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 
  25 #ifndef SHARE_LOGGING_LOGSTREAM_HPP
  26 #define SHARE_LOGGING_LOGSTREAM_HPP
  27 
  28 #include "logging/log.hpp"
  29 #include "logging/logHandle.hpp"
  30 #include "memory/resourceArea.hpp"
  31 #include "utilities/ostream.hpp"
  32 
  33 
  34 class LogStream : public outputStream {
  35   friend class LogStreamTest_TestLineBufferAllocation_test_vm_Test; // see test/native/logging/test_logStream.cpp
  36   friend class LogStreamTest_TestLineBufferAllocationCap_test_vm_Test; // see test/native/logging/test_logStream.cpp
  37 
  38   // Helper class, maintains the line buffer. For small line lengths,
  39   // we avoid malloc and use a fixed sized member char array. If LogStream
  40   // is allocated on the stack, this means small lines are assembled
  41   // directly on the stack.
  42   class LineBuffer {
  43     char _smallbuf[64];
  44     char* _buf;
  45     size_t _cap;
  46     size_t _pos;
  47     void try_ensure_cap(size_t cap);
  48   public:
  49     LineBuffer();
  50     ~LineBuffer();
  51     bool is_empty() const { return _pos == 0; }
  52     const char* buffer() const { return _buf; }
  53     void append(const char* s, size_t len);
  54     void reset();
  55   };
  56   LineBuffer  _current_line;
  57   LogTargetHandle _log_handle;
  58 
  59   // Prevent operator new for LogStream.
  60   static void* operator new (size_t);
  61   static void* operator new[] (size_t);
  62 
  63 public:
  64   // Constructor to support creation from a LogTarget instance.
  65   //
  66   // LogTarget(Debug, gc) log;
  67   // LogStreamBase(log) stream;
  68   template <LogLevelType level, LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag>
  69   LogStream(const LogTargetImpl<level, T0, T1, T2, T3, T4, GuardTag>& type_carrier) :
  70       _log_handle(level, &LogTagSetMapping<T0, T1, T2, T3, T4>::tagset()) {}
  71 
  72   // Constructor to support creation from typed (likely NULL) pointer. Mostly used by the logging framework.
  73   //
  74   // LogStreamBase stream(log.debug());
  75   //  or
  76   // LogStreamBase stream((LogTargetImpl<level, T0, T1, T2, T3, T4, GuardTag>*)NULL);
  77   template <LogLevelType level, LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag>
  78   LogStream(const LogTargetImpl<level, T0, T1, T2, T3, T4, GuardTag>* type_carrier) :
  79       _log_handle(level, &LogTagSetMapping<T0, T1, T2, T3, T4>::tagset()) {}
  80 
  81   // Destructor writes any unfinished output left in the line buffer.
  82   ~LogStream();
  83 
  84   // Constructor to support creation from a LogTargetHandle.
  85   //
  86   // LogTarget(Debug, gc) log;
  87   // LogTargetHandle(log) handle;
  88   // LogStreamBase stream(handle);
  89   LogStream(LogTargetHandle handle) : _log_handle(handle) {}
  90 
  91   // Constructor to support creation from a log level and tagset.
  92   //
  93   // LogStreamBase(level, tageset);
  94   LogStream(LogLevelType level, LogTagSet* tagset) : _log_handle(level, tagset) {}
  95 
  96   void write(const char* s, size_t len);
  97 };
  98 
  99 // Support creation of a LogStream without having to provide a LogTarget pointer.
 100 #define LogStreamHandle(level, ...) LogStreamTemplate<LogLevel::level, LOG_TAGS(__VA_ARGS__)>
 101 
 102 template <LogLevelType level, LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag>
 103 class LogStreamTemplate : public LogStream {
 104 public:
 105   LogStreamTemplate() : LogStream((LogTargetImpl<level, T0, T1, T2, T3, T4, GuardTag>*)NULL) {}
 106 };
 107 
 108 #endif // SHARE_LOGGING_LOGSTREAM_HPP