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_LOGMESSAGE_HPP

    25 #define SHARE_VM_LOGGING_LOGMESSAGE_HPP

    26 

    27 #include "logging/log.hpp"

    28 #include "logging/logMessageBuffer.hpp"

    29 #include "logging/logPrefix.hpp"

    30 #include "logging/logTag.hpp"

    31 

    32 // The LogMessage class represents a multi-part/multi-line message

    33 // that is guaranteed to be sent and written to the log outputs

    34 // in a way that prevents interleaving by other log messages.

    35 //

    36 // The interface of LogMessage is very similar to the Log class,

    37 // with printf functions for each level (trace(), debug(), etc).

    38 // The difference is that these functions will append/write to the

    39 // LogMessage, which only buffers the message-parts until the whole

    40 // message is sent to a log (using Log::write). Internal buffers

    41 // are C heap allocated lazily on first write. LogMessages are

    42 // automatically written when they go out of scope.

    43 //

    44 // Example usage:

    45 //

    46 // {

    47 //   LogMessage(logging) msg;

    48 //   if (msg.is_debug()) {

    49 //     msg.debug("debug message");

    50 //     msg.trace("additional trace information");

    51 //   }

    52 // }

    53 //

    54 // Log outputs on trace level will see both of the messages above,

    55 // and the trace line will immediately follow the debug line.

    56 // They will have identical decorations (apart from level).

    57 // Log outputs on debug level will see the debug message,

    58 // but not the trace message.

    59 //

    60 #define LogMessage(...) LogMessageImpl<LOG_TAGS(__VA_ARGS__)>

    61 template <LogTagType T0, LogTagType T1 = LogTag::__NO_TAG, LogTagType T2 = LogTag::__NO_TAG,

    62           LogTagType T3 = LogTag::__NO_TAG, LogTagType T4 = LogTag::__NO_TAG, LogTagType GuardTag = LogTag::__NO_TAG>

    63 class LogMessageImpl : public LogMessageBuffer {

    64  private:

    65   LogImpl<T0, T1, T2, T3, T4, GuardTag> _log;

    66   bool _has_content;

    67 

    68  public:

    69   LogMessageImpl() : _has_content(false) {

    70   }

    71 

    72   ~LogMessageImpl() {

    73     if (_has_content) {

    74       flush();

    75     }

    76   }

    77 

    78   void flush() {

    79     _log.write(*this);

    80     reset();

    81   }

    82 

    83   void reset() {

    84     _has_content = false;

    85     LogMessageBuffer::reset();

    86   }

    87 

    88   ATTRIBUTE_PRINTF(3, 0)

    89   void vwrite(LogLevelType level, const char* fmt, va_list args) {

    90     if (!_has_content) {

    91       _has_content = true;

    92       set_prefix(LogPrefix<T0, T1, T2, T3, T4>::prefix);

    93     }

    94     LogMessageBuffer::vwrite(level, fmt, args);

    95   }

    96 

    97 #define LOG_LEVEL(level, name) \

    98   bool is_##name() const { \

    99     return _log.is_level(LogLevel::level); \

   100   }

   101   LOG_LEVEL_LIST

   102 #undef LOG_LEVEL

   103 };

   104 

   105 #endif // SHARE_VM_LOGGING_LOGMESSAGE_HPP