1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "content/renderer/accessibility/accessibility_node_serializer.h"
9 #include "base/strings/string_number_conversions.h"
10 #include "base/strings/string_util.h"
11 #include "base/strings/utf_string_conversions.h"
12 #include "content/renderer/accessibility/blink_ax_enum_conversion.h"
13 #include "third_party/WebKit/public/platform/WebRect.h"
14 #include "third_party/WebKit/public/platform/WebSize.h"
15 #include "third_party/WebKit/public/platform/WebString.h"
16 #include "third_party/WebKit/public/platform/WebVector.h"
17 #include "third_party/WebKit/public/web/WebAXEnums.h"
18 #include "third_party/WebKit/public/web/WebAXObject.h"
19 #include "third_party/WebKit/public/web/WebDocument.h"
20 #include "third_party/WebKit/public/web/WebDocumentType.h"
21 #include "third_party/WebKit/public/web/WebElement.h"
22 #include "third_party/WebKit/public/web/WebFormControlElement.h"
23 #include "third_party/WebKit/public/web/WebFrame.h"
24 #include "third_party/WebKit/public/web/WebInputElement.h"
25 #include "third_party/WebKit/public/web/WebNode.h"
27 using base::UTF16ToUTF8;
28 using blink::WebAXObject;
29 using blink::WebDocument;
30 using blink::WebDocumentType;
31 using blink::WebElement;
33 using blink::WebVector;
38 // Returns true if |ancestor| is the first unignored parent of |child|,
39 // which means that when walking up the parent chain from |child|,
40 // |ancestor| is the *first* ancestor that isn't marked as
41 // accessibilityIsIgnored().
42 bool IsParentUnignoredOf(const WebAXObject& ancestor,
43 const WebAXObject& child) {
44 WebAXObject parent = child.parentObject();
45 while (!parent.isDetached() && parent.accessibilityIsIgnored())
46 parent = parent.parentObject();
47 return parent.equals(ancestor);
50 bool IsTrue(std::string html_value) {
51 return LowerCaseEqualsASCII(html_value, "true");
54 std::string GetEquivalentAriaRoleString(const ui::AXRole role) {
56 case ui::AX_ROLE_ARTICLE:
58 case ui::AX_ROLE_BANNER:
60 case ui::AX_ROLE_COMPLEMENTARY:
61 return "complementary";
62 case ui::AX_ROLE_CONTENT_INFO:
63 case ui::AX_ROLE_FOOTER:
65 case ui::AX_ROLE_MAIN:
67 case ui::AX_ROLE_NAVIGATION:
69 case ui::AX_ROLE_REGION:
78 } // Anonymous namespace
80 void SerializeAccessibilityNode(
81 const WebAXObject& src,
82 ui::AXNodeData* dst) {
83 dst->role = AXRoleFromBlink(src.role());
84 dst->state = AXStateFromBlink(src);
85 dst->location = src.boundingBoxRect();
87 std::string name = base::UTF16ToUTF8(src.title());
90 if (src.valueDescription().length()) {
91 dst->AddStringAttribute(ui::AX_ATTR_VALUE,
92 UTF16ToUTF8(src.valueDescription()));
94 dst->AddStringAttribute(ui::AX_ATTR_VALUE, UTF16ToUTF8(src.stringValue()));
97 if (dst->role == ui::AX_ROLE_COLOR_WELL) {
99 src.colorValue(r, g, b);
100 dst->AddIntAttribute(ui::AX_ATTR_COLOR_VALUE_RED, r);
101 dst->AddIntAttribute(ui::AX_ATTR_COLOR_VALUE_GREEN, g);
102 dst->AddIntAttribute(ui::AX_ATTR_COLOR_VALUE_BLUE, b);
105 if (dst->role == ui::AX_ROLE_INLINE_TEXT_BOX) {
106 dst->AddIntAttribute(ui::AX_ATTR_TEXT_DIRECTION,
107 AXTextDirectionFromBlink(src.textDirection()));
109 WebVector<int> src_character_offsets;
110 src.characterOffsets(src_character_offsets);
111 std::vector<int32> character_offsets;
112 character_offsets.reserve(src_character_offsets.size());
113 for (size_t i = 0; i < src_character_offsets.size(); ++i)
114 character_offsets.push_back(src_character_offsets[i]);
115 dst->AddIntListAttribute(ui::AX_ATTR_CHARACTER_OFFSETS, character_offsets);
117 WebVector<int> src_word_starts;
118 WebVector<int> src_word_ends;
119 src.wordBoundaries(src_word_starts, src_word_ends);
120 std::vector<int32> word_starts;
121 std::vector<int32> word_ends;
122 word_starts.reserve(src_word_starts.size());
123 word_ends.reserve(src_word_starts.size());
124 for (size_t i = 0; i < src_word_starts.size(); ++i) {
125 word_starts.push_back(src_word_starts[i]);
126 word_ends.push_back(src_word_ends[i]);
128 dst->AddIntListAttribute(ui::AX_ATTR_WORD_STARTS, word_starts);
129 dst->AddIntListAttribute(ui::AX_ATTR_WORD_ENDS, word_ends);
132 if (src.accessKey().length())
133 dst->AddStringAttribute(ui::AX_ATTR_ACCESS_KEY,
134 UTF16ToUTF8(src.accessKey()));
135 if (src.actionVerb().length())
136 dst->AddStringAttribute(ui::AX_ATTR_ACTION, UTF16ToUTF8(src.actionVerb()));
137 if (src.isAriaReadOnly())
138 dst->AddBoolAttribute(ui::AX_ATTR_ARIA_READONLY, true);
139 if (src.isButtonStateMixed())
140 dst->AddBoolAttribute(ui::AX_ATTR_BUTTON_MIXED, true);
141 if (src.canSetValueAttribute())
142 dst->AddBoolAttribute(ui::AX_ATTR_CAN_SET_VALUE, true);
143 if (src.accessibilityDescription().length()) {
144 dst->AddStringAttribute(ui::AX_ATTR_DESCRIPTION,
145 UTF16ToUTF8(src.accessibilityDescription()));
147 if (src.hasComputedStyle()) {
148 dst->AddStringAttribute(ui::AX_ATTR_DISPLAY,
149 UTF16ToUTF8(src.computedStyleDisplay()));
151 if (src.helpText().length())
152 dst->AddStringAttribute(ui::AX_ATTR_HELP, UTF16ToUTF8(src.helpText()));
153 if (src.keyboardShortcut().length()) {
154 dst->AddStringAttribute(ui::AX_ATTR_SHORTCUT,
155 UTF16ToUTF8(src.keyboardShortcut()));
157 if (!src.titleUIElement().isDetached()) {
158 dst->AddIntAttribute(ui::AX_ATTR_TITLE_UI_ELEMENT,
159 src.titleUIElement().axID());
161 if (!src.url().isEmpty())
162 dst->AddStringAttribute(ui::AX_ATTR_URL, src.url().spec());
164 if (dst->role == ui::AX_ROLE_HEADING)
165 dst->AddIntAttribute(ui::AX_ATTR_HIERARCHICAL_LEVEL, src.headingLevel());
166 else if ((dst->role == ui::AX_ROLE_TREE_ITEM ||
167 dst->role == ui::AX_ROLE_ROW) &&
168 src.hierarchicalLevel() > 0) {
169 dst->AddIntAttribute(ui::AX_ATTR_HIERARCHICAL_LEVEL,
170 src.hierarchicalLevel());
173 // Treat the active list box item as focused.
174 if (dst->role == ui::AX_ROLE_LIST_BOX_OPTION &&
175 src.isSelectedOptionActive()) {
176 dst->state |= (1 << ui::AX_STATE_FOCUSED);
179 if (src.canvasHasFallbackContent())
180 dst->AddBoolAttribute(ui::AX_ATTR_CANVAS_HAS_FALLBACK, true);
182 WebNode node = src.node();
183 bool is_iframe = false;
184 std::string live_atomic;
185 std::string live_busy;
186 std::string live_status;
187 std::string live_relevant;
189 if (!node.isNull() && node.isElementNode()) {
190 WebElement element = node.to<WebElement>();
191 is_iframe = (element.tagName() == base::ASCIIToUTF16("IFRAME"));
193 if (LowerCaseEqualsASCII(element.getAttribute("aria-expanded"), "true"))
194 dst->state |= (1 << ui::AX_STATE_EXPANDED);
196 // TODO(ctguil): The tagName in WebKit is lower cased but
197 // HTMLElement::nodeName calls localNameUpper. Consider adding
198 // a WebElement method that returns the original lower cased tagName.
199 dst->AddStringAttribute(
200 ui::AX_ATTR_HTML_TAG,
201 StringToLowerASCII(UTF16ToUTF8(element.tagName())));
202 for (unsigned i = 0; i < element.attributeCount(); ++i) {
203 std::string name = StringToLowerASCII(base::UTF16ToUTF8(
204 element.attributeLocalName(i)));
205 std::string value = base::UTF16ToUTF8(element.attributeValue(i));
206 dst->html_attributes.push_back(std::make_pair(name, value));
209 if (dst->role == ui::AX_ROLE_EDITABLE_TEXT ||
210 dst->role == ui::AX_ROLE_TEXT_AREA ||
211 dst->role == ui::AX_ROLE_TEXT_FIELD) {
212 dst->AddIntAttribute(ui::AX_ATTR_TEXT_SEL_START, src.selectionStart());
213 dst->AddIntAttribute(ui::AX_ATTR_TEXT_SEL_END, src.selectionEnd());
215 WebVector<int> src_line_breaks;
216 src.lineBreaks(src_line_breaks);
217 if (src_line_breaks.size() > 0) {
218 std::vector<int32> line_breaks;
219 line_breaks.reserve(src_line_breaks.size());
220 for (size_t i = 0; i < src_line_breaks.size(); ++i)
221 line_breaks.push_back(src_line_breaks[i]);
222 dst->AddIntListAttribute(ui::AX_ATTR_LINE_BREAKS, line_breaks);
227 if (element.hasAttribute("role")) {
228 dst->AddStringAttribute(ui::AX_ATTR_ROLE,
229 UTF16ToUTF8(element.getAttribute("role")));
231 std::string role = GetEquivalentAriaRoleString(dst->role);
233 dst->AddStringAttribute(ui::AX_ATTR_ROLE, role);
236 // Live region attributes
237 live_atomic = base::UTF16ToUTF8(element.getAttribute("aria-atomic"));
238 live_busy = base::UTF16ToUTF8(element.getAttribute("aria-busy"));
239 live_status = base::UTF16ToUTF8(element.getAttribute("aria-live"));
240 live_relevant = base::UTF16ToUTF8(element.getAttribute("aria-relevant"));
243 // Walk up the parent chain to set live region attributes of containers
244 std::string container_live_atomic;
245 std::string container_live_busy;
246 std::string container_live_status;
247 std::string container_live_relevant;
248 WebAXObject container_accessible = src;
249 while (!container_accessible.isDetached()) {
250 WebNode container_node = container_accessible.node();
251 if (!container_node.isNull() && container_node.isElementNode()) {
252 WebElement container_elem = container_node.to<WebElement>();
253 if (container_elem.hasAttribute("aria-atomic") &&
254 container_live_atomic.empty()) {
255 container_live_atomic =
256 base::UTF16ToUTF8(container_elem.getAttribute("aria-atomic"));
258 if (container_elem.hasAttribute("aria-busy") &&
259 container_live_busy.empty()) {
260 container_live_busy =
261 base::UTF16ToUTF8(container_elem.getAttribute("aria-busy"));
263 if (container_elem.hasAttribute("aria-live") &&
264 container_live_status.empty()) {
265 container_live_status =
266 base::UTF16ToUTF8(container_elem.getAttribute("aria-live"));
268 if (container_elem.hasAttribute("aria-relevant") &&
269 container_live_relevant.empty()) {
270 container_live_relevant =
271 base::UTF16ToUTF8(container_elem.getAttribute("aria-relevant"));
274 container_accessible = container_accessible.parentObject();
277 if (!live_atomic.empty())
278 dst->AddBoolAttribute(ui::AX_ATTR_LIVE_ATOMIC, IsTrue(live_atomic));
279 if (!live_busy.empty())
280 dst->AddBoolAttribute(ui::AX_ATTR_LIVE_BUSY, IsTrue(live_busy));
281 if (!live_status.empty())
282 dst->AddStringAttribute(ui::AX_ATTR_LIVE_STATUS, live_status);
283 if (!live_relevant.empty())
284 dst->AddStringAttribute(ui::AX_ATTR_LIVE_RELEVANT, live_relevant);
286 if (!container_live_atomic.empty()) {
287 dst->AddBoolAttribute(ui::AX_ATTR_CONTAINER_LIVE_ATOMIC,
288 IsTrue(container_live_atomic));
290 if (!container_live_busy.empty()) {
291 dst->AddBoolAttribute(ui::AX_ATTR_CONTAINER_LIVE_BUSY,
292 IsTrue(container_live_busy));
294 if (!container_live_status.empty()) {
295 dst->AddStringAttribute(ui::AX_ATTR_CONTAINER_LIVE_STATUS,
296 container_live_status);
298 if (!container_live_relevant.empty()) {
299 dst->AddStringAttribute(ui::AX_ATTR_CONTAINER_LIVE_RELEVANT,
300 container_live_relevant);
303 if (dst->role == ui::AX_ROLE_PROGRESS_INDICATOR ||
304 dst->role == ui::AX_ROLE_SCROLL_BAR ||
305 dst->role == ui::AX_ROLE_SLIDER ||
306 dst->role == ui::AX_ROLE_SPIN_BUTTON) {
307 dst->AddFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE, src.valueForRange());
308 dst->AddFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE,
309 src.maxValueForRange());
310 dst->AddFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE,
311 src.minValueForRange());
314 if (dst->role == ui::AX_ROLE_DOCUMENT ||
315 dst->role == ui::AX_ROLE_WEB_AREA) {
316 dst->AddStringAttribute(ui::AX_ATTR_HTML_TAG, "#document");
317 const WebDocument& document = src.document();
319 name = UTF16ToUTF8(document.title());
320 dst->AddStringAttribute(ui::AX_ATTR_DOC_TITLE,
321 UTF16ToUTF8(document.title()));
322 dst->AddStringAttribute(ui::AX_ATTR_DOC_URL, document.url().spec());
323 dst->AddStringAttribute(
324 ui::AX_ATTR_DOC_MIMETYPE,
325 document.isXHTMLDocument() ? "text/xhtml" : "text/html");
326 dst->AddBoolAttribute(ui::AX_ATTR_DOC_LOADED, src.isLoaded());
327 dst->AddFloatAttribute(ui::AX_ATTR_DOC_LOADING_PROGRESS,
328 src.estimatedLoadingProgress());
330 const WebDocumentType& doctype = document.doctype();
331 if (!doctype.isNull()) {
332 dst->AddStringAttribute(ui::AX_ATTR_DOC_DOCTYPE,
333 UTF16ToUTF8(doctype.name()));
336 const gfx::Size& scroll_offset = document.frame()->scrollOffset();
337 dst->AddIntAttribute(ui::AX_ATTR_SCROLL_X, scroll_offset.width());
338 dst->AddIntAttribute(ui::AX_ATTR_SCROLL_Y, scroll_offset.height());
340 const gfx::Size& min_offset = document.frame()->minimumScrollOffset();
341 dst->AddIntAttribute(ui::AX_ATTR_SCROLL_X_MIN, min_offset.width());
342 dst->AddIntAttribute(ui::AX_ATTR_SCROLL_Y_MIN, min_offset.height());
344 const gfx::Size& max_offset = document.frame()->maximumScrollOffset();
345 dst->AddIntAttribute(ui::AX_ATTR_SCROLL_X_MAX, max_offset.width());
346 dst->AddIntAttribute(ui::AX_ATTR_SCROLL_Y_MAX, max_offset.height());
349 if (dst->role == ui::AX_ROLE_TABLE) {
350 int column_count = src.columnCount();
351 int row_count = src.rowCount();
352 if (column_count > 0 && row_count > 0) {
353 std::set<int32> unique_cell_id_set;
354 std::vector<int32> cell_ids;
355 std::vector<int32> unique_cell_ids;
356 dst->AddIntAttribute(ui::AX_ATTR_TABLE_COLUMN_COUNT, column_count);
357 dst->AddIntAttribute(ui::AX_ATTR_TABLE_ROW_COUNT, row_count);
358 WebAXObject header = src.headerContainerObject();
359 if (!header.isDetached())
360 dst->AddIntAttribute(ui::AX_ATTR_TABLE_HEADER_ID, header.axID());
361 for (int i = 0; i < column_count * row_count; ++i) {
362 WebAXObject cell = src.cellForColumnAndRow(
363 i % column_count, i / column_count);
365 if (!cell.isDetached()) {
366 cell_id = cell.axID();
367 if (unique_cell_id_set.find(cell_id) == unique_cell_id_set.end()) {
368 unique_cell_id_set.insert(cell_id);
369 unique_cell_ids.push_back(cell_id);
372 cell_ids.push_back(cell_id);
374 dst->AddIntListAttribute(ui::AX_ATTR_CELL_IDS, cell_ids);
375 dst->AddIntListAttribute(ui::AX_ATTR_UNIQUE_CELL_IDS, unique_cell_ids);
379 if (dst->role == ui::AX_ROLE_ROW) {
380 dst->AddIntAttribute(ui::AX_ATTR_TABLE_ROW_INDEX, src.rowIndex());
381 WebAXObject header = src.rowHeader();
382 if (!header.isDetached())
383 dst->AddIntAttribute(ui::AX_ATTR_TABLE_ROW_HEADER_ID, header.axID());
386 if (dst->role == ui::AX_ROLE_COLUMN) {
387 dst->AddIntAttribute(ui::AX_ATTR_TABLE_COLUMN_INDEX, src.columnIndex());
388 WebAXObject header = src.columnHeader();
389 if (!header.isDetached())
390 dst->AddIntAttribute(ui::AX_ATTR_TABLE_COLUMN_HEADER_ID, header.axID());
393 if (dst->role == ui::AX_ROLE_CELL ||
394 dst->role == ui::AX_ROLE_ROW_HEADER ||
395 dst->role == ui::AX_ROLE_COLUMN_HEADER) {
396 dst->AddIntAttribute(ui::AX_ATTR_TABLE_CELL_COLUMN_INDEX,
397 src.cellColumnIndex());
398 dst->AddIntAttribute(ui::AX_ATTR_TABLE_CELL_COLUMN_SPAN,
399 src.cellColumnSpan());
400 dst->AddIntAttribute(ui::AX_ATTR_TABLE_CELL_ROW_INDEX, src.cellRowIndex());
401 dst->AddIntAttribute(ui::AX_ATTR_TABLE_CELL_ROW_SPAN, src.cellRowSpan());
404 dst->AddStringAttribute(ui::AX_ATTR_NAME, name);
406 // Add the ids of *indirect* children - those who are children of this node,
407 // but whose parent is *not* this node. One example is a table
408 // cell, which is a child of both a row and a column. Because the cell's
409 // parent is the row, the row adds it as a child, and the column adds it
410 // as an indirect child.
411 int child_count = src.childCount();
412 for (int i = 0; i < child_count; ++i) {
413 WebAXObject child = src.childAt(i);
414 std::vector<int32> indirect_child_ids;
415 if (!is_iframe && !child.isDetached() && !IsParentUnignoredOf(src, child))
416 indirect_child_ids.push_back(child.axID());
417 if (indirect_child_ids.size() > 0) {
418 dst->AddIntListAttribute(
419 ui::AX_ATTR_INDIRECT_CHILD_IDS, indirect_child_ids);
424 bool ShouldIncludeChildNode(
425 const WebAXObject& parent,
426 const WebAXObject& child) {
427 // The child may be invalid due to issues in webkit accessibility code.
428 // Don't add children that are invalid thus preventing a crash.
429 // https://bugs.webkit.org/show_bug.cgi?id=44149
430 // TODO(ctguil): We may want to remove this check as webkit stabilizes.
431 if (child.isDetached())
434 // Skip children whose parent isn't this - see indirect_child_ids, above.
435 // As an exception, include children of an iframe element.
436 bool is_iframe = false;
437 WebNode node = parent.node();
438 if (!node.isNull() && node.isElementNode()) {
439 WebElement element = node.to<WebElement>();
440 is_iframe = (element.tagName() == base::ASCIIToUTF16("IFRAME"));
443 return (is_iframe || IsParentUnignoredOf(parent, child));
446 } // namespace content