src/gtest/src/gtest-printers.cc

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  29 //
  30 // Author: wan@google.com (Zhanyong Wan)
  31
  32 // Google Test - The Google C++ Testing Framework
  33 //
  34 // This file implements a universal value printer that can print a
  35 // value of any type T:
  36 //
  37 //   void ::testing::internal::UniversalPrinter<T>::Print(value, ostream_ptr);
  38 //
  39 // It uses the << operator when possible, and prints the bytes in the
  40 // object otherwise.  A user can override its behavior for a class
  41 // type Foo by defining either operator<<(::std::ostream&, const Foo&)
  42 // or void PrintTo(const Foo&, ::std::ostream*) in the namespace that
  43 // defines Foo.
  44
  45 #include "gtest/gtest-printers.h"
  46 #include <ctype.h>
  47 #include <stdio.h>
  48 #include <cwchar>
  49 #include <ostream>  // NOLINT
  50 #include <string>
  51 #include "gtest/internal/gtest-port.h"
  52
  53 namespace testing {
  54
  55 namespace {
  56
  57 using ::std::ostream;
  58
  59 // Prints a segment of bytes in the given object.
  60 GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
  61 GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
  62 GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
  63 void PrintByteSegmentInObjectTo(const unsigned char* obj_bytes, size_t start,
  64                                 size_t count, ostream* os) {
  65   char text[5] = "";
  66   for (size_t i = 0; i != count; i++) {
  67     const size_t j = start + i;
  68     if (i != 0) {
  69       // Organizes the bytes into groups of 2 for easy parsing by
  70       // human.
  71       if ((j % 2) == 0)
  72         *os << ' ';
  73       else
  74         *os << '-';
  75     }
  76     GTEST_SNPRINTF_(text, sizeof(text), "%02X", obj_bytes[j]);
  77     *os << text;
  78   }
  79 }
  80
  81 // Prints the bytes in the given value to the given ostream.
  82 void PrintBytesInObjectToImpl(const unsigned char* obj_bytes, size_t count,
  83                               ostream* os) {
  84   // Tells the user how big the object is.
  85   *os << count << "-byte object <";
  86
  87   const size_t kThreshold = 132;
  88   const size_t kChunkSize = 64;
  89   // If the object size is bigger than kThreshold, we'll have to omit
  90   // some details by printing only the first and the last kChunkSize
  91   // bytes.
  92   // TODO(wan): let the user control the threshold using a flag.
  93   if (count < kThreshold) {
  94     PrintByteSegmentInObjectTo(obj_bytes, 0, count, os);
  95   } else {
  96     PrintByteSegmentInObjectTo(obj_bytes, 0, kChunkSize, os);
  97     *os << " ... ";
  98     // Rounds up to 2-byte boundary.
  99     const size_t resume_pos = (count - kChunkSize + 1)/2*2;
 100     PrintByteSegmentInObjectTo(obj_bytes, resume_pos, count - resume_pos, os);
 101   }
 102   *os << ">";
 103 }
 104
 105 }  // namespace
 106
 107 namespace internal2 {
 108
 109 // Delegates to PrintBytesInObjectToImpl() to print the bytes in the
 110 // given object.  The delegation simplifies the implementation, which
 111 // uses the << operator and thus is easier done outside of the
 112 // ::testing::internal namespace, which contains a << operator that
 113 // sometimes conflicts with the one in STL.
 114 void PrintBytesInObjectTo(const unsigned char* obj_bytes, size_t count,
 115                           ostream* os) {
 116   PrintBytesInObjectToImpl(obj_bytes, count, os);
 117 }
 118
 119 }  // namespace internal2
 120
 121 namespace internal {
 122
 123 // Depending on the value of a char (or wchar_t), we print it in one
 124 // of three formats:
 125 //   - as is if it's a printable ASCII (e.g. 'a', '2', ' '),
 126 //   - as a hexidecimal escape sequence (e.g. '\x7F'), or
 127 //   - as a special escape sequence (e.g. '\r', '\n').
 128 enum CharFormat {
 129   kAsIs,
 130   kHexEscape,
 131   kSpecialEscape
 132 };
 133
 134 // Returns true if c is a printable ASCII character.  We test the
 135 // value of c directly instead of calling isprint(), which is buggy on
 136 // Windows Mobile.
 137 inline bool IsPrintableAscii(wchar_t c) {
 138   return 0x20 <= c && c <= 0x7E;
 139 }
 140
 141 // Prints a wide or narrow char c as a character literal without the
 142 // quotes, escaping it when necessary; returns how c was formatted.
 143 // The template argument UnsignedChar is the unsigned version of Char,
 144 // which is the type of c.
 145 template <typename UnsignedChar, typename Char>
 146 static CharFormat PrintAsCharLiteralTo(Char c, ostream* os) {
 147   switch (static_cast<wchar_t>(c)) {
 148     case L'\0':
 149       *os << "\\0";
 150       break;
 151     case L'\'':
 152       *os << "\\'";
 153       break;
 154     case L'\\':
 155       *os << "\\\\";
 156       break;
 157     case L'\a':
 158       *os << "\\a";
 159       break;
 160     case L'\b':
 161       *os << "\\b";
 162       break;
 163     case L'\f':
 164       *os << "\\f";
 165       break;
 166     case L'\n':
 167       *os << "\\n";
 168       break;
 169     case L'\r':
 170       *os << "\\r";
 171       break;
 172     case L'\t':
 173       *os << "\\t";
 174       break;
 175     case L'\v':
 176       *os << "\\v";
 177       break;
 178     default:
 179       if (IsPrintableAscii(c)) {
 180         *os << static_cast<char>(c);
 181         return kAsIs;
 182       } else {
 183         *os << "\\x" + String::FormatHexInt(static_cast<UnsignedChar>(c));
 184         return kHexEscape;
 185       }
 186   }
 187   return kSpecialEscape;
 188 }
 189
 190 // Prints a wchar_t c as if it's part of a string literal, escaping it when
 191 // necessary; returns how c was formatted.
 192 static CharFormat PrintAsStringLiteralTo(wchar_t c, ostream* os) {
 193   switch (c) {
 194     case L'\'':
 195       *os << "'";
 196       return kAsIs;
 197     case L'"':
 198       *os << "\\\"";
 199       return kSpecialEscape;
 200     default:
 201       return PrintAsCharLiteralTo<wchar_t>(c, os);
 202   }
 203 }
 204
 205 // Prints a char c as if it's part of a string literal, escaping it when
 206 // necessary; returns how c was formatted.
 207 static CharFormat PrintAsStringLiteralTo(char c, ostream* os) {
 208   return PrintAsStringLiteralTo(
 209       static_cast<wchar_t>(static_cast<unsigned char>(c)), os);
 210 }
 211
 212 // Prints a wide or narrow character c and its code.  '\0' is printed
 213 // as "'\\0'", other unprintable characters are also properly escaped
 214 // using the standard C++ escape sequence.  The template argument
 215 // UnsignedChar is the unsigned version of Char, which is the type of c.
 216 template <typename UnsignedChar, typename Char>
 217 void PrintCharAndCodeTo(Char c, ostream* os) {
 218   // First, print c as a literal in the most readable form we can find.
 219   *os << ((sizeof(c) > 1) ? "L'" : "'");
 220   const CharFormat format = PrintAsCharLiteralTo<UnsignedChar>(c, os);
 221   *os << "'";
 222
 223   // To aid user debugging, we also print c's code in decimal, unless
 224   // it's 0 (in which case c was printed as '\\0', making the code
 225   // obvious).
 226   if (c == 0)
 227     return;
 228   *os << " (" << static_cast<int>(c);
 229
 230   // For more convenience, we print c's code again in hexidecimal,
 231   // unless c was already printed in the form '\x##' or the code is in
 232   // [1, 9].
 233   if (format == kHexEscape || (1 <= c && c <= 9)) {
 234     // Do nothing.
 235   } else {
 236     *os << ", 0x" << String::FormatHexInt(static_cast<UnsignedChar>(c));
 237   }
 238   *os << ")";
 239 }
 240
 241 void PrintTo(unsigned char c, ::std::ostream* os) {
 242   PrintCharAndCodeTo<unsigned char>(c, os);
 243 }
 244 void PrintTo(signed char c, ::std::ostream* os) {
 245   PrintCharAndCodeTo<unsigned char>(c, os);
 246 }
 247
 248 // Prints a wchar_t as a symbol if it is printable or as its internal
 249 // code otherwise and also as its code.  L'\0' is printed as "L'\\0'".
 250 void PrintTo(wchar_t wc, ostream* os) {
 251   PrintCharAndCodeTo<wchar_t>(wc, os);
 252 }
 253
 254 // Prints the given array of characters to the ostream.  CharType must be either
 255 // char or wchar_t.
 256 // The array starts at begin, the length is len, it may include '\0' characters
 257 // and may not be NUL-terminated.
 258 template <typename CharType>
 259 GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
 260 GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
 261 GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
 262 static void PrintCharsAsStringTo(
 263     const CharType* begin, size_t len, ostream* os) {
 264   const char* const kQuoteBegin = sizeof(CharType) == 1 ? "\"" : "L\"";
 265   *os << kQuoteBegin;
 266   bool is_previous_hex = false;
 267   for (size_t index = 0; index < len; ++index) {
 268     const CharType cur = begin[index];
 269     if (is_previous_hex && IsXDigit(cur)) {
 270       // Previous character is of '\x..' form and this character can be
 271       // interpreted as another hexadecimal digit in its number. Break string to
 272       // disambiguate.
 273       *os << "\" " << kQuoteBegin;
 274     }
 275     is_previous_hex = PrintAsStringLiteralTo(cur, os) == kHexEscape;
 276   }
 277   *os << "\"";
 278 }
 279
 280 // Prints a (const) char/wchar_t array of 'len' elements, starting at address
 281 // 'begin'.  CharType must be either char or wchar_t.
 282 template <typename CharType>
 283 GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
 284 GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
 285 GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
 286 static void UniversalPrintCharArray(
 287     const CharType* begin, size_t len, ostream* os) {
 288   // The code
 289   //   const char kFoo[] = "foo";
 290   // generates an array of 4, not 3, elements, with the last one being '\0'.
 291   //
 292   // Therefore when printing a char array, we don't print the last element if
 293   // it's '\0', such that the output matches the string literal as it's
 294   // written in the source code.
 295   if (len > 0 && begin[len - 1] == '\0') {
 296     PrintCharsAsStringTo(begin, len - 1, os);
 297     return;
 298   }
 299
 300   // If, however, the last element in the array is not '\0', e.g.
 301   //    const char kFoo[] = { 'f', 'o', 'o' };
 302   // we must print the entire array.  We also print a message to indicate
 303   // that the array is not NUL-terminated.
 304   PrintCharsAsStringTo(begin, len, os);
 305   *os << " (no terminating NUL)";
 306 }
 307
 308 // Prints a (const) char array of 'len' elements, starting at address 'begin'.
 309 void UniversalPrintArray(const char* begin, size_t len, ostream* os) {
 310   UniversalPrintCharArray(begin, len, os);
 311 }
 312
 313 // Prints a (const) wchar_t array of 'len' elements, starting at address
 314 // 'begin'.
 315 void UniversalPrintArray(const wchar_t* begin, size_t len, ostream* os) {
 316   UniversalPrintCharArray(begin, len, os);
 317 }
 318
 319 // Prints the given C string to the ostream.
 320 void PrintTo(const char* s, ostream* os) {
 321   if (s == NULL) {
 322     *os << "NULL";
 323   } else {
 324     *os << ImplicitCast_<const void*>(s) << " pointing to ";
 325     PrintCharsAsStringTo(s, strlen(s), os);
 326   }
 327 }
 328
 329 // MSVC compiler can be configured to define whar_t as a typedef
 330 // of unsigned short. Defining an overload for const wchar_t* in that case
 331 // would cause pointers to unsigned shorts be printed as wide strings,
 332 // possibly accessing more memory than intended and causing invalid
 333 // memory accesses. MSVC defines _NATIVE_WCHAR_T_DEFINED symbol when
 334 // wchar_t is implemented as a native type.
 335 #if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
 336 // Prints the given wide C string to the ostream.
 337 void PrintTo(const wchar_t* s, ostream* os) {
 338   if (s == NULL) {
 339     *os << "NULL";
 340   } else {
 341     *os << ImplicitCast_<const void*>(s) << " pointing to ";
 342     PrintCharsAsStringTo(s, std::wcslen(s), os);
 343   }
 344 }
 345 #endif  // wchar_t is native
 346
 347 // Prints a ::string object.
 348 #if GTEST_HAS_GLOBAL_STRING
 349 void PrintStringTo(const ::string& s, ostream* os) {
 350   PrintCharsAsStringTo(s.data(), s.size(), os);
 351 }
 352 #endif  // GTEST_HAS_GLOBAL_STRING
 353
 354 void PrintStringTo(const ::std::string& s, ostream* os) {
 355   PrintCharsAsStringTo(s.data(), s.size(), os);
 356 }
 357
 358 // Prints a ::wstring object.
 359 #if GTEST_HAS_GLOBAL_WSTRING
 360 void PrintWideStringTo(const ::wstring& s, ostream* os) {
 361   PrintCharsAsStringTo(s.data(), s.size(), os);
 362 }
 363 #endif  // GTEST_HAS_GLOBAL_WSTRING
 364
 365 #if GTEST_HAS_STD_WSTRING
 366 void PrintWideStringTo(const ::std::wstring& s, ostream* os) {
 367   PrintCharsAsStringTo(s.data(), s.size(), os);
 368 }
 369 #endif  // GTEST_HAS_STD_WSTRING
 370
 371 }  // namespace internal
 372
 373 }  // namespace testing