The Tor Browser: dom/ipc/TabContext.h@7e26c7da4463 (annotated)

dom/ipc/TabContext.h@7e26c7da4463 (annotated)

dom/ipc/TabContext.h

Wed, 31 Dec 2014 06:55:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:50 +0100
changeset 2: 7e26c7da4463
permissions: -rw-r--r--

Added tag UPSTREAM_283F7C6 for changeset ca08bd8f51b2

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set sw=2 ts=8 et 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 mozilla_dom_TabContext_h
 #define mozilla_dom_TabContext_h
 #include "mozilla/layout/RenderFrameUtils.h"
 #include "mozIApplication.h"
 #include "nsCOMPtr.h"
 namespace mozilla {
 namespace dom {
 struct IPCTabContext;
 /**
  * TabContext encapsulates information about an iframe that may be a mozbrowser
  * or mozapp.  You can ask whether a TabContext corresponds to a mozbrowser or
  * mozapp, get the app that contains the browser, and so on.
  *
  * TabParent and TabChild both inherit from TabContext, and you can also have
  * standalone TabContext objects.
  *
  * This class is immutable except by calling one of the protected
  * SetTabContext*() methods (and those methods can only be called once).  See
  * also MutableTabContext.
  */
 class TabContext
 {
 protected:
   typedef mozilla::layout::ScrollingBehavior ScrollingBehavior;
 public:
   TabContext();
   /* (The implicit copy-constructor and operator= are fine.) */
   /**
    * Generates IPCTabContext of type BrowserFrameIPCTabContext or
    * AppFrameIPCTabContext from this TabContext's information.
    */
   IPCTabContext AsIPCTabContext() const;
   /**
    * Does this TabContext correspond to a mozbrowser?  (<iframe mozbrowser
    * mozapp> is not a browser.)
    *
    * If IsBrowserElement() is true, HasOwnApp() and HasAppOwnerApp() are
    * guaranteed to be false.
    *
    * If IsBrowserElement() is false, HasBrowserOwnerApp() is guaranteed to be
    * false.
    */
   bool IsBrowserElement() const;
   /**
    * Does this TabContext correspond to a mozbrowser or mozapp?  This is
    * equivalent to IsBrowserElement() || HasOwnApp().
    */
   bool IsBrowserOrApp() const;
   /**
    * OwnAppId() returns the id of the app which directly corresponds to this
    * context's frame.  GetOwnApp() returns the corresponding app object, and
    * HasOwnApp() returns true iff GetOwnApp() would return a non-null value.
    *
    * If HasOwnApp() is true, IsBrowserElement() is guaranteed to be false.
    */
   uint32_t OwnAppId() const;
   already_AddRefed<mozIApplication> GetOwnApp() const;
   bool HasOwnApp() const;
   /**
    * BrowserOwnerAppId() gets the ID of the app which contains this browser
    * frame.  If this is not a browser frame (i.e., if !IsBrowserElement()), then
    * BrowserOwnerAppId() is guaranteed to return NO_APP_ID.
    *
    * Even if we are a browser frame, BrowserOwnerAppId() may still return
    * NO_APP_ID, if this browser frame is not contained inside an app.
    */
   uint32_t BrowserOwnerAppId() const;
   already_AddRefed<mozIApplication> GetBrowserOwnerApp() const;
   bool HasBrowserOwnerApp() const;
   /**
    * AppOwnerAppId() gets the ID of the app which contains this app frame.  If
    * this is not an app frame (i.e., if !HasOwnApp()), then AppOwnerAppId() is
    * guaranteed to return NO_APP_ID.
    *
    * Even if we are an app frame, AppOwnerAppId() may still return NO_APP_ID, if
    * this app frame is not contained inside an app.
    */
   uint32_t AppOwnerAppId() const;
   already_AddRefed<mozIApplication> GetAppOwnerApp() const;
   bool HasAppOwnerApp() const;
   /**
    * OwnOrContainingAppId() gets the ID of this frame, if HasOwnApp().  If this
    * frame does not have its own app, it gets the ID of the app which contains
    * this frame (i.e., the result of {Browser,App}OwnerAppId(), as applicable).
    */
   uint32_t OwnOrContainingAppId() const;
   already_AddRefed<mozIApplication> GetOwnOrContainingApp() const;
   bool HasOwnOrContainingApp() const;
   /**
    * Return the requested scrolling behavior for this frame.
    */
   ScrollingBehavior GetScrollingBehavior() const { return mScrollingBehavior; }
 protected:
   friend class MaybeInvalidTabContext;
   /**
    * These protected mutator methods let you modify a TabContext once.  Further
    * attempts to modify a given TabContext will fail (the method will return
    * false).
    *
    * These mutators will also fail if the TabContext was created with anything
    * other than the no-args constructor.
    */
   /**
    * Set this TabContext to match the given TabContext.
    */
   bool SetTabContext(const TabContext& aContext);
   /**
    * Set this TabContext to be an app frame (with the given own app) inside the
    * given app.  Either or both apps may be null.
    */
   bool SetTabContextForAppFrame(mozIApplication* aOwnApp,
                                 mozIApplication* aAppFrameOwnerApp,
                                 ScrollingBehavior aRequestedBehavior);
   /**
    * Set this TabContext to be a browser frame inside the given app (which may
    * be null).
    */
   bool SetTabContextForBrowserFrame(mozIApplication* aBrowserFrameOwnerApp,
                                     ScrollingBehavior aRequestedBehavior);
   /**
    * Set this TabContext to be a normal non-browser non-app frame.
    */
   bool SetTabContextForNormalFrame(ScrollingBehavior aRequestedBehavior);
 private:
   /**
    * Has this TabContext been initialized?  If so, mutator methods will fail.
    */
   bool mInitialized;
   /**
    * This TabContext's own app.  If this is non-null, then this
    * TabContext corresponds to an app, and mIsBrowser must be false.
    */
   nsCOMPtr<mozIApplication> mOwnApp;
   /**
    * A cache of mOwnApp->GetLocalId().  Speed really does matter here, since we
    * read this ID often during process startup.
    */
   uint32_t mOwnAppId;
   /**
    * This TabContext's containing app.  If mIsBrowser, this corresponds to the
    * app which contains the browser frame; otherwise, this corresponds to the
    * app which contains the app frame.
    */
   nsCOMPtr<mozIApplication> mContainingApp;
   /*
    * Cache of mContainingApp->GetLocalId().
    */
   uint32_t mContainingAppId;
   /**
    * The requested scrolling behavior for this frame.
    */
   ScrollingBehavior mScrollingBehavior;
   /**
    * Does this TabContext correspond to a browser element?
    *
    * If this is true, mOwnApp must be null.
    */
   bool mIsBrowser;
 };
 /**
  * MutableTabContext is the same as MaybeInvalidTabContext, except the mutation
  * methods are public instead of protected.  You can still only call these
  * mutation methods once on a given object.
  */
 class MutableTabContext : public TabContext
 {
 public:
   bool SetTabContext(const TabContext& aContext)
   {
     return TabContext::SetTabContext(aContext);
   }
   bool SetTabContextForAppFrame(mozIApplication* aOwnApp, mozIApplication* aAppFrameOwnerApp,
                                 ScrollingBehavior aRequestedBehavior)
   {
     return TabContext::SetTabContextForAppFrame(aOwnApp, aAppFrameOwnerApp,
                                                 aRequestedBehavior);
   }
   bool SetTabContextForBrowserFrame(mozIApplication* aBrowserFrameOwnerApp,
                                     ScrollingBehavior aRequestedBehavior)
   {
     return TabContext::SetTabContextForBrowserFrame(aBrowserFrameOwnerApp,
                                                     aRequestedBehavior);
   }
   bool SetTabContextForNormalFrame(ScrollingBehavior aRequestedBehavior)
   {
     return TabContext::SetTabContextForNormalFrame(aRequestedBehavior);
   }
 };
 /**
  * MaybeInvalidTabContext is a simple class that lets you transform an
  * IPCTabContext into a TabContext.
  *
  * The issue is that an IPCTabContext is not necessarily valid; for example, it
  * might specify an app-id which doesn't exist.  So to convert an IPCTabContext
  * into a TabContext, you construct a MaybeInvalidTabContext, check whether it's
  * valid, and, if so, read out your TabContext.
  *
  * Example usage:
  *
  *   void UseTabContext(const TabContext& aTabContext);
  *
  *   void CreateTab(const IPCTabContext& aContext) {
  *     MaybeInvalidTabContext tc(aContext);
  *     if (!tc.IsValid()) {
  *       NS_ERROR(nsPrintfCString("Got an invalid IPCTabContext: %s",
  *                                tc.GetInvalidReason()));
  *       return;
  *     }
  *     UseTabContext(tc.GetTabContext());
  *   }
  */
 class MaybeInvalidTabContext
 {
 public:
   /**
    * This constructor copies the information in aContext and sets IsValid() as
    * appropriate.
    */
   MaybeInvalidTabContext(const IPCTabContext& aContext);
   /**
    * Was the IPCTabContext we received in our constructor valid?
    */
   bool IsValid();
   /**
    * If IsValid(), this function returns null.  Otherwise, it returns a
    * human-readable string indicating why the IPCTabContext passed to our
    * constructor was not valid.
    */
   const char* GetInvalidReason();
   /**
    * If IsValid(), this function returns a reference to a TabContext
    * corresponding to the IPCTabContext passed to our constructor.  If
    * !IsValid(), this function crashes.
    */
   const TabContext& GetTabContext();
 private:
   MaybeInvalidTabContext(const MaybeInvalidTabContext&) MOZ_DELETE;
   MaybeInvalidTabContext& operator=(const MaybeInvalidTabContext&) MOZ_DELETE;
   const char* mInvalidReason;
   MutableTabContext mTabContext;
 };
 } // namespace dom
 } // namespace mozilla
 #endif

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dom/ipc/TabContext.h@7e26c7da4463 (annotated)

dom/ipc/TabContext.h