HTML5 parser optimizations

UPGRADING.INTERNALS

@@ -184,6 +184,7 @@ PHP 8.4 INTERNALS UPGRADE NOTES
    - Removed the "properties" HashTable field from php_libxml_node_object.
    - Added a way to attached private data to a php_libxml_ref_obj.
    - Added a way to fix a class type onto php_libxml_ref_obj.
+   - Added php_libxml_uses_internal_errors().
 
  e. ext/date
    - Added the php_format_date_ex() API to format instances of php_date_obj.

ext/dom/html_document.c

@@ -245,35 +245,43 @@ static void dom_find_line_and_column_using_cache(
 		offset = application_data->current_input_length;
 	}
 
+	size_t last_column = cache->last_column;
+	size_t last_line = cache->last_line;
+	size_t last_offset = cache->last_offset;
+
 	/* Either unicode or UTF-8 data */
 	if (application_data->current_input_codepoints != NULL) {
-		while (cache->last_offset < offset) {
-			if (application_data->current_input_codepoints[cache->last_offset] == 0x000A /* Unicode codepoint for line feed */) {
-				cache->last_line++;
-				cache->last_column = 1;
+		while (last_offset < offset) {
+			if (application_data->current_input_codepoints[last_offset] == 0x000A /* Unicode codepoint for line feed */) {
+				last_line++;
+				last_column = 1;
 			} else {
-				cache->last_column++;
+				last_column++;
 			}
-			cache->last_offset++;
+			last_offset++;
 		}
 	} else {
-		while (cache->last_offset < offset) {
-			const lxb_char_t current = application_data->current_input_characters[cache->last_offset];
+		while (last_offset < offset) {
+			const lxb_char_t current = application_data->current_input_characters[last_offset];
 			if (current == '\n') {
-				cache->last_line++;
-				cache->last_column = 1;
-				cache->last_offset++;
+				last_line++;
+				last_column = 1;
+				last_offset++;
 			} else {
 				/* See Lexbor tokenizer patch
 				 * Note for future self: branchlessly computing the length and jumping by the length would be nice,
 				 * however it takes so many instructions to do so that it is slower than this naive method. */
 				if ((current & 0b11000000) != 0b10000000) {
-					cache->last_column++;
+					last_column++;
 				}
-				cache->last_offset++;
+				last_offset++;
 			}
 		}
 	}
+
+	cache->last_column = last_column;
+	cache->last_line = last_line;
+	cache->last_offset = last_offset;
 }
 
 static void dom_lexbor_libxml2_bridge_tokenizer_error_reporter(
@@ -517,8 +525,16 @@ static bool dom_decode_encode_fast_path(
 	const lxb_char_t *buf_ref = *buf_ref_ref;
 	const lxb_char_t *last_output = buf_ref;
 	while (buf_ref != buf_end) {
-		const lxb_char_t *buf_ref_backup = buf_ref;
 		/* Fast path converts non-validated UTF-8 -> validated UTF-8 */
+		if (decoding_encoding_ctx->decode.u.utf_8.need == 0 && *buf_ref < 0x80) {
+			/* Fast path within the fast path: try to skip non-mb bytes in bulk if we are not in a state where we
+			 * need more UTF-8 bytes to complete a sequence.
+			 * It might be tempting to use SIMD here, but it turns out that this is less efficient because
+			 * we need to process the same byte multiple times sometimes when mixing ASCII with multibyte. */
+			buf_ref++;
+			continue;
+		}
+		const lxb_char_t *buf_ref_backup = buf_ref;
 		lxb_codepoint_t codepoint = lxb_encoding_decode_utf_8_single(&decoding_encoding_ctx->decode, &buf_ref, buf_end);
 		if (UNEXPECTED(codepoint > LXB_ENCODING_MAX_CODEPOINT)) {
 			size_t skip = buf_ref - buf_ref_backup; /* Skip invalid data, it's replaced by the UTF-8 replacement bytes */
@@ -749,6 +765,16 @@ PHP_METHOD(DOM_HTMLDocument, createEmpty)
 	RETURN_THROWS();
 }
 
+/* Only bother to register error handling when the error reports can become observable. */
+static bool dom_should_register_error_handlers(zend_long options)
+{
+	if (options & XML_PARSE_NOERROR) {
+		return false;
+	}
+
+	return php_libxml_uses_internal_errors() || ((EG(error_reporting) | EG(user_error_handler_error_reporting)) & E_WARNING);
+}
+
 PHP_METHOD(DOM_HTMLDocument, createFromString)
 {
 	const char *source, *override_encoding = NULL;
@@ -777,7 +803,7 @@ PHP_METHOD(DOM_HTMLDocument, createFromString)
 	dom_reset_line_column_cache(&application_data.cache_tokenizer);
 	lexbor_libxml2_bridge_parse_context ctx;
 	lexbor_libxml2_bridge_parse_context_init(&ctx);
-	if (!(options & XML_PARSE_NOERROR)) {
+	if (dom_should_register_error_handlers(options)) {
 		lexbor_libxml2_bridge_parse_set_error_callbacks(
 			&ctx,
 			dom_lexbor_libxml2_bridge_tokenizer_error_reporter,
@@ -936,7 +962,7 @@ PHP_METHOD(DOM_HTMLDocument, createFromFile)
 	dom_reset_line_column_cache(&application_data.cache_tokenizer);
 	lexbor_libxml2_bridge_parse_context ctx;
 	lexbor_libxml2_bridge_parse_context_init(&ctx);
-	if (!(options & XML_PARSE_NOERROR)) {
+	if (dom_should_register_error_handlers(options)) {
 		lexbor_libxml2_bridge_parse_set_error_callbacks(
 			&ctx,
 			dom_lexbor_libxml2_bridge_tokenizer_error_reporter,

ext/dom/tests/modern/html/parser/user_error_handler.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Parse HTML document with user error handler and error_reporting(0)
+--EXTENSIONS--
+dom
+--INI--
+error_reporting=0
+--FILE--
+<?php
+
+set_error_handler(function ($errno, $errstr, $errfile, $errline) {
+    var_dump($errno, $errstr);
+}, E_WARNING);
+
+DOM\HTMLDocument::createFromString('<html></html>');
+
+?>
+--EXPECT--
+int(2)
+string(113) "DOM\HTMLDocument::createFromString(): tree error unexpected-token-in-initial-mode in Entity, line: 1, column: 2-5"

ext/libxml/libxml.c

@@ -1055,23 +1055,22 @@ PHP_FUNCTION(libxml_set_streams_context)
 }
 /* }}} */
 
+PHP_LIBXML_API bool php_libxml_uses_internal_errors(void)
+{
+	return xmlStructuredError == php_libxml_structured_error_handler;
+}
+
 /* {{{ Disable libxml errors and allow user to fetch error information as needed */
 PHP_FUNCTION(libxml_use_internal_errors)
 {
-	xmlStructuredErrorFunc current_handler;
-	bool use_errors, use_errors_is_null = 1, retval;
+	bool use_errors, use_errors_is_null = true;
 
 	ZEND_PARSE_PARAMETERS_START(0, 1)
 		Z_PARAM_OPTIONAL
 		Z_PARAM_BOOL_OR_NULL(use_errors, use_errors_is_null)
 	ZEND_PARSE_PARAMETERS_END();
 
-	current_handler = xmlStructuredError;
-	if (current_handler && current_handler == php_libxml_structured_error_handler) {
-		retval = 1;
-	} else {
-		retval = 0;
-	}
+	bool retval = php_libxml_uses_internal_errors();
 
 	if (use_errors_is_null) {
 		RETURN_BOOL(retval);

ext/libxml/php_libxml.h

@@ -163,6 +163,7 @@ PHP_LIBXML_API void php_libxml_issue_error(int level, const char *msg);
 PHP_LIBXML_API bool php_libxml_disable_entity_loader(bool disable);
 PHP_LIBXML_API void php_libxml_set_old_ns(xmlDocPtr doc, xmlNsPtr ns);
 PHP_LIBXML_API php_stream_context *php_libxml_get_stream_context(void);
+PHP_LIBXML_API bool php_libxml_uses_internal_errors(void);
 
 PHP_LIBXML_API zend_string *php_libxml_sniff_charset_from_string(const char *start, const char *end);
 PHP_LIBXML_API zend_string *php_libxml_sniff_charset_from_stream(const php_stream *s);