1 /*
   2  * Copyright (c) 2015, 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_LOG_HPP
  25 #define SHARE_VM_LOGGING_LOG_HPP
  26 
  27 #include "logging/logLevel.hpp"
  28 #include "logging/logPrefix.hpp"
  29 #include "logging/logTagSet.hpp"
  30 #include "logging/logTag.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "memory/allocation.inline.hpp"
  33 #include "runtime/os.hpp"
  34 #include "utilities/debug.hpp"
  35 #include "utilities/ostream.hpp"
  36 
  37 //
  38 // Logging macros
  39 //
  40 // Usage:
  41 //   log_<level>(<comma separated log tags>)(<printf-style log arguments>);
  42 // e.g.
  43 //   log_debug(logging)("message %d", i);
  44 //
  45 // Note that these macros will not evaluate the arguments unless the logging is enabled.
  46 //
  47 #define log_error(...)   (!log_is_enabled(Error, __VA_ARGS__))   ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Error>
  48 #define log_warning(...) (!log_is_enabled(Warning, __VA_ARGS__)) ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Warning>
  49 #define log_info(...)    (!log_is_enabled(Info, __VA_ARGS__))    ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Info>
  50 #define log_debug(...)   (!log_is_enabled(Debug, __VA_ARGS__))   ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Debug>
  51 #define log_trace(...)   (!log_is_enabled(Trace, __VA_ARGS__))   ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Trace>
  52 
  53 // Macros for logging that should be excluded in product builds.
  54 // Available for levels Info, Debug and Trace. Includes test macro that
  55 // evaluates to false in product builds.
  56 #ifndef PRODUCT
  57 #define log_develop_info(...)  (!log_is_enabled(Info, __VA_ARGS__))   ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Info>
  58 #define log_develop_debug(...) (!log_is_enabled(Debug, __VA_ARGS__)) ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Debug>
  59 #define log_develop_trace(...) (!log_is_enabled(Trace, __VA_ARGS__))  ? (void)0 : Log<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Trace>
  60 #define log_develop_is_enabled(level, ...)  log_is_enabled(level, __VA_ARGS__)
  61 #else
  62 #define DUMMY_ARGUMENT_CONSUMER(...)
  63 #define log_develop_info(...)  DUMMY_ARGUMENT_CONSUMER
  64 #define log_develop_debug(...) DUMMY_ARGUMENT_CONSUMER
  65 #define log_develop_trace(...) DUMMY_ARGUMENT_CONSUMER
  66 #define log_develop_is_enabled(...)  false
  67 #endif
  68 
  69 // Convenience macro to test if the logging is enabled on the specified level for given tags.
  70 #define log_is_enabled(level, ...) (Log<LOG_TAGS(__VA_ARGS__)>::is_level(LogLevel::level))
  71 
  72 //
  73 // Log class for more advanced logging scenarios.
  74 // Has printf-style member functions for each log level (trace(), debug(), etc).
  75 //
  76 // Also has outputStream compatible API for the different log-levels.
  77 // The streams are resource allocated when requested and are accessed through
  78 // calls to <level>_stream() functions (trace_stream(), debug_stream(), etc).
  79 //
  80 // Example usage:
  81 //   LogHandle(logging) log;
  82 //   if (log.is_debug()) {
  83 //     ...
  84 //     log.debug("result = %d", result).trace(" tracing info");
  85 //     obj->print_on(log.debug_stream());
  86 //   }
  87 //
  88 #define LogHandle(...)  Log<LOG_TAGS(__VA_ARGS__)>
  89 
  90 template <LogTagType T0, LogTagType T1 = LogTag::__NO_TAG, LogTagType T2 = LogTag::__NO_TAG, LogTagType T3 = LogTag::__NO_TAG,
  91           LogTagType T4 = LogTag::__NO_TAG, LogTagType GuardTag = LogTag::__NO_TAG>
  92 class Log VALUE_OBJ_CLASS_SPEC {
  93  private:
  94   static const size_t LogBufferSize = 512;
  95  public:
  96   // Make sure no more than the maximum number of tags have been given.
  97   // The GuardTag allows this to be detected if/when it happens. If the GuardTag
  98   // is not __NO_TAG, the number of tags given exceeds the maximum allowed.
  99   STATIC_ASSERT(GuardTag == LogTag::__NO_TAG); // Number of logging tags exceeds maximum supported!
 100 
 101   // Empty constructor to avoid warnings on MSVC about unused variables
 102   // when the log instance is only used for static functions.
 103   Log() {
 104   }
 105 
 106   static bool is_level(LogLevelType level) {
 107     return LogTagSetMapping<T0, T1, T2, T3, T4>::tagset().is_level(level);
 108   }
 109 
 110   template <LogLevelType Level>
 111   ATTRIBUTE_PRINTF(1, 2)
 112   static void write(const char* fmt, ...) {
 113     va_list args;
 114     va_start(args, fmt);
 115     vwrite<Level>(fmt, args);
 116     va_end(args);
 117   };
 118 
 119   template <LogLevelType Level>
 120   ATTRIBUTE_PRINTF(1, 0)
 121   static void vwrite(const char* fmt, va_list args) {
 122     char buf[LogBufferSize];
 123     va_list saved_args;         // For re-format on buf overflow.
 124     va_copy(saved_args, args);
 125     size_t prefix_len = LogPrefix<T0, T1, T2, T3, T4>::prefix(buf, sizeof(buf));
 126     // Check that string fits in buffer; resize buffer if necessary
 127     int ret = os::log_vsnprintf(buf + prefix_len, sizeof(buf) - prefix_len, fmt, args);
 128     assert(ret >= 0, "Log message buffer issue");
 129     if ((size_t)ret >= sizeof(buf)) {
 130       size_t newbuf_len = prefix_len + ret + 1;
 131       char* newbuf = NEW_C_HEAP_ARRAY(char, newbuf_len, mtLogging);
 132       prefix_len = LogPrefix<T0, T1, T2, T3, T4>::prefix(newbuf, newbuf_len);
 133       ret = os::log_vsnprintf(newbuf + prefix_len, newbuf_len - prefix_len, fmt, saved_args);
 134       assert(ret >= 0, "Log message buffer issue");
 135       puts<Level>(newbuf);
 136       FREE_C_HEAP_ARRAY(char, newbuf);
 137     } else {
 138       puts<Level>(buf);
 139     }
 140   }
 141 
 142   template <LogLevelType Level>
 143   static void puts(const char* string) {
 144     LogTagSetMapping<T0, T1, T2, T3, T4>::tagset().log(Level, string);
 145   }
 146 
 147 #define LOG_LEVEL(level, name) ATTRIBUTE_PRINTF(2, 0) \
 148   Log& v##name(const char* fmt, va_list args) { \
 149     vwrite<LogLevel::level>(fmt, args); \
 150     return *this; \
 151   } \
 152   Log& name(const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3) { \
 153     va_list args; \
 154     va_start(args, fmt); \
 155     vwrite<LogLevel::level>(fmt, args); \
 156     va_end(args); \
 157     return *this; \
 158   } \
 159   static bool is_##name() { \
 160     return is_level(LogLevel::level); \
 161   } \
 162   static outputStream* name##_stream() { \
 163     return new logStream(write<LogLevel::level>); \
 164   }
 165   LOG_LEVEL_LIST
 166 #undef LOG_LEVEL
 167 };
 168 
 169 #endif // SHARE_VM_LOGGING_LOG_HPP