/*+
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 * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.+
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.+
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 *+
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 * This code is free software; you can redistribute it and/or modify it+
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 * under the terms of the GNU General Public License version 2 only, as+
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 * published by the Free Software Foundation.+
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 *+
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 * This code is distributed in the hope that it will be useful, but WITHOUT+
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or+
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License+
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 * version 2 for more details (a copy is included in the LICENSE file that+
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 * accompanied this code).+
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 *+
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 * You should have received a copy of the GNU General Public License version+
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 * 2 along with this work; if not, write to the Free Software Foundation,+
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.+
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 *+
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA+
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 * or visit www.oracle.com if you need additional information or have any+
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 * questions.+
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 *+
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 */+
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+
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#ifndef SHARE_CLASSFILE_PROTECTIONDOMAINCACHE_HPP+
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#define SHARE_CLASSFILE_PROTECTIONDOMAINCACHE_HPP+
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+
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#include "oops/oop.hpp"+
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#include "oops/weakHandle.hpp"+
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#include "memory/iterator.hpp"+
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#include "utilities/hashtable.hpp"+
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+
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// This class caches the approved protection domains that can access loaded classes.+
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// Dictionary entry pd_set point to entries in this hashtable.   Please refer+
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// to dictionary.hpp pd_set for more information about how protection domain entries+
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// are used.+
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// This table is walked during GC, rather than the class loader data graph dictionaries.+
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class ProtectionDomainCacheEntry : public HashtableEntry<WeakHandle<vm_class_loader_data>, mtClass> {+
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  friend class VMStructs;+
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 public:+
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  oop object();+
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  oop object_no_keepalive();+
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+
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  ProtectionDomainCacheEntry* next() {+
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    return (ProtectionDomainCacheEntry*)HashtableEntry<WeakHandle<vm_class_loader_data>, mtClass>::next();+
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  }+
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+
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  ProtectionDomainCacheEntry** next_addr() {+
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    return (ProtectionDomainCacheEntry**)HashtableEntry<WeakHandle<vm_class_loader_data>, mtClass>::next_addr();+
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  }+
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+
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  void verify();+
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};+
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+
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// The ProtectionDomainCacheTable contains all protection domain oops. The+
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// dictionary entries reference its entries instead of having references to oops+
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// directly.+
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// This is used to speed up system dictionary iteration: the oops in the+
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// protection domain are the only ones referring the Java heap. So when there is+
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// need to update these, instead of going over every entry of the system dictionary,+
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// we only need to iterate over this set.+
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// The amount of different protection domains used is typically magnitudes smaller+
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// than the number of system dictionary entries (loaded classes).+
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class ProtectionDomainCacheTable : public Hashtable<WeakHandle<vm_class_loader_data>, mtClass> {+
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  friend class VMStructs;+
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private:+
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  ProtectionDomainCacheEntry* bucket(int i) const {+
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    return (ProtectionDomainCacheEntry*) Hashtable<WeakHandle<vm_class_loader_data>, mtClass>::bucket(i);+
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  }+
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+
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  // The following method is not MT-safe and must be done under lock.+
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  ProtectionDomainCacheEntry** bucket_addr(int i) {+
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    return (ProtectionDomainCacheEntry**) Hashtable<WeakHandle<vm_class_loader_data>, mtClass>::bucket_addr(i);+
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  }+
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+
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  ProtectionDomainCacheEntry* new_entry(unsigned int hash, WeakHandle<vm_class_loader_data> protection_domain) {+
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    ProtectionDomainCacheEntry* entry = (ProtectionDomainCacheEntry*)+
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      Hashtable<WeakHandle<vm_class_loader_data>, mtClass>::new_entry(hash, protection_domain);+
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    return entry;+
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  }+
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+
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  static unsigned int compute_hash(Handle protection_domain);+
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+
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  int index_for(Handle protection_domain);+
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  ProtectionDomainCacheEntry* add_entry(int index, unsigned int hash, Handle protection_domain);+
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  ProtectionDomainCacheEntry* find_entry(int index, Handle protection_domain);+
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+
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  bool _dead_entries;+
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  int _total_oops_removed;+
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+
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public:+
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  ProtectionDomainCacheTable(int table_size);+
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  ProtectionDomainCacheEntry* get(Handle protection_domain);+
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+
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  void unlink();+
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+
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  void print_on(outputStream* st) const;+
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  void verify();+
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+
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  bool has_work() { return _dead_entries; }+
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  void trigger_cleanup();+
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+
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  int removed_entries_count() { return _total_oops_removed; };+
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};+
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+
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+
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class ProtectionDomainEntry :public CHeapObj<mtClass> {+
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  friend class VMStructs;+
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 public:+
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  ProtectionDomainEntry* _next;+
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  ProtectionDomainCacheEntry* _pd_cache;+
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+
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  ProtectionDomainEntry(ProtectionDomainCacheEntry* pd_cache, ProtectionDomainEntry* next) {+
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    _pd_cache = pd_cache;+
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    _next     = next;+
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  }+
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+
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  ProtectionDomainEntry* next() { return _next; }+
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  void set_next(ProtectionDomainEntry* entry) { _next = entry; }+
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  oop object();+
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  oop object_no_keepalive();+
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};+
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#endif // SHARE_CLASSFILE_PROTECTIONDOMAINCACHE_HPP+
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