Remove TextDatabase from the history service.

chrome/browser/history/text_database.cc

-// 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.
-
-#include <limits>
-#include <set>
-#include <string>
-
-#include "chrome/browser/history/text_database.h"
-
-#include "base/file_util.h"
-#include "base/logging.h"
-#include "base/metrics/histogram.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/stringprintf.h"
-#include "base/strings/utf_string_conversions.h"
-#include "chrome/browser/diagnostics/sqlite_diagnostics.h"
-#include "sql/statement.h"
-#include "sql/transaction.h"
-
-// There are two tables in each database, one full-text search (FTS) table which
-// indexes the contents and title of the pages. The other is a regular SQLITE
-// table which contains non-indexed information about the page. All columns of
-// a FTS table are indexed using the text search algorithm, which isn't what we
-// want for things like times. If this were in the FTS table, there would be
-// different words in the index for each time number.
-//
-// "pages" FTS table:
-//   url    URL of the page so searches will match the URL.
-//   title  Title of the page.
-//   body   Body of the page.
-//
-// "info" regular table:
-//   time     Time the corresponding FTS entry was visited.
-//
-// We do joins across these two tables by using their internal rowids, which we
-// keep in sync between the two tables. The internal rowid is the only part of
-// an FTS table that is indexed like a normal table, and the index over it is
-// free since sqlite always indexes the internal rowid.
-
-namespace history {
-
-namespace {
-
-// Version 1 uses FTS2 for index files.
-// Version 2 uses FTS3.
-static const int kCurrentVersionNumber = 2;
-static const int kCompatibleVersionNumber = 2;
-
-// Snippet computation relies on the index of the columns in the original
-// create statement. These are the 0-based indices (as strings) of the
-// corresponding columns.
-const char kTitleColumnIndex[] = "1";
-const char kBodyColumnIndex[] = "2";
-
-// The string prepended to the database identifier to generate the filename.
-const base::FilePath::CharType kFilePrefix[] =
-    FILE_PATH_LITERAL("History Index ");
-
-}  // namespace
-
-TextDatabase::Match::Match() {}
-
-TextDatabase::Match::~Match() {}
-
-TextDatabase::TextDatabase(const base::FilePath& path,
-                           DBIdent id,
-                           bool allow_create)
-    : path_(path),
-      ident_(id),
-      allow_create_(allow_create) {
-  // Compute the file name.
-  file_name_ = path_.Append(IDToFileName(ident_));
-}
-
-TextDatabase::~TextDatabase() {
-}
-
-// static
-const base::FilePath::CharType* TextDatabase::file_base() {
-  return kFilePrefix;
-}
-
-// static
-base::FilePath TextDatabase::IDToFileName(DBIdent id) {
-  // Identifiers are intended to be a combination of the year and month, for
-  // example, 200801 for January 2008. We convert this to
-  // "History Index 2008-01". However, we don't make assumptions about this
-  // scheme: the caller should assign IDs as it feels fit with the knowledge
-  // that they will apppear on disk in this form.
-  base::FilePath::StringType filename(file_base());
-  base::StringAppendF(&filename, FILE_PATH_LITERAL("%d-%02d"),
-                      id / 100, id % 100);
-  return base::FilePath(filename);
-}
-
-// static
-TextDatabase::DBIdent TextDatabase::FileNameToID(
-    const base::FilePath& file_path) {
-  base::FilePath::StringType file_name = file_path.BaseName().value();
-
-  // We don't actually check the prefix here. Since the file system could
-  // be case insensitive in ways we can't predict (NTFS), checking could
-  // potentially be the wrong thing to do. Instead, we just look for a suffix.
-  static const size_t kIDStringLength = 7;  // Room for "xxxx-xx".
-  if (file_name.length() < kIDStringLength)
-    return 0;
-  const base::FilePath::StringType suffix(
-      &file_name[file_name.length() - kIDStringLength]);
-
-  if (suffix.length() != kIDStringLength ||
-      suffix[4] != FILE_PATH_LITERAL('-')) {
-    return 0;
-  }
-
-  // TODO: Once StringPiece supports a templated interface over the
-  // underlying string type, use it here instead of substr, since that
-  // will avoid needless string copies.  StringPiece cannot be used
-  // right now because base::FilePath::StringType could use either 8 or 16 bit
-  // characters, depending on the OS.
-  int year, month;
-  base::StringToInt(suffix.substr(0, 4), &year);
-  base::StringToInt(suffix.substr(5, 2), &month);
-
-  return year * 100 + month;
-}
-
-bool TextDatabase::Init() {
-  // Make sure, if we're not allowed to create the file, that it exists.
-  if (!allow_create_) {
-    if (!file_util::PathExists(file_name_))
-      return false;
-  }
-
-  db_.set_histogram_tag("Text");
-
-  // Set the database page size to something a little larger to give us
-  // better performance (we're typically seek rather than bandwidth limited).
-  // This only has an effect before any tables have been created, otherwise
-  // this is a NOP. Must be a power of 2 and a max of 8192.
-  db_.set_page_size(4096);
-
-  // The default cache size is 2000 which give >8MB of data. Since we will often
-  // have 2-3 of these objects, each with their own 8MB, this adds up very fast.
-  // We therefore reduce the size so when there are multiple objects, we're not
-  // too big.
-  db_.set_cache_size(512);
-
-  // Run the database in exclusive mode. Nobody else should be accessing the
-  // database while we're running, and this will give somewhat improved perf.
-  db_.set_exclusive_locking();
-
-  // Attach the database to our index file.
-  if (!db_.Open(file_name_))
-    return false;
-
-  // Meta table tracking version information.
-  if (!meta_table_.Init(&db_, kCurrentVersionNumber, kCompatibleVersionNumber))
-    return false;
-  if (meta_table_.GetCompatibleVersionNumber() > kCurrentVersionNumber) {
-    // This version is too new. We don't bother notifying the user on this
-    // error, and just fail to use the file. Normally if they have version skew,
-    // they will get it for the main history file and it won't be necessary
-    // here. If that's not the case, since this is only indexed data, it's
-    // probably better to just not give FTS results than strange errors when
-    // everything else is working OK.
-    LOG(WARNING) << "Text database is too new.";
-    return false;
-  }
-
-  return CreateTables();
-}
-
-void TextDatabase::BeginTransaction() {
-  db_.BeginTransaction();
-}
-
-void TextDatabase::CommitTransaction() {
-  db_.CommitTransaction();
-}
-
-bool TextDatabase::CreateTables() {
-  // FTS table of page contents.
-  if (!db_.DoesTableExist("pages")) {
-    if (!db_.Execute("CREATE VIRTUAL TABLE pages USING fts3("
-                     "TOKENIZE icu,"
-                     "url LONGVARCHAR,"
-                     "title LONGVARCHAR,"
-                     "body LONGVARCHAR)"))
-      return false;
-  }
-
-  // Non-FTS table containing URLs and times so we can efficiently find them
-  // using a regular index (all FTS columns are special and are treated as
-  // full-text-search, which is not what we want when retrieving this data).
-  if (!db_.DoesTableExist("info")) {
-    // Note that there is no point in creating an index over time. Since
-    // we must always query the entire FTS table (it can not efficiently do
-    // subsets), we will always end up doing that first, and joining the info
-    // table off of that.
-    if (!db_.Execute("CREATE TABLE info(time INTEGER NOT NULL)"))
-      return false;
-  }
-
-  // Create the index.
-  return db_.Execute("CREATE INDEX IF NOT EXISTS info_time ON info(time)");
-}
-
-bool TextDatabase::AddPageData(base::Time time,
-                               const std::string& url,
-                               const std::string& title,
-                               const std::string& contents) {
-  sql::Transaction committer(&db_);
-  if (!committer.Begin())
-    return false;
-
-  // Add to the pages table.
-  sql::Statement add_to_pages(db_.GetCachedStatement(SQL_FROM_HERE,
-      "INSERT INTO pages (url, title, body) VALUES (?,?,?)"));
-  add_to_pages.BindString(0, url);
-  add_to_pages.BindString(1, title);
-  add_to_pages.BindString(2, contents);
-  if (!add_to_pages.Run())
-    return false;
-
-  int64 rowid = db_.GetLastInsertRowId();
-
-  // Add to the info table with the same rowid.
-  sql::Statement add_to_info(db_.GetCachedStatement(SQL_FROM_HERE,
-      "INSERT INTO info (rowid, time) VALUES (?,?)"));
-  add_to_info.BindInt64(0, rowid);
-  add_to_info.BindInt64(1, time.ToInternalValue());
-
-  if (!add_to_info.Run())
-    return false;
-
-  return committer.Commit();
-}
-
-void TextDatabase::DeletePageData(base::Time time, const std::string& url) {
-  // First get all rows that match. Selecing on time (which has an index) allows
-  // us to avoid brute-force searches on the full-text-index table (there will
-  // generally be only one match per time).
-  sql::Statement select_ids(db_.GetCachedStatement(SQL_FROM_HERE,
-      "SELECT info.rowid "
-      "FROM info JOIN pages ON info.rowid = pages.rowid "
-      "WHERE info.time=? AND pages.url=?"));
-  select_ids.BindInt64(0, time.ToInternalValue());
-  select_ids.BindString(1, url);
-
-  std::set<int64> rows_to_delete;
-  while (select_ids.Step())
-    rows_to_delete.insert(select_ids.ColumnInt64(0));
-
-  // Delete from the pages table.
-  sql::Statement delete_page(db_.GetCachedStatement(SQL_FROM_HERE,
-      "DELETE FROM pages WHERE rowid=?"));
-
-  for (std::set<int64>::const_iterator i = rows_to_delete.begin();
-       i != rows_to_delete.end(); ++i) {
-    delete_page.BindInt64(0, *i);
-    if (!delete_page.Run())
-      return;
-    delete_page.Reset(true);
-  }
-
-  // Delete from the info table.
-  sql::Statement delete_info(db_.GetCachedStatement(SQL_FROM_HERE,
-      "DELETE FROM info WHERE rowid=?"));
-
-  for (std::set<int64>::const_iterator i = rows_to_delete.begin();
-       i != rows_to_delete.end(); ++i) {
-    delete_info.BindInt64(0, *i);
-    if (!delete_info.Run())
-      return;
-    delete_info.Reset(true);
-  }
-}
-
-void TextDatabase::Optimize() {
-  sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
-      "SELECT OPTIMIZE(pages) FROM pages LIMIT 1"));
-  statement.Run();
-}
-
-bool TextDatabase::GetTextMatches(const std::string& query,
-                                  const QueryOptions& options,
-                                  std::vector<Match>* results,
-                                  URLSet* found_urls) {
-  std::string sql = "SELECT url, title, time, offsets(pages), body FROM pages "
-                    "LEFT OUTER JOIN info ON pages.rowid = info.rowid WHERE ";
-  sql += options.body_only ? "body " : "pages ";
-  sql += "MATCH ? AND time >= ? AND time < ? ";
-  // Times may not be unique, so also sort by rowid to ensure a stable order.
-  sql += "ORDER BY time DESC, info.rowid DESC";
-
-  // Generate unique IDs for the two possible variations of the statement,
-  // so they don't share the same cached prepared statement.
-  sql::StatementID body_only_id = SQL_FROM_HERE;
-  sql::StatementID pages_id = SQL_FROM_HERE;
-
-  sql::Statement statement(db_.GetCachedStatement(
-      (options.body_only ? body_only_id : pages_id), sql.c_str()));
-
-  statement.BindString(0, query);
-  statement.BindInt64(1, options.EffectiveBeginTime());
-  statement.BindInt64(2, options.EffectiveEndTime());
-
-  // |results| may not be initially empty, so keep track of how many were added
-  // by this call.
-  int result_count = 0;
-
-  while (statement.Step()) {
-    // TODO(brettw) allow canceling the query in the middle.
-    // if (canceled_or_something)
-    //   break;
-
-    GURL url(statement.ColumnString(0));
-    URLSet::const_iterator found_url = found_urls->find(url);
-    if (found_url != found_urls->end())
-      continue;  // Don't add this duplicate.
-
-    if (++result_count > options.EffectiveMaxCount())
-      break;
-
-    // Fill the results into the vector (avoid copying the URL with Swap()).
-    results->resize(results->size() + 1);
-    Match& match = results->at(results->size() - 1);
-    match.url.Swap(&url);
-
-    match.title = statement.ColumnString16(1);
-    match.time = base::Time::FromInternalValue(statement.ColumnInt64(2));
-
-    // Extract any matches in the title.
-    std::string offsets_str = statement.ColumnString(3);
-    Snippet::ExtractMatchPositions(offsets_str, kTitleColumnIndex,
-                                   &match.title_match_positions);
-    Snippet::ConvertMatchPositionsToWide(statement.ColumnString(1),
-                                         &match.title_match_positions);
-
-    // Extract the matches in the body.
-    Snippet::MatchPositions match_positions;
-    Snippet::ExtractMatchPositions(offsets_str, kBodyColumnIndex,
-                                   &match_positions);
-
-    // Compute the snippet based on those matches.
-    std::string body = statement.ColumnString(4);
-    match.snippet.ComputeSnippet(match_positions, body);
-  }
-  statement.Reset(true);
-  return result_count > options.EffectiveMaxCount();
-}
-
-}  // namespace history