libcxx/src/filesystem/format_string.h

   1 //===----------------------------------------------------------------------===////
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===////
   8
   9 #ifndef FILESYSTEM_FORMAT_STRING_H
  10 #define FILESYSTEM_FORMAT_STRING_H
  11
  12 #include <__assert>
  13 #include <__config>
  14 #include <array>
  15 #include <cstdarg>
  16 #include <cstddef>
  17 #include <cstdio>
  18 #include <string>
  19
  20 #if defined(_LIBCPP_WIN32API)
  21 #  define PATHSTR(x) (L##x)
  22 #  define PATH_CSTR_FMT "\"%ls\""
  23 #else
  24 #  define PATHSTR(x) (x)
  25 #  define PATH_CSTR_FMT "\"%s\""
  26 #endif
  27
  28 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
  29
  30 namespace detail {
  31
  32 inline _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 0) string vformat_string(const char* msg, va_list ap) {
  33   array<char, 256> buf;
  34
  35   va_list apcopy;
  36   va_copy(apcopy, ap);
  37   int ret = ::vsnprintf(buf.data(), buf.size(), msg, apcopy);
  38   va_end(apcopy);
  39
  40   string result;
  41   if (static_cast<size_t>(ret) < buf.size()) {
  42     result.assign(buf.data(), static_cast<size_t>(ret));
  43   } else {
  44     // we did not provide a long enough buffer on our first attempt. The
  45     // return value is the number of bytes (excluding the null byte) that are
  46     // needed for formatting.
  47     size_t size_with_null = static_cast<size_t>(ret) + 1;
  48     result.__resize_default_init(size_with_null - 1);
  49     ret = ::vsnprintf(&result[0], size_with_null, msg, ap);
  50     _LIBCPP_ASSERT_UNCATEGORIZED(static_cast<size_t>(ret) == (size_with_null - 1), "TODO");
  51   }
  52   return result;
  53 }
  54
  55 inline _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 2) string format_string(const char* msg, ...) {
  56   string ret;
  57   va_list ap;
  58   va_start(ap, msg);
  59 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  60   try {
  61 #endif // _LIBCPP_HAS_NO_EXCEPTIONS
  62     ret = detail::vformat_string(msg, ap);
  63 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  64   } catch (...) {
  65     va_end(ap);
  66     throw;
  67   }
  68 #endif // _LIBCPP_HAS_NO_EXCEPTIONS
  69   va_end(ap);
  70   return ret;
  71 }
  72
  73 } // end namespace detail
  74
  75 _LIBCPP_END_NAMESPACE_FILESYSTEM
  76
  77 #endif // FILESYSTEM_FORMAT_STRING_H