blob: 5c0bd8c42977237b487928e9d1fbf94d8c04d8d6 [file] [log] [blame]
// 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 <stddef.h>
#include <string>
#include <unordered_map>
#include "base/gtest_prod_util.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "content/browser/isolation_context.h"
#include "content/common/content_export.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/render_process_host_observer.h"
class GURL;
namespace content {
class RenderProcessHost;
class SiteInstanceImpl;
// BrowsingInstance class
// A browsing instance corresponds to the notion of a "unit of related browsing
// contexts" in the HTML 5 spec. Intuitively, it represents a collection of
// tabs and frames that can have script connections to each other. In that
// sense, it reflects the user interface, and not the contents of the tabs and
// frames.
// We further subdivide a BrowsingInstance into SiteInstances, which represent
// the documents within each BrowsingInstance that are from the same site and
// thus can have script access to each other. Different SiteInstances can
// safely run in different processes, because their documents cannot access
// each other's contents (due to the same origin policy).
// It is important to only have one SiteInstance per site within a given
// BrowsingInstance. This is because any two documents from the same site
// might be able to script each other if they are in the same BrowsingInstance.
// Thus, they must be rendered in the same process.
// A BrowsingInstance is live as long as any SiteInstance has a reference to
// it. A SiteInstance is live as long as any NavigationEntry or RenderViewHost
// have references to it. Because both classes are RefCounted, they do not
// need to be manually deleted.
// BrowsingInstance has no public members, as it is designed to be
// visible only from the SiteInstance class. To get a new
// SiteInstance that is part of the same BrowsingInstance, use
// SiteInstance::GetRelatedSiteInstance. Because of this,
// BrowsingInstances and SiteInstances are tested together in
// Note that a browsing instance in the browser is independently tracked in
// the renderer inside blink::Page::RelatedPages() method (in theory the browser
// and renderer should always stay in sync).
class CONTENT_EXPORT BrowsingInstance final
: public base::RefCounted<BrowsingInstance>,
public RenderProcessHostObserver {
friend class base::RefCounted<BrowsingInstance>;
friend class SiteInstanceImpl;
FRIEND_TEST_ALL_PREFIXES(SiteInstanceTest, OneSiteInstancePerSite);
// Return an ID of the next BrowsingInstance to be created. This ID is
// guaranteed to be higher than any ID of an existing BrowsingInstance. This
// does *not* increment the global counter used for assigning
// BrowsingInstance IDs: that happens only in the BrowsingInstance
// constructor.
static BrowsingInstanceId NextBrowsingInstanceId();
// Create a new BrowsingInstance.
explicit BrowsingInstance(BrowserContext* context);
~BrowsingInstance() final;
// RenderProcessHostObserver implementation.
void RenderProcessHostDestroyed(RenderProcessHost* host) final;
// Get the browser context to which this BrowsingInstance belongs.
BrowserContext* GetBrowserContext() const;
// Get the IsolationContext associated with this BrowsingInstance. This can
// be used to track this BrowsingInstance in other areas of the code, along
// with any other state needed to make isolation decisions.
const IsolationContext& isolation_context() { return isolation_context_; }
// Returns whether this BrowsingInstance has registered a SiteInstance for
// the site of the given URL.
bool HasSiteInstance(const GURL& url);
// Get the SiteInstance responsible for rendering the given URL. Should
// create a new one if necessary, but should not create more than one
// SiteInstance per site.
// |allow_default_instance| should be set to true in cases where the caller
// is ok with |url| sharing a process with other sites that do not require
// a dedicated process. Note that setting this to true means that the
// SiteInstanceImpl you get back may return "http://unisolated.invalid" for
// GetSiteURL() and lock_url() calls because the default instance is not
// bound to a single site.
scoped_refptr<SiteInstanceImpl> GetSiteInstanceForURL(
const GURL& url,
bool allow_default_instance);
// Gets site and lock URLs for |url| that are identical with what these
// values would be if we called GetSiteInstanceForURL() with the same
// |url| and |allow_default_instance|. This method is used when we need this
// information, but do not want to create a SiteInstance yet.
void GetSiteAndLockForURL(const GURL& url,
bool allow_default_instance,
GURL* site_url,
GURL* lock_url);
// Helper function used by GetSiteInstanceForURL() and GetSiteAndLockForURL()
// that returns an existing SiteInstance from |site_instance_map_| or
// returns |default_site_instance_| if |allow_default_instance| is true and
// other conditions are met. If there is no existing SiteInstance that is
// appropriate for |url|, |allow_default_instance| combination, then a nullptr
// is returned.
// Note: This method is not intended to be called by code outside this object.
scoped_refptr<SiteInstanceImpl> GetSiteInstanceForURLHelper(
const GURL& url,
bool allow_default_instance);
// Adds the given SiteInstance to our map, to ensure that we do not create
// another SiteInstance for the same site.
void RegisterSiteInstance(SiteInstanceImpl* site_instance);
// Removes the given SiteInstance from our map, after all references to it
// have been deleted. This means it is safe to create a new SiteInstance
// if the user later visits a page from this site, within this
// BrowsingInstance.
void UnregisterSiteInstance(SiteInstanceImpl* site_instance);
// Tracks the number of WebContents currently in this BrowsingInstance.
size_t active_contents_count() const { return active_contents_count_; }
void increment_active_contents_count() { active_contents_count_++; }
void decrement_active_contents_count() {
DCHECK_LT(0u, active_contents_count_);
// Stores the process that should be used if a SiteInstance doesn't need
// a dedicated process.
void SetDefaultProcess(RenderProcessHost* default_process);
RenderProcessHost* default_process() const { return default_process_; }
bool IsDefaultSiteInstance(const SiteInstanceImpl* site_instance) const;
// Map of site to SiteInstance, to ensure we only have one SiteInstance per
// site.
typedef std::unordered_map<std::string, SiteInstanceImpl*> SiteInstanceMap;
// The next available browser-global BrowsingInstance ID.
static int next_browsing_instance_id_;
// The IsolationContext associated with this BrowsingInstance. This will not
// change after the BrowsingInstance is constructed.
// This holds a common BrowserContext to which all SiteInstances in this
// BrowsingInstance must belong.
const IsolationContext isolation_context_;
// Map of site to SiteInstance, to ensure we only have one SiteInstance per
// site. The site string should be the possibly_invalid_spec() of a GURL
// obtained with SiteInstanceImpl::GetSiteForURL. Note that this map may not
// contain every active SiteInstance, because a race exists where two
// SiteInstances can be assigned to the same site. This is ok in rare cases.
// It also does not contain SiteInstances which have not yet been assigned a
// site, such as about:blank. See NavigatorImpl::ShouldAssignSiteForURL.
// This map only contains instances that map to a single site. The
// |default_site_instance_|, which associates multiple sites with a single
// instance, is not contained in this map.
SiteInstanceMap site_instance_map_;
// Number of WebContentses currently using this BrowsingInstance.
size_t active_contents_count_;
// The process to use for any SiteInstance in this BrowsingInstance that
// doesn't require a dedicated process.
RenderProcessHost* default_process_;
// SiteInstance to use if a URL does not correspond to an instance in
// |site_instance_map_| and it does not require a dedicated process.
// This field and |default_process_| are mutually exclusive and this field
// should only be set if kProcessSharingWithStrictSiteInstances is not
// enabled.
scoped_refptr<SiteInstanceImpl> default_site_instance_;
} // namespace content