/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this file,

 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef TabGroup_h

#define TabGroup_h

#include "nsHashKeys.h"

#include "nsISupportsImpl.h"

#include "nsIPrincipal.h"

#include "nsTHashtable.h"

#include "nsString.h"

#include "mozilla/Atomics.h"

#include "mozilla/SchedulerGroup.h"

#include "mozilla/RefPtr.h"

class mozIDOMWindowProxy;

class nsIDocShellTreeItem;

class nsIDocument;

class nsPIDOMWindowOuter;

namespace mozilla {

class AbstractThread;

class ThrottledEventQueue;

namespace dom {

class TabChild;

// Two browsing contexts are considered "related" if they are reachable from one

// another through window.opener, window.parent, or window.frames. This is the

// spec concept of a "unit of related browsing contexts"

//

// Two browsing contexts are considered "similar-origin" if they can be made to

// have the same origin by setting document.domain. This is the spec concept of

// a "unit of similar-origin related browsing contexts"

//

// A TabGroup is a set of browsing contexts which are all "related". Within a

// TabGroup, browsing contexts are broken into "similar-origin" DocGroups. In

// more detail, a DocGroup is actually a collection of documents, and a

// TabGroup is a collection of DocGroups. A TabGroup typically will contain

// (through its DocGroups) the documents from one or more tabs related by

// window.opener. A DocGroup is a member of exactly one TabGroup.

class DocGroup;

class TabChild;

class TabGroup final : public SchedulerGroup,

                       public LinkedListElement<TabGroup>

{

private:

  class HashEntry : public nsCStringHashKey

  {

  public:

    // NOTE: Weak reference. The DocGroup destructor removes itself from its

    // owning TabGroup.

    DocGroup* mDocGroup;

    explicit HashEntry(const nsACString* aKey);

  };

  typedef nsTHashtable<HashEntry> DocGroupMap;

public:

  typedef DocGroupMap::Iterator Iterator;

  friend class DocGroup;

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TabGroup, override)

  static TabGroup*

  GetChromeTabGroup();

  // Checks if the TabChild already has a TabGroup assigned to it in

  // IPDL. Returns this TabGroup if it does. This could happen if the parent

  // process created the PBrowser and we needed to assign a TabGroup immediately

  // upon receiving the IPDL message. This method is main thread only.

  static TabGroup* GetFromActor(TabChild* aTabChild);

  static TabGroup* GetFromWindow(mozIDOMWindowProxy* aWindow);

  explicit TabGroup(bool aIsChrome = false);

  // Get the docgroup for the corresponding doc group key.

  // Returns null if the given key hasn't been seen yet.

  already_AddRefed<DocGroup>

  GetDocGroup(const nsACString& aKey);

  already_AddRefed<DocGroup>

  AddDocument(const nsACString& aKey, nsIDocument* aDocument);

  // Join the specified TabGroup, returning a reference to it. If aTabGroup is

  // nullptr, create a new tabgroup to join.

  static already_AddRefed<TabGroup>

  Join(nsPIDOMWindowOuter* aWindow, TabGroup* aTabGroup);

  void Leave(nsPIDOMWindowOuter* aWindow);

  Iterator Iter()

  {

    return mDocGroups.Iter();

  }

  // Returns the size of the set of "similar-origin" DocGroups. To

  // only consider DocGroups with at least one active document, call

  // Count with 'aActiveOnly' = true

  uint32_t Count(bool aActiveOnly = false) const;

  // Returns the nsIDocShellTreeItem with the given name, searching each of the

  // docShell trees which are within this TabGroup. It will pass itself as

  // aRequestor to each docShellTreeItem which it asks to search for the name,

  // and will not search the docShellTreeItem which is passed as aRequestor.

  //

  // This method is used in order to correctly namespace named windows based on

  // their unit of related browsing contexts.

  //

  // It is illegal to pass in the special case-insensitive names "_blank",

  // "_self", "_parent" or "_top", as those should be handled elsewhere.

  nsresult

  FindItemWithName(const nsAString& aName,

                   nsIDocShellTreeItem* aRequestor,

                   nsIDocShellTreeItem* aOriginalRequestor,

                   nsIDocShellTreeItem** aFoundItem);

  nsTArray<nsPIDOMWindowOuter*> GetTopLevelWindows() const;

  const nsTArray<nsPIDOMWindowOuter*>& GetWindows() { return mWindows; }

  // This method is always safe to call off the main thread. The nsIEventTarget

  // can always be used off the main thread.

  nsISerialEventTarget* EventTargetFor(TaskCategory aCategory) const override;

  void WindowChangedBackgroundStatus(bool aIsNowBackground);

  // Returns true if all of the TabGroup's top-level windows are in

  // the background.

  bool IsBackground() const override;

  // Increase/Decrease the number of IndexedDB transactions/databases for the

  // decision making of the preemption in the scheduler.

  Atomic<uint32_t>& IndexedDBTransactionCounter()

  {

    return mNumOfIndexedDBTransactions;

  }

  Atomic<uint32_t>& IndexedDBDatabaseCounter()

  {

    return mNumOfIndexedDBDatabases;

  }

  static LinkedList<TabGroup>* GetTabGroupList()

  {

    return sTabGroups;

  }

  // This returns true if all the window objects in all the TabGroups are

  // either inactive (for example in bfcache) or are in background tabs which

  // can be throttled.

  static bool HasOnlyThrottableTabs();

private:

  virtual AbstractThread*

  AbstractMainThreadForImpl(TaskCategory aCategory) override;

  TabGroup* AsTabGroup() override { return this; }

  void EnsureThrottledEventQueues();

  ~TabGroup();

  // Thread-safe members

  Atomic<bool> mLastWindowLeft;

  Atomic<bool> mThrottledQueuesInitialized;

  Atomic<uint32_t> mNumOfIndexedDBTransactions;

  Atomic<uint32_t> mNumOfIndexedDBDatabases;

  const bool mIsChrome;

  // Main thread only

  DocGroupMap mDocGroups;

  nsTArray<nsPIDOMWindowOuter*> mWindows;

  uint32_t mForegroundCount;

  static LinkedList<TabGroup>* sTabGroups;

};

} // namespace dom

} // namespace mozilla

#endif // defined(TabGroup_h)