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