dom/base/BindContext.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* State that is passed down to BindToTree. */
   8
   9 #ifndef mozilla_dom_BindContext_h__
  10 #define mozilla_dom_BindContext_h__
  11
  12 #include "mozilla/Attributes.h"
  13 #include "mozilla/dom/Element.h"
  14 #include "mozilla/dom/ShadowRoot.h"
  15 #include "nsINode.h"
  16
  17 namespace mozilla {
  18 namespace dom {
  19
  20 class Document;
  21
  22 struct MOZ_STACK_CLASS BindContext final {
  23   // The document that owns the tree we're getting bound to.
  24   //
  25   // This is mostly an optimization to avoid silly pointer-chases to get the
  26   // OwnerDoc().
  27   Document& OwnerDoc() const { return mDoc; }
  28
  29   // Whether we're getting connected.
  30   //
  31   // https://dom.spec.whatwg.org/#connected
  32   bool InComposedDoc() const { return mInComposedDoc; }
  33
  34   // Whether we're getting bound to the document tree.
  35   //
  36   // https://dom.spec.whatwg.org/#in-a-document-tree
  37   bool InUncomposedDoc() const { return mInUncomposedDoc; }
  38
  39   Document* GetComposedDoc() const { return mInComposedDoc ? &mDoc : nullptr; }
  40
  41   Document* GetUncomposedDoc() const {
  42     return mInUncomposedDoc ? &mDoc : nullptr;
  43   }
  44
  45   // Whether our subtree root is changing as a result of this operation.
  46   bool SubtreeRootChanges() const { return mSubtreeRootChanges; }
  47
  48   // Autofocus is allowed only if the is in the same origin as the top level
  49   // document.
  50   // https://html.spec.whatwg.org/multipage/interaction.html#the-autofocus-attribute:same-origin
  51   // In addition, the document should not be already loaded and the
  52   // "browser.autofocus" preference should be 'true'.
  53   bool AllowsAutoFocus() const;
  54
  55   // This constructor should be used for regular appends to content.
  56   explicit BindContext(nsINode& aParent)
  57       : mDoc(*aParent.OwnerDoc()),
  58         mInComposedDoc(aParent.IsInComposedDoc()),
  59         mInUncomposedDoc(aParent.IsInUncomposedDoc()),
  60         mSubtreeRootChanges(true) {}
  61
  62   // When re-binding a shadow host into a tree, we re-bind all the shadow tree
  63   // from the root. In that case, the shadow tree contents remain within the
  64   // same subtree root.  So children should avoid doing silly things like adding
  65   // themselves to the ShadowRoot's id table twice or what not.
  66   //
  67   // This constructor is only meant to be used in that situation.
  68   explicit BindContext(ShadowRoot& aShadowRoot)
  69       : mDoc(*aShadowRoot.OwnerDoc()),
  70         mInComposedDoc(aShadowRoot.IsInComposedDoc()),
  71         mInUncomposedDoc(false),
  72         mSubtreeRootChanges(false) {}
  73
  74   // This constructor is meant to be used when inserting native-anonymous
  75   // children into a subtree.
  76   enum ForNativeAnonymous { ForNativeAnonymous };
  77   BindContext(Element& aParentElement, enum ForNativeAnonymous)
  78       : mDoc(*aParentElement.OwnerDoc()),
  79         mInComposedDoc(aParentElement.IsInComposedDoc()),
  80         mInUncomposedDoc(aParentElement.IsInUncomposedDoc()),
  81         mSubtreeRootChanges(true) {
  82     MOZ_ASSERT(mInComposedDoc, "Binding NAC in a disconnected subtree?");
  83   }
  84
  85  private:
  86   // Returns true iff the document is in the same origin as the top level
  87   // document.
  88   bool IsSameOriginAsTop() const;
  89
  90   Document& mDoc;
  91
  92   const bool mInComposedDoc;
  93   const bool mInUncomposedDoc;
  94
  95   // Whether the bind operation will change the subtree root of the content
  96   // we're binding.
  97   const bool mSubtreeRootChanges;
  98 };
  99
 100 }  // namespace dom
 101 }  // namespace mozilla
 102
 103 #endif