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// Copyright (c) 2006-2008 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 "base/basictypes.h"
#include "base/logging.h"
// This class is for scoping only.
class PageTransition {
// Types of transitions between pages. These are stored in the history
// database to separate visits, and are reported by the renderer for page
// navigations.
// WARNING: don't change these numbers. They are written directly into the
// history database, so future versions will need the same values to match
// the enums.
// A type is made of a core value and a set of qualifiers. A type has one
// core value and 0 or or more qualifiers.
enum {
// User got to this page by clicking a link on another page.
LINK = 0,
// User got this page by typing the URL in the URL bar. This should not be
// used for cases where the user selected a choice that didn't look at all
// like a URL; see GENERATED below.
// We also use this for other "explicit" navigation actions.
TYPED = 1,
// User got to this page through a suggestion in the UI, for example,
// through the destinations page.
// This is a subframe navigation. This is any content that is automatically
// loaded in a non-toplevel frame. For example, if a page consists of
// several frames containing ads, those ad URLs will have this transition
// type. The user may not even realize the content in these pages is a
// separate frame, so may not care about the URL (see MANUAL below).
// For subframe navigations that are explicitly requested by the user and
// generate new navigation entries in the back/forward list. These are
// probably more important than frames that were automatically loaded in
// the background because the user probably cares about the fact that this
// link was loaded.
// User got to this page by typing in the URL bar and selecting an entry
// that did not look like a URL. For example, a match might have the URL
// of a Google search result page, but appear like "Search Google for ...".
// These are not quite the same as TYPED navigations because the user
// didn't type or see the destination URL.
// See also KEYWORD.
// The page was specified in the command line or is the start page.
// The user filled out values in a form and submitted it. NOTE that in
// some situations submitting a form does not result in this transition
// type. This can happen if the form uses script to submit the contents.
// The user "reloaded" the page, either by hitting the reload button or by
// hitting enter in the address bar. NOTE: This is distinct from the
// concept of whether a particular load uses "reload semantics" (i.e.
// bypasses cached data). For this reason, lots of code needs to pass
// around the concept of whether a load should be treated as a "reload"
// separately from their tracking of this transition type, which is mainly
// used for proper scoring for consumers who care about how frequently a
// user typed/visited a particular URL.
// SessionRestore and undo tab close use this transition type too.
// The url was generated from a replaceable keyword other than the default
// search provider. If the user types a keyword (which also applies to
// tab-to-search) in the omnibox this qualifier is applied to the transition
// type of the generated url. TemplateURLModel then may generate an
// additional visit with a transition type of KEYWORD_GENERATED against the
// url 'http://' + keyword. For example, if you do a tab-to-search against
// wikipedia the generated url has a transition qualifer of KEYWORD, and
// TemplateURLModel generates a visit for '' with a transition
// Corresponds to a visit generated for a keyword. See description of
// KEYWORD for more details.
// ADDING NEW CORE VALUE? Be sure to update the LAST_CORE and CORE_MASK
// values below.
// Qualifiers
// Any of the core values above can be augmented by one or more qualifiers.
// These qualifiers further define the transition.
// The beginning of a navigation chain.
CHAIN_START = 0x10000000,
// The last transition in a redirect chain.
CHAIN_END = 0x20000000,
// Redirects caused by JavaScript or a meta refresh tag on the page.
CLIENT_REDIRECT = 0x40000000,
// Redirects sent from the server by HTTP headers. It might be nice to
// break this out into 2 types in the future, permanent or temporary, if we
// can get that information from WebKit.
SERVER_REDIRECT = 0x80000000,
// Used to test whether a transition involves a redirect.
IS_REDIRECT_MASK = 0xC0000000,
// General mask defining the bits used for the qualifiers.
// The type used for the bitfield.
typedef unsigned int Type;
static bool ValidType(int32 type) {
Type t = StripQualifier(static_cast<Type>(type));
return (t >= 0 && t <= LAST_CORE);
static Type FromInt(int32 type) {
if (!ValidType(type)) {
NOTREACHED() << "Invalid transition type " << type;
// Return a safe default so we don't have corrupt data in release mode.
return LINK;
return static_cast<Type>(type);
// Returns true if the given transition is a top-level frame transition, or
// false if the transition was for a subframe.
static bool IsMainFrame(Type type) {
int32 t = StripQualifier(type);
return (t != AUTO_SUBFRAME && t != MANUAL_SUBFRAME);
// Returns whether a transition involves a redirection
static bool IsRedirect(Type type) {
return (type & IS_REDIRECT_MASK) != 0;
// Simplifies the provided transition by removing any qualifier
static Type StripQualifier(Type type) {
return static_cast<Type>(type & ~QUALIFIER_MASK);
// Return the qualifier
static int32 GetQualifier(Type type) {
return type & QUALIFIER_MASK;