1 /* 2 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 #ifndef SHARE_VM_LOGGING_LOGOUTPUTLIST_HPP 25 #define SHARE_VM_LOGGING_LOGOUTPUTLIST_HPP 26 27 #include "logging/logLevel.hpp" 28 #include "memory/allocation.hpp" 29 #include "utilities/globalDefinitions.hpp" 30 31 class LogOutput; 32 33 // Data structure to keep track of log outputs for a given tagset. 34 // Essentially a sorted linked list going from error level outputs 35 // to outputs of finer levels. Keeps an index from each level to 36 // the first node in the list for the corresponding level. 37 // This allows a log message on, for example, info level to jump 38 // straight into the list where the first info level output can 39 // be found. The log message will then be printed on that output, 40 // as well as all outputs in nodes that follow in the list (which 41 // can be additional info level outputs and/or debug and trace outputs). 42 // 43 // Each instance keeps track of the number of current readers of the list. 44 // To remove a node from the list the node must first be unlinked, 45 // and the memory for that node can be freed whenever the removing 46 // thread observes an active reader count of 0 (after unlinking it). 47 class LogOutputList { 48 private: 49 struct LogOutputNode : public CHeapObj<mtLogging> { 50 LogOutput* _value; 51 LogOutputNode* _next; 52 LogLevelType _level; 53 }; 54 55 LogOutputNode* _level_start[LogLevel::Count]; 56 volatile jint _active_readers; 57 58 LogOutputNode* find(const LogOutput* output) const; 59 void remove_output(LogOutputNode* node); 60 void add_output(LogOutput* output, LogLevelType level); 61 void update_output_level(LogOutputNode* node, LogLevelType level); 62 63 // Bookkeeping functions to keep track of number of active readers/iterators for the list. 64 jint increase_readers(); 65 jint decrease_readers(); 66 void wait_until_no_readers() const; 67 68 public: 69 LogOutputList() : _active_readers(0) { 70 for (size_t i = 0; i < LogLevel::Count; i++) { 71 _level_start[i] = NULL; 72 } 73 } 74 75 // Test if the outputlist has an output for the given level. 76 bool is_level(LogLevelType level) const { 77 return _level_start[level] != NULL; 78 } 79 80 LogLevelType level_for(const LogOutput* output) const { 81 LogOutputNode* node = this->find(output); 82 if (node == NULL) { 83 return LogLevel::Off; 84 } 85 return node->_level; 86 } 87 88 // Set (add/update/remove) the output to the specified level. 89 void set_output_level(LogOutput* output, LogLevelType level); 90 91 class Iterator { 92 friend class LogOutputList; 93 private: 94 LogOutputNode* _current; 95 LogOutputList* _list; 96 Iterator(LogOutputList* list, LogOutputNode* start) : _current(start), _list(list) { 97 } 98 99 public: 100 ~Iterator() { 101 _list->decrease_readers(); 102 } 103 104 LogOutput* operator*() { 105 return _current->_value; 106 } 107 108 void operator++(int) { 109 _current = _current->_next; 110 } 111 112 bool operator!=(const LogOutputNode *ref) const { 113 return _current != ref; 114 } 115 116 LogLevelType level() const { 117 return _current->_level; 118 } 119 }; 120 121 Iterator iterator(LogLevelType level = LogLevel::Last) { 122 increase_readers(); 123 return Iterator(this, _level_start[level]); 124 } 125 126 LogOutputNode* end() const { 127 return NULL; 128 } 129 }; 130 131 #endif // SHARE_VM_LOGGING_LOGOUTPUTLIST_HPP