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fb76ae538d
This change reworks how TabContext stores its data. Before, it stored an app-id and translated that into an app; now we do the reverse. This lets us guarantee that HasOwnApp() is true iff GetOwnApp() is non-null. We added a new class, MaybeInvalidTabContext to assist with converting from an IPCTabContext to a TabContext. This allows us to ensure that a TabContext object is never invalid.
281 lines
8.8 KiB
C++
281 lines
8.8 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set sw=2 ts=8 et tw=80 : */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_dom_TabContext_h
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#define mozilla_dom_TabContext_h
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#include "mozilla/Assertions.h"
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#include "mozilla/dom/PContent.h"
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#include "mozilla/dom/PBrowser.h"
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#include "mozilla/layout/RenderFrameUtils.h"
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#include "nsIScriptSecurityManager.h"
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#include "mozIApplication.h"
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namespace mozilla {
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namespace dom {
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/**
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* TabContext encapsulates information about an iframe that may be a mozbrowser
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* or mozapp. You can ask whether a TabContext corresponds to a mozbrowser or
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* mozapp, get the app that contains the browser, and so on.
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*
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* TabParent and TabChild both inherit from TabContext, and you can also have
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* standalone TabContext objects.
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*
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* This class is immutable except by calling one of the protected
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* SetTabContext*() methods (and those methods can only be called once). See
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* also MutableTabContext.
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*/
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class TabContext
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{
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protected:
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typedef mozilla::layout::ScrollingBehavior ScrollingBehavior;
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public:
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TabContext();
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/* (The implicit copy-constructor and operator= are fine.) */
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/**
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* Generates IPCTabContext of type BrowserFrameIPCTabContext or
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* AppFrameIPCTabContext from this TabContext's information.
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*/
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IPCTabContext AsIPCTabContext() const;
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/**
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* Does this TabContext correspond to a mozbrowser? (<iframe mozbrowser
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* mozapp> is not a browser.)
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*
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* If IsBrowserElement() is true, HasOwnApp() and HasAppOwnerApp() are
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* guaranteed to be false.
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*
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* If IsBrowserElement() is false, HasBrowserOwnerApp() is guaranteed to be
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* false.
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*/
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bool IsBrowserElement() const;
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/**
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* Does this TabContext correspond to a mozbrowser or mozapp? This is
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* equivalent to IsBrowserElement() || HasOwnApp().
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*/
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bool IsBrowserOrApp() const;
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/**
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* OwnAppId() returns the id of the app which directly corresponds to this
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* context's frame. GetOwnApp() returns the corresponding app object, and
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* HasOwnApp() returns true iff GetOwnApp() would return a non-null value.
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*
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* If HasOwnApp() is true, IsBrowserElement() is guaranteed to be false.
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*/
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uint32_t OwnAppId() const;
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already_AddRefed<mozIApplication> GetOwnApp() const;
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bool HasOwnApp() const;
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/**
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* BrowserOwnerAppId() gets the ID of the app which contains this browser
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* frame. If this is not a browser frame (i.e., if !IsBrowserElement()), then
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* BrowserOwnerAppId() is guaranteed to return NO_APP_ID.
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*
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* Even if we are a browser frame, BrowserOwnerAppId() may still return
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* NO_APP_ID, if this browser frame is not contained inside an app.
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*/
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uint32_t BrowserOwnerAppId() const;
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already_AddRefed<mozIApplication> GetBrowserOwnerApp() const;
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bool HasBrowserOwnerApp() const;
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/**
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* AppOwnerAppId() gets the ID of the app which contains this app frame. If
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* this is not an app frame (i.e., if !HasOwnApp()), then AppOwnerAppId() is
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* guaranteed to return NO_APP_ID.
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*
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* Even if we are an app frame, AppOwnerAppId() may still return NO_APP_ID, if
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* this app frame is not contained inside an app.
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*/
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uint32_t AppOwnerAppId() const;
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already_AddRefed<mozIApplication> GetAppOwnerApp() const;
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bool HasAppOwnerApp() const;
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/**
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* OwnOrContainingAppId() gets the ID of this frame, if HasOwnApp(). If this
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* frame does not have its own app, it gets the ID of the app which contains
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* this frame (i.e., the result of {Browser,App}OwnerAppId(), as applicable).
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*/
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uint32_t OwnOrContainingAppId() const;
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already_AddRefed<mozIApplication> GetOwnOrContainingApp() const;
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bool HasOwnOrContainingApp() const;
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/**
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* Return the requested scrolling behavior for this frame.
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*/
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ScrollingBehavior GetScrollingBehavior() const { return mScrollingBehavior; }
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protected:
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friend class MaybeInvalidTabContext;
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/**
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* These protected mutator methods let you modify a TabContext once. Further
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* attempts to modify a given TabContext will fail (the method will return
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* false).
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*
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* These mutators will also fail if the TabContext was created with anything
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* other than the no-args constructor.
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*/
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/**
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* Set this TabContext to match the given TabContext.
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*/
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bool SetTabContext(const TabContext& aContext);
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/**
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* Set this TabContext to be an app frame (with the given own app) inside the
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* given app. Either or both apps may be null.
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*/
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bool SetTabContextForAppFrame(mozIApplication* aOwnApp,
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mozIApplication* aAppFrameOwnerApp,
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ScrollingBehavior aRequestedBehavior);
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/**
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* Set this TabContext to be a browser frame inside the given app (which may
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* be null).
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*/
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bool SetTabContextForBrowserFrame(mozIApplication* aBrowserFrameOwnerApp,
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ScrollingBehavior aRequestedBehavior);
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private:
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/**
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* Has this TabContext been initialized? If so, mutator methods will fail.
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*/
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bool mInitialized;
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/**
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* This TabContext's own app. If this is non-null, then this
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* TabContext corresponds to an app, and mIsBrowser must be false.
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*/
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nsCOMPtr<mozIApplication> mOwnApp;
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/**
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* A cache of mOwnApp->GetLocalId(). Speed really does matter here, since we
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* read this ID often during process startup.
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*/
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uint32_t mOwnAppId;
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/**
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* This TabContext's containing app. If mIsBrowser, this corresponds to the
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* app which contains the browser frame; otherwise, this corresponds to the
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* app which contains the app frame.
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*/
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nsCOMPtr<mozIApplication> mContainingApp;
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/*
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* Cache of mContainingApp->GetLocalId().
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*/
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uint32_t mContainingAppId;
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/**
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* The requested scrolling behavior for this frame.
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*/
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ScrollingBehavior mScrollingBehavior;
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/**
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* Does this TabContext correspond to a browser element?
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*
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* If this is true, mOwnApp must be null.
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*/
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bool mIsBrowser;
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};
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/**
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* MutableTabContext is the same as MaybeInvalidTabContext, except the mutation
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* methods are public instead of protected. You can still only call these
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* mutation methods once on a given object.
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*/
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class MutableTabContext : public TabContext
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{
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public:
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bool SetTabContext(const TabContext& aContext)
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{
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return TabContext::SetTabContext(aContext);
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}
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bool SetTabContextForAppFrame(mozIApplication* aOwnApp, mozIApplication* aAppFrameOwnerApp,
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ScrollingBehavior aRequestedBehavior)
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{
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return TabContext::SetTabContextForAppFrame(aOwnApp, aAppFrameOwnerApp,
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aRequestedBehavior);
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}
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bool SetTabContextForBrowserFrame(mozIApplication* aBrowserFrameOwnerApp,
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ScrollingBehavior aRequestedBehavior)
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{
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return TabContext::SetTabContextForBrowserFrame(aBrowserFrameOwnerApp,
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aRequestedBehavior);
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}
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};
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/**
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* MaybeInvalidTabContext is a simple class that lets you transform an
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* IPCTabContext into a TabContext.
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*
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* The issue is that an IPCTabContext is not necessarily valid; for example, it
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* might specify an app-id which doesn't exist. So to convert an IPCTabContext
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* into a TabContext, you construct a MaybeInvalidTabContext, check whether it's
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* valid, and, if so, read out your TabContext.
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*
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* Example usage:
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*
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* void UseTabContext(const TabContext& aTabContext);
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*
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* void CreateTab(const IPCTabContext& aContext) {
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* MaybeInvalidTabContext tc(aContext);
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* if (!tc.IsValid()) {
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* NS_ERROR(nsPrintfCString("Got an invalid IPCTabContext: %s",
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* tc.GetInvalidReason()));
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* return;
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* }
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* UseTabContext(tc.GetTabContext());
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* }
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*/
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class MaybeInvalidTabContext
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{
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public:
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/**
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* This constructor copies the information in aContext and sets IsValid() as
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* appropriate.
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*/
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MaybeInvalidTabContext(const IPCTabContext& aContext);
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/**
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* Was the IPCTabContext we received in our constructor valid?
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*/
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bool IsValid();
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/**
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* If IsValid(), this function returns null. Otherwise, it returns a
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* human-readable string indicating why the IPCTabContext passed to our
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* constructor was not valid.
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*/
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const char* GetInvalidReason();
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/**
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* If IsValid(), this function returns a reference to a TabContext
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* corresponding to the IPCTabContext passed to our constructor. If
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* !IsValid(), this function crashes.
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*/
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const TabContext& GetTabContext();
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private:
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MaybeInvalidTabContext(const MaybeInvalidTabContext&) MOZ_DELETE;
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MaybeInvalidTabContext& operator=(const MaybeInvalidTabContext&) MOZ_DELETE;
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const char* mInvalidReason;
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MutableTabContext mTabContext;
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};
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} // namespace dom
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} // namespace mozilla
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#endif
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