history_url_provider.h revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d
1// Copyright (c) 2012 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#ifndef CHROME_BROWSER_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_ 6#define CHROME_BROWSER_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_ 7 8#include <string> 9#include <vector> 10 11#include "base/compiler_specific.h" 12#include "base/synchronization/cancellation_flag.h" 13#include "chrome/browser/autocomplete/autocomplete_input.h" 14#include "chrome/browser/autocomplete/history_provider.h" 15#include "chrome/browser/autocomplete/history_provider_util.h" 16#include "chrome/browser/autocomplete/url_prefix.h" 17#include "chrome/browser/search_engines/search_terms_data.h" 18#include "chrome/browser/search_engines/template_url.h" 19 20class Profile; 21 22namespace base { 23class MessageLoop; 24} 25 26namespace history { 27class HistoryBackend; 28class URLDatabase; 29} 30 31// How history autocomplete works 32// ============================== 33// 34// Read down this diagram for temporal ordering. 35// 36// Main thread History thread 37// ----------- -------------- 38// AutocompleteController::Start 39// -> HistoryURLProvider::Start 40// -> RunAutocompletePasses 41// -> SuggestExactInput 42// [params_ allocated] 43// -> DoAutocomplete (for inline autocomplete) 44// -> URLDatabase::AutocompleteForPrefix (on in-memory DB) 45// -> HistoryService::ScheduleAutocomplete 46// (return to controller) ---- 47// / 48// HistoryBackend::ScheduleAutocomplete 49// -> HistoryURLProvider::ExecuteWithDB 50// -> DoAutocomplete 51// -> URLDatabase::AutocompleteForPrefix 52// / 53// HistoryService::QueryComplete 54// [params_ destroyed] 55// -> AutocompleteProviderListener::OnProviderUpdate 56// 57// The autocomplete controller calls us, and must be called back, on the main 58// thread. When called, we run two autocomplete passes. The first pass runs 59// synchronously on the main thread and queries the in-memory URL database. 60// This pass promotes matches for inline autocomplete if applicable. We do 61// this synchronously so that users get consistent behavior when they type 62// quickly and hit enter, no matter how loaded the main history database is. 63// Doing this synchronously also prevents inline autocomplete from being 64// "flickery" in the AutocompleteEdit. Because the in-memory DB does not have 65// redirect data, results other than the top match might change between the 66// two passes, so we can't just decide to use this pass' matches as the final 67// results. 68// 69// The second autocomplete pass uses the full history database, which must be 70// queried on the history thread. Start() asks the history service schedule to 71// callback on the history thread with a pointer to the main database. When we 72// are done doing queries, we schedule a task on the main thread that notifies 73// the AutocompleteController that we're done. 74// 75// The communication between these threads is done using a 76// HistoryURLProviderParams object. This is allocated in the main thread, and 77// normally deleted in QueryComplete(). So that both autocomplete passes can 78// use the same code, we also use this to hold results during the first 79// autocomplete pass. 80// 81// While the second pass is running, the AutocompleteController may cancel the 82// request. This can happen frequently when the user is typing quickly. In 83// this case, the main thread sets params_->cancel, which the background thread 84// checks periodically. If it finds the flag set, it stops what it's doing 85// immediately and calls back to the main thread. (We don't delete the params 86// on the history thread, because we should only do that when we can safely 87// NULL out params_, and that must be done on the main thread.) 88 89// Used to communicate autocomplete parameters between threads via the history 90// service. 91struct HistoryURLProviderParams { 92 HistoryURLProviderParams(const AutocompleteInput& input, 93 bool trim_http, 94 const std::string& languages, 95 TemplateURL* default_search_provider, 96 const SearchTermsData& search_terms_data); 97 ~HistoryURLProviderParams(); 98 99 base::MessageLoop* message_loop; 100 101 // A copy of the autocomplete input. We need the copy since this object will 102 // live beyond the original query while it runs on the history thread. 103 AutocompleteInput input; 104 105 // Should inline autocompletion be disabled? This is initalized from 106 // |input.prevent_inline_autocomplete()|, but set to false is the input 107 // contains trailing white space. 108 bool prevent_inline_autocomplete; 109 110 // Set when "http://" should be trimmed from the beginning of the URLs. 111 bool trim_http; 112 113 // Set by the main thread to cancel this request. If this flag is set when 114 // the query runs, the query will be abandoned. This allows us to avoid 115 // running queries that are no longer needed. Since we don't care if we run 116 // the extra queries, the lack of signaling is not a problem. 117 base::CancellationFlag cancel_flag; 118 119 // Set by ExecuteWithDB() on the history thread when the query could not be 120 // performed because the history system failed to properly init the database. 121 // If this is set when the main thread is called back, it avoids changing 122 // |matches_| at all, so it won't delete the default match 123 // RunAutocompletePasses() creates. 124 bool failed; 125 126 // List of matches written by the history thread. We keep this separate list 127 // to avoid having the main thread read the provider's matches while the 128 // history thread is manipulating them. The provider copies this list back 129 // to matches_ on the main thread in QueryComplete(). 130 ACMatches matches; 131 132 // Languages we should pass to gfx::GetCleanStringFromUrl. 133 std::string languages; 134 135 // When true, we should avoid calling SuggestExactInput(). 136 bool dont_suggest_exact_input; 137 138 // The default search provider and search terms data necessary to cull results 139 // that correspond to searches (on the default engine). These can only be 140 // obtained on the UI thread, so we have to copy them into here to pass them 141 // to the history thread. We use a scoped_ptr<TemplateURL> for the DSP since 142 // TemplateURLs can't be copied by value. We use a scoped_ptr<SearchTermsData> 143 // so that we can store a snapshot of the SearchTermsData accessible from the 144 // history thread. 145 scoped_ptr<TemplateURL> default_search_provider; 146 scoped_ptr<SearchTermsData> search_terms_data; 147 148 private: 149 DISALLOW_COPY_AND_ASSIGN(HistoryURLProviderParams); 150}; 151 152// This class is an autocomplete provider and is also a pseudo-internal 153// component of the history system. See comments above. 154class HistoryURLProvider : public HistoryProvider { 155 public: 156 // Various values used in scoring, made public so other providers 157 // can insert results in appropriate ranges relative to these. 158 static const int kScoreForBestInlineableResult; 159 static const int kScoreForUnvisitedIntranetResult; 160 static const int kScoreForWhatYouTypedResult; 161 static const int kBaseScoreForNonInlineableResult; 162 163 HistoryURLProvider(AutocompleteProviderListener* listener, Profile* profile); 164 165#ifdef UNIT_TEST 166 HistoryURLProvider(AutocompleteProviderListener* listener, 167 Profile* profile, 168 const std::string& languages) 169 : HistoryProvider(listener, profile, 170 AutocompleteProvider::TYPE_HISTORY_URL), 171 params_(NULL), 172 cull_redirects_(true), 173 create_shorter_match_(true), 174 search_url_database_(true), 175 languages_(languages) {} 176#endif 177 178 // Returns a match corresponding to exactly what the user has typed. 179 // NOTE: This does not set the relevance of the returned match, as different 180 // callers want different behavior. Callers must set this manually. 181 // This function is static so SearchProvider may construct similar matches. 182 static AutocompleteMatch SuggestExactInput(AutocompleteProvider* provider, 183 const AutocompleteInput& input, 184 bool trim_http); 185 186 // AutocompleteProvider 187 virtual void Start(const AutocompleteInput& input, 188 bool minimal_changes) OVERRIDE; 189 virtual void Stop(bool clear_cached_results) OVERRIDE; 190 191 // Runs the history query on the history thread, called by the history 192 // system. The history database MAY BE NULL in which case it is not 193 // available and we should return no data. Also schedules returning the 194 // results to the main thread 195 void ExecuteWithDB(history::HistoryBackend* backend, 196 history::URLDatabase* db, 197 HistoryURLProviderParams* params); 198 199 // Actually runs the autocomplete job on the given database, which is 200 // guaranteed not to be NULL. 201 void DoAutocomplete(history::HistoryBackend* backend, 202 history::URLDatabase* db, 203 HistoryURLProviderParams* params); 204 205 // Dispatches the results to the autocomplete controller. Called on the 206 // main thread by ExecuteWithDB when the results are available. 207 // Frees params_gets_deleted on exit. 208 void QueryComplete(HistoryURLProviderParams* params_gets_deleted); 209 210 private: 211 enum MatchType { 212 NORMAL, 213 WHAT_YOU_TYPED, 214 INLINE_AUTOCOMPLETE, 215 UNVISITED_INTRANET, // An intranet site that has never been visited. 216 }; 217 class VisitClassifier; 218 219 ~HistoryURLProvider(); 220 221 // Determines the relevance for a match, given its type. If 222 // |match_type| is NORMAL, |match_number| is a number [0, 223 // kMaxSuggestions) indicating the relevance of the match (higher == 224 // more relevant). For other values of |match_type|, |match_number| 225 // is ignored. Only called some of the time; for some matches, 226 // relevancy scores are assigned consecutively decreasing (1416, 227 // 1415, 1414, ...). 228 int CalculateRelevance(MatchType match_type, size_t match_number) const; 229 230 // Helper function that actually launches the two autocomplete passes. 231 void RunAutocompletePasses(const AutocompleteInput& input, 232 bool fixup_input_and_run_pass_1); 233 234 // Given a |match| containing the "what you typed" suggestion created by 235 // SuggestExactInput(), looks up its info in the DB. If found, fills in the 236 // title from the DB, promotes the match's priority to that of an inline 237 // autocomplete match (maybe it should be slightly better?), and places it on 238 // the front of |matches| (so we pick the right matches to throw away 239 // when culling redirects to/from it). Returns whether a match was promoted. 240 bool FixupExactSuggestion(history::URLDatabase* db, 241 const AutocompleteInput& input, 242 const VisitClassifier& classifier, 243 AutocompleteMatch* match, 244 history::HistoryMatches* matches) const; 245 246 // Helper function for FixupExactSuggestion, this returns true if the input 247 // corresponds to some intranet URL where the user has previously visited the 248 // host in question. In this case the input should be treated as a URL. 249 bool CanFindIntranetURL(history::URLDatabase* db, 250 const AutocompleteInput& input) const; 251 252 // Determines if |match| is suitable for inline autocomplete. If so, and if 253 // |params| is non-NULL, promotes the match. Returns whether |match| is 254 // suitable for inline autocomplete. 255 bool PromoteMatchForInlineAutocomplete(HistoryURLProviderParams* params, 256 const history::HistoryMatch& match); 257 258 // Sees if a shorter version of the best match should be created, and if so 259 // places it at the front of |matches|. This can suggest history URLs that 260 // are prefixes of the best match (if they've been visited enough, compared to 261 // the best match), or create host-only suggestions even when they haven't 262 // been visited before: if the user visited http://example.com/asdf once, 263 // we'll suggest http://example.com/ even if they've never been to it. 264 void PromoteOrCreateShorterSuggestion( 265 history::URLDatabase* db, 266 const HistoryURLProviderParams& params, 267 bool have_what_you_typed_match, 268 const AutocompleteMatch& what_you_typed_match, 269 history::HistoryMatches* matches); 270 271 // Sorts the given list of matches. 272 void SortMatches(history::HistoryMatches* matches) const; 273 274 // Removes results that have been rarely typed or visited, and not any time 275 // recently. The exact parameters for this heuristic can be found in the 276 // function body. Also culls results corresponding to queries from the default 277 // search engine. These are low-quality, difficult-to-understand matches for 278 // users, and the SearchProvider should surface past queries in a better way 279 // anyway. 280 void CullPoorMatches(history::HistoryMatches* matches, 281 HistoryURLProviderParams* params) const; 282 283 // Removes results that redirect to each other, leaving at most |max_results| 284 // results. 285 void CullRedirects(history::HistoryBackend* backend, 286 history::HistoryMatches* matches, 287 size_t max_results) const; 288 289 // Helper function for CullRedirects, this removes all but the first 290 // occurance of [any of the set of strings in |remove|] from the |matches| 291 // list. 292 // 293 // The return value is the index of the item that is after the item in the 294 // input identified by |source_index|. If |source_index| or an item before 295 // is removed, the next item will be shifted, and this allows the caller to 296 // pick up on the next one when this happens. 297 size_t RemoveSubsequentMatchesOf(history::HistoryMatches* matches, 298 size_t source_index, 299 const std::vector<GURL>& remove) const; 300 301 // Converts a line from the database into an autocomplete match for display. 302 AutocompleteMatch HistoryMatchToACMatch( 303 HistoryURLProviderParams* params, 304 const history::HistoryMatch& history_match, 305 MatchType match_type, 306 int relevance); 307 308 // Params for the current query. The provider should not free this directly; 309 // instead, it is passed as a parameter through the history backend, and the 310 // parameter itself is freed once it's no longer needed. The only reason we 311 // keep this member is so we can set the cancel bit on it. 312 HistoryURLProviderParams* params_; 313 314 // If true, HistoryURL provider should lookup and cull redirects. If 315 // false, it returns matches that may be redirects to each other and 316 // simply hopes the default AutoCompleteController behavior to remove 317 // URLs that are likely duplicates (http://google.com <-> 318 // https://www.google.com/, etc.) will do a good enough job. 319 bool cull_redirects_; 320 321 // Used in PromoteOrCreateShorterSuggestion(). If true, we may create 322 // shorter suggestions even when they haven't been visited before: 323 // if the user visited http://example.com/asdf once, we'll suggest 324 // http://example.com/ even if they've never been to it. 325 bool create_shorter_match_; 326 327 // Whether to query the history URL database to match. Even if 328 // false, we still use the URL database to decide if the 329 // URL-what-you-typed was visited before or not. If false, the only 330 // possible result that HistoryURL provider can return is 331 // URL-what-you-typed. This variable is not part of params_ because 332 // it never changes after the HistoryURLProvider is initialized. 333 // It's used to aid the transition to get all URLs from history to 334 // be scored in the HistoryQuick provider only. 335 bool search_url_database_; 336 337 // Only used by unittests; if non-empty, overrides accept-languages in the 338 // profile's pref system. 339 std::string languages_; 340}; 341 342#endif // CHROME_BROWSER_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_ 343