1 files changed, 107 insertions, 0 deletions
diff --git a/parser/html/nsHtml5AtomTable.h b/parser/html/nsHtml5AtomTable.h
new file mode 100644
index 000000000..43f9b5f2f
--- /dev/null
+++ b/parser/html/nsHtml5AtomTable.h
@@ -0,0 +1,107 @@
+/* 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 "nsAutoPtr.h"
+#include "nsIAtom.h"
+#include "nsIThread.h"
+
+class nsHtml5Atom;
+
+class nsHtml5AtomEntry : public nsStringHashKey
+{
+  public:
+    explicit 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 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();
+    
+    /**
+     * 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