summaryrefslogtreecommitdiff
path: root/dom/base/nsReferencedElement.cpp
blob: 4d708eb167ea3c27af6e9703b175e0d0ed899fd6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
/* -*- 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/. */

#include "nsReferencedElement.h"
#include "nsContentUtils.h"
#include "nsIURI.h"
#include "nsBindingManager.h"
#include "nsEscape.h"
#include "nsXBLPrototypeBinding.h"
#include "nsIDOMNode.h"
#include "nsIDOMElement.h"
#include "nsCycleCollectionParticipant.h"

void
nsReferencedElement::Reset(nsIContent* aFromContent, nsIURI* aURI,
                           bool aWatch, bool aReferenceImage)
{
  MOZ_ASSERT(aFromContent, "Reset() expects non-null content pointer");

  Unlink();

  if (!aURI)
    return;

  nsAutoCString refPart;
  aURI->GetRef(refPart);
  // Unescape %-escapes in the reference. The result will be in the
  // origin charset of the URL, hopefully...
  NS_UnescapeURL(refPart);

  nsAutoCString charset;
  aURI->GetOriginCharset(charset);
  nsAutoString ref;
  nsresult rv = nsContentUtils::ConvertStringFromEncoding(charset,
                                                          refPart,
                                                          ref);
  if (NS_FAILED(rv) || ref.IsEmpty()) {
    return;
  }

  // Get the current document
  nsIDocument *doc = aFromContent->OwnerDoc();
  if (!doc)
    return;

  nsIContent* bindingParent = aFromContent->GetBindingParent();
  if (bindingParent) {
    nsXBLBinding* binding = bindingParent->GetXBLBinding();
    if (!binding) {
      // This happens, for example, if aFromContent is part of the content
      // inserted by a call to nsIDocument::InsertAnonymousContent, which we
      // also want to handle.  (It also happens for <use>'s anonymous
      // content etc.)
      Element* anonRoot =
        doc->GetAnonRootIfInAnonymousContentContainer(aFromContent);
      if (anonRoot) {
        mElement = nsContentUtils::MatchElementId(anonRoot, ref);
        // We don't have watching working yet for anonymous content, so bail out here.
        return;
      }
    } else {
      bool isEqualExceptRef;
      rv = aURI->EqualsExceptRef(binding->PrototypeBinding()->DocURI(),
                                 &isEqualExceptRef);
      if (NS_SUCCEEDED(rv) && isEqualExceptRef) {
        // XXX sXBL/XBL2 issue
        // Our content is an anonymous XBL element from a binding inside the
        // same document that the referenced URI points to. In order to avoid
        // the risk of ID collisions we restrict ourselves to anonymous
        // elements from this binding; specifically, URIs that are relative to
        // the binding document should resolve to the copy of the target
        // element that has been inserted into the bound document.
        // If the URI points to a different document we don't need this
        // restriction.
        nsINodeList* anonymousChildren =
          doc->BindingManager()->GetAnonymousNodesFor(bindingParent);

        if (anonymousChildren) {
          uint32_t length;
          anonymousChildren->GetLength(&length);
          for (uint32_t i = 0; i < length && !mElement; ++i) {
            mElement =
              nsContentUtils::MatchElementId(anonymousChildren->Item(i), ref);
          }
        }

        // We don't have watching working yet for XBL, so bail out here.
        return;
      }
    }
  }

  bool isEqualExceptRef;
  rv = aURI->EqualsExceptRef(doc->GetDocumentURI(), &isEqualExceptRef);
  if (NS_FAILED(rv) || !isEqualExceptRef) {
    RefPtr<nsIDocument::ExternalResourceLoad> load;
    doc = doc->RequestExternalResource(aURI, aFromContent,
                                       getter_AddRefs(load));
    if (!doc) {
      if (!load || !aWatch) {
        // Nothing will ever happen here
        return;
      }

      DocumentLoadNotification* observer =
        new DocumentLoadNotification(this, ref);
      mPendingNotification = observer;
      if (observer) {
        load->AddObserver(observer);
      }
      // Keep going so we set up our watching stuff a bit
    }
  }

  if (aWatch) {
    nsCOMPtr<nsIAtom> atom = NS_Atomize(ref);
    if (!atom)
      return;
    atom.swap(mWatchID);
  }

  mReferencingImage = aReferenceImage;

  HaveNewDocument(doc, aWatch, ref);
}

void
nsReferencedElement::ResetWithID(nsIContent* aFromContent, const nsString& aID,
                                 bool aWatch)
{
  nsIDocument *doc = aFromContent->OwnerDoc();
  if (!doc)
    return;

  // XXX Need to take care of XBL/XBL2

  if (aWatch) {
    nsCOMPtr<nsIAtom> atom = NS_Atomize(aID);
    if (!atom)
      return;
    atom.swap(mWatchID);
  }

  mReferencingImage = false;

  HaveNewDocument(doc, aWatch, aID);
}

void
nsReferencedElement::HaveNewDocument(nsIDocument* aDocument, bool aWatch,
                                     const nsString& aRef)
{
  if (aWatch) {
    mWatchDocument = aDocument;
    if (mWatchDocument) {
      mElement = mWatchDocument->AddIDTargetObserver(mWatchID, Observe, this,
                                                     mReferencingImage);
    }
    return;
  }
  
  if (!aDocument) {
    return;
  }

  Element *e = mReferencingImage ? aDocument->LookupImageElement(aRef) :
                                   aDocument->GetElementById(aRef);
  if (e) {
    mElement = e;
  }
}

void
nsReferencedElement::Traverse(nsCycleCollectionTraversalCallback* aCB)
{
  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCB, "mWatchDocument");
  aCB->NoteXPCOMChild(mWatchDocument);
  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCB, "mContent");
  aCB->NoteXPCOMChild(mElement);
}

void
nsReferencedElement::Unlink()
{
  if (mWatchDocument && mWatchID) {
    mWatchDocument->RemoveIDTargetObserver(mWatchID, Observe, this,
                                           mReferencingImage);
  }
  if (mPendingNotification) {
    mPendingNotification->Clear();
    mPendingNotification = nullptr;
  }
  mWatchDocument = nullptr;
  mWatchID = nullptr;
  mElement = nullptr;
  mReferencingImage = false;
}

bool
nsReferencedElement::Observe(Element* aOldElement,
                             Element* aNewElement, void* aData)
{
  nsReferencedElement* p = static_cast<nsReferencedElement*>(aData);
  if (p->mPendingNotification) {
    p->mPendingNotification->SetTo(aNewElement);
  } else {
    NS_ASSERTION(aOldElement == p->mElement, "Failed to track content!");
    ChangeNotification* watcher =
      new ChangeNotification(p, aOldElement, aNewElement);
    p->mPendingNotification = watcher;
    nsContentUtils::AddScriptRunner(watcher);
  }
  bool keepTracking = p->IsPersistent();
  if (!keepTracking) {
    p->mWatchDocument = nullptr;
    p->mWatchID = nullptr;
  }
  return keepTracking;
}

NS_IMPL_ISUPPORTS_INHERITED0(nsReferencedElement::ChangeNotification,
                             mozilla::Runnable)

NS_IMPL_ISUPPORTS(nsReferencedElement::DocumentLoadNotification,
                  nsIObserver)

NS_IMETHODIMP
nsReferencedElement::DocumentLoadNotification::Observe(nsISupports* aSubject,
                                                       const char* aTopic,
                                                       const char16_t* aData)
{
  NS_ASSERTION(PL_strcmp(aTopic, "external-resource-document-created") == 0,
               "Unexpected topic");
  if (mTarget) {
    nsCOMPtr<nsIDocument> doc = do_QueryInterface(aSubject);
    mTarget->mPendingNotification = nullptr;
    NS_ASSERTION(!mTarget->mElement, "Why do we have content here?");
    // If we got here, that means we had Reset() called with aWatch ==
    // true.  So keep watching if IsPersistent().
    mTarget->HaveNewDocument(doc, mTarget->IsPersistent(), mRef);
    mTarget->ElementChanged(nullptr, mTarget->mElement);
  }
  return NS_OK;
}