Utils/Logger: Fix 'senf::log::DefaultArea as empty-string' ambiguity

Utils/Logger/AreaRegistry.test.cc

@@ -37,7 +37,9 @@
 
 BOOST_AUTO_UNIT_TEST(areaRegistry)
 {
-    char const * areas[] = { "", "senf::log::test::Foo", "senf::log::test::myArea" };
+    char const * areas[] = { "senf::log::DefaultArea", 
+                             "senf::log::test::Foo", 
+                             "senf::log::test::myArea" };
 
     BOOST_CHECK_EQUAL_COLLECTIONS( senf::log::AreaRegistry::instance().begin(),
                                    senf::log::AreaRegistry::instance().end(),

Utils/Logger/Definitions.hh

@@ -107,12 +107,11 @@ namespace log {
             };                                                                                    \
         }
 
-        /** \brief Default global log stream */
-        SENF_LOG_DEF_STREAM(Debug, MESSAGE, MESSAGE, MESSAGE);
+    /** \brief Default global log stream */
+    SENF_LOG_DEF_STREAM(Debug, MESSAGE, MESSAGE, MESSAGE);
 
-        /** \brief Default global log area */
-        SENF_LOG_DEF_AREA_I(DefaultArea,
-                            std::string v_name() const { return ""; });
+    /** \brief Default global log area */
+    SENF_LOG_DEF_AREA(DefaultArea);
 
     ///\}
     ///\}

Utils/Logger/IOStreamTarget.cc

@@ -68,7 +68,7 @@ prefix_ void senf::log::IOStreamTarget::v_write(boost::posix_time::ptime timesta
 
     for (; i != i_end; ++i) {
         stream_ << timestamp << sep;
-        if (! area.empty())
+        if (area != "senf::log::DefaultArea")
             stream_ << "[" << area << "] ";
         stream_ << *i << "\n";
         sep = '-';

Utils/Logger/IOStreamTarget.hh

@@ -43,6 +43,8 @@ namespace log {
         <pre>
         <date> [<area>] <message>
         </pre>
+
+        The \e area will be omitted it it is \c senf::log::DefaultArea.
         
         The date formatting is set using the Boost.DateTime date_facet, e.g.:
         \code

Utils/Logger/Levels.hh

@@ -39,9 +39,37 @@ namespace log {
         
         These are the valid log levels with some additional special values:
 
-        \c DISABLED is a special value used as level limit to disable all messages.
+        <dl><dt>VERBOSE</dt><dd>Really verbose log messages. Messages at this level are used for
+        internal debugging. They should be enabled only selectively within the areas currently under
+        inspection.</dd>
 
-        \c NONE is used to in some special places to inherit the default log level.
+        <dt>NOTICE</dt><dd>Arbitrary unimportant notice. Message which normally should be disabled
+        but might be informative to better understand the programs operation.</dd>
+
+        <dt>MESSAGE</dt><dd>Purely informative message which should be displayed if not explicitly
+        disabled.</dd>
+
+        <dt>IMPORTANT</dt><dd>Important information or warning which really should be read.</dd>
+
+        <dt>CRITICAL</dt><dd>Error condition which does not terminate the program completely but has
+        non-reversible adverse effects</dd>
+        
+        <dt>FATAL</dt><dd>Error condition which does terminate program execution or enforces a
+        restart or some kind of re-initialization with loss of state and context.</dd></dl>
+
+        There are also some special values which <em>must not be used as a log level</em>:
+        
+        <dl><dt>DISABLED</dt><dd>Disable all log messages.</dd> 
+
+        <dt>NONE</dt><dd>Special value which signifies inheritance of the default log
+        level.</dd></dl>
+
+        Log levels are classes, not numbers. Each log level class has a \c value member which gives
+        that levels numeric priority. The larger the number, the more important the message is.
+
+        \implementation The log levels need to be classes since areas and streams are classes: Since
+            log arguments (stream, area and level) may appear in any order and number, it is much
+            simpler to parse them if they are all of the same type.
      */
 
     ///\ingroup loglevels
@@ -67,9 +95,13 @@ namespace log {
         \see loglevels */
     struct CRITICAL  : public detail::LevelBase { static unsigned const value = 5; };
 
+    /** \brief Log level FATAL
+        \see loglevels */
+    struct FATAL     : public detail::LevelBase { static unsigned const value = 6; };
+
     /** \brief Disable logging
         \see loglevels */
-    struct DISABLED  : public detail::LevelBase { static unsigned const value = 6; };
+    struct DISABLED  : public detail::LevelBase { static unsigned const value = 7; };
 
     /** \brief Inherit log level
         \see loglevels */

Utils/Logger/Mainpage.dox

@@ -40,7 +40,7 @@
     Log messages are arbitrarily created throughout the code using simple log statements (which are
     macros). Besides the log message itself, every log message is labeled with additional
     information: The \e stream, the \e area and a log \e level. If the message is not compile-time
-    disabled, the message is then directed to one of several log \e targets.
+    disabled, the message is then directed to one or several log \e targets.
 
     A \e stream combines log messages with a single purpose: Debug messages, access logging and so
     on. Any number of streams may be defined. There is one predefined default stream called \c
@@ -48,7 +48,8 @@
 
     The \e area gives information about the source location of the message. Areas may be defined and
     assigned arbitrarily but should be used to label messages from a single class or subsystem. It
-    is possible to reuse a class as it's own area tag, which is often desireable.  (see: \ref
+    is possible to reuse a class as it's own area tag, which is often desireable.  There is a
+    default area \c senf::log::DefaultArea which is used, when no other area is assigned. (see: \ref
     SENF_LOG_DEF_AREA, \ref SENF_LOG_CLASS_AREA)
 
     The log \e level gives information on the importance of the message. The list of log-levels is

Utils/Logger/Target.hh

@@ -379,9 +379,7 @@ namespace log {
                                              somehow format and write the log message. 
 
                                              Every log message always possesses a complete set of
-                                             meta information (\a stream, \a area and \a level). The
-                                             \a area may be an empty string if the message was
-                                             written from the senf::log::DefaultArea.
+                                             meta information (\a stream, \a area and \a level).
 
                                              \note This member must \e not block since it may be
                                                  called from any unknown context. This prohibits

Utils/Logger/Target.test.cc

@@ -81,7 +81,7 @@ BOOST_AUTO_UNIT_TEST(target)
         "senf::log::Debug-senf::log::test::Foo-VERBOSE-REJECT",
         "senf::log::Debug--NONE-ACCEPT",
         "senf::log::test::myStream-senf::log::test::Foo-VERBOSE-ACCEPT",
-        "senf::log::test::myStream--NONE-REJECT",
+        "senf::log::test::myStream-senf::log::DefaultArea-NONE-REJECT",
         "senf::log::test::myStream--IMPORTANT-REJECT",
     };