1 /* 2 * Copyright (c) 2015, 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 "runtime/atomic.hpp" 30 #include "utilities/globalDefinitions.hpp" 31 32 class LogOutput; 33 34 // Data structure to keep track of log outputs for a given tagset. 35 // Essentially a sorted linked list going from error level outputs 36 // to outputs of finer levels. Keeps an index from each level to 37 // the first node in the list for the corresponding level. 38 // This allows a log message on, for example, info level to jump 39 // straight into the list where the first info level output can 40 // be found. The log message will then be printed on that output, 41 // as well as all outputs in nodes that follow in the list (which 42 // can be additional info level outputs and/or debug and trace outputs). 43 // 44 // Each instance keeps track of the number of current readers of the list. 45 // To remove a node from the list the node must first be unlinked, 46 // and the memory for that node can be freed whenever the removing 47 // thread observes an active reader count of 0 (after unlinking it). 48 class LogOutputList VALUE_OBJ_CLASS_SPEC { 49 private: 50 struct LogOutputNode : public CHeapObj<mtLogging> { 51 LogOutput* _value; 52 LogOutputNode* _next; 53 LogLevelType _level; 54 }; 55 56 LogOutputNode* _level_start[LogLevel::Count]; 57 volatile jint _active_readers; 58 59 LogOutputNode* find(const LogOutput* output) const; 60 void remove_output(LogOutputNode* node); 61 void add_output(LogOutput* output, LogLevelType level); 62 void update_output_level(LogOutputNode* node, LogLevelType level); 63 64 public: 65 LogOutputList() : _active_readers(0) { 66 for (size_t i = 0; i < LogLevel::Count; i++) { 67 _level_start[i] = NULL; 68 } 69 } 70 71 // Test if the outputlist has an output for the given level. 72 bool is_level(LogLevelType level) const { 73 return _level_start[level] != NULL; 74 } 75 76 LogLevelType level_for(const LogOutput* output) const { 77 LogOutputNode* node = this->find(output); 78 if (node == NULL) { 79 return LogLevel::Off; 80 } 81 return node->_level; 82 } 83 84 // Set (add/update/remove) the output to the specified level. 85 void set_output_level(LogOutput* output, LogLevelType level); 86 87 // Bookkeeping functions to keep track of number of active readers/iterators for the list. 88 jint increase_readers(); 89 jint decrease_readers(); 90 void wait_until_no_readers() const; 91 92 class Iterator VALUE_OBJ_CLASS_SPEC { 93 friend class LogOutputList; 94 private: 95 LogOutputNode* _current; 96 LogOutputList* _list; 97 Iterator(LogOutputList* list, LogOutputNode* start) : _current(start), _list(list) { 98 } 99 100 public: 101 ~Iterator() { 102 _list->decrease_readers(); 103 } 104 105 LogOutput* operator*() { 106 return _current->_value; 107 } 108 109 void operator++(int) { 110 _current = _current->_next; 111 } 112 113 bool operator!=(const LogOutputNode *ref) const { 114 return _current != ref; 115 } 116 }; 117 118 Iterator iterator(LogLevelType level = LogLevel::Last) { 119 increase_readers(); 120 return Iterator(this, _level_start[level]); 121 } 122 123 LogOutputNode* end() const { 124 return NULL; 125 } 126 }; 127 128 #endif // SHARE_VM_LOGGING_LOGOUTPUTLIST_HPP