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 "memory/allocation.hpp"
  30 #include "utilities/globalDefinitions.hpp"
  31 
  32 class LogDecorations;
  33 class LogTagSet;
  34 
  35 // The base class/interface for log outputs.
  36 // Keeps track of the latest configuration string,
  37 // and its selected decorators.
  38 class LogOutput : public CHeapObj<mtLogging> {
  39   // Make LogConfiguration a friend to allow it to modify the configuration string.
  40   friend class LogConfiguration;
  41 
  42  private:
  43   static const size_t InitialConfigBufferSize = 256;
  44   char* _config_string;
  45   size_t _config_string_buffer_size;
  46   char* _option_string;
  47 
  48  protected:
  49   LogDecorators _decorators;
  50 
  51   // Clears any previous config description in preparation of reconfiguration.
  52   void clear_config_string();
  53   // Adds the tagset on the given level to the config description (e.g. "tag1+tag2=level").
  54   void add_to_config_string(const LogTagSet* ts, LogLevelType level);
  55   // Replaces the current config description with the given string.
  56   void set_config_string(const char* string);
  57   // Replaces the current output option with the given string.
  58   void set_option_string(const char* string);
  59 
  60  public:
  61   static LogOutput* const Stdout;
  62   static LogOutput* const Stderr;
  63 
  64   void set_decorators(const LogDecorators &decorators) {
  65     _decorators = decorators;
  66   }
  67 
  68   const LogDecorators& decorators() const {
  69     return _decorators;
  70   }
  71 
  72   const char* config_string() const {
  73     return _config_string;
  74   }
  75 
  76   const char* option_string() const {
  77     return _option_string;
  78   }
  79 
  80   LogOutput() : _config_string(NULL), _config_string_buffer_size(0), _option_string(NULL) {
  81   }
  82 
  83   virtual ~LogOutput();
  84 
  85   // If the output can be rotated, trigger a forced rotation, otherwise do nothing.
  86   // Log outputs with rotation capabilities should override this.
  87   virtual void force_rotate() {
  88     // Do nothing by default.
  89   }
  90 
  91   virtual const char* name() const = 0;
  92   virtual bool initialize(const char* options) = 0;
  93   virtual int write(const LogDecorations &decorations, const char* msg) = 0;
  94 };
  95 
  96 #endif // SHARE_VM_LOGGING_LOGOUTPUT_HPP