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_LOGPREFIX_HPP
  25 #define SHARE_VM_LOGGING_LOGPREFIX_HPP
  26 
  27 #include "gc/shared/gcId.hpp"
  28 #include "logging/logTag.hpp"
  29 
  30 // Prefixes prepend each log message for a specified tagset with the given prefix.
  31 // A prefix consists of a format string and a value or callback. Prefixes are added
  32 // after the decorations but before the log message.
  33 //
  34 // List of prefixes for specific tags and/or tagsets.
  35 // Syntax: LOG_PREFIX(<printf format>, <value/callback for value>, LOG_TAGS(<chosen log tags>))
  36 #define LOG_PREFIX_LIST // Currently unused/empty
  37 
  38 // The empty prefix, used when there's no prefix defined.
  39 template <LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag = LogTag::__NO_TAG>
  40 struct LogPrefix : public AllStatic {
  41   STATIC_ASSERT(GuardTag == LogTag::__NO_TAG);
  42   static size_t prefix(char* buf, size_t len) {
  43     return 0;
  44   }
  45 };
  46 
  47 #define LOG_PREFIX(fmt, fn, ...) \
  48 template <> struct LogPrefix<__VA_ARGS__> { \
  49   static size_t prefix(char* buf, size_t len) { \
  50     int ret = jio_snprintf(buf, len, fmt, fn); \
  51     assert(ret >= 0, \
  52            err_msg("Failed to prefix log message using prefix ('%s', '%s'), log buffer too small?", fmt, #fn)); \
  53     return ret; \
  54   } \
  55 };
  56 LOG_PREFIX_LIST
  57 #undef LOG_PREFIX
  58 
  59 #endif // SHARE_VM_LOGGING_LOGPREFIX_HPP