1 /*
   2  * Copyright (c) 2016, 2019, 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_LOGGING_LOGMESSAGEBUFFER_HPP
  25 #define SHARE_LOGGING_LOGMESSAGEBUFFER_HPP
  26 
  27 #include "logging/logDecorations.hpp"
  28 #include "logging/logLevel.hpp"
  29 #include "memory/allocation.hpp"
  30 
  31 class LogMessageBuffer : public CHeapObj<mtLogging> {
  32   friend class LogMessageTest_nwrite_test_vm_Test;
  33 
  34  protected:
  35   struct LogLine {
  36     LogLevelType level;
  37     size_t message_offset;
  38   };
  39   static const size_t InitialLineCapacity = 10;
  40   static const size_t InitialMessageBufferCapacity = 1024;
  41 
  42   Arena* _arena;
  43   size_t _message_buffer_size;
  44   size_t _message_buffer_capacity;
  45   char* _message_buffer;
  46 
  47   size_t _line_count;
  48   size_t _line_capacity;
  49   LogLine* _lines;
  50 
  51   bool _allocated;
  52   LogLevelType _least_detailed_level;
  53   size_t (*_prefix_fn)(char*, size_t);
  54 
  55   void initialize_buffers();
  56   template<typename T>
  57   void grow(T*& buffer, size_t& capacity, size_t minimum_length = 0);
  58 
  59  private:
  60   NONCOPYABLE(LogMessageBuffer);
  61 
  62  public:
  63   LogMessageBuffer(Arena* arena = NULL);
  64   ~LogMessageBuffer();
  65 
  66   static size_t initial_buffer_size();
  67 
  68   class Iterator {
  69    private:
  70     const LogMessageBuffer& _message;
  71     size_t _current_line_index;
  72     LogLevelType _level;
  73     LogDecorations &_decorations;
  74 
  75     void skip_messages_with_finer_level();
  76 
  77    public:
  78     Iterator(const LogMessageBuffer& message, LogLevelType level, LogDecorations& decorations)
  79         : _message(message), _current_line_index(0), _level(level), _decorations(decorations) {
  80       skip_messages_with_finer_level();
  81     }
  82 
  83     void operator++(int) {
  84       _current_line_index++;
  85       skip_messages_with_finer_level();
  86     }
  87 
  88     bool is_at_end() {
  89       return _current_line_index == _message._line_count;
  90     }
  91 
  92     const char* message() const {
  93       return _message._message_buffer + _message._lines[_current_line_index].message_offset;
  94     }
  95 
  96     const LogDecorations& decorations() {
  97       _decorations.set_level(_message._lines[_current_line_index].level);
  98       return _decorations;
  99     }
 100   };
 101 
 102   void reset();
 103 
 104   Arena* arena() const {
 105     return _arena;
 106   }
 107 
 108   LogLevelType least_detailed_level() const {
 109     return _least_detailed_level;
 110   }
 111 
 112   Iterator iterator(LogLevelType level, LogDecorations& decorations) const {
 113     return Iterator(*this, level, decorations);
 114   }
 115 
 116   // Lines in LogMessageBuffers are not automatically prefixed based on tags
 117   // like regular simple messages (see LogPrefix.hpp for more about prefixes).
 118   // It is, however, possible to specify a prefix per LogMessageBuffer,
 119   // using set_prefix(). Lines added to the LogMessageBuffer after a prefix
 120   // function has been set will be prefixed automatically.
 121   // Setting this to NULL will disable prefixing.
 122   void set_prefix(size_t (*prefix_fn)(char*, size_t)) {
 123     _prefix_fn = prefix_fn;
 124   }
 125 
 126   void write_n(LogLevelType level, const char * s, size_t written);
 127 
 128   ATTRIBUTE_PRINTF(3, 4)
 129   void write(LogLevelType level, const char* fmt, ...);
 130 
 131   ATTRIBUTE_PRINTF(3, 0)
 132   virtual void vwrite(LogLevelType level, const char* fmt, va_list args);
 133 
 134 #define LOG_LEVEL(level, name) \
 135   LogMessageBuffer& v##name(const char* fmt, va_list args) ATTRIBUTE_PRINTF(2, 0); \
 136   LogMessageBuffer& name(const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3);
 137   LOG_LEVEL_LIST
 138 #undef LOG_LEVEL
 139 };
 140 
 141 #endif // SHARE_LOGGING_LOGMESSAGEBUFFER_HPP