Move InMemoryURLIndex into chrome/browser/autocomplete

chrome/browser/history/in_memory_url_index.h

-// 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.
-
-#ifndef CHROME_BROWSER_HISTORY_IN_MEMORY_URL_INDEX_H_
-#define CHROME_BROWSER_HISTORY_IN_MEMORY_URL_INDEX_H_
-
-#include <functional>
-#include <map>
-#include <set>
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/files/file_path.h"
-#include "base/gtest_prod_util.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-#include "base/strings/string16.h"
-#include "base/task/cancelable_task_tracker.h"
-#include "components/history/core/browser/history_db_task.h"
-#include "components/history/core/browser/history_service_observer.h"
-#include "components/history/core/browser/history_types.h"
-#include "components/history/core/browser/scored_history_match.h"
-#include "sql/connection.h"
-
-class HistoryService;
-class HistoryQuickProviderTest;
-
-namespace base {
-class Time;
-}
-
-namespace in_memory_url_index {
-class InMemoryURLIndexCacheItem;
-}
-
-namespace history {
-
-namespace imui = in_memory_url_index;
-
-class HistoryDatabase;
-class URLIndexPrivateData;
-
-// The URL history source.
-// Holds portions of the URL database in memory in an indexed form.  Used to
-// quickly look up matching URLs for a given query string.  Used by
-// the HistoryURLProvider for inline autocomplete and to provide URL
-// matches to the omnibox.
-//
-// Note about multi-byte codepoints and the data structures in the
-// InMemoryURLIndex class: One will quickly notice that no effort is made to
-// insure that multi-byte character boundaries are detected when indexing the
-// words and characters in the URL history database except when converting
-// URL strings to lowercase. Multi-byte-edness makes no difference when
-// indexing or when searching the index as the final filtering of results
-// is dependent on the comparison of a string of bytes, not individual
-// characters. While the lookup of those bytes during a search in the
-// |char_word_map_| could serve up words in which the individual char16
-// occurs as a portion of a composite character the next filtering step
-// will eliminate such words except in the case where a single character
-// is being searched on and which character occurs as the second char16 of a
-// multi-char16 instance.
-class InMemoryURLIndex : public HistoryServiceObserver,
-                         public base::SupportsWeakPtr<InMemoryURLIndex> {
- public:
-  // Defines an abstract class which is notified upon completion of restoring
-  // the index's private data either by reading from the cache file or by
-  // rebuilding from the history database.
-  class RestoreCacheObserver {
-   public:
-    virtual ~RestoreCacheObserver();
-
-    // Callback that lets the observer know that the restore operation has
-    // completed. |succeeded| indicates if the restore was successful. This is
-    // called on the UI thread.
-    virtual void OnCacheRestoreFinished(bool succeeded) = 0;
-  };
-
-  // Defines an abstract class which is notified upon completion of saving
-  // the index's private data to the cache file.
-  class SaveCacheObserver {
-   public:
-    virtual ~SaveCacheObserver();
-
-    // Callback that lets the observer know that the save succeeded.
-    // This is called on the UI thread.
-    virtual void OnCacheSaveFinished(bool succeeded) = 0;
-  };
-
-  // |history_service| which may be null during unit testing is used to register
-  // |as an HistoryServiceObserver. |history_dir| is a path to the directory
-  // containing the history database within the profile wherein the cache and
-  // transaction journals will be stored. |languages| gives a list of language
-  // encodings by which URLs and omnibox searches are broken down into words and
-  // characters.
-  InMemoryURLIndex(HistoryService* history_service,
-                   const base::FilePath& history_dir,
-                   const std::string& languages);
-  ~InMemoryURLIndex() override;
-
-  // Opens and prepares the index of historical URL visits. If the index private
-  // data cannot be restored from its cache file then it is rebuilt from the
-  // history database.
-  void Init();
-
-  // Signals that any outstanding initialization should be canceled and
-  // flushes the cache to disk.
-  void ShutDown();
-
-  // Scans the history index and returns a vector with all scored, matching
-  // history items. This entry point simply forwards the call on to the
-  // URLIndexPrivateData class. For a complete description of this function
-  // refer to that class.  If |cursor_position| is base::string16::npos, the
-  // function doesn't do anything special with the cursor; this is equivalent
-  // to the cursor being at the end.  In total, |max_matches| of items will be
-  // returned in the |ScoredHistoryMatches| vector.
-  ScoredHistoryMatches HistoryItemsForTerms(
-      const base::string16& term_string,
-      size_t cursor_position,
-      size_t max_matches,
-      const ScoredHistoryMatch::Builder& builder);
-
-  // Deletes the index entry, if any, for the given |url|.
-  void DeleteURL(const GURL& url);
-
-  // Sets the optional observers for completion of restoral and saving of the
-  // index's private data.
-  void set_restore_cache_observer(
-      RestoreCacheObserver* restore_cache_observer) {
-    restore_cache_observer_ = restore_cache_observer;
-  }
-  void set_save_cache_observer(SaveCacheObserver* save_cache_observer) {
-    save_cache_observer_ = save_cache_observer;
-  }
-
-  // Indicates that the index restoration is complete.
-  bool restored() const {
-    return restored_;
-  }
-
- private:
-  friend class ::HistoryQuickProviderTest;
-  friend class InMemoryURLIndexTest;
-  friend class InMemoryURLIndexCacheTest;
-  FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, ExpireRow);
-  FRIEND_TEST_ALL_PREFIXES(LimitedInMemoryURLIndexTest, Initialization);
-
-  // HistoryDBTask used to rebuild our private data from the history database.
-  class RebuildPrivateDataFromHistoryDBTask : public HistoryDBTask {
-   public:
-    explicit RebuildPrivateDataFromHistoryDBTask(
-        InMemoryURLIndex* index,
-        const std::string& languages,
-        const std::set<std::string>& scheme_whitelist);
-
-    bool RunOnDBThread(HistoryBackend* backend,
-                       history::HistoryDatabase* db) override;
-    void DoneRunOnMainThread() override;
-
-   private:
-    ~RebuildPrivateDataFromHistoryDBTask() override;
-
-    InMemoryURLIndex* index_;  // Call back to this index at completion.
-    std::string languages_;    // Languages for word-breaking.
-    std::set<std::string> scheme_whitelist_;  // Schemes to be indexed.
-    bool succeeded_;  // Indicates if the rebuild was successful.
-    scoped_refptr<URLIndexPrivateData> data_;  // The rebuilt private data.
-
-    DISALLOW_COPY_AND_ASSIGN(RebuildPrivateDataFromHistoryDBTask);
-  };
-
-  // Initializes all index data members in preparation for restoring the index
-  // from the cache or a complete rebuild from the history database.
-  void ClearPrivateData();
-
-  // Constructs a file path for the cache file within the same directory where
-  // the history database is kept and saves that path to |file_path|. Returns
-  // true if |file_path| can be successfully constructed. (This function
-  // provided as a hook for unit testing.)
-  bool GetCacheFilePath(base::FilePath* file_path);
-
-  // Restores the index's private data from the cache file stored in the history
-  // directory.
-  void PostRestoreFromCacheFileTask();
-
-  // Schedules a history task to rebuild our private data from the history
-  // database.
-  void ScheduleRebuildFromHistory();
-
-  // Callback used by RebuildPrivateDataFromHistoryDBTask to signal completion
-  // or rebuilding our private data from the history database. |succeeded|
-  // will be true if the rebuild was successful. |data| will point to a new
-  // instanceof the private data just rebuilt.
-  void DoneRebuidingPrivateDataFromHistoryDB(
-      bool succeeded,
-      scoped_refptr<URLIndexPrivateData> private_data);
-
-  // Rebuilds the history index from the history database in |history_db|.
-  // Used for unit testing only.
-  void RebuildFromHistory(HistoryDatabase* history_db);
-
-  // Determines if the private data was successfully reloaded from the cache
-  // file or if the private data must be rebuilt from the history database.
-  // |private_data_ptr|'s data will be NULL if the cache file load failed. If
-  // successful, sets the private data and notifies any
-  // |restore_cache_observer_|. Otherwise, kicks off a rebuild from the history
-  // database.
-  void OnCacheLoadDone(scoped_refptr<URLIndexPrivateData> private_data_ptr);
-
-  // Callback function that sets the private data from the just-restored-from-
-  // file |private_data|. Notifies any |restore_cache_observer_| that the
-  // restore has succeeded.
-  void OnCacheRestored(URLIndexPrivateData* private_data);
-
-  // Posts a task to cache the index private data and write the cache file to
-  // the history directory.
-  void PostSaveToCacheFileTask();
-
-  // Saves private_data_ to the given |path|. Runs on the UI thread.
-  // Provided for unit testing so that a test cache file can be used.
-  void DoSaveToCacheFile(const base::FilePath& path);
-
-  // Notifies the observer, if any, of the success of the private data caching.
-  // |succeeded| is true on a successful save.
-  void OnCacheSaveDone(bool succeeded);
-
-  // HistoryServiceObserver:
-  void OnURLVisited(HistoryService* history_service,
-                    ui::PageTransition transition,
-                    const URLRow& row,
-                    const RedirectList& redirects,
-                    base::Time visit_time) override;
-  void OnURLsModified(HistoryService* history_service,
-                      const URLRows& changed_urls) override;
-  void OnURLsDeleted(HistoryService* history_service,
-                     bool all_history,
-                     bool expired,
-                     const URLRows& deleted_rows,
-                     const std::set<GURL>& favicon_urls) override;
-  void OnHistoryServiceLoaded(HistoryService* history_service) override;
-
-  // Sets the directory wherein the cache file will be maintained.
-  // For unit test usage only.
-  void set_history_dir(const base::FilePath& dir_path) {
-    history_dir_ = dir_path;
-  }
-
-  // Returns a pointer to our private data. For unit testing only.
-  URLIndexPrivateData* private_data() { return private_data_.get(); }
-
-  // Returns a pointer to our private data cancelable request tracker. For
-  // unit testing only.
-  base::CancelableTaskTracker* private_data_tracker() {
-    return &private_data_tracker_;
-  }
-
-  // Returns the set of whitelisted schemes. For unit testing only.
-  const std::set<std::string>& scheme_whitelist() { return scheme_whitelist_; }
-
-  // The HistoryService; may be null when testing.
-  HistoryService* history_service_;
-
-  // Directory where cache file resides. This is, except when unit testing,
-  // the same directory in which the history database is found. It should never
-  // be empty.
-  base::FilePath history_dir_;
-
-  // Languages used during the word-breaking process during indexing.
-  std::string languages_;
-
-  // Only URLs with a whitelisted scheme are indexed.
-  std::set<std::string> scheme_whitelist_;
-
-  // The index's durable private data.
-  scoped_refptr<URLIndexPrivateData> private_data_;
-
-  // Observers to notify upon restoral or save of the private data cache.
-  RestoreCacheObserver* restore_cache_observer_;
-  SaveCacheObserver* save_cache_observer_;
-
-  base::CancelableTaskTracker private_data_tracker_;
-  base::CancelableTaskTracker cache_reader_tracker_;
-
-  // Set to true once the shutdown process has begun.
-  bool shutdown_;
-
-  // Set to true once the index restoration is complete.
-  bool restored_;
-
-  // Set to true when changes to the index have been made and the index needs
-  // to be cached. Set to false when the index has been cached. Used as a
-  // temporary safety check to insure that the cache is saved before the
-  // index has been destructed.
-  bool needs_to_be_cached_;
-
-  // This flag is set to true,if we want to listen to the
-  // HistoryServiceLoaded Notification.
-  bool listen_to_history_service_loaded_;
-
-  DISALLOW_COPY_AND_ASSIGN(InMemoryURLIndex);
-};
-
-}  // namespace history
-
-#endif  // CHROME_BROWSER_HISTORY_IN_MEMORY_URL_INDEX_H_