[freetype2] priyesh_LogLibrary afa548b: Added a flag to toggle ON/OFF the printing of FT_COMPONENT and Timestamp with actual log message

[Priyesh Kumar]

branch: priyesh_LogLibrary
commit afa548bb749b02af69b94153d3e08d146409643e
Author: Priyeshkkumar <priyeshkkumar@gmail.com>
Commit: Priyeshkkumar <priyeshkkumar@gmail.com>

    Added a flag to toggle ON/OFF the printing of FT_COMPONENT and Timestamp 
with actual log message
---
 [priyesh]ChangeLog                  |  22 ++++++
 include/freetype/ftlogging.h        |   3 +-
 include/freetype/internal/ftdebug.h |  67 +++++++++++-------
 src/base/ftdebug.c                  | 133 ++++++++++++++++++++++++++++++------
 4 files changed, 178 insertions(+), 47 deletions(-)

diff --git a/[priyesh]ChangeLog b/[priyesh]ChangeLog
index 43c9d5c..503a99d 100644
--- a/[priyesh]ChangeLog
+++ b/[priyesh]ChangeLog
@@ -1,3 +1,25 @@
+2020-07-13  Priyesh Kumar   <priyeshkkumar@gmail.com>
+
+    * include/freetype/ftlogging.h: Changed the definition of callback 
+      function `ft_custom_log_handler` now it also provides FT_COMPONENT
+      value to the external log handeling function.
+    
+    * include/freetype/internal/ftdebug.h:
+        1. Added a function `FT_Callback()` which is used when user sets an
+           external log handeling callback function.
+        2. Code Cleanup and resolved [ -Wunused-variable ] warnings
+        3. Added a macro `FT_Log` to handle the `FT_TRACE` 
+    * src/base/ftdebug.c:
+        1. Updated code to print FT_COMPONENT and TimeStamp. 
+        2. Code Cleanup.
+        3.Added support of flag within `FT2_DEBUG` env variable to control 
+          the printing of extra info( time-stamp and FT_COMPONENT ):
+            3.1 '-v' for printing FT_COMPONENT along with actual log message
+            3.2 '-t' for printing TimeStamp along with actual log message
+            3.3 '-tv' or '-vt' for printing both FT_COMPONENT and TimeStamp
+                 along with actual log message.
+        4. Added definition of function `FT_Callback()`
+
 2020-07-04  Priyesh Kumar   <priyeshkkumar@gmail.com>
     
     * Added code to print FT_COMPONENT along with TimeStamp with each log
diff --git a/include/freetype/ftlogging.h b/include/freetype/ftlogging.h
index 195d768..256a21d 100644
--- a/include/freetype/ftlogging.h
+++ b/include/freetype/ftlogging.h
@@ -22,7 +22,8 @@ FT_BEGIN_HEADER
 
   /* An external callback function to be used to define an output handler */
   typedef void 
-  (*ft_custom_log_handler)( const char* fmt, va_list args ); 
+  (*ft_custom_log_handler)( const char* ft_component, const char* fmt, 
+                            va_list args ); 
 
 
   /**************************************************************************
diff --git a/include/freetype/internal/ftdebug.h 
b/include/freetype/internal/ftdebug.h
index 1722d39..2f45ce4 100644
--- a/include/freetype/internal/ftdebug.h
+++ b/include/freetype/internal/ftdebug.h
@@ -109,6 +109,40 @@ FT_BEGIN_HEADER
    *  
    */
 
+#ifdef FT_LOGGING
+
+#define FT_Log( level, varformat )                                         \
+          do                                                               \
+          {                                                                \
+            ft_add_tag( FT_LOGGING_TAG( FT_COMPONENT ) );                  \
+                                                                           \
+            if( ft_trace_levels[FT_TRACE_COMP( FT_COMPONENT )] >= level )  \
+            {                                                              \
+              if( custom_output_handler != NULL )                          \
+                FT_Callback varformat;                                     \
+              else                                                         \
+                dlg_trace varformat;                                       \
+            }                                                              \
+                                                                           \
+            ft_remove_tag( FT_LOGGING_TAG( FT_COMPONENT ) );               \
+          }while( 0 )
+
+#else 
+
+#define FT_Log( level, varformat )                                         \
+          do                                                               \
+          {                                                                \
+            if ( ft_trace_levels[FT_TRACE_COMP( FT_COMPONENT )] >= level ) \
+            {                                                              \
+              FT_Message varformat;                                        \
+            }                                                              \
+          } while ( 0 )
+
+#endif /* FT_LOGGING */
+
+
+
+
 #ifdef FT_DEBUG_LEVEL_TRACE
 
 #define FT_LOGGING_TAG( x ) FT_LOGGING_TAG_( x )
@@ -126,16 +160,7 @@ ft_remove_tag( const char* tag );
 #define FT_TRACE_COMP( x )   FT_TRACE_COMP_( x )
 #define FT_TRACE_COMP_( x )  trace_ ## x
 
-#define FT_TRACE( level, varformat )                                       \
-          do                                                               \
-          {                                                                \
-            if ( ft_trace_levels[FT_TRACE_COMP( FT_COMPONENT )] >= level ) \
-            {                                                              \
-              ft_add_tag( FT_LOGGING_TAG( FT_COMPONENT ) );                \
-              FT_Message varformat;                                        \
-              ft_remove_tag( FT_LOGGING_TAG( FT_COMPONENT ) );             \
-            }                                                              \
-          } while ( 0 )
+#define FT_TRACE( level, varformat )   FT_Log( level, varformat )              
                 
 
 #else /* !FT_DEBUG_LEVEL_TRACE */
 
@@ -351,26 +376,17 @@ ft_remove_tag( const char* tag );
   /**************************************************************************
    * 
    * Variable used when FT_LOGGING is enabled to control logging:
-   * 1. ft_default_trace_level: stores the value of trace levels which are 
-   *    provided to FreeType using FT2_DEBUG environment variable.
    * 
-   * 2. ft_custom_trace_level: stores the value of custom trace level which 
-   *    is provided by user at run-time.
-   * 
-   * 3. custom_output_handler: stores the function pointer to the callback 
+   * 1. ft_custom_output_handler: stores the function pointer to the callback 
    *    function provided by user.
    * 
-   * 4. ft_default_output_handler: stores the function pointer which is used 
+   * 2. ft_default_log_handler: stores the function pointer which is used 
    *    internally by FreeType to print logs to file.
    * 
-   * 5. ft_fileptr: store the FILE*
-   *     
+   * These are defined in ftdebug.c
    */ 
-  static const char* ft_default_trace_level = NULL;
-  static const char* ft_custom_trace_level = NULL;
-  static ft_custom_log_handler custom_output_handler = NULL;
-  static dlg_handler ft_default_log_handler = NULL;
-  static FILE* ft_fileptr = NULL;
+  extern ft_custom_log_handler custom_output_handler;
+  extern dlg_handler ft_default_log_handler;
 
   /**************************************************************************
    * 
@@ -386,6 +402,9 @@ ft_remove_tag( const char* tag );
   FT_BASE( void )
   ft_logging_deinit( void );
 
+  FT_BASE( void )
+  FT_Callback( const char* fmt, ... );
+
 
 #endif /* FT_LOGGING */  
 
diff --git a/src/base/ftdebug.c b/src/base/ftdebug.c
index 74e967d..a1fc99e 100644
--- a/src/base/ftdebug.c
+++ b/src/base/ftdebug.c
@@ -44,6 +44,62 @@
 #include <freetype/freetype.h>
 #include <freetype/internal/ftdebug.h>
 
+#ifdef FT_LOGGING
+
+  /**************************************************************************
+   * 
+   * Variable used when FT_LOGGING is enabled to control logging:
+   * 
+   * 1. ft_default_trace_level: stores the value of trace levels which are 
+   *    provided to FreeType using FT2_DEBUG environment variable.
+   * 
+   * 2. ft_custom_trace_level: stores the value of custom trace level which 
+   *    is provided by user at run-time.
+   * 
+   * 3. ft_component: a string that holds the name of FT_COMPONENT
+   * 
+   * 4. ft_fileptr: store the FILE*
+   * 
+   * 5. ft_component_flag: a flag when is true, prints FT_COMPONENT along 
+   *    with log message if `-v` is defined in FT2_DEBUG
+   * 6. ft_timestamp_flag: a flag when is true, prints time in millisec along
+   *    with log message if `-t` is define in FT2_DEBUG
+   * 7. ft_have_newline_char: It is used to differentiate between a log 
+   *    message with '\n' char and log message without '\n' char  
+   * 
+   * Static Variables are defined here to remove [ -Wunused-variable ] 
+   * warning
+   *     
+   */ 
+  static const char* ft_default_trace_level = NULL;
+  static const char* ft_custom_trace_level = NULL;
+  static const char* ft_component = NULL;
+  static FILE* ft_fileptr = NULL;
+  static bool ft_component_flag = false;
+  static bool ft_timestamp_flag = false;
+  static bool ft_have_newline_char = true;
+
+  ft_custom_log_handler custom_output_handler = NULL;
+  dlg_handler ft_default_log_handler = NULL;
+
+  /* different types of dlg features to be used according to the flags     */
+  /* passed in FT2_DEBUG environment variable                              */
+
+  static unsigned int features_component = dlg_output_threadsafe 
+                                          | dlg_output_tags;
+  static unsigned int features_timestamp = dlg_output_threadsafe 
+                                          | dlg_output_time
+                                          | dlg_output_time_msecs; 
+  static unsigned int features_both = dlg_output_threadsafe 
+                                      | dlg_output_time_msecs 
+                                      |dlg_output_time
+                                      | dlg_output_tags ;
+  static unsigned int features_none = dlg_output_threadsafe;
+
+
+
+#endif
+
 
 #ifdef FT_DEBUG_LEVEL_ERROR
 
@@ -53,25 +109,12 @@
   FT_Message( const char*  fmt,
               ... )
   {
-#ifdef FT_LOGGING
-
-    if( custom_output_handler != NULL )
-    {
-      va_list  ap;
-      va_start( ap, fmt );
-      custom_output_handler( fmt, ap );
-      va_end( ap );
-    }
-    else
-      dlg_trace( fmt );
-#else
     va_list  ap;
 
 
     va_start( ap, fmt );
     vfprintf( stderr, fmt, ap );
     va_end( ap );
-#endif /* FT_LOGGING */
   }
 
 
@@ -230,10 +273,40 @@ else
 
       for ( ; *p; p++ )
       {
+       
         /* skip leading whitespace and separators */
         if ( *p == ' ' || *p == '\t' || *p == ',' || *p == ';' || *p == '=' )
           continue;
 
+#ifdef FT_LOGGING
+        /* check extra arguments for logging */
+        if( *p == '-' )
+        {
+          const char* r = ++p;
+          if( *r == 'v' )
+          {
+            ft_component_flag = true;
+            const char* s = ++r;
+            if( *s == 't' )
+            {
+              ft_timestamp_flag = true;
+              p++;
+            }
+            p++;
+          }
+          else if( *r == 't' )
+          {
+            ft_timestamp_flag = true;
+            const char* s = ++r;
+            if( *s == 'v' )
+            {
+              ft_component_flag = true;
+              p++;
+            }
+            p++;
+          }
+        }
+#endif 
         /* read toggle name, followed by ':' */
         q = p;
         while ( *p && *p != ':' )
@@ -379,18 +452,24 @@ else
   ft_log_handler( const struct dlg_origin* origin, 
                               const char* string, void* data )
   {
-     unsigned int features; 
-     if( origin->tags[0] == "error_log" )
-     {
-      features = dlg_output_threadsafe | dlg_output_tags ;
-     }
+     static unsigned int features ;
+     if( ft_timestamp_flag && ft_component_flag && ft_have_newline_char )
+      features = features_both;
+     else if( ft_component_flag && ft_have_newline_char)
+      features = features_component;
+     else if( ft_timestamp_flag && ft_have_newline_char )
+      features = features_timestamp;
      else
-     {
-      features = dlg_output_threadsafe | dlg_output_tags | dlg_output_time ;
-     }
-     
+      features = features_none;
+
+      
           dlg_generic_output_stream( ft_fileptr, features, origin, string, 
                                 dlg_default_output_styles );
+
+     if( strchr( string, '\n' ) )
+       ft_have_newline_char = true;   
+     else
+       ft_have_newline_char = false;  
   }
 
  /**************************************************************************
@@ -438,8 +517,18 @@ else
   }
 
   FT_BASE_DEF( void )
+  FT_Callback( const char* fmt, ... )
+  {
+    va_list ap;
+    va_start( ap, fmt );
+    custom_output_handler( ft_component , fmt, ap ); 
+    va_end( ap );
+  }
+
+  FT_BASE_DEF( void )
   ft_add_tag( const char* tag )
   {
+    ft_component = tag;
     dlg_add_tag( tag, NULL );
   }