// 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 "chrome/browser/tab_contents/site_instance.h"

#include "chrome/browser/renderer_host/browser_render_process_host.h"
#include "chrome/common/url_constants.h"
#include "chrome/common/notification_service.h"
#include "net/base/registry_controlled_domain.h"

SiteInstance::SiteInstance(BrowsingInstance* browsing_instance)
    : browsing_instance_(browsing_instance),
      render_process_host_factory_(NULL),
      process_(NULL),
      max_page_id_(-1),
      has_site_(false) {
  DCHECK(browsing_instance);

  NotificationService::current()->AddObserver(this,
      NotificationType::RENDERER_PROCESS_TERMINATED,
      NotificationService::AllSources());
}

SiteInstance::~SiteInstance() {
  // Now that no one is referencing us, we can safely remove ourselves from
  // the BrowsingInstance.  Any future visits to a page from this site
  // (within the same BrowsingInstance) can safely create a new SiteInstance.
  if (has_site_)
    browsing_instance_->UnregisterSiteInstance(this);

  NotificationService::current()->RemoveObserver(this,
      NotificationType::RENDERER_PROCESS_TERMINATED,
      NotificationService::AllSources());
}

RenderProcessHost* SiteInstance::GetProcess() {
  // Create a new process if ours went away or was reused.
  if (!process_) {
    // See if we should reuse an old process
    if (RenderProcessHost::ShouldTryToUseExistingProcessHost())
      process_ = RenderProcessHost::GetExistingProcessHost(
          browsing_instance_->profile());

    // Otherwise (or if that fails), create a new one.
    if (!process_) {
      if (render_process_host_factory_) {
        process_ = render_process_host_factory_->CreateRenderProcessHost(
            browsing_instance_->profile());
      } else {
        process_ = new BrowserRenderProcessHost(browsing_instance_->profile());
      }
    }

    // Make sure the process starts at the right max_page_id
    process_->UpdateMaxPageID(max_page_id_);
  }
  DCHECK(process_);

  return process_;
}

void SiteInstance::SetSite(const GURL& url) {
  // A SiteInstance's site should not change.
  // TODO(creis): When following links or script navigations, we can currently
  // render pages from other sites in this SiteInstance.  This will eventually
  // be fixed, but until then, we should still not set the site of a
  // SiteInstance more than once.
  DCHECK(!has_site_);

  // Remember that this SiteInstance has been used to load a URL, even if the
  // URL is invalid.
  has_site_ = true;
  site_ = GetSiteForURL(url);

  // Now that we have a site, register it with the BrowsingInstance.  This
  // ensures that we won't create another SiteInstance for this site within
  // the same BrowsingInstance, because all same-site pages within a
  // BrowsingInstance can script each other.
  browsing_instance_->RegisterSiteInstance(this);
}

bool SiteInstance::HasRelatedSiteInstance(const GURL& url) {
  return browsing_instance_->HasSiteInstance(url);
}

SiteInstance* SiteInstance::GetRelatedSiteInstance(const GURL& url) {
  return browsing_instance_->GetSiteInstanceForURL(url);
}

/*static*/
SiteInstance* SiteInstance::CreateSiteInstance(Profile* profile) {
  return new SiteInstance(new BrowsingInstance(profile));
}

/*static*/
GURL SiteInstance::GetSiteForURL(const GURL& url) {
  // URLs with no host should have an empty site.
  GURL site;

  // TODO(creis): For many protocols, we should just treat the scheme as the
  // site, since there is no host.  e.g., file:, about:, chrome:

  // If the url has a host, then determine the site.
  if (url.has_host()) {
    // Only keep the scheme and registered domain as given by GetOrigin.  This
    // may also include a port, which we need to drop.
    site = url.GetOrigin();

    // Remove port, if any.
    if (site.has_port()) {
      GURL::Replacements rep;
      rep.ClearPort();
      site = site.ReplaceComponents(rep);
    }

    // If this URL has a registered domain, we only want to remember that part.
    std::string domain =
        net::RegistryControlledDomainService::GetDomainAndRegistry(url);
    if (!domain.empty()) {
      GURL::Replacements rep;
      rep.SetHostStr(domain);
      site = site.ReplaceComponents(rep);
    }
  }
  return site;
}

/*static*/
bool SiteInstance::IsSameWebSite(const GURL& url1, const GURL& url2) {
  // We infer web site boundaries based on the registered domain name of the
  // top-level page and the scheme.  We do not pay attention to the port if
  // one is present, because pages served from different ports can still
  // access each other if they change their document.domain variable.

  // We must treat javascript: URLs as part of the same site, regardless of
  // the site.
  if (url1.SchemeIs(chrome::kJavaScriptScheme) ||
      url2.SchemeIs(chrome::kJavaScriptScheme))
    return true;

  // We treat about:crash, about:hang, and about:shorthang as the same site as
  // any URL, since they are used as demos for crashing/hanging a process.
  GURL about_crash = GURL("about:crash");
  GURL about_hang = GURL("about:hang");
  GURL about_shorthang = GURL("about:shorthang");
  if (url1 == about_crash || url2 == about_crash ||
    url1 == about_hang || url2 == about_hang ||
    url1 == about_shorthang || url2 == about_shorthang)
    return true;

  // If either URL is invalid, they aren't part of the same site.
  if (!url1.is_valid() || !url2.is_valid()) {
    return false;
  }

  // If the schemes differ, they aren't part of the same site.
  if (url1.scheme() != url2.scheme()) {
    return false;
  }

  return net::RegistryControlledDomainService::SameDomainOrHost(url1, url2);
}

void SiteInstance::Observe(NotificationType type,
                           const NotificationSource& source,
                           const NotificationDetails& details) {
  DCHECK(type == NotificationType::RENDERER_PROCESS_TERMINATED);
  RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
  if (rph == process_)
    process_ = NULL;
}