (error != CSS_OK)
		return error;

	return css__stylesheet_selector_append_specific(c->sheet, parent, 
			&specific);
}

css_error parseSelectorSpecifics(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_selector **parent)
{
	css_error error;
	const css_token *token;

	/* specifics -> specific* */
	while ((token = parserutils_vector_peek(vector, *ctx)) != NULL &&
			token->type != CSS_TOKEN_S && 
			tokenIsChar(token, '+') == false &&
			tokenIsChar(token, '>') == false &&
			tokenIsChar(token, '~') == false &&
			tokenIsChar(token, ',') == false) {
		error = parseAppendSpecific(c, vector, ctx, parent);
		if (error != CSS_OK)
			return error;
	}

	return CSS_OK;
}

css_error parseTypeSelector(css_language *c, const parserutils_vector *vector,
		int *ctx, css_qname *qname)
{
	const css_token *token;
	css_error error;
	lwc_string *prefix = NULL;

	/* type_selector    -> namespace_prefix? element_name
	 * namespace_prefix -> [ IDENT | '*' ]? '|'
	 * element_name	    -> IDENT | '*'
	 */

	token = parserutils_vector_peek(vector, *ctx);
	if (token == NULL)
		return CSS_INVALID;

	if (tokenIsChar(token, '|') == false) {
		prefix = token->idata;

		parserutils_vector_iterate(vector, ctx);

		token = parserutils_vector_peek(vector, *ctx);
	}

	if (token != NULL && tokenIsChar(token, '|')) {
		/* Have namespace prefix */
		parserutils_vector_iterate(vector, ctx);

		/* Expect element_name */
		token = parserutils_vector_iterate(vector, ctx);

		if (token == NULL || (token->type != CSS_TOKEN_IDENT &&
				tokenIsChar(token, '*') == false)) {
			return CSS_INVALID;
		}

		error = lookupNamespace(c, prefix, &qname->ns);
		if (error != CSS_OK)
			return error;

		qname->name = token->idata;
	} else {
		/* No namespace prefix */
		if (c->default_namespace == NULL) {
			qname->ns = c->strings[UNIVERSAL];
		} else {
			qname->ns = c->default_namespace;
		}

		qname->name = prefix;
	}

	return CSS_OK;
}

css_error parseSimpleSelector(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_selector **result)
{
	int orig_ctx = *ctx;
	css_error error;
	const css_token *token;
	css_selector *selector;
	css_qname qname;

	/* simple_selector  -> type_selector specifics
	 *		    -> specific specifics
	 */

	token = parserutils_vector_peek(vector, *ctx);
	if (token == NULL)
		return CSS_INVALID;

	if (token->type == CSS_TOKEN_IDENT || tokenIsChar(token, '*') ||
			tokenIsChar(token, '|')) {
		/* Have type selector */
		error = parseTypeSelector(c, vector, ctx, &qname);
		if (error != CSS_OK) {
			*ctx = orig_ctx;
			return error;
		}

		error = css__stylesheet_selector_create(c->sheet,
				&qname, &selector);
		if (error != CSS_OK) {
			*ctx = orig_ctx;
			return error;
		}
	} else {
		/* Universal selector */
		if (c->default_namespace == NULL)
			qname.ns = c->strings[UNIVERSAL];
		else
			qname.ns = c->default_namespace;

		qname.name = c->strings[UNIVERSAL];

		error = css__stylesheet_selector_create(c->sheet,
				&qname, &selector);
		if (error != CSS_OK)
			return error;

		/* Ensure we have at least one specific selector */
		error = parseAppendSpecific(c, vector, ctx, &selector);
		if (error != CSS_OK) {
			css__stylesheet_selector_destroy(c->sheet, selector);
			return error;
		}
	}

	error = parseSelectorSpecifics(c, vector, ctx, &selector);
	if (error != CSS_OK) {
		css__stylesheet_selector_destroy(c->sheet, selector);
		return error;
	}

	*result = selector;

	return CSS_OK;
}

css_error parseCombinator(css_language *c, const parserutils_vector *vector,
		int *ctx, css_combinator *result)
{
	const css_token *token;
	css_combinator comb = CSS_COMBINATOR_NONE;

	/* combinator	   -> ws '+' ws | ws '>' ws | ws '~' ws | ws1 */

	UNUSED(c);

	while ((token = parserutils_vector_peek(vector, *ctx)) != NULL) {
		if (tokenIsChar(token, '+'))
			comb = CSS_COMBINATOR_SIBLING;
		else if (tokenIsChar(token, '>'))
			comb = CSS_COMBINATOR_PARENT;
		else if (tokenIsChar(token, '~'))
			comb = CSS_COMBINATOR_GENERIC_SIBLING;
		else if (token->type == CSS_TOKEN_S)
			comb = CSS_COMBINATOR_ANCESTOR;
		else
			break;

		parserutils_vector_iterate(vector, ctx);

		/* If we've seen a '+', '>', or '~', we're done. */
		if (comb != CSS_COMBINATOR_ANCESTOR)
			break;
	}

	/* No valid combinator found */
	if (comb == CSS_COMBINATOR_NONE)
		return CSS_INVALID;

	/* Consume any trailing whitespace */
	consumeWhitespace(vector, ctx);

	*result = comb;

	return CSS_OK;
}

css_error parseSelector(css_language *c, const parserutils_vector *vector, 
		int *ctx, css_selector **result)
{
	css_error error;
	const css_token *token = NULL;
	css_selector *selector = NULL;

	/* selector -> simple_selector [ combinator simple_selector ]* ws
	 * 
	 * Note, however, that, as combinator can be wholly whitespace,
	 * there's an ambiguity as to whether "ws" has been reached. We 
	 * resolve this by attempting to extract a combinator, then 
	 * recovering when we detect that we've reached the end of the
	 * selector.
	 */

	error = parseSimpleSelector(c, vector, ctx, &selector);
	if (error != CSS_OK)
		return error;
	*result = selector;

	while ((token = parserutils_vector_peek(vector, *ctx)) != NULL &&
			tokenIsChar(token, ',') == false) {
		css_combinator comb = CSS_COMBINATOR_NONE;
		css_selector *other = NULL;

		error = parseCombinator(c, vector, ctx, &comb);
		if (error != CSS_OK)
			return error;

		/* In the case of "html , body { ... }", the whitespace after
		 * "html" and "body" will be considered an ancestor combinator.
		 * This clearly is not the case, however. Therefore, as a 
		 * special case, if we've got an ancestor combinator and there 
		 * are no further tokens, or if the next token is a comma,
		 * we ignore the supposed combinator and continue. */
		if (comb == CSS_COMBINATOR_ANCESTOR && 
				((token = parserutils_vector_peek(vector, 
					*ctx)) == NULL || 
				tokenIsChar(token, ',')))
			continue;

		error = parseSimpleSelector(c, vector, ctx, &other);
		if (error != CSS_OK)
			return error;

		*result = other;

		error = css__stylesheet_selector_combine(c->sheet,
				comb, selector, other);
		if (error != CSS_OK) {
			css__stylesheet_selector_destroy(c->sheet, selector);
			return error;
		}

		selector = other;
	}

	return CSS_OK;
}

css_error parseSelectorList(css_language *c, const parserutils_vector *vector,
		css_rule *rule)
{
	css_error error;
	const css_token *token = NULL;
	css_selector *selector = NULL;
	int ctx = 0;

	/* Strip any leading whitespace (can happen if in nested block) */
	consumeWhitespace(vector, &ctx);

	/* selector_list   -> selector [ ',' ws selector ]* */

	error = parseSelector(c, vector, &ctx, &selector);
	if (error != CSS_OK) {
		if (selector != NULL)
			css__stylesheet_selector_destroy(c->sheet, selector);
		return error;
	}

	assert(selector != NULL);

	error = css__stylesheet_rule_add_selector(c->sheet, rule, selector);
	if (error != CSS_OK) {
		css__stylesheet_selector_destroy(c->sheet, selector);
		return error;
	}

	while (parserutils_vector_peek(vector, ctx) != NULL) {
		token = parserutils_vector_iterate(vector, &ctx);
		if (tokenIsChar(token, ',') == false)
			return CSS_INVALID;

		consumeWhitespace(vector, &ctx);

		selector = NULL;

		error = parseSelector(c, vector, &ctx, &selector);
		if (error != CSS_OK) {
			if (selector != NULL) {
				css__stylesheet_selector_destroy(c->sheet, 
						selector);
			}
			return error;
		}

		assert(selector != NULL);

		error = css__stylesheet_rule_add_selector(c->sheet, rule, 
				selector);
		if (error != CSS_OK) {
			css__stylesheet_selector_destroy(c->sheet, selector);
			return error;
		}
	}

	return CSS_OK;
}

/******************************************************************************
 * Property parsing functions						      *
 ******************************************************************************/

css_error parseProperty(css_language *c, const css_token *property, 
		const parserutils_vector *vector, int *ctx, css_rule *rule)
{
	css_error error;
	css_prop_handler handler = NULL;
	int i = 0;
	uint8_t flags = 0;
	css_style *style = NULL;
	const css_token *token;

	/* Find property index */
	/** \todo improve on this linear search */
	for (i = FIRST_PROP; i <= LAST_PROP; i++) {
		bool match = false;

		if (lwc_string_caseless_isequal(property->idata, c->strings[i],
				&match) == lwc_error_ok && match)
			break;
	}
	if (i == LAST_PROP + 1)
		return CSS_INVALID;

	/* Get handler */
	handler = property_handlers[i - FIRST_PROP];
	assert(handler != NULL);

	/* allocate style */
	error = css__stylesheet_style_create(c->sheet, &style);
	if (error != CSS_OK) 
		return error;

	assert (style != NULL);

	/* Call the handler */
	error = handler(c, vector, ctx, style);
	if (error != CSS_OK) {
		css__stylesheet_style_destroy(style);
		return error;
	}

	/* Determine if this declaration is important or not */
	error = css__parse_important(c, vector, ctx, &flags);
	if (error != CSS_OK) {
		css__stylesheet_style_destroy(style);
		return error;
	}

	/* Ensure that we've exhausted all the input */
	consumeWhitespace(vector, ctx);
	token = parserutils_vector_iterate(vector, ctx);
	if (token != NULL) {
		/* Trailing junk, so discard declaration */
                css__stylesheet_style_destroy(style);
		return CSS_INVALID;
	}

	/* If it's important, then mark the style appropriately */
	if (flags != 0)
		css__make_style_important(style);

	/* Append style to rule */
	error = css__stylesheet_rule_append_style(c->sheet, rule, style);
	if (error != CSS_OK) {
                css__stylesheet_style_destroy(style);
		return error;
	}

	/* Style owned or destroyed by stylesheet, so forget about it */

	return CSS_OK;
}

