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parser: Simplify the element_in_specific_scope calls
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The old implementation using 2 tagsets was being rather wasteful with
stack space, allocating 2 whole sets when one of them always contains a
single tag element. Knowing that the `expected` elements must always be
in the HTML namespace, we can simplify these APIs by passing an array of
elements and stop allocating so much space on the stack.
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@vmg
vmg committed Feb 16, 2015
1 parent a81d7e6 commit 900e904
Showing 1 changed file with 31 additions and 40 deletions.
71 changes: 31 additions & 40 deletions src/parser.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1313,40 +1313,38 @@ static GumboQuirksModeEnum compute_quirks_mode(
// names. For example, "has an element in list scope" looks for an element of
// the given qualified name within the nearest enclosing <ol> or <ul>, along
// with a bunch of generic element types that serve to "firewall" their content
// from the rest of the document.
static bool has_an_element_in_specific_scope(GumboParser* parser, gumbo_tagset expected, bool negate, const gumbo_tagset tags) {
// from the rest of the document. Note that because of the way the spec is written,
// all elements are expected to be in the HTML namespace
static bool has_an_element_in_specific_scope(GumboParser* parser,
int expected_size, const GumboTag *expected, bool negate, const gumbo_tagset tags) {
GumboVector* open_elements = &parser->_parser_state->_open_elements;
for (int i = open_elements->length; --i >= 0; ) {
const GumboNode* node = open_elements->data[i];
if (node->type != GUMBO_NODE_ELEMENT && node->type != GUMBO_NODE_TEMPLATE) {
if (node->type != GUMBO_NODE_ELEMENT && node->type != GUMBO_NODE_TEMPLATE)
continue;

GumboTag node_tag = node->v.element.tag;
GumboNamespaceEnum node_ns = node->v.element.tag_namespace;
for (int j = 0; j < expected_size; ++j) {
if (node_tag == expected[j] && node_ns == GUMBO_NAMESPACE_HTML)
return true;
}
if (TAGSET_INCLUDES(expected, node->v.element.tag_namespace, node->v.element.tag)) {
return true;
}
bool found_qualname = false;
if (TAGSET_INCLUDES(tags, node->v.element.tag_namespace, node->v.element.tag)) {
found_qualname = true;
}
if (negate != found_qualname) {

bool found = TAGSET_INCLUDES(tags, node_ns, node_tag);
if (negate != found)
return false;
}
}
return false;
}

// Checks for the presence of an open element of the specified tag type.
static bool has_open_element(GumboParser* parser, GumboTag tag) {
gumbo_tagset qualset = {0};
qualset[(int) tag] = (1 << (int) GUMBO_NAMESPACE_HTML);
return has_an_element_in_specific_scope(parser, qualset, false, (gumbo_tagset) { TAG(HTML) } );
return has_an_element_in_specific_scope(parser, 1, &tag, false, (gumbo_tagset) { TAG(HTML) } );
}

// http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#has-an-element-in-scope
static bool has_an_element_in_scope(GumboParser* parser, GumboTag tag) {
gumbo_tagset qualset = {0};
qualset[(int) tag] = (1 << (int) GUMBO_NAMESPACE_HTML);
return has_an_element_in_specific_scope(parser, qualset, false, (gumbo_tagset) { TAG(APPLET),
return has_an_element_in_specific_scope(parser, 1, &tag, false, (gumbo_tagset) { TAG(APPLET),
TAG(CAPTION), TAG(HTML), TAG(TABLE), TAG(TD), TAG(TH), TAG(MARQUEE),
TAG(OBJECT), TAG(TEMPLATE), TAG_MATHML(MI), TAG_MATHML(MO), TAG_MATHML(MN),
TAG_MATHML(MS), TAG_MATHML(MTEXT), TAG_MATHML(ANNOTATION_XML),
Expand Down Expand Up @@ -1383,19 +1381,17 @@ static bool has_node_in_scope(GumboParser* parser, const GumboNode* node) {

// Like has_an_element_in_scope, but restricts the expected qualified name to a
// range of possible qualified names instead of just a single one.
static bool has_an_element_in_scope_with_tagname(GumboParser* parser, gumbo_tagset qualset) {
return has_an_element_in_specific_scope(parser, qualset, false, (gumbo_tagset) { TAG(APPLET),
TAG(CAPTION), TAG(HTML), TAG(TABLE), TAG(TD), TAG(TH), TAG(MARQUEE),
TAG(OBJECT), TAG(TEMPLATE), TAG_MATHML(MI), TAG_MATHML(MO), TAG_MATHML(MN),
TAG_MATHML(MS), TAG_MATHML(MTEXT), TAG_MATHML(ANNOTATION_XML),
TAG_SVG(FOREIGNOBJECT), TAG_SVG(DESC), TAG_SVG(TITLE) });
static bool has_an_element_in_scope_with_tagname(GumboParser* parser, int expected_len, const GumboTag expected[]) {
return has_an_element_in_specific_scope(parser, expected_len, expected, false, (gumbo_tagset) {
TAG(APPLET), TAG(CAPTION), TAG(HTML), TAG(TABLE), TAG(TD), TAG(TH), TAG(MARQUEE),
TAG(OBJECT), TAG(TEMPLATE), TAG_MATHML(MI), TAG_MATHML(MO), TAG_MATHML(MN),
TAG_MATHML(MS), TAG_MATHML(MTEXT), TAG_MATHML(ANNOTATION_XML),
TAG_SVG(FOREIGNOBJECT), TAG_SVG(DESC), TAG_SVG(TITLE) });
}

// http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#has-an-element-in-list-item-scope
static bool has_an_element_in_list_scope(GumboParser* parser, GumboTag tag) {
gumbo_tagset qualset = {0};
qualset[(int)tag] = (1 << (int)(GUMBO_NAMESPACE_HTML));
return has_an_element_in_specific_scope(parser, qualset, false, (gumbo_tagset) { TAG(APPLET),
return has_an_element_in_specific_scope(parser, 1, &tag, false, (gumbo_tagset) { TAG(APPLET),
TAG(CAPTION), TAG(HTML), TAG(TABLE), TAG(TD), TAG(TH), TAG(MARQUEE),
TAG(OBJECT), TAG(TEMPLATE), TAG_MATHML(MI), TAG_MATHML(MO), TAG_MATHML(MN),
TAG_MATHML(MS), TAG_MATHML(MTEXT), TAG_MATHML(ANNOTATION_XML),
Expand All @@ -1405,9 +1401,7 @@ static bool has_an_element_in_list_scope(GumboParser* parser, GumboTag tag) {

// http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#has-an-element-in-button-scope
static bool has_an_element_in_button_scope(GumboParser* parser, GumboTag tag) {
gumbo_tagset qualset = {0};
qualset[(int) tag] = (1 << (int)(GUMBO_NAMESPACE_HTML));
return has_an_element_in_specific_scope(parser, qualset, false, (gumbo_tagset) { TAG(APPLET),
return has_an_element_in_specific_scope(parser, 1, &tag, false, (gumbo_tagset) { TAG(APPLET),
TAG(CAPTION), TAG(HTML), TAG(TABLE), TAG(TD), TAG(TH), TAG(MARQUEE),
TAG(OBJECT), TAG(TEMPLATE), TAG_MATHML(MI), TAG_MATHML(MO), TAG_MATHML(MN),
TAG_MATHML(MS), TAG_MATHML(MTEXT), TAG_MATHML(ANNOTATION_XML),
Expand All @@ -1416,17 +1410,13 @@ static bool has_an_element_in_button_scope(GumboParser* parser, GumboTag tag) {

// http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#has-an-element-in-table-scope
static bool has_an_element_in_table_scope(GumboParser* parser, GumboTag tag) {
gumbo_tagset qualset = {0};
qualset[(int) tag] = (1 << (int)(GUMBO_NAMESPACE_HTML));
return has_an_element_in_specific_scope(parser, qualset, false, (gumbo_tagset) { TAG(HTML),
return has_an_element_in_specific_scope(parser, 1, &tag, false, (gumbo_tagset) { TAG(HTML),
TAG(TABLE), TAG(TEMPLATE) });
}

// http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#has-an-element-in-select-scope
static bool has_an_element_in_select_scope(GumboParser* parser, GumboTag tag) {
gumbo_tagset qualset = {0};
qualset[(int) tag] = (1 << (int)(GUMBO_NAMESPACE_HTML));
return has_an_element_in_specific_scope(parser, qualset, true, (gumbo_tagset) { TAG(OPTGROUP), TAG(OPTION) });
return has_an_element_in_specific_scope(parser, 1, &tag, true, (gumbo_tagset) { TAG(OPTGROUP), TAG(OPTION) });
}

// http://www.whatwg.org/specs/web-apps/current-work/complete/tokenization.html#generate-implied-end-tags
Expand Down Expand Up @@ -2566,10 +2556,11 @@ static bool handle_in_body(GumboParser* parser, GumboToken* token) {
return false;
}
return implicitly_close_tags(parser, token, GUMBO_NAMESPACE_HTML, token_tag);
} else if (tag_in(token, kEndTag, (gumbo_tagset) { TAG(H1), TAG(H2), TAG(H3),
TAG(H4), TAG(H5), TAG(H6) })) {
if (!has_an_element_in_scope_with_tagname(parser, (gumbo_tagset) { TAG(H1), TAG(H2), TAG(H3), TAG(H4),
TAG(H5), TAG(H6) })) {
} else if (tag_in(token, kEndTag, (gumbo_tagset) {
TAG(H1), TAG(H2), TAG(H3), TAG(H4), TAG(H5), TAG(H6) })) {
if (!has_an_element_in_scope_with_tagname(parser, 6, (GumboTag[]) {
GUMBO_TAG_H1, GUMBO_TAG_H2, GUMBO_TAG_H3,
GUMBO_TAG_H4, GUMBO_TAG_H5, GUMBO_TAG_H6})) {
// No heading open; ignore the token entirely.
parser_add_parse_error(parser, token);
ignore_token(parser);
Expand Down

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