Modify AccessibilityTreeFormatter to build up an internal representation of the tree

content/browser/accessibility/accessibility_tree_formatter.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/accessibility/accessibility_tree_formatter.h"
 
+#include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/string_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/port/browser/render_widget_host_view_port.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 
 namespace content {
 namespace {
 const int kIndentSpaces = 4;
 const char* kSkipString = "@NO_DUMP";
 }
 
 AccessibilityTreeFormatter::AccessibilityTreeFormatter(
-    BrowserAccessibility* node)
-    : node_(node) {
+    BrowserAccessibility* root)
+    : root_(root) {
   Initialize();
 }
 
 // static
 AccessibilityTreeFormatter* AccessibilityTreeFormatter::Create(
     RenderViewHost* rvh) {
   RenderWidgetHostViewPort* host_view = static_cast<RenderWidgetHostViewPort*>(
       WebContents::FromRenderViewHost(rvh)->GetRenderWidgetHostView());
 
   BrowserAccessibilityManager* manager =
       host_view->GetBrowserAccessibilityManager();
   if (!manager)
     return NULL;
 
   BrowserAccessibility* root = manager->GetRoot();
   return new AccessibilityTreeFormatter(root);
 }
 
 
 AccessibilityTreeFormatter::~AccessibilityTreeFormatter() {
 }
 
+void AccessibilityTreeFormatter::BuildAccessibilityTree(
+    DictionaryValue* dict) {
+  RecursiveBuildAccessibilityTree(root_, dict);
+}
+
 void AccessibilityTreeFormatter::FormatAccessibilityTree(
     string16* contents) {
-  RecursiveFormatAccessibilityTree(node_, contents, 0);
+  DictionaryValue dict;
+  BuildAccessibilityTree(&dict);
+  RecursiveFormatAccessibilityTree(&dict, contents);
+}
+
+void AccessibilityTreeFormatter::RecursiveBuildAccessibilityTree(
+    BrowserAccessibility* node, DictionaryValue* dict) {
+  AddProperties(node, dict);
+  ListValue* children = new ListValue;
+  dict->Set("children", children);

[dmazzoni, 2013/04/08 05:46:35]

Put dict field names in a constant at the top of this file, inside the anonymous
namespace, something like:

namespace {
const int kIndentSpaces = 4;
...
const char[] kChildrenDictAttr = "children";
}

[aboxhall, 2013/04/10 03:09:34]

Done (there was actually only this one).

+  for (size_t i = 0; i < node->children().size(); ++i) {
+    BrowserAccessibility* child_node = node->children()[i];
+    DictionaryValue* child_dict = new DictionaryValue;
+    children->Append(child_dict);
+    RecursiveBuildAccessibilityTree(child_node, child_dict);
+  }
 }
 
 void AccessibilityTreeFormatter::RecursiveFormatAccessibilityTree(
-    BrowserAccessibility* node, string16* contents, int indent) {
-  scoped_array<char> prefix(new char[indent + 1]);
-  for (int i = 0; i < indent; ++i)
-    prefix[i] = ' ';
-  prefix[indent] = '\0';
-
-  string16 line = ToString(node, prefix.get());
+    DictionaryValue* dict, string16* contents, int depth) {
+  string16 line = ToString(dict, string16(depth * kIndentSpaces, ' '));

[dmazzoni, 2013/04/08 05:46:35]

Thanks - I didn't realize you could construct a string this way!

[aboxhall, 2013/04/10 03:09:34]

Hehe - I was thinking "surely there's a more efficient way" so I looked up the
STL docs. It's neat!

   if (line.find(ASCIIToUTF16(kSkipString)) != string16::npos)
     return;
 
   *contents += line;
-  for (size_t i = 0; i < node->children().size(); ++i) {
-    RecursiveFormatAccessibilityTree(node->children()[i], contents,
-                                     indent + kIndentSpaces);
+  ListValue* children;
+  dict->GetList("children", &children);

[dmazzoni, 2013/04/08 05:46:35]

Make sure this uses the constant!

[aboxhall, 2013/04/10 03:09:34]

Done.

[aboxhall, 2013/04/10 03:09:34]

Done.

+  DictionaryValue* child_dict;
+  for (size_t i = 0; i < children->GetSize(); i++) {
+    children->GetDictionary(i, &child_dict);
+    RecursiveFormatAccessibilityTree(child_dict, contents, depth + 1);
   }
 }
 
 #if (!defined(OS_WIN) && !defined(OS_MACOSX))
 string16 AccessibilityTreeFormatter::ToString(BrowserAccessibility* node,
                                               char* prefix) {
   return UTF8ToUTF16(prefix) + base::IntToString16(node->renderer_id()) +
        ASCIIToUTF16("\n");
 }
 
@@ skipping 42 matching lines @@
         allow = true;
       else if (iter->type == Filter::ALLOW)
         allow = (!MatchPattern(text, UTF8ToUTF16("*=''")));
       else
         allow = false;
     }
   }
   return allow;
 }
 
-void AccessibilityTreeFormatter::StartLine() {
-  line_.clear();
-}
-
-void AccessibilityTreeFormatter::Add(
-    bool include_by_default, const string16& attr) {
+void AccessibilityTreeFormatter::WriteAttribute(
+    bool include_by_default, const string16& attr, string16* line) {
   if (attr.empty())
     return;
   if (!MatchesFilters(attr, include_by_default))
     return;
-  if (!line_.empty())
-    line_ += ASCIIToUTF16(" ");
-  line_ += attr;
-}
-
-string16 AccessibilityTreeFormatter::FinishLine() {
-  return line_;
+  if (!line->empty())
+    *line += ASCIIToUTF16(" ");
+  *line += attr;
 }
 
 }  // namespace content