michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsContentSupportMap_h__
michael@0: #define nsContentSupportMap_h__
michael@0: 
michael@0: #include "pldhash.h"
michael@0: #include "nsTemplateMatch.h"
michael@0: 
michael@0: /**
michael@0:  * The nsContentSupportMap maintains a mapping from a "resource element"
michael@0:  * in the content tree to the nsTemplateMatch that was used to instantiate it. This
michael@0:  * is necessary to allow the XUL content to be built lazily. Specifically,
michael@0:  * when building "resumes" on a partially-built content element, the builder
michael@0:  * will walk upwards in the content tree to find the first element with an
michael@0:  * 'id' attribute. This element is assumed to be the "resource element",
michael@0:  * and allows the content builder to access the nsTemplateMatch (variable assignments
michael@0:  * and rule information).
michael@0:  */
michael@0: class nsContentSupportMap {
michael@0: public:
michael@0:     nsContentSupportMap() { Init(); }
michael@0:     ~nsContentSupportMap() { Finish(); }
michael@0: 
michael@0:     nsresult Put(nsIContent* aElement, nsTemplateMatch* aMatch) {
michael@0:         if (!mMap.ops)
michael@0:             return NS_ERROR_NOT_INITIALIZED;
michael@0: 
michael@0:         PLDHashEntryHdr* hdr = PL_DHashTableOperate(&mMap, aElement, PL_DHASH_ADD);
michael@0:         if (!hdr)
michael@0:             return NS_ERROR_OUT_OF_MEMORY;
michael@0: 
michael@0:         Entry* entry = reinterpret_cast<Entry*>(hdr);
michael@0:         NS_ASSERTION(entry->mMatch == nullptr, "over-writing entry");
michael@0:         entry->mContent = aElement;
michael@0:         entry->mMatch   = aMatch;
michael@0:         return NS_OK; }
michael@0: 
michael@0:     bool Get(nsIContent* aElement, nsTemplateMatch** aMatch) {
michael@0:         if (!mMap.ops)
michael@0:             return false;
michael@0: 
michael@0:         PLDHashEntryHdr* hdr = PL_DHashTableOperate(&mMap, aElement, PL_DHASH_LOOKUP);
michael@0:         if (PL_DHASH_ENTRY_IS_FREE(hdr))
michael@0:             return false;
michael@0: 
michael@0:         Entry* entry = reinterpret_cast<Entry*>(hdr);
michael@0:         *aMatch = entry->mMatch;
michael@0:         return true; }
michael@0: 
michael@0:     nsresult Remove(nsIContent* aElement);
michael@0: 
michael@0:     void Clear() { Finish(); Init(); }
michael@0: 
michael@0: protected:
michael@0:     PLDHashTable mMap;
michael@0: 
michael@0:     void Init();
michael@0:     void Finish();
michael@0: 
michael@0:     struct Entry {
michael@0:         PLDHashEntryHdr  mHdr;
michael@0:         nsIContent*      mContent;
michael@0:         nsTemplateMatch* mMatch;
michael@0:     };
michael@0: };
michael@0: 
michael@0: #endif