Add PrerenderLocalPredictor, which will eventually perform

chrome/browser/history/visit_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 "chrome/browser/history/visit_database.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <set>
 
 #include "base/logging.h"
 #include "base/string_number_conversions.h"
 #include "chrome/browser/history/url_database.h"
 #include "chrome/browser/history/visit_filter.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/common/page_transition_types.h"
 #include "sql/statement.h"
 
 // Rows, in order, of the visit table.
 #define HISTORY_VISIT_ROW_FIELDS \
     " id,url,visit_time,from_visit,transition,segment_id,is_indexed," \
     "visit_duration "
 
 namespace history {
 
-VisitDatabase::VisitDatabase() {
+VisitDatabase::VisitDatabase() :
+    observers_(new ObserverListThreadSafe<VisitDatabaseObserver>()) {
 }
 
 VisitDatabase::~VisitDatabase() {
 }
 
 bool VisitDatabase::InitVisitTable() {
   if (!GetDB().DoesTableExist("visits")) {
     if (!GetDB().Execute("CREATE TABLE visits("
         "id INTEGER PRIMARY KEY,"
         "url INTEGER NOT NULL," // key of the URL this corresponds to
@@ skipping 113 matching lines @@
     statement1.BindInt64(0, visit->visit_id);
     statement1.BindInt64(1, source);
 
     if (!statement1.Run()) {
       VLOG(0) << "Failed to execute visit_source insert statement:  "
               << "id = " << visit->visit_id;
       return 0;
     }
   }
 
+  BriefVisitInfo info;
+  info.url_id = visit->url_id;
+  info.time = visit->visit_time;
+  info.transition = visit->transition;
+  observers_->Notify(&VisitDatabaseObserver::OnAddVisit, info);
+
   return visit->visit_id;
 }
 
 void VisitDatabase::DeleteVisit(const VisitRow& visit) {
   // Patch around this visit. Any visits that this went to will now have their
   // "source" be the deleted visit's source.
   sql::Statement update_chain(GetDB().GetCachedStatement(SQL_FROM_HERE,
       "UPDATE visits SET from_visit=? WHERE from_visit=?"));
   update_chain.BindInt64(0, visit.referring_visit);
   update_chain.BindInt64(1, visit.visit_id);
@@ skipping 380 matching lines @@
   if (!GetDB().DoesColumnExist("visits", "visit_duration")) {
     // Old versions don't have the visit_duration column, we modify the table
     // to add that field.
     if (!GetDB().Execute("ALTER TABLE visits "
         "ADD COLUMN visit_duration INTEGER DEFAULT 0 NOT NULL"))
       return false;
   }
   return true;
 }
 
+void VisitDatabase::AddVisitDatabaseObserver(VisitDatabaseObserver* observer) {
+  observers_->AddObserver(observer);
+}
+
+void VisitDatabase::RemoveVisitDatabaseObserver(
+    VisitDatabaseObserver* observer) {
+  observers_->RemoveObserver(observer);
+}
+
+void VisitDatabase::GetBriefVisitInfoOfMostRecentVisits(
+    int max_visits,
+    std::vector<BriefVisitInfo>* result_vector) {
+  result_vector->clear();
+
+  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
+      "SELECT url,visit_time,transition FROM visits "
+      "ORDER BY id DESC LIMIT ?"));
+
+  statement.BindInt64(0, max_visits);
+
+  if (!statement.is_valid())
+    return;
+
+  while (statement.Step()) {
+    BriefVisitInfo info;
+    info.url_id = statement.ColumnInt64(0);
+    info.time = base::Time::FromInternalValue(statement.ColumnInt64(1));
+    info.transition = content::PageTransitionFromInt(statement.ColumnInt(2));
+    result_vector->push_back(info);
+  }
+}
+
 }  // namespace history