1 /****************************************************************************
   2  *
   3  * pserror.h
   4  *
   5  *   Adobe's code for error handling (specification).
   6  *
   7  * Copyright 2006-2013 Adobe Systems Incorporated.
   8  *
   9  * This software, and all works of authorship, whether in source or
  10  * object code form as indicated by the copyright notice(s) included
  11  * herein (collectively, the "Work") is made available, and may only be
  12  * used, modified, and distributed under the FreeType Project License,
  13  * LICENSE.TXT.  Additionally, subject to the terms and conditions of the
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  15  * to any individual or legal entity exercising permissions granted by
  16  * the FreeType Project License and this section (hereafter, "You" or
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  18  * royalty-free, irrevocable (except as stated in this section) patent
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  21  * patent claims licensable by such contributor that are necessarily
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  29  * the date such litigation is filed.
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  36  */
  37 
  38 
  39 #ifndef PSERROR_H_
  40 #define PSERROR_H_
  41 
  42 
  43 #include FT_MODULE_ERRORS_H
  44 
  45 #undef FTERRORS_H_
  46 
  47 #undef  FT_ERR_PREFIX
  48 #define FT_ERR_PREFIX  CF2_Err_
  49 #define FT_ERR_BASE    FT_Mod_Err_CF2
  50 
  51 
  52 #include FT_ERRORS_H
  53 #include "psft.h"
  54 
  55 
  56 FT_BEGIN_HEADER
  57 
  58 
  59   /*
  60    * A poor-man error facility.
  61    *
  62    * This code being written in vanilla C, doesn't have the luxury of a
  63    * language-supported exception mechanism such as the one available in
  64    * Java.  Instead, we are stuck with using error codes that must be
  65    * carefully managed and preserved.  However, it is convenient for us to
  66    * model our error mechanism on a Java-like exception mechanism.
  67    * When we assign an error code we are thus `throwing' an error.
  68    *
  69    * The preservation of an error code is done by coding convention.
  70    * Upon a function call if the error code is anything other than
  71    * `FT_Err_Ok', which is guaranteed to be zero, we
  72    * will return without altering that error.  This will allow the
  73    * error to propagate and be handled at the appropriate location in
  74    * the code.
  75    *
  76    * This allows a style of code where the error code is initialized
  77    * up front and a block of calls are made with the error code only
  78    * being checked after the block.  If a new error occurs, the original
  79    * error will be preserved and a functional no-op should result in any
  80    * subsequent function that has an initial error code not equal to
  81    * `FT_Err_Ok'.
  82    *
  83    * Errors are encoded by calling the `FT_THROW' macro.  For example,
  84    *
  85    * {
  86    *   FT_Error  e;
  87    *
  88    *
  89    *   ...
  90    *   e = FT_THROW( Out_Of_Memory );
  91    * }
  92    *
  93    */
  94 
  95 
  96   /* Set error code to a particular value. */
  97   FT_LOCAL( void )
  98   cf2_setError( FT_Error*  error,
  99                 FT_Error   value );
 100 
 101 
 102   /*
 103    * A macro that conditionally sets an error code.
 104    *
 105    * This macro will first check whether `error' is set;
 106    * if not, it will set it to `e'.
 107    *
 108   */
 109 #define CF2_SET_ERROR( error, e )              \
 110           cf2_setError( error, FT_THROW( e ) )
 111 
 112 
 113 FT_END_HEADER
 114 
 115 
 116 #endif /* PSERROR_H_ */
 117 
 118 
 119 /* END */