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_LOGOUTPUT_HPP
  25 #define SHARE_VM_LOGGING_LOGOUTPUT_HPP
  26 
  27 #include "logging/logDecorators.hpp"
  28 #include "logging/logLevel.hpp"
  29 #include "logging/logMessageBuffer.hpp"
  30 #include "memory/allocation.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 
  33 class LogDecorations;
  34 class LogMessageBuffer;
  35 class LogTagSet;
  36 
  37 // The base class/interface for log outputs.
  38 // Keeps track of the latest configuration string,
  39 // and its selected decorators.
  40 class LogOutput : public CHeapObj<mtLogging> {
  41   // Make LogConfiguration a friend to allow it to modify the configuration string.
  42   friend class LogConfiguration;
  43 
  44  private:
  45   static const size_t InitialConfigBufferSize = 256;
  46   char* _config_string;
  47   size_t _config_string_buffer_size;
  48 
  49  protected:
  50   LogDecorators _decorators;
  51 
  52   // Clears any previous config description in preparation of reconfiguration.
  53   void clear_config_string();
  54   // Adds the tagset on the given level to the config description (e.g. "tag1+tag2=level").
  55   void add_to_config_string(const LogTagSet* ts, LogLevelType level);
  56   // Replaces the current config description with the given string.
  57   void set_config_string(const char* string);
  58 
  59  public:
  60   static LogOutput* const Stdout;
  61   static LogOutput* const Stderr;
  62 
  63   void set_decorators(const LogDecorators &decorators) {
  64     _decorators = decorators;
  65   }
  66 
  67   const LogDecorators& decorators() const {
  68     return _decorators;
  69   }
  70 
  71   const char* config_string() const {
  72     return _config_string;
  73   }
  74 
  75   LogOutput() : _config_string(NULL), _config_string_buffer_size(0) {
  76   }
  77 
  78   virtual ~LogOutput();
  79 
  80   // If the output can be rotated, trigger a forced rotation, otherwise do nothing.
  81   // Log outputs with rotation capabilities should override this.
  82   virtual void force_rotate() {
  83     // Do nothing by default.
  84   }
  85 
  86   virtual const char* name() const = 0;
  87   virtual bool initialize(const char* options) = 0;
  88   virtual int write(const LogDecorations& decorations, const char* msg) = 0;
  89   virtual int write(LogMessageBuffer::Iterator msg_iterator) = 0;
  90 };
  91 
  92 #endif // SHARE_VM_LOGGING_LOGOUTPUT_HPP