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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /parser/html/nsHtml5AtomTable.h | |
parent | Initial commit. (diff) | |
download | thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.tar.xz thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'parser/html/nsHtml5AtomTable.h')
-rw-r--r-- | parser/html/nsHtml5AtomTable.h | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/parser/html/nsHtml5AtomTable.h b/parser/html/nsHtml5AtomTable.h new file mode 100644 index 0000000000..4130f05745 --- /dev/null +++ b/parser/html/nsHtml5AtomTable.h @@ -0,0 +1,91 @@ +/* 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 nsHtml5AtomTable_h +#define nsHtml5AtomTable_h + +#include "nsHashKeys.h" +#include "nsTHashtable.h" +#include "nsAtom.h" +#include "nsISerialEventTarget.h" + +#define RECENTLY_USED_PARSER_ATOMS_SIZE 31 + +/** + * 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 IsStatic() returns 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(); + + // NOTE: We rely on mRecentlyUsedParserAtoms keeping alive the returned atom, + // but the caller is responsible to take a reference before calling GetAtom + // again. + nsAtom* GetAtom(const nsAString& aKey); + + /** + * Empties the table. + */ + void Clear() { + for (uint32_t i = 0; i < RECENTLY_USED_PARSER_ATOMS_SIZE; ++i) { + mRecentlyUsedParserAtoms[i] = nullptr; + } + } + +#ifdef DEBUG + void SetPermittedLookupEventTarget(nsISerialEventTarget* aEventTarget) { + mPermittedLookupEventTarget = aEventTarget; + } +#endif + + private: + RefPtr<nsAtom> mRecentlyUsedParserAtoms[RECENTLY_USED_PARSER_ATOMS_SIZE]; +#ifdef DEBUG + nsCOMPtr<nsISerialEventTarget> mPermittedLookupEventTarget; +#endif +}; + +#endif // nsHtml5AtomTable_h |