1 files changed, 367 insertions, 0 deletions
diff --git a/accessible/base/nsTextEquivUtils.cpp b/accessible/base/nsTextEquivUtils.cpp
new file mode 100644
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+++ b/accessible/base/nsTextEquivUtils.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsTextEquivUtils.h"
+
+#include "LocalAccessible.h"
+#include "LocalAccessible-inl.h"
+#include "AccIterator.h"
+#include "nsCoreUtils.h"
+#include "mozilla/dom/Text.h"
+#include "nsIContentInlines.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+/**
+ * The accessible for which we are computing a text equivalent. It is useful
+ * for bailing out during recursive text computation, or for special cases
+ * like step f. of the ARIA implementation guide.
+ */
+static const Accessible* sInitiatorAcc = nullptr;
+
+////////////////////////////////////////////////////////////////////////////////
+// nsTextEquivUtils. Public.
+
+nsresult nsTextEquivUtils::GetNameFromSubtree(
+    const LocalAccessible* aAccessible, nsAString& aName) {
+  aName.Truncate();
+
+  if (sInitiatorAcc) return NS_OK;
+
+  sInitiatorAcc = aAccessible;
+  if (GetRoleRule(aAccessible->Role()) == eNameFromSubtreeRule) {
+    // XXX: is it necessary to care the accessible is not a document?
+    if (aAccessible->IsContent()) {
+      nsAutoString name;
+      AppendFromAccessibleChildren(aAccessible, &name);
+      name.CompressWhitespace();
+      if (!nsCoreUtils::IsWhitespaceString(name)) aName = name;
+    }
+  }
+
+  sInitiatorAcc = nullptr;
+
+  return NS_OK;
+}
+
+nsresult nsTextEquivUtils::GetTextEquivFromIDRefs(
+    const LocalAccessible* aAccessible, nsAtom* aIDRefsAttr,
+    nsAString& aTextEquiv) {
+  aTextEquiv.Truncate();
+
+  nsIContent* content = aAccessible->GetContent();
+  if (!content) return NS_OK;
+
+  nsIContent* refContent = nullptr;
+  IDRefsIterator iter(aAccessible->Document(), content, aIDRefsAttr);
+  while ((refContent = iter.NextElem())) {
+    if (!aTextEquiv.IsEmpty()) aTextEquiv += ' ';
+
+    nsresult rv =
+        AppendTextEquivFromContent(aAccessible, refContent, &aTextEquiv);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsTextEquivUtils::AppendTextEquivFromContent(
+    const LocalAccessible* aInitiatorAcc, nsIContent* aContent,
+    nsAString* aString) {
+  // Prevent recursion which can cause infinite loops.
+  if (sInitiatorAcc) return NS_OK;
+
+  sInitiatorAcc = aInitiatorAcc;
+
+  // If the given content is not visible or isn't accessible then go down
+  // through the DOM subtree otherwise go down through accessible subtree and
+  // calculate the flat string.
+  nsIFrame* frame = aContent->GetPrimaryFrame();
+  bool isVisible = frame && frame->StyleVisibility()->IsVisible();
+
+  nsresult rv = NS_ERROR_FAILURE;
+  bool goThroughDOMSubtree = true;
+
+  if (isVisible) {
+    LocalAccessible* accessible =
+        aInitiatorAcc->Document()->GetAccessible(aContent);
+    if (accessible) {
+      rv = AppendFromAccessible(accessible, aString);
+      goThroughDOMSubtree = false;
+    }
+  }
+
+  if (goThroughDOMSubtree) rv = AppendFromDOMNode(aContent, aString);
+
+  sInitiatorAcc = nullptr;
+  return rv;
+}
+
+nsresult nsTextEquivUtils::AppendTextEquivFromTextContent(nsIContent* aContent,
+                                                          nsAString* aString) {
+  if (aContent->IsText()) {
+    if (aContent->TextLength() > 0) {
+      nsIFrame* frame = aContent->GetPrimaryFrame();
+      if (frame) {
+        nsIFrame::RenderedText text = frame->GetRenderedText(
+            0, UINT32_MAX, nsIFrame::TextOffsetType::OffsetsInContentText,
+            nsIFrame::TrailingWhitespace::DontTrim);
+        aString->Append(text.mString);
+      } else {
+        // If aContent is an object that is display: none, we have no a frame.
+        aContent->GetAsText()->AppendTextTo(*aString);
+      }
+    }
+
+    return NS_OK;
+  }
+
+  if (aContent->IsHTMLElement() &&
+      aContent->NodeInfo()->Equals(nsGkAtoms::br)) {
+    aString->AppendLiteral("\r\n");
+    return NS_OK;
+  }
+
+  return NS_OK_NO_NAME_CLAUSE_HANDLED;
+}
+
+nsresult nsTextEquivUtils::AppendFromDOMChildren(nsIContent* aContent,
+                                                 nsAString* aString) {
+  for (nsIContent* childContent = aContent->GetFirstChild(); childContent;
+       childContent = childContent->GetNextSibling()) {
+    nsresult rv = AppendFromDOMNode(childContent, aString);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsTextEquivUtils. Private.
+
+nsresult nsTextEquivUtils::AppendFromAccessibleChildren(
+    const Accessible* aAccessible, nsAString* aString) {
+  nsresult rv = NS_OK_NO_NAME_CLAUSE_HANDLED;
+
+  uint32_t childCount = aAccessible->ChildCount();
+  for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
+    Accessible* child = aAccessible->ChildAt(childIdx);
+    rv = AppendFromAccessible(child, aString);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return rv;
+}
+
+nsresult nsTextEquivUtils::AppendFromAccessible(Accessible* aAccessible,
+                                                nsAString* aString) {
+  // XXX: is it necessary to care the accessible is not a document?
+  bool isHTMLBlock = false;
+  if (aAccessible->IsLocal() && aAccessible->AsLocal()->IsContent()) {
+    nsIContent* content = aAccessible->AsLocal()->GetContent();
+    nsresult rv = AppendTextEquivFromTextContent(content, aString);
+    if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) return rv;
+    if (!content->IsText()) {
+      nsIFrame* frame = content->GetPrimaryFrame();
+      if (frame) {
+        // If this is a block level frame (as opposed to span level), we need to
+        // add spaces around that block's text, so we don't get words jammed
+        // together in final name.
+        const nsStyleDisplay* display = frame->StyleDisplay();
+        if (display->IsBlockOutsideStyle() ||
+            display->mDisplay == StyleDisplay::TableCell) {
+          isHTMLBlock = true;
+          if (!aString->IsEmpty()) {
+            aString->Append(char16_t(' '));
+          }
+        }
+      }
+    }
+  }
+
+  bool isEmptyTextEquiv = true;
+
+  // If the name is from tooltip then append it to result string in the end
+  // (see h. step of name computation guide).
+  nsAutoString text;
+  if (aAccessible->Name(text) != eNameFromTooltip) {
+    isEmptyTextEquiv = !AppendString(aString, text);
+  }
+
+  // Implementation of f. step.
+  nsresult rv = AppendFromValue(aAccessible, aString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) isEmptyTextEquiv = false;
+
+  // Implementation of g) step of text equivalent computation guide. Go down
+  // into subtree if accessible allows "text equivalent from subtree rule" or
+  // it's not root and not control.
+  if (isEmptyTextEquiv) {
+    if (ShouldIncludeInSubtreeCalculation(aAccessible)) {
+      rv = AppendFromAccessibleChildren(aAccessible, aString);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) isEmptyTextEquiv = false;
+    }
+  }
+
+  // Implementation of h. step
+  if (isEmptyTextEquiv && !text.IsEmpty()) {
+    AppendString(aString, text);
+    if (isHTMLBlock) {
+      aString->Append(char16_t(' '));
+    }
+    return NS_OK;
+  }
+
+  if (!isEmptyTextEquiv && isHTMLBlock) {
+    aString->Append(char16_t(' '));
+  }
+  return rv;
+}
+
+nsresult nsTextEquivUtils::AppendFromValue(Accessible* aAccessible,
+                                           nsAString* aString) {
+  if (GetRoleRule(aAccessible->Role()) != eNameFromValueRule) {
+    return NS_OK_NO_NAME_CLAUSE_HANDLED;
+  }
+
+  // Implementation of step f. of text equivalent computation. If the given
+  // accessible is not root accessible (the accessible the text equivalent is
+  // computed for in the end) then append accessible value. Otherwise append
+  // value if and only if the given accessible is in the middle of its parent.
+
+  nsAutoString text;
+  if (aAccessible != sInitiatorAcc) {
+    aAccessible->Value(text);
+
+    return AppendString(aString, text) ? NS_OK : NS_OK_NO_NAME_CLAUSE_HANDLED;
+  }
+
+  // XXX: is it necessary to care the accessible is not a document?
+  if (aAccessible->IsDoc()) return NS_ERROR_UNEXPECTED;
+
+  for (Accessible* next = aAccessible->NextSibling(); next;
+       next = next->NextSibling()) {
+    if (!IsWhitespaceLeaf(next)) {
+      for (Accessible* prev = aAccessible->PrevSibling(); prev;
+           prev = prev->PrevSibling()) {
+        if (!IsWhitespaceLeaf(prev)) {
+          aAccessible->Value(text);
+
+          return AppendString(aString, text) ? NS_OK
+                                             : NS_OK_NO_NAME_CLAUSE_HANDLED;
+        }
+      }
+    }
+  }
+
+  return NS_OK_NO_NAME_CLAUSE_HANDLED;
+}
+
+nsresult nsTextEquivUtils::AppendFromDOMNode(nsIContent* aContent,
+                                             nsAString* aString) {
+  nsresult rv = AppendTextEquivFromTextContent(aContent, aString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) return NS_OK;
+
+  if (aContent->IsXULElement()) {
+    nsAutoString textEquivalent;
+    if (aContent->NodeInfo()->Equals(nsGkAtoms::label, kNameSpaceID_XUL)) {
+      aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::value,
+                                     textEquivalent);
+    } else {
+      aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::label,
+                                     textEquivalent);
+    }
+
+    if (textEquivalent.IsEmpty()) {
+      aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::tooltiptext,
+                                     textEquivalent);
+    }
+
+    AppendString(aString, textEquivalent);
+  }
+
+  return AppendFromDOMChildren(aContent, aString);
+}
+
+bool nsTextEquivUtils::AppendString(nsAString* aString,
+                                    const nsAString& aTextEquivalent) {
+  if (aTextEquivalent.IsEmpty()) return false;
+
+  // Insert spaces to insure that words from controls aren't jammed together.
+  if (!aString->IsEmpty() && !nsCoreUtils::IsWhitespace(aString->Last())) {
+    aString->Append(char16_t(' '));
+  }
+
+  aString->Append(aTextEquivalent);
+
+  if (!nsCoreUtils::IsWhitespace(aString->Last())) {
+    aString->Append(char16_t(' '));
+  }
+
+  return true;
+}
+
+uint32_t nsTextEquivUtils::GetRoleRule(role aRole) {
+#define ROLE(geckoRole, stringRole, ariaRole, atkRole, macRole, macSubrole, \
+             msaaRole, ia2Role, androidClass, nameRule)                     \
+  case roles::geckoRole:                                                    \
+    return nameRule;
+
+  switch (aRole) {
+#include "RoleMap.h"
+    default:
+      MOZ_CRASH("Unknown role.");
+  }
+
+#undef ROLE
+}
+
+bool nsTextEquivUtils::ShouldIncludeInSubtreeCalculation(
+    Accessible* aAccessible) {
+  uint32_t nameRule = GetRoleRule(aAccessible->Role());
+  if (nameRule == eNameFromSubtreeRule) {
+    return true;
+  }
+  if (!(nameRule & eNameFromSubtreeIfReqRule)) {
+    return false;
+  }
+
+  if (aAccessible == sInitiatorAcc) {
+    // We're calculating the text equivalent for this accessible, but this
+    // accessible should only be included when calculating the text equivalent
+    // for something else.
+    return false;
+  }
+
+  // sInitiatorAcc can be null when, for example, LocalAccessible::Value calls
+  // GetTextEquivFromSubtree.
+  role initiatorRole = sInitiatorAcc ? sInitiatorAcc->Role() : roles::NOTHING;
+  if (initiatorRole == roles::OUTLINEITEM &&
+      aAccessible->Role() == roles::GROUPING) {
+    // Child treeitems are contained in a group. We don't want to include those
+    // in the parent treeitem's text equivalent.
+    return false;
+  }
+
+  return true;
+}
+
+bool nsTextEquivUtils::IsWhitespaceLeaf(Accessible* aAccessible) {
+  if (!aAccessible || !aAccessible->IsTextLeaf()) {
+    return false;
+  }
+
+  nsAutoString name;
+  aAccessible->Name(name);
+  return nsCoreUtils::IsWhitespaceString(name);
+}