Cut down on double hashing and code needlessly using hash table iterators
https://bugs.webkit.org/show_bug.cgi?id=120611

Reviewed by Andreas Kling.

Source/WebCore:

Some of these changes are primarily code cleanup, but others could provide
a small code size and speed improvement by avoiding extra hashing.

* Modules/geolocation/Geolocation.cpp:
(WebCore::Geolocation::Watchers::find): Use get instead of find.
(WebCore::Geolocation::Watchers::remove): Use take instead of find.
(WebCore::Geolocation::makeCachedPositionCallbacks): Use the return
value from remove to avoid hashing twice.

* Modules/webaudio/AudioContext.cpp:
(WebCore::AudioContext::addAutomaticPullNode): Use the return value from
add to avoid hashing twice.
(WebCore::AudioContext::removeAutomaticPullNode): Use the return value
from remove to avoid hashing twice.

* Modules/webaudio/AudioNodeInput.cpp:
(WebCore::AudioNodeInput::connect): Use the return value from add to avoid
hashing twice.
(WebCore::AudioNodeInput::disconnect): Use the return value from remove
to avoid hashing twice.

* Modules/webaudio/AudioParam.cpp:
(WebCore::AudioParam::connect): Use the return value from add to avoid
hashing twice.
(WebCore::AudioParam::disconnect): Use the return value from remove to
avoid hashing twice.

* bridge/NP_jsobject.cpp:
(ObjectMap::remove): Use remove instead of find/remove.

* dom/Node.cpp:
(WebCore::Node::~Node): Use the return value from remove instead of
find/remove.

* inspector/InspectorProfilerAgent.cpp:
(WebCore::InspectorProfilerAgent::removeProfile): Remove needless
calls to contains.

* loader/DocumentLoader.cpp:
(WebCore::DocumentLoader::removeSubresourceLoader): Use the return
value from remove instead of find/remove.

* loader/ResourceLoadScheduler.cpp:
(WebCore::ResourceLoadScheduler::HostInformation::remove): Use the
return value from remove to avoid hashing twice.

* loader/appcache/ApplicationCacheGroup.cpp:
(WebCore::ApplicationCacheGroup::disassociateDocumentLoader): Use
remove instead of find/remove.
(WebCore::ApplicationCacheGroup::cacheDestroyed): Removed a needless
call to contains to avoid hashing twice. It's fine to do the check
for an empty hash table unconditionally.

* page/DOMWindow.cpp:
(WebCore::addUnloadEventListener): Eliminated a local variable for clarity.
(WebCore::removeUnloadEventListener): Ditto. Also use remove instead
of find/remove.
(WebCore::removeAllUnloadEventListeners): Ditto. Also use removeAll instead
of find/removeAll.
(WebCore::addBeforeUnloadEventListener): Ditto.
(WebCore::removeBeforeUnloadEventListener): Ditto.
(WebCore::removeAllBeforeUnloadEventListeners): Ditto.

* page/FrameView.cpp:
(WebCore::FrameView::removeViewportConstrainedObject): Use the return
value from remove to avoid hashing twice.
(WebCore::FrameView::removeScrollableArea): Use the return value from
remove instead of find/remove.
(WebCore::FrameView::containsScrollableArea): Use && instead of an if
statement in a way that is idiomatic for this kind of function.

* page/Page.cpp:
(WebCore::Page::addRelevantRepaintedObject): Use the return value from
remove instead of find/remove.

* page/PageGroup.cpp:
(WebCore::PageGroup::removeUserScriptsFromWorld): Use remove instead
of find/remove.
(WebCore::PageGroup::removeUserStyleSheetsFromWorld): Use the return
value from remove instead of find/remove.

* page/PerformanceUserTiming.cpp:
(WebCore::clearPeformanceEntries): Removed a needless call to contains.

* platform/graphics/DisplayRefreshMonitor.cpp:
(WebCore::DisplayRefreshMonitor::removeClient): Use the return value
from remove instead of find/remove.
(WebCore::DisplayRefreshMonitorManager::displayDidRefresh): Use remove
instead of find/remove.

* platform/graphics/blackberry/LayerRenderer.cpp:
(WebCore::LayerRenderer::removeLayer): Use the return value from remove
instead of find/remove.

* platform/win/WindowMessageBroadcaster.cpp:
(WebCore::WindowMessageBroadcaster::removeListener): Use remove instead
of find/remove. It's fine to do the check for an empty hash table unconditionally.

* plugins/PluginDatabase.cpp:
(WebCore::PluginDatabase::removeDisabledPluginFile): Use the return value
from remove instead of find/remove.

* rendering/style/StyleCustomFilterProgramCache.cpp:
(WebCore::StyleCustomFilterProgramCache::lookup): Use get instead of find.
(WebCore::StyleCustomFilterProgramCache::add): Use contains instead of find
in an assertion.
(WebCore::StyleCustomFilterProgramCache::remove): Use remove instead of
find/remove.

* svg/SVGCursorElement.cpp:
(WebCore::SVGCursorElement::removeClient): Use the return value from remove
instead of find/remove.

* svg/SVGDocumentExtensions.cpp:
(WebCore::SVGDocumentExtensions::removeResource): Removed an unneeded call
to contains.
(WebCore::SVGDocumentExtensions::removeAllTargetReferencesForElement): Use
remove instead of find/remove. It's fine to do the check for an empty hash
table unconditionally.
(WebCore::SVGDocumentExtensions::removeAllElementReferencesForTarget): Use
remove instead of find/remove. Also removed unhelpful assertions. One is
already done by HashMap, and the other is just checking a basic invariant
of every HashMap that doesn't need to be checked.

* svg/graphics/SVGImageCache.cpp:
(WebCore::SVGImageCache::removeClientFromCache): Removed an unneeded call
to contains.

* svg/properties/SVGAnimatedProperty.cpp:
(WebCore::SVGAnimatedProperty::~SVGAnimatedProperty): Use the version of
remove that takes an iterator rather than the one that takes a key, so
we don't need to redo the hashing.

Source/WebKit2:

* Platform/CoreIPC/Connection.cpp:
(CoreIPC::Connection::waitForMessage): Use take instead of find/remove.

* UIProcess/WebPreferences.cpp:
(WebKit::WebPreferences::removePageGroup): Use the return value from remove
instead of find/remove.

* WebProcess/Geolocation/GeolocationPermissionRequestManager.cpp:
(WebKit::GeolocationPermissionRequestManager::cancelRequestForGeolocation):
(WebKit::GeolocationPermissionRequestManager::didReceiveGeolocationPermissionDecision):
Use take instead of find/remove.

* WebProcess/Plugins/Netscape/NetscapePlugin.cpp:
(WebKit::NetscapePlugin::frameDidFinishLoading): Use take instead of find/remove.
(WebKit::NetscapePlugin::frameDidFail): Use take instead of find/remove.

* WebProcess/WebPage/WebBackForwardListProxy.cpp:
(WebKit::WebBackForwardListProxy::removeItem): Use take instead of find/remove.

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::didFinishCheckingText): Use take instead of get/remove so we
hash only once.
(WebKit::WebPage::didCancelCheckingText): Ditto.
(WebKit::WebPage::stopExtendingIncrementalRenderingSuppression): Use the return
value from remove instead of contains/remove so we hash only once.

Source/WTF:

Double hashing is common in code that needs to combine a remove with some
action to only be done if the code is removed. The only way to avoid it is
to write code using find and a hash table iterator. To help with this, add
a boolean return value to remove functions to indicate if anything was removed.

Double hashing also happens in code that does a get followed by a remove.
The take function is helpful in this case. To help with this, add a takeFirst
funciton to ListHashSet.

* wtf/HashCountedSet.h:
(WTF::HashCountedSet::removeAll): Added a boolean return value, analogous to the one
that the HashCountedSet::remove function already has.

* wtf/HashMap.h:
(WTF::HashMap::remove): Added a boolean return value, true if something was removed.
* wtf/HashSet.h:
(WTF::HashSet::remove): Ditto.
* wtf/RefPtrHashMap.h:
(WTF::RefPtrHashMap::remove): Ditto.

* wtf/ListHashSet.h:
(WTF::ListHashSet::takeFirst): Added.
(WTF::ListHashSet::takeLast): Added.
(WTF::ListHashSet::remove): Added a boolean return value, true if something was removed.

* wtf/WTFThreadData.h:
(JSC::IdentifierTable::remove): Use the new remove return value to get rid of most of
the code in this function.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154967 268f45cc-cd09-0410-ab3c-d52691b4dbfc
* inspector/InspectorProfilerAgent.cpp:
(WebCore::InspectorProfilerAgent::removeProfile): Fix braces here; a review
comment I forgot to address in my last check-in.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154968 268f45cc-cd09-0410-ab3c-d52691b4dbfc