Add a class to parse answer json.

components/omnibox/suggestion_answer.h

+// Copyright 2014 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.
+
+#ifndef COMPONENTS_OMNIBOX_SUGGESTION_ANSWER_H_
+#define COMPONENTS_OMNIBOX_SUGGESTION_ANSWER_H_
+
+#include <string>
+#include <vector>
+
+#include "url/gurl.h"
+
+namespace base {
+class DictionaryValue;
+}
+
+// Structured representation of the JSON payload of a suggestion with an answer.
+// An answer has exactly two image lines, so called because they are a
+// combination of text and an optional image URL.  Each image line has 1 or more
+// text fields, each of which is required to contain a string and an integer
+// type.  The text fields are contained in a non-empty vector and two optional
+// named properties, referred to as "additional text" and "status text".
+//
+// When represented in the UI, these elements should be styled and laid out
+// according to the specification at https://goto.google.com/ais_api.
+class SuggestionAnswer {
+ public:
+  class TextField {
+   public:
+    // Constructs an empty, invalid field.
+    TextField();
+    ~TextField();
+
+    static void ParseTextField(
+        const base::DictionaryValue* field_json, TextField* text_field);
+
+    bool is_valid() const { return !text_.empty() && type_ >= 0; }
+
+    const std::string& text() const { return text_; }
+    int type() const { return type_; }
+
+    bool Equals(const TextField& field) const;
+
+    // Removes all data. After this call, the field will be invalid.
+    void Clear();
+
+   private:
+    std::string text_;
+    int type_;
+  };
+
+  typedef std::vector<TextField> TextFields;
+
+  class ImageLine {
+   public:
+    // Constructs an empty, invalid line.
+    ImageLine();
+    ~ImageLine();
+
+    static void ParseImageLine(
+        const base::DictionaryValue* line_json, ImageLine* image_line);
+
+    // A line is only valid if the JSON representation was successfully parsed
+    // and all expected constraints were met (primarily, that there was at least
+    // one text field in the repeated text field property).
+    bool is_valid() const { return is_valid_; }
+
+    const TextFields& text_fields() const { return text_fields_; }
+
+    bool has_additional_text() const { return additional_text_.is_valid(); }
+    const TextField& additional_text() const { return additional_text_; }
+
+    bool has_status_text() const { return status_text_.is_valid(); }
+    const TextField& status_text() const { return status_text_; }
+
+    bool has_image_url() const { return image_url_.is_valid(); }
+    const GURL& image_url() const { return image_url_; }
+
+    bool Equals(const ImageLine& line) const;
+
+    // Removes all data. After this call, the line will be invalid.
+    void Clear();
+
+   private:
+    TextFields text_fields_;
+    TextField additional_text_;
+    TextField status_text_;
+    GURL image_url_;
+    bool is_valid_;
+  };
+
+  // Constructs an empty, invalid answer.
+  SuggestionAnswer();
+  ~SuggestionAnswer();
+
+  // Parses |answer_json| and populates |answer| with the contents. When this
+  // method returns, |answer| is guaranteed to either be valid and containing
+  // the contents of |answer_json| or empty (from a call to Clear()) if the data
+  // is malformed or missing required elements.
+  static void ParseAnswer(
+        const std::string& answer_json, SuggestionAnswer* answer);
+  static void ParseAnswer(
+        const base::DictionaryValue* answer_json, SuggestionAnswer* answer);
+
+  // An answer is valid only if a type has been set, the JSON representation was
+  // successfully parsed, and all expected constraints were met (primarily that
+  // there were exactly two properly formed image lines).
+  bool is_valid() const {
+    return type_ >= 0 && first_line_.is_valid() && second_line_.is_valid();
+  }
+
+  const ImageLine& first_line() const { return first_line_; }
+  const ImageLine& second_line() const { return second_line_; }
+
+  // Answer type accessors.  Valid types must be non-negative and
+  // are defined at https://goto.google.com/visual_element_configuration.
+  int type() const { return type_; }
+  void set_type(int type) { type_ = type; }
+
+  bool Equals(const SuggestionAnswer& answer) const;
+
+  // Removes all data. After this call, the answer will be invalid.
+  void Clear();
+
+  typedef std::vector<GURL> URLs;
+
+  // Gets any URLs of any images in Answers results.  Any existing URLs in
+  // |urls| will be removed.
+  void GetImageURLs(URLs* urls) const;
+
+ private:
+  ImageLine first_line_;
+  ImageLine second_line_;
+  int type_;
+
+  // No DISALLOW_COPY_AND_ASSIGN because the copy and assignment operators for
+  // SuggestionAnswer (and its inner classes) are used in AutocompleteMatch's
+  // copy constructor and assignment operator as well as in search provider
+  // logic.
+};
+
+#endif  // COMPONENTS_OMNIBOX_SUGGESTION_ANSWER_H_