Next step integrating the HistoryQuickProvider: Implement index initializatio...

chrome/browser/history/in_memory_url_index.cc

 // Copyright (c) 2010 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 "chrome/browser/history/in_memory_url_index.h"
 
+#include <algorithm>
+#include <limits>
+
+#include "app/l10n_util.h"
+#include "base/i18n/word_iterator.h"
+#include "base/string_util.h"
+#include "base/time.h"
+#include "base/utf_string_conversions.h"
 #include "chrome/browser/history/url_database.h"
+#include "net/base/escape.h"
+#include "net/base/net_util.h"
+
+using base::Time;
+using base::TimeDelta;
 
 namespace history {
 
+InMemoryURLIndex::InMemoryURLIndex() : history_item_count_(0) {}
+
+InMemoryURLIndex::~InMemoryURLIndex() {}
+
 // Indexing
 
-bool InMemoryURLIndex::Init(history::URLDatabase* history_db) {
-  bool success = true;
-  // TODO(mrossetti): Implement.
-  return success;
+bool InMemoryURLIndex::Init(history::URLDatabase* history_db,
+                            const string16& languages) {
+  // TODO(mrossetti): Register for profile/language change notifications.
+  languages_ = languages;
+  // Reset our indexes.
+  char_word_map_.clear();
+  word_id_history_map_.clear();
+  if (!history_db)
+    return false;
+  URLDatabase::URLEnumerator history_enum;
+  if (history_db->InitURLEnumeratorForEverything(&history_enum)) {
+    URLRow row;
+    Time recent_threshold = InMemoryURLIndex::RecentThreshold();
+    while (history_enum.GetNextURL(&row)) {
+      // Do some filtering so that we only get history items which could
+      // possibly pass the HistoryURLProvider::CullPoorMatches filter later.
+      if ((row.typed_count() > kLowQualityMatchTypedLimit) ||
+          (row.visit_count() > kLowQualityMatchVisitLimit) ||
+          (row.last_visit() >= recent_threshold)) {
+        if (!IndexRow(row))
+          return false;
+      }
+    }
+  }
+  return true;
+}
+
+bool InMemoryURLIndex::IndexRow(URLRow row) {
+  const GURL& gurl(row.url());
+  string16 url(WideToUTF16(net::FormatUrl(gurl, UTF16ToWide(languages_),
+      net::kFormatUrlOmitUsernamePassword,
+      UnescapeRule::SPACES | UnescapeRule::URL_SPECIAL_CHARS, NULL, NULL,
+      NULL)));
+
+  // TODO(mrossetti): Find or implement a ConvertPercentEncoding and use it
+  // on the url.
+
+  // TODO(mrossetti): Detect row_id > std::numeric_limits<HistoryID>::max().
+  HistoryID history_id = static_cast<HistoryID>(row.id());
+
+  // Add the row for quick lookup in the history info store.
+  url = l10n_util::ToLower(url);
+  URLRow new_row(GURL(url), row.id());
+  new_row.set_visit_count(row.visit_count());
+  new_row.set_typed_count(row.typed_count());
+  new_row.set_last_visit(row.last_visit());
+  new_row.set_title(row.title());
+  history_info_map_.insert(std::make_pair(history_id, new_row));
+
+  // Split into individual, unique words.
+  String16Set words = WordsFromString16(url);
+
+  // For each word, add a new entry into the word index referring to the
+  // associated history item.
+  for (String16Set::iterator iter = words.begin();
+       iter != words.end(); ++iter) {
+    String16Set::value_type uni_word = *iter;
+    AddWordToIndex(uni_word, history_id);
+  }
+  ++history_item_count_;
+  return true;
+}
+
+// Utility Functions
+
+InMemoryURLIndex::String16Set InMemoryURLIndex::WordsFromString16(
+    const string16& uni_string) {
+  String16Set words;
+
+  // TODO(mrossetti): Replace all | and _'s with a space, all % quoted
+  // characters with real characters, and break into words, using
+  // appropriate string16 functions.
+  WordIterator iter(&uni_string, WordIterator::BREAK_WORD);
+  if (iter.Init()) {
+    while (iter.Advance()) {
+      if (iter.IsWord()) {
+        words.insert(iter.GetWord());
+      }
+    }
+  }
+  return words;
+}
+
+InMemoryURLIndex::Char16Set InMemoryURLIndex::CharactersFromString16(
+    const string16& uni_word) {
+  Char16Set characters;
+  for (string16::const_iterator iter = uni_word.begin();
+       iter != uni_word.end(); ++iter)
+    characters.insert(*iter);
+  return characters;
+}
+
+void InMemoryURLIndex::AddWordToIndex(const string16& uni_word,
+                                      HistoryID history_id) {
+  WordMap::iterator word_pos = word_map_.find(uni_word);
+  if (word_pos != word_map_.end())
+    UpdateWordHistory(word_pos->second, history_id);
+  else
+    AddWordHistory(uni_word, history_id);
+}
+
+void InMemoryURLIndex::UpdateWordHistory(WordID word_id, HistoryID history_id) {
+    WordIDHistoryMap::iterator history_pos = word_id_history_map_.find(word_id);
+    DCHECK(history_pos != word_id_history_map_.end());
+    HistoryIDSet& history_id_set(history_pos->second);
+    history_id_set.insert(history_id);
+}
+
+// Add a new word to the word list and the word map, and then create a
+// new entry in the word/history map.
+void InMemoryURLIndex::AddWordHistory(const string16& uni_word,
+                                      HistoryID history_id) {
+  word_list_.push_back(uni_word);
+  WordID word_id = word_list_.size() - 1;
+  DCHECK(word_map_.insert(std::make_pair(uni_word, word_id)).second);
+  HistoryIDSet history_id_set;
+  history_id_set.insert(history_id);
+  DCHECK(word_id_history_map_.insert(
+      std::make_pair(word_id, history_id_set)).second);
+  // For each character in the newly added word (i.e. a word that is not
+  // already in the word index), add the word to the character index.
+  Char16Set characters = CharactersFromString16(uni_word);
+  for (Char16Set::iterator uni_char_iter = characters.begin();
+       uni_char_iter != characters.end(); ++uni_char_iter) {
+    Char16Set::value_type uni_string = *uni_char_iter;
+    CharWordIDMap::iterator char_iter = char_word_map_.find(uni_string);
+    if (char_iter != char_word_map_.end()) {
+      // Update existing entry in the char/word index.
+      WordIDSet& word_id_set(char_iter->second);
+      word_id_set.insert(word_id);
+    } else {
+      // Create a new entry in the char/word index.
+      WordIDSet word_id_set;
+      word_id_set.insert(word_id);
+      DCHECK(char_word_map_.insert(std::make_pair(uni_string,
+          word_id_set)).second);
+    }
+  }
+}
+
+// static
+Time InMemoryURLIndex::RecentThreshold() {
+  return Time::Now() - TimeDelta::FromDays(kLowQualityMatchAgeLimitInDays);
 }
 
 }  // namespace history