1// Copyright 2014 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.
4//
5// This file contains the keyword autocomplete provider. The keyword provider
6// is responsible for remembering/suggesting user "search keyword queries"
7// (e.g.  "imdb Godzilla") and then fixing them up into valid URLs.  An
8// instance of it gets created and managed by the autocomplete controller.
9// KeywordProvider uses a TemplateURLService to find the set of keywords.
10
11#ifndef COMPONENTS_OMNIBOX_KEYWORD_PROVIDER_H_
12#define COMPONENTS_OMNIBOX_KEYWORD_PROVIDER_H_
13
14#include <string>
15
16#include "base/basictypes.h"
17#include "base/compiler_specific.h"
18#include "base/memory/scoped_ptr.h"
19#include "components/metrics/proto/omnibox_input_type.pb.h"
20#include "components/omnibox/autocomplete_input.h"
21#include "components/omnibox/autocomplete_provider.h"
22#include "components/omnibox/keyword_extensions_delegate.h"
23
24class AutocompleteProviderListener;
25class KeywordExtensionsDelegate;
26class TemplateURL;
27class TemplateURLService;
28
29// Autocomplete provider for keyword input.
30//
31// After construction, the autocomplete controller repeatedly calls Start()
32// with some user input, each time expecting to receive a small set of the best
33// matches (either synchronously or asynchronously).
34//
35// To construct these matches, the provider treats user input as a series of
36// whitespace-delimited tokens and tries to match the first token as the prefix
37// of a known "keyword".  A keyword is some string that maps to a search query
38// URL; the rest of the user's input is taken as the input to the query.  For
39// example, the keyword "bug" might map to the URL "http://b/issue?id=%s", so
40// input like "bug 123" would become "http://b/issue?id=123".
41//
42// Because we do prefix matching, user input could match more than one keyword
43// at once.  (Example: the input "f jazz" matches all keywords starting with
44// "f".)  We return the best matches, up to three.
45//
46// The resulting matches are shown with content specified by the keyword
47// (usually "Search [name] for %s"), description "(Keyword: [keyword])", and
48// action "[keyword] %s".  If the user has typed a (possibly partial) keyword
49// but no search terms, the suggested result is shown greyed out, with
50// "<enter term(s)>" as the substituted input, and does nothing when selected.
51class KeywordProvider : public AutocompleteProvider {
52 public:
53  KeywordProvider(AutocompleteProviderListener* listener,
54                  TemplateURLService* model);
55
56  void set_extensions_delegate(
57      scoped_ptr<KeywordExtensionsDelegate> extensions_delegate) {
58    extensions_delegate_ = extensions_delegate.Pass();
59  }
60
61  // Extracts the next whitespace-delimited token from input and returns it.
62  // Sets |remaining_input| to everything after the first token (skipping over
63  // the first intervening whitespace).
64  // If |trim_leading_whitespace| is true then leading whitespace in
65  // |*remaining_input| will be trimmed.
66  static base::string16 SplitKeywordFromInput(const base::string16& input,
67                                              bool trim_leading_whitespace,
68                                              base::string16* remaining_input);
69
70  // Returns the replacement string from the user input. The replacement
71  // string is the portion of the input that does not contain the keyword.
72  // For example, the replacement string for "b blah" is blah.
73  // If |trim_leading_whitespace| is true then leading whitespace in
74  // replacement string will be trimmed.
75  static base::string16 SplitReplacementStringFromInput(
76      const base::string16& input,
77      bool trim_leading_whitespace);
78
79  // Returns the matching substituting keyword for |input|, or NULL if there
80  // is no keyword for the specified input.  If the matching keyword was found,
81  // updates |input|'s text and cursor position.
82  static const TemplateURL* GetSubstitutingTemplateURLForInput(
83      TemplateURLService* model,
84      AutocompleteInput* input);
85
86  // If |text| corresponds (in the sense of
87  // TemplateURLModel::CleanUserInputKeyword()) to an enabled, substituting
88  // keyword, returns that keyword; returns the empty string otherwise.
89  base::string16 GetKeywordForText(const base::string16& text) const;
90
91  // Creates a fully marked-up AutocompleteMatch for a specific keyword.
92  AutocompleteMatch CreateVerbatimMatch(const base::string16& text,
93                                        const base::string16& keyword,
94                                        const AutocompleteInput& input);
95
96  // AutocompleteProvider:
97  virtual void Start(const AutocompleteInput& input,
98                     bool minimal_changes) OVERRIDE;
99  virtual void Stop(bool clear_cached_results) OVERRIDE;
100
101 private:
102  friend class KeywordExtensionsDelegateImpl;
103
104  virtual ~KeywordProvider();
105
106  // Extracts the keyword from |input| into |keyword|. Any remaining characters
107  // after the keyword are placed in |remaining_input|. Returns true if |input|
108  // is valid and has a keyword. This makes use of SplitKeywordFromInput to
109  // extract the keyword and remaining string, and uses
110  // TemplateURLService::CleanUserInputKeyword to remove unnecessary characters.
111  // In general use this instead of SplitKeywordFromInput.
112  // Leading whitespace in |*remaining_input| will be trimmed.
113  static bool ExtractKeywordFromInput(const AutocompleteInput& input,
114                                      base::string16* keyword,
115                                      base::string16* remaining_input);
116
117  // Determines the relevance for some input, given its type, whether the user
118  // typed the complete keyword, and whether the user is in "prefer keyword
119  // matches" mode, and whether the keyword supports replacement.
120  // If |allow_exact_keyword_match| is false, the relevance for complete
121  // keywords that support replacements is degraded.
122  static int CalculateRelevance(metrics::OmniboxInputType::Type type,
123                                bool complete,
124                                bool support_replacement,
125                                bool prefer_keyword,
126                                bool allow_exact_keyword_match);
127
128  // Creates a fully marked-up AutocompleteMatch from the user's input.
129  // If |relevance| is negative, calculate a relevance based on heuristics.
130  AutocompleteMatch CreateAutocompleteMatch(
131      const TemplateURL* template_url,
132      const AutocompleteInput& input,
133      size_t prefix_length,
134      const base::string16& remaining_input,
135      bool allowed_to_be_default_match,
136      int relevance);
137
138  // Fills in the "destination_url" and "contents" fields of |match| with the
139  // provided user input and keyword data.
140  void FillInURLAndContents(const base::string16& remaining_input,
141                            const TemplateURL* element,
142                            AutocompleteMatch* match) const;
143
144  TemplateURLService* GetTemplateURLService() const;
145
146  AutocompleteProviderListener* listener_;
147
148  // Model for the keywords.
149  TemplateURLService* model_;
150
151  // Delegate to handle the extensions-only logic for KeywordProvider.
152  // NULL when extensions are not enabled. May be NULL for tests.
153  scoped_ptr<KeywordExtensionsDelegate> extensions_delegate_;
154
155  DISALLOW_COPY_AND_ASSIGN(KeywordProvider);
156};
157
158#endif  // COMPONENTS_OMNIBOX_KEYWORD_PROVIDER_H_
159