gecko-dev/dom/xul/templates/nsContentSupportMap.h

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2.0 KiB
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */
#ifndef nsContentSupportMap_h__
#define nsContentSupportMap_h__
#include "PLDHashTable.h"
#include "nsTemplateMatch.h"
/**
* The nsContentSupportMap maintains a mapping from a "resource element"
* in the content tree to the nsTemplateMatch that was used to instantiate it. This
* is necessary to allow the XUL content to be built lazily. Specifically,
* when building "resumes" on a partially-built content element, the builder
* will walk upwards in the content tree to find the first element with an
* 'id' attribute. This element is assumed to be the "resource element",
* and allows the content builder to access the nsTemplateMatch (variable assignments
* and rule information).
*/
class nsContentSupportMap {
public:
nsContentSupportMap() : mMap(PLDHashTable::StubOps(), sizeof(Entry)) { }
~nsContentSupportMap() { }
nsresult Put(nsIContent* aElement, nsTemplateMatch* aMatch) {
PLDHashEntryHdr* hdr = mMap.Add(aElement, mozilla::fallible);
if (!hdr)
return NS_ERROR_OUT_OF_MEMORY;
Entry* entry = static_cast<Entry*>(hdr);
NS_ASSERTION(entry->mMatch == nullptr, "over-writing entry");
entry->mContent = aElement;
entry->mMatch = aMatch;
return NS_OK;
}
bool Get(nsIContent* aElement, nsTemplateMatch** aMatch) {
PLDHashEntryHdr* hdr = mMap.Search(aElement);
if (!hdr)
return false;
Entry* entry = static_cast<Entry*>(hdr);
*aMatch = entry->mMatch;
return true;
}
void Remove(nsIContent* aElement);
void Clear() { mMap.Clear(); }
protected:
PLDHashTable mMap;
struct Entry : public PLDHashEntryHdr {
nsIContent* mContent;
nsTemplateMatch* mMatch;
};
};
#endif