diff options
Diffstat (limited to 'layout/style/MediaQueryList.cpp')
| -rw-r--r-- | layout/style/MediaQueryList.cpp | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/layout/style/MediaQueryList.cpp b/layout/style/MediaQueryList.cpp new file mode 100644 index 000000000..069e049c4 --- /dev/null +++ b/layout/style/MediaQueryList.cpp @@ -0,0 +1,207 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */ +/* 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/. */ + +/* implements DOM interface for querying and observing media queries */ + +#include "mozilla/dom/MediaQueryList.h" +#include "nsPresContext.h" +#include "nsIMediaList.h" +#include "nsCSSParser.h" +#include "nsIDocument.h" + +namespace mozilla { +namespace dom { + +MediaQueryList::MediaQueryList(nsIDocument *aDocument, + const nsAString &aMediaQueryList) + : mDocument(aDocument), + mMediaList(new nsMediaList), + mMatchesValid(false) +{ + PR_INIT_CLIST(this); + + nsCSSParser parser; + parser.ParseMediaList(aMediaQueryList, nullptr, 0, mMediaList, false); +} + +MediaQueryList::~MediaQueryList() +{ + if (mDocument) { + PR_REMOVE_LINK(this); + } +} + +NS_IMPL_CYCLE_COLLECTION_CLASS(MediaQueryList) + +NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(MediaQueryList) + NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument) + NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCallbacks) + NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS +NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END + +NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(MediaQueryList) + if (tmp->mDocument) { + PR_REMOVE_LINK(tmp); + NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument) + } + tmp->RemoveAllListeners(); + NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER +NS_IMPL_CYCLE_COLLECTION_UNLINK_END + +NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(MediaQueryList) + +NS_INTERFACE_MAP_BEGIN(MediaQueryList) + NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY + NS_INTERFACE_MAP_ENTRY(nsISupports) + NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(MediaQueryList) +NS_INTERFACE_MAP_END + +NS_IMPL_CYCLE_COLLECTING_ADDREF(MediaQueryList) +NS_IMPL_CYCLE_COLLECTING_RELEASE(MediaQueryList) + +void +MediaQueryList::GetMedia(nsAString &aMedia) +{ + mMediaList->GetText(aMedia); +} + +bool +MediaQueryList::Matches() +{ + if (!mMatchesValid) { + MOZ_ASSERT(!HasListeners(), + "when listeners present, must keep mMatches current"); + RecomputeMatches(); + } + + return mMatches; +} + +void +MediaQueryList::AddListener(MediaQueryListListener& aListener) +{ + if (!HasListeners()) { + // When we have listeners, the pres context owns a reference to + // this. This is a cyclic reference that can only be broken by + // cycle collection. + NS_ADDREF_THIS(); + } + + if (!mMatchesValid) { + MOZ_ASSERT(!HasListeners(), + "when listeners present, must keep mMatches current"); + RecomputeMatches(); + } + + for (uint32_t i = 0; i < mCallbacks.Length(); ++i) { + if (aListener == *mCallbacks[i]) { + // Already registered + return; + } + } + + if (!mCallbacks.AppendElement(&aListener, fallible)) { + if (!HasListeners()) { + // Append failed; undo the AddRef above. + NS_RELEASE_THIS(); + } + } +} + +void +MediaQueryList::RemoveListener(MediaQueryListListener& aListener) +{ + for (uint32_t i = 0; i < mCallbacks.Length(); ++i) { + if (aListener == *mCallbacks[i]) { + mCallbacks.RemoveElementAt(i); + if (!HasListeners()) { + // See NS_ADDREF_THIS() in AddListener. + NS_RELEASE_THIS(); + } + break; + } + } +} + +void +MediaQueryList::RemoveAllListeners() +{ + bool hadListeners = HasListeners(); + mCallbacks.Clear(); + if (hadListeners) { + // See NS_ADDREF_THIS() in AddListener. + NS_RELEASE_THIS(); + } +} + +void +MediaQueryList::RecomputeMatches() +{ + if (!mDocument) { + return; + } + + if (mDocument->GetParentDocument()) { + // Flush frames on the parent so our prescontext will get + // recreated as needed. + mDocument->GetParentDocument()->FlushPendingNotifications(Flush_Frames); + // That might have killed our document, so recheck that. + if (!mDocument) { + return; + } + } + + nsIPresShell* shell = mDocument->GetShell(); + if (!shell) { + // XXXbz What's the right behavior here? Spec doesn't say. + return; + } + + nsPresContext* presContext = shell->GetPresContext(); + if (!presContext) { + // XXXbz What's the right behavior here? Spec doesn't say. + return; + } + + mMatches = mMediaList->Matches(presContext, nullptr); + mMatchesValid = true; +} + +void +MediaQueryList::MediumFeaturesChanged( + nsTArray<HandleChangeData>& aListenersToNotify) +{ + mMatchesValid = false; + + if (HasListeners()) { + bool oldMatches = mMatches; + RecomputeMatches(); + if (mMatches != oldMatches) { + for (uint32_t i = 0, i_end = mCallbacks.Length(); i != i_end; ++i) { + HandleChangeData *d = aListenersToNotify.AppendElement(fallible); + if (d) { + d->mql = this; + d->callback = mCallbacks[i]; + } + } + } + } +} + +nsISupports* +MediaQueryList::GetParentObject() const +{ + return mDocument; +} + +JSObject* +MediaQueryList::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) +{ + return MediaQueryListBinding::Wrap(aCx, this, aGivenProto); +} + +} // namespace dom +} // namespace mozilla |