Autofill: Document ExtractFieldsFromControlElements().

components/autofill/content/renderer/form_autofill_util.cc

 // Copyright 2013 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 "components/autofill/content/renderer/form_autofill_util.h"
 
 #include <map>
 #include <set>
 
 #include "base/command_line.h"
@@ skipping 880 matching lines @@
       const_cast<blink::WebNode&>(node).childNodes();
   size_t length = children.length();
   for (size_t i = 0; i < length; ++i) {
     const blink::WebNode& item = children.item(i);
     if (IsWebNodeVisibleImpl(item, depth - 1))
       return true;
   }
   return false;
 }
 
+// Extracts the fields from |control_elements| with |extract_mask| to
+// |form_fields|. The extracted fields are also placed in |element_map|.
+// |form_fields| and |element_map| should start out empty.
+// |fields_extracted| should have as many elements as |control_elements|,
+// initialized to false.
+// Returns true if the number of fields extracted is within
+// [1, kMaxParseableFields].
 bool ExtractFieldsFromControlElements(
     const WebVector<WebFormControlElement>& control_elements,
     ExtractMask extract_mask,
     ScopedVector<FormFieldData>* form_fields,
     std::vector<bool>* fields_extracted,
     std::map<WebFormControlElement, FormFieldData*>* element_map) {
+  DCHECK(form_fields->empty());
+  DCHECK(element_map->empty());
+  DCHECK_EQ(control_elements.size(), fields_extracted->size());
+
   for (size_t i = 0; i < control_elements.size(); ++i) {
     const WebFormControlElement& control_element = control_elements[i];
 
     if (!IsAutofillableElement(control_element))
       continue;
 
     // Create a new FormFieldData, fill it out and map it to the field's name.
     FormFieldData* form_field = new FormFieldData;
     WebFormControlElementToFormField(control_element, extract_mask, form_field);
     form_fields->push_back(form_field);
     (*element_map)[control_element] = form_field;
     (*fields_extracted)[i] = true;
+
+    // To avoid overly expensive computation, we impose a maximum number of
+    // allowable fields.
+    if (form_fields->size() > kMaxParseableFields)
+      return false;
   }
 
-  // If we failed to extract any fields, give up.  Also, to avoid overly
-  // expensive computation, we impose a maximum number of allowable fields.
-  if (form_fields->empty() || form_fields->size() > kMaxParseableFields)
-    return false;
-  return true;
+  // Succeeded if fields were extracted.
+  return !form_fields->empty();
 }
 
 // For each label element, get the corresponding form control element, use the
 // form control element's name as a key into the
 // <WebFormControlElement, FormFieldData> map to find the previously created
 // FormFieldData and set the FormFieldData's label to the
 // label.firstChild().nodeValue() of the label element.
 void MatchLabelsAndFields(
     const WebElementCollection& labels,
     std::map<WebFormControlElement, FormFieldData*>* element_map) {
@@ skipping 579 matching lines @@
 
 gfx::RectF GetScaledBoundingBox(float scale, WebElement* element) {
   gfx::Rect bounding_box(element->boundsInViewportSpace());
   return gfx::RectF(bounding_box.x() * scale,
                     bounding_box.y() * scale,
                     bounding_box.width() * scale,
                     bounding_box.height() * scale);
 }
 
 }  // namespace autofill