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::dom {
  18
  19 class Document;
  20
  21 struct MOZ_STACK_CLASS BindContext final {
  22   // The document that owns the tree we're getting bound to.
  23   //
  24   // This is mostly an optimization to avoid silly pointer-chases to get the
  25   // OwnerDoc().
  26   Document& OwnerDoc() const { return mDoc; }
  27
  28   // Whether we're getting connected.
  29   //
  30   // https://dom.spec.whatwg.org/#connected
  31   bool InComposedDoc() const { return mInComposedDoc; }
  32
  33   // Whether we're getting bound to the document tree.
  34   //
  35   // https://dom.spec.whatwg.org/#in-a-document-tree
  36   bool InUncomposedDoc() const { return mInUncomposedDoc; }
  37
  38   Document* GetComposedDoc() const { return mInComposedDoc ? &mDoc : nullptr; }
  39
  40   Document* GetUncomposedDoc() const {
  41     return mInUncomposedDoc ? &mDoc : nullptr;
  42   }
  43
  44   // Whether our subtree root is changing as a result of this operation.
  45   bool SubtreeRootChanges() const { return mSubtreeRootChanges; }
  46
  47   // Autofocus is allowed only if the is in the same origin as the top level
  48   // document.
  49   // https://html.spec.whatwg.org/multipage/interaction.html#the-autofocus-attribute:same-origin
  50   // In addition, the document should not be already loaded and the
  51   // "browser.autofocus" preference should be 'true'.
  52   bool AllowsAutoFocus() const;
  53
  54   // This constructor should be used for regular appends to content.
  55   explicit BindContext(nsINode& aParent)
  56       : mDoc(*aParent.OwnerDoc()),
  57         mInComposedDoc(aParent.IsInComposedDoc()),
  58         mInUncomposedDoc(aParent.IsInUncomposedDoc()),
  59         mSubtreeRootChanges(true) {}
  60
  61   // When re-binding a shadow host into a tree, we re-bind all the shadow tree
  62   // from the root. In that case, the shadow tree contents remain within the
  63   // same subtree root.  So children should avoid doing silly things like adding
  64   // themselves to the ShadowRoot's id table twice or what not.
  65   //
  66   // This constructor is only meant to be used in that situation.
  67   explicit BindContext(ShadowRoot& aShadowRoot)
  68       : mDoc(*aShadowRoot.OwnerDoc()),
  69         mInComposedDoc(aShadowRoot.IsInComposedDoc()),
  70         mInUncomposedDoc(false),
  71         mSubtreeRootChanges(false) {}
  72
  73   // This constructor is meant to be used when inserting native-anonymous
  74   // children into a subtree.
  75   enum ForNativeAnonymous { ForNativeAnonymous };
  76   BindContext(Element& aParentElement, enum ForNativeAnonymous)
  77       : mDoc(*aParentElement.OwnerDoc()),
  78         mInComposedDoc(aParentElement.IsInComposedDoc()),
  79         mInUncomposedDoc(aParentElement.IsInUncomposedDoc()),
  80         mSubtreeRootChanges(true) {
  81     MOZ_ASSERT(mInComposedDoc, "Binding NAC in a disconnected subtree?");
  82   }
  83
  84  private:
  85   // Returns true iff the document is in the same origin as the top level
  86   // document.
  87   bool IsSameOriginAsTop() const;
  88
  89   Document& mDoc;
  90
  91   const bool mInComposedDoc;
  92   const bool mInUncomposedDoc;
  93
  94   // Whether the bind operation will change the subtree root of the content
  95   // we're binding.
  96   const bool mSubtreeRootChanges;
  97 };
  98
  99 }  // namespace mozilla::dom
 100
 101 #endif