| // 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. |
| |
| #ifndef CONTENT_BROWSER_BROWSING_INSTANCE_H_ |
| #define CONTENT_BROWSER_BROWSING_INSTANCE_H_ |
| |
| #include "base/containers/hash_tables.h" |
| #include "base/lazy_instance.h" |
| #include "base/logging.h" |
| #include "base/memory/ref_counted.h" |
| #include "content/common/content_export.h" |
| #include "content/public/browser/browser_context.h" |
| |
| class GURL; |
| |
| namespace content { |
| class SiteInstance; |
| 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 |
| // site_instance_unittest.cc. |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| class CONTENT_EXPORT BrowsingInstance |
| : public base::RefCounted<BrowsingInstance> { |
| protected: |
| // Create a new BrowsingInstance. |
| explicit BrowsingInstance(BrowserContext* context); |
| |
| // Get the browser context to which this BrowsingInstance belongs. |
| BrowserContext* browser_context() const { return browser_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. |
| SiteInstance* GetSiteInstanceForURL(const GURL& url); |
| |
| // Adds the given SiteInstance to our map, to ensure that we do not create |
| // another SiteInstance for the same site. |
| void RegisterSiteInstance(SiteInstance* 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(SiteInstance* 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_); |
| active_contents_count_--; |
| } |
| |
| friend class SiteInstanceImpl; |
| friend class SiteInstance; |
| |
| friend class base::RefCounted<BrowsingInstance>; |
| |
| // Virtual to allow tests to extend it. |
| virtual ~BrowsingInstance(); |
| |
| private: |
| // Map of site to SiteInstance, to ensure we only have one SiteInstance per |
| // site. |
| typedef base::hash_map<std::string, SiteInstance*> SiteInstanceMap; |
| |
| // Common browser context to which all SiteInstances in this BrowsingInstance |
| // must belong. |
| BrowserContext* const browser_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. |
| SiteInstanceMap site_instance_map_; |
| |
| // Number of WebContentses currently using this BrowsingInstance. |
| size_t active_contents_count_; |
| |
| DISALLOW_COPY_AND_ASSIGN(BrowsingInstance); |
| }; |
| |
| } // namespace content |
| |
| #endif // CONTENT_BROWSER_BROWSING_INSTANCE_H_ |