The Tor Browser: layout/style/MediaQueryList.cpp@925c144e1f1f

     1 /* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 /* implements DOM interface for querying and observing media queries */

     8 #include "mozilla/dom/MediaQueryList.h"

     9 #include "nsPresContext.h"

    10 #include "nsIMediaList.h"

    11 #include "nsCSSParser.h"

    12 #include "nsIDocument.h"

    14 namespace mozilla {

    15 namespace dom {

    17 MediaQueryList::MediaQueryList(nsPresContext *aPresContext,

    18                                const nsAString &aMediaQueryList)

    19   : mPresContext(aPresContext),

    20     mMediaList(new nsMediaList),

    21     mMatchesValid(false)

    22 {

    23   PR_INIT_CLIST(this);

    25   SetIsDOMBinding();

    27   nsCSSParser parser;

    28   parser.ParseMediaList(aMediaQueryList, nullptr, 0, mMediaList, false);

    29 }

    31 MediaQueryList::~MediaQueryList()

    32 {

    33   if (mPresContext) {

    34     PR_REMOVE_LINK(this);

    35   }

    36 }

    38 NS_IMPL_CYCLE_COLLECTION_CLASS(MediaQueryList)

    40 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(MediaQueryList)

    41   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPresContext)

    42   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCallbacks)

    43   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS

    44 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

    46 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(MediaQueryList)

    47   if (tmp->mPresContext) {

    48     PR_REMOVE_LINK(tmp);

    49     NS_IMPL_CYCLE_COLLECTION_UNLINK(mPresContext)

    50   }

    51   tmp->RemoveAllListeners();

    52   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER

    53 NS_IMPL_CYCLE_COLLECTION_UNLINK_END

    55 NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(MediaQueryList)

    57 NS_INTERFACE_MAP_BEGIN(MediaQueryList)

    58   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY

    59   NS_INTERFACE_MAP_ENTRY(nsISupports)

    60   NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(MediaQueryList)

    61 NS_INTERFACE_MAP_END

    63 NS_IMPL_CYCLE_COLLECTING_ADDREF(MediaQueryList)

    64 NS_IMPL_CYCLE_COLLECTING_RELEASE(MediaQueryList)

    66 void

    67 MediaQueryList::GetMedia(nsAString &aMedia)

    68 {

    69   mMediaList->GetText(aMedia);

    70 }

    72 bool

    73 MediaQueryList::Matches()

    74 {

    75   if (!mMatchesValid) {

    76     NS_ABORT_IF_FALSE(!HasListeners(),

    77                       "when listeners present, must keep mMatches current");

    78     RecomputeMatches();

    79   }

    81   return mMatches;

    82 }

    84 void

    85 MediaQueryList::AddListener(MediaQueryListListener& aListener)

    86 {

    87   if (!HasListeners()) {

    88     // When we have listeners, the pres context owns a reference to

    89     // this.  This is a cyclic reference that can only be broken by

    90     // cycle collection.

    91     NS_ADDREF_THIS();

    92   }

    94   if (!mMatchesValid) {

    95     NS_ABORT_IF_FALSE(!HasListeners(),

    96                       "when listeners present, must keep mMatches current");

    97     RecomputeMatches();

    98   }

   100   for (uint32_t i = 0; i < mCallbacks.Length(); ++i) {

   101     if (aListener == *mCallbacks[i]) {

   102       // Already registered

   103       return;

   104     }

   105   }

   107   mCallbacks.AppendElement(&aListener);

   108   if (!HasListeners()) {

   109     // Append failed; undo the AddRef above.

   110     NS_RELEASE_THIS();

   111   }

   112 }

   114 void

   115 MediaQueryList::RemoveListener(MediaQueryListListener& aListener)

   116 {

   117   for (uint32_t i = 0; i < mCallbacks.Length(); ++i) {

   118     if (aListener == *mCallbacks[i]) {

   119       mCallbacks.RemoveElementAt(i);

   120       if (!HasListeners()) {

   121         // See NS_ADDREF_THIS() in AddListener.

   122         NS_RELEASE_THIS();

   123       }

   124       break;

   125     }

   126   }

   127 }

   129 void

   130 MediaQueryList::RemoveAllListeners()

   131 {

   132   bool hadListeners = HasListeners();

   133   mCallbacks.Clear();

   134   if (hadListeners) {

   135     // See NS_ADDREF_THIS() in AddListener.

   136     NS_RELEASE_THIS();

   137   }

   138 }

   140 void

   141 MediaQueryList::RecomputeMatches()

   142 {

   143   if (!mPresContext) {

   144     return;

   145   }

   147   mMatches = mMediaList->Matches(mPresContext, nullptr);

   148   mMatchesValid = true;

   149 }

   151 void

   152 MediaQueryList::MediumFeaturesChanged(NotifyList &aListenersToNotify)

   153 {

   154   mMatchesValid = false;

   156   if (HasListeners()) {

   157     bool oldMatches = mMatches;

   158     RecomputeMatches();

   159     if (mMatches != oldMatches) {

   160       for (uint32_t i = 0, i_end = mCallbacks.Length(); i != i_end; ++i) {

   161         HandleChangeData *d = aListenersToNotify.AppendElement();

   162         if (d) {

   163           d->mql = this;

   164           d->callback = mCallbacks[i];

   165         }

   166       }

   167     }

   168   }

   169 }

   171 nsISupports*

   172 MediaQueryList::GetParentObject() const

   173 {

   174   if (!mPresContext) {

   175     return nullptr;

   176   }

   177   return mPresContext->Document();

   178 }

   180 JSObject*

   181 MediaQueryList::WrapObject(JSContext* aCx)

   182 {

   183   return MediaQueryListBinding::Wrap(aCx, this);

   184 }

   186 } // namespace dom

   187 } // namespace mozilla

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