gecko-dev/parser/html/nsHtml5AtomTable.h

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/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is HTML Parser C++ Translator code.
*
* The Initial Developer of the Original Code is
* Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Henri Sivonen <hsivonen@iki.fi>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef nsHtml5AtomTable_h_
#define nsHtml5AtomTable_h_
#include "nsHashKeys.h"
#include "nsTHashtable.h"
#include "nsAutoPtr.h"
#include "nsIAtom.h"
#include "nsIThread.h"
class nsHtml5Atom;
class nsHtml5AtomEntry : public nsStringHashKey
{
public:
nsHtml5AtomEntry(KeyTypePointer aStr);
nsHtml5AtomEntry(const nsHtml5AtomEntry& aOther);
~nsHtml5AtomEntry();
inline nsHtml5Atom* GetAtom() {
return mAtom;
}
private:
nsAutoPtr<nsHtml5Atom> mAtom;
};
/**
* nsHtml5AtomTable provides non-locking lookup and creation of atoms for
* nsHtml5Parser or nsHtml5StreamParser.
*
* The hashtable holds dynamically allocated atoms that are private to an
* instance of nsHtml5Parser or nsHtml5StreamParser. (Static atoms are used on
* interned nsHtml5ElementNames and interned nsHtml5AttributeNames. Also, when
* the doctype name is 'html', that identifier needs to be represented as a
* static atom.)
*
* Each instance of nsHtml5Parser has a single instance of nsHtml5AtomTable,
* and each instance of nsHtml5StreamParser has a single instance of
* nsHtml5AtomTable. Dynamic atoms obtained from an nsHtml5AtomTable are valid
* for == comparison with each other or with atoms declared in nsHtml5Atoms
* within the nsHtml5Tokenizer and the nsHtml5TreeBuilder instances owned by
* the same nsHtml5Parser/nsHtml5StreamParser instance that owns the
* nsHtml5AtomTable instance.
*
* Dynamic atoms (atoms whose IsStaticAtom() returns PR_FALSE) obtained from
* nsHtml5AtomTable must be re-obtained from another atom table when there's a
* need to migrate atoms from an nsHtml5Parser to its nsHtml5StreamParser
* (re-obtain from the other nsHtml5AtomTable), from an nsHtml5Parser to its
* owner nsHtml5Parser (re-obtain from the other nsHtml5AtomTable) or from the
* parser to the DOM (re-obtain from the application-wide atom table). To
* re-obtain an atom from another atom table, obtain a string from the atom
* using ToString(nsAString&) and look up an atom in the other table using that
* string.
*
* An instance of nsHtml5AtomTable that belongs to an nsHtml5Parser is only
* accessed from the main thread. An instance of nsHtml5AtomTable that belongs
* to an nsHtml5StreamParser is accessed both from the main thread and from the
* thread that executes the runnables of the nsHtml5StreamParser instance.
* However, the threads never access the nsHtml5AtomTable instance concurrently
* in the nsHtml5StreamParser case.
*
* Methods on the atoms obtained from nsHtml5AtomTable may be called on any
* thread, although they only need to be called on the main thread or on the
* thread working for the nsHtml5StreamParser when nsHtml5AtomTable belongs to
* an nsHtml5StreamParser.
*
* Dynamic atoms obtained from nsHtml5AtomTable are deleted when the
* nsHtml5AtomTable itself is destructed, which happens when the owner
* nsHtml5Parser or nsHtml5StreamParser is destructed.
*/
class nsHtml5AtomTable
{
public:
nsHtml5AtomTable();
~nsHtml5AtomTable();
/**
* Must be called after the constructor before use. Returns PR_TRUE
* when successful and PR_FALSE on OOM failure.
*/
inline PRBool Init() {
return mTable.Init();
}
/**
* Obtains the atom for the given string in the scope of this atom table.
*/
nsIAtom* GetAtom(const nsAString& aKey);
/**
* Empties the table.
*/
void Clear() {
mTable.Clear();
}
#ifdef DEBUG
void SetPermittedLookupThread(nsIThread* aThread) {
mPermittedLookupThread = aThread;
}
#endif
private:
nsTHashtable<nsHtml5AtomEntry> mTable;
#ifdef DEBUG
nsCOMPtr<nsIThread> mPermittedLookupThread;
#endif
};
#endif // nsHtml5AtomTable_h_