Added public APIs to set new/default trace level, started working on Callback function

[priyesh]ChangeLog

@@ -1,3 +1,28 @@
+2020-07-02  Priyesh Kumar   <priyeshkkumar@gmail.com>
+
+    * Fixed some code layout
+
+    * Added a new header- `include/freetype/ftlogging.h` for public APIs to 
+      use when using logging:
+      1. FT_Trace_Set_Level(): Used to change trace level of components at 
+          runtime.
+      2. FT_Trace_Set_Default_Level(): Used to set the default value of trace
+         level(which is supplied by env FT2_DEBUG)
+    
+    * include/freetype/internal/ftdebug.h:
+      1. Added dlg support for FT_ERROR, now error messages are also written 
+         on file if FT_LOGGING is enabled. 
+      2. Changed `ft_debug_init()`: now it takes an argument of type const
+         char* which is used to specify trace level.
+    
+    * src/base/ftobjs.c: Changed `ft_debug_init()`, now it passes an argument
+      to define trace level.
+
+    * src/base/ftdebug.c: Added definitions of public APIs 
+      `FT_Trace_Set_Default_Level()` and `FT_Trace_Set_Level()`
+
+    * Strated working on Callback. 
+
 2020-06-30  Priyesh Kumar   <priyeshkkumar@gmail.com>
 
     * Adding new line at end of file

include/freetype/ftlogging.h

@@ -0,0 +1,30 @@
+#include FT_CONFIG_CONFIG_H
+
+FT_BEGIN_HEADER
+
+ /***************************************************************************
+  * 
+  * If FT_LOGGING is enabled, user can change the trace level at run time 
+  * using the function `FT_Trace_Set_Level()` by passing the desired trace
+  * level as an argument.
+  * User can also set the default trace level which is supplied by 
+  * environment variable `FT2_DEBUG`
+  * 
+  */ 
+
+  typedef void
+  (*ft_ouput_handler)( const char* string ); 
+
+  FT_EXPORT( void )
+  FT_Trace_Set_Level( const char* level );
+
+  FT_EXPORT( void )
+  FT_Trace_Set_Default_Level( void );
+
+  FT_EXPORT( void )
+  FT_Trace_Set_Output( ft_ouput_handler handler ); 
+
+  FT_EXPORT( void )
+  FT_Trace_Set_Default_Output();
+
+FT_END_HEADER

include/freetype/internal/ftdebug.h

@@ -29,11 +29,18 @@
 #include FT_CONFIG_CONFIG_H
 #include <freetype/freetype.h>
 
-  /* Additional include files for supporting logging in FreeType using    */
-  /* external logging library ~ src/dlg                                   */
-  /*                                                                      */
+  /**************************************************************************
+   *
+   * Additional include files for supporting logging in FreeType using   
+   * external logging library ~ src/dlg and freetype/ftlogging.h  
+   *                                  
+   */ 
+                                                                      
+#ifdef FT_LOGGING
 #include <../src/dlg/include/dlg/dlg.h>
 #include <../src/dlg/include/dlg/output.h>
+#include <freetype/ftlogging.h>
+#endif /* FT_LOGGING */
 
 
 FT_BEGIN_HEADER
@@ -104,6 +111,8 @@ FT_BEGIN_HEADER
 
 #ifdef FT_LOGGING
 
+  static ft_ouput_handler freetype_output_handler = NULL;
+  
 #undef FT_Log
 #define FT_Log dlg_trace
 
@@ -117,7 +126,7 @@ FT_BEGIN_HEADER
  */
 
  FT_BASE( void ) 
- ft_freetype_output_handler( const struct dlg_origin* origin, 
+ ft_default_output_handler( const struct dlg_origin* origin, 
  const char* string, void* data );
 
 #else
@@ -247,8 +256,22 @@ FT_BEGIN_HEADER
 
 #ifdef FT_DEBUG_LEVEL_ERROR
 
+#ifdef FT_LOGGING
+
+#define FT_ERROR( varformat )                                               \
+          do                                                                \
+          {                                                                 \
+          dlg_add_tag( "error_log", NULL );                                 \
+          dlg_trace varformat;                                              \
+          dlg_remove_tag( "error_log", NULL );                              \  
+          } while ( 0 )                            
+
+#else
+
 #define FT_ERROR( varformat )  FT_Message  varformat
 
+#endif /* FT_LOGGING */
+
 #else  /* !FT_DEBUG_LEVEL_ERROR */
 
 #define FT_ERROR( varformat )  do { } while ( 0 )      /* nothing */
@@ -318,7 +341,7 @@ FT_BEGIN_HEADER
 
 
   FT_BASE( void )
-  ft_debug_init( void );
+  ft_debug_init( const char* level );
 
 #ifdef FT_LOGGING
 

src/base/ftdebug.c

@@ -193,9 +193,9 @@
    * runtime errors), and 7 means _very_ verbose.
    */
   FT_BASE_DEF( void )
-  ft_debug_init( void )
+  ft_debug_init( const char* level )
   {
-    const char*  ft2_debug = ft_getenv( "FT2_DEBUG" );
+    const char*  ft2_debug = level;
 
 
     if ( ft2_debug )
@@ -274,7 +274,7 @@
 
 
   FT_BASE_DEF( void )
-  ft_debug_init( void )
+  ft_debug_init( const char* level )
   {
     /* nothing */
   }
@@ -337,10 +337,10 @@
   ft_logging_init( void )
   {
     fileptr = fopen( "freetype2.log", "w" );
-    ft_debug_init();
+    FT_Trace_Set_Default_Level();
     
     /* We need to set the default FreeType specific dlg's output handler */
-    dlg_set_handler( &ft_freetype_output_handler, NULL );
+    dlg_set_handler( &ft_default_output_handler, NULL );
   }
 
   FT_BASE_DEF( void )
@@ -349,15 +349,14 @@
     fclose( fileptr );
   }
 
-  FT_BASE_DEF( void )
-
   /*************************************************************************
    * 
    * TODO:
    * 1. Add support for priniting FT_COMPONENT
    *    
-   */ 
-  ft_freetype_output_handler( const struct dlg_origin* origin, 
+   */
+  FT_BASE_DEF( void ) 
+  ft_default_output_handler( const struct dlg_origin* origin, 
                               const char* string, void* data )
  {
      unsigned int features = dlg_output_threadsafe /*| dlg_output_tags*/ ;
@@ -365,6 +364,41 @@
                                 dlg_default_output_styles );
  }
 
+ /**************************************************************************
+  * 
+  * 
+  * 
+  */
+  FT_EXPORT_DEF( void )
+  FT_Trace_Set_Level( const char* level )
+  {  
+    ft_debug_init( level );
+  }
+
+  FT_EXPORT_DEF( void )
+  FT_Trace_Set_Default_Level( void )
+  {
+    ft_debug_init( ft_getenv( "FT2_DEBUG" ) );
+  }
+
+/****************************************************************************
+ * 
+ * 
+ * 
+ */
+
+  FT_EXPORT_DEF( void )
+  FT_Trace_Set_Output( ft_ouput_handler handler )
+  {
+    freetype_output_handler = handler;
+  }
+
+  FT_EXPORT_DEF( void )
+  FT_Trace_Set_Default_Output()
+  {
+    freetype_output_handler = NULL;
+  }
+
 #endif /* FT_LOGGING */
 
 /* END */

src/base/ftobjs.c

@@ -5276,7 +5276,7 @@
 #ifndef FT_LOGGING 
 #ifdef FT_DEBUG_LEVEL_ERROR
     /* init debugging support */
-    ft_debug_init();
+    ft_debug_init( ft_getenv( "FT2_DEBUG" ) );
 #endif /* FT_DEBUG_LEVEL_ERROR */
 #endif /* FT_LOGGING */