1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/parser/html/nsHtml5AtomTable.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,107 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#ifndef nsHtml5AtomTable_h
1.9 +#define nsHtml5AtomTable_h
1.10 +
1.11 +#include "nsHashKeys.h"
1.12 +#include "nsTHashtable.h"
1.13 +#include "nsAutoPtr.h"
1.14 +#include "nsIAtom.h"
1.15 +#include "nsIThread.h"
1.16 +
1.17 +class nsHtml5Atom;
1.18 +
1.19 +class nsHtml5AtomEntry : public nsStringHashKey
1.20 +{
1.21 + public:
1.22 + nsHtml5AtomEntry(KeyTypePointer aStr);
1.23 + nsHtml5AtomEntry(const nsHtml5AtomEntry& aOther);
1.24 + ~nsHtml5AtomEntry();
1.25 + inline nsHtml5Atom* GetAtom()
1.26 + {
1.27 + return mAtom;
1.28 + }
1.29 + private:
1.30 + nsAutoPtr<nsHtml5Atom> mAtom;
1.31 +};
1.32 +
1.33 +/**
1.34 + * nsHtml5AtomTable provides non-locking lookup and creation of atoms for
1.35 + * nsHtml5Parser or nsHtml5StreamParser.
1.36 + *
1.37 + * The hashtable holds dynamically allocated atoms that are private to an
1.38 + * instance of nsHtml5Parser or nsHtml5StreamParser. (Static atoms are used on
1.39 + * interned nsHtml5ElementNames and interned nsHtml5AttributeNames. Also, when
1.40 + * the doctype name is 'html', that identifier needs to be represented as a
1.41 + * static atom.)
1.42 + *
1.43 + * Each instance of nsHtml5Parser has a single instance of nsHtml5AtomTable,
1.44 + * and each instance of nsHtml5StreamParser has a single instance of
1.45 + * nsHtml5AtomTable. Dynamic atoms obtained from an nsHtml5AtomTable are valid
1.46 + * for == comparison with each other or with atoms declared in nsHtml5Atoms
1.47 + * within the nsHtml5Tokenizer and the nsHtml5TreeBuilder instances owned by
1.48 + * the same nsHtml5Parser/nsHtml5StreamParser instance that owns the
1.49 + * nsHtml5AtomTable instance.
1.50 + *
1.51 + * Dynamic atoms (atoms whose IsStaticAtom() returns false) obtained from
1.52 + * nsHtml5AtomTable must be re-obtained from another atom table when there's a
1.53 + * need to migrate atoms from an nsHtml5Parser to its nsHtml5StreamParser
1.54 + * (re-obtain from the other nsHtml5AtomTable), from an nsHtml5Parser to its
1.55 + * owner nsHtml5Parser (re-obtain from the other nsHtml5AtomTable) or from the
1.56 + * parser to the DOM (re-obtain from the application-wide atom table). To
1.57 + * re-obtain an atom from another atom table, obtain a string from the atom
1.58 + * using ToString(nsAString&) and look up an atom in the other table using that
1.59 + * string.
1.60 + *
1.61 + * An instance of nsHtml5AtomTable that belongs to an nsHtml5Parser is only
1.62 + * accessed from the main thread. An instance of nsHtml5AtomTable that belongs
1.63 + * to an nsHtml5StreamParser is accessed both from the main thread and from the
1.64 + * thread that executes the runnables of the nsHtml5StreamParser instance.
1.65 + * However, the threads never access the nsHtml5AtomTable instance concurrently
1.66 + * in the nsHtml5StreamParser case.
1.67 + *
1.68 + * Methods on the atoms obtained from nsHtml5AtomTable may be called on any
1.69 + * thread, although they only need to be called on the main thread or on the
1.70 + * thread working for the nsHtml5StreamParser when nsHtml5AtomTable belongs to
1.71 + * an nsHtml5StreamParser.
1.72 + *
1.73 + * Dynamic atoms obtained from nsHtml5AtomTable are deleted when the
1.74 + * nsHtml5AtomTable itself is destructed, which happens when the owner
1.75 + * nsHtml5Parser or nsHtml5StreamParser is destructed.
1.76 + */
1.77 +class nsHtml5AtomTable
1.78 +{
1.79 + public:
1.80 + nsHtml5AtomTable();
1.81 + ~nsHtml5AtomTable();
1.82 +
1.83 + /**
1.84 + * Obtains the atom for the given string in the scope of this atom table.
1.85 + */
1.86 + nsIAtom* GetAtom(const nsAString& aKey);
1.87 +
1.88 + /**
1.89 + * Empties the table.
1.90 + */
1.91 + void Clear()
1.92 + {
1.93 + mTable.Clear();
1.94 + }
1.95 +
1.96 +#ifdef DEBUG
1.97 + void SetPermittedLookupThread(nsIThread* aThread)
1.98 + {
1.99 + mPermittedLookupThread = aThread;
1.100 + }
1.101 +#endif
1.102 +
1.103 + private:
1.104 + nsTHashtable<nsHtml5AtomEntry> mTable;
1.105 +#ifdef DEBUG
1.106 + nsCOMPtr<nsIThread> mPermittedLookupThread;
1.107 +#endif
1.108 +};
1.109 +
1.110 +#endif // nsHtml5AtomTable_h
