src/base/TextException.h

   1 /*
   2  * Copyright (C) 1996-2014 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID__TEXTEXCEPTION_H
  10 #define SQUID__TEXTEXCEPTION_H
  11
  12 // Origin: xstd/TextException
  13
  14 #include <exception>
  15
  16 static unsigned int FileNameHashCached(const char *fname);
  17
  18 // simple exception to report custom errors
  19 // we may want to change the interface to be able to report system errors
  20
  21 class TextException: public std::exception
  22 {
  23
  24 public:
  25     TextException();
  26     TextException(const char *aMessage, const char *aFileName = 0, int aLineNo = -1, unsigned int anId =0);
  27     TextException(const TextException& right);
  28     virtual ~TextException() throw();
  29
  30     // unique exception ID for transaction error detail logging
  31     unsigned int id() const { return theId; }
  32
  33     virtual const char *what() const throw();
  34
  35     TextException& operator=(const TextException &right);
  36
  37 public:
  38     char *message; // read-only
  39
  40 protected:
  41     /// a small integer hash value to semi-uniquely identify the source file
  42     static unsigned int FileNameHash(const char *fname);
  43
  44     // optional location information
  45     const char *theFileName;
  46     int theLineNo;
  47     unsigned int theId;
  48
  49     friend unsigned int FileNameHashCached(const char *fname);
  50 };
  51
  52 //inline
  53 //ostream &operator <<(ostream &os, const TextException &exx) {
  54 //    return exx.print(os);
  55 //}
  56
  57 /// caches the result of FileNameHash() for each translation unit
  58 static unsigned int
  59 FileNameHashCached(const char *fname)
  60 {
  61     static const char *lastFname = 0;
  62     static int lastHash = 0;
  63     // __FILE__ changes when we #include files
  64     if (lastFname != fname) { // cheap pointer comparison
  65         lastFname = fname;
  66         lastHash = TextException::FileNameHash(fname);
  67     }
  68     return lastHash;
  69 }
  70
  71 ///  Avoids "defined but not used" warnings for FileNameHashCached
  72 class FileNameHashCacheUser
  73 {
  74     bool use(void *ptr=NULL) { return ptr != (void*)&FileNameHashCached; }
  75 };
  76
  77 #if !defined(TexcHere)
  78 #    define TexcHere(msg) TextException((msg), __FILE__, __LINE__, \
  79                                          (FileNameHashCached(__FILE__)<<14) | (__LINE__ & 0x3FFF))
  80 #endif
  81
  82 void Throw(const char *message, const char *fileName, int lineNo, unsigned int id);
  83
  84 // Must(condition) is like assert(condition) but throws an exception instead
  85 #if !defined(Must)
  86 #   define Must(cond) ((cond) ? \
  87         (void)0 : \
  88                       (void)Throw(#cond, __FILE__, __LINE__, \
  89                                   (FileNameHashCached(__FILE__)<<14) | (__LINE__ & 0x3FFF)))
  90 #endif
  91
  92 #endif /* SQUID__TEXTEXCEPTION_H */