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nsDOMMediaQueryList.cpp
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nsDOMMediaQueryList.cpp
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/* 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 "nsDOMMediaQueryList.h"
#include "nsPresContext.h"
#include "nsIMediaList.h"
#include "nsCSSParser.h"
#include "nsDOMClassInfoID.h" // DOMCI_DATA
nsDOMMediaQueryList::nsDOMMediaQueryList(nsPresContext *aPresContext,
const nsAString &aMediaQueryList)
: mPresContext(aPresContext),
mMediaList(new nsMediaList),
mMatchesValid(false)
{
PR_INIT_CLIST(this);
nsCSSParser parser;
parser.ParseMediaList(aMediaQueryList, nullptr, 0, mMediaList, false);
}
nsDOMMediaQueryList::~nsDOMMediaQueryList()
{
if (mPresContext) {
PR_REMOVE_LINK(this);
}
}
NS_IMPL_CYCLE_COLLECTION_CLASS(nsDOMMediaQueryList)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDOMMediaQueryList)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPresContext)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mListeners)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDOMMediaQueryList)
if (tmp->mPresContext) {
PR_REMOVE_LINK(tmp);
NS_IMPL_CYCLE_COLLECTION_UNLINK(mPresContext)
}
tmp->RemoveAllListeners();
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
DOMCI_DATA(MediaQueryList, nsDOMMediaQueryList)
NS_INTERFACE_MAP_BEGIN(nsDOMMediaQueryList)
NS_INTERFACE_MAP_ENTRY(nsIDOMMediaQueryList)
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(nsDOMMediaQueryList)
NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(MediaQueryList)
NS_INTERFACE_MAP_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMMediaQueryList)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMMediaQueryList)
NS_IMETHODIMP
nsDOMMediaQueryList::GetMedia(nsAString &aMedia)
{
mMediaList->GetText(aMedia);
return NS_OK;
}
NS_IMETHODIMP
nsDOMMediaQueryList::GetMatches(bool *aMatches)
{
if (!mMatchesValid) {
NS_ABORT_IF_FALSE(!HasListeners(),
"when listeners present, must keep mMatches current");
RecomputeMatches();
}
*aMatches = mMatches;
return NS_OK;
}
NS_IMETHODIMP
nsDOMMediaQueryList::AddListener(nsIDOMMediaQueryListListener *aListener)
{
if (!aListener) {
return NS_OK;
}
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) {
NS_ABORT_IF_FALSE(!HasListeners(),
"when listeners present, must keep mMatches current");
RecomputeMatches();
}
if (!mListeners.Contains(aListener)) {
mListeners.AppendElement(aListener);
if (!HasListeners()) {
// Append failed; undo the AddRef above.
NS_RELEASE_THIS();
}
}
return NS_OK;
}
NS_IMETHODIMP
nsDOMMediaQueryList::RemoveListener(nsIDOMMediaQueryListListener *aListener)
{
bool removed = mListeners.RemoveElement(aListener);
NS_ABORT_IF_FALSE(!mListeners.Contains(aListener),
"duplicate occurrence of listeners");
if (removed && !HasListeners()) {
// See NS_ADDREF_THIS() in AddListener.
NS_RELEASE_THIS();
}
return NS_OK;
}
void
nsDOMMediaQueryList::RemoveAllListeners()
{
bool hadListeners = HasListeners();
mListeners.Clear();
if (hadListeners) {
// See NS_ADDREF_THIS() in AddListener.
NS_RELEASE_THIS();
}
}
void
nsDOMMediaQueryList::RecomputeMatches()
{
if (!mPresContext) {
return;
}
mMatches = mMediaList->Matches(mPresContext, nullptr);
mMatchesValid = true;
}
void
nsDOMMediaQueryList::MediumFeaturesChanged(NotifyList &aListenersToNotify)
{
mMatchesValid = false;
if (mListeners.Length()) {
bool oldMatches = mMatches;
RecomputeMatches();
if (mMatches != oldMatches) {
for (uint32_t i = 0, i_end = mListeners.Length(); i != i_end; ++i) {
HandleChangeData *d = aListenersToNotify.AppendElement();
if (d) {
d->mql = this;
d->listener = mListeners[i];
}
}
}
}
}