ceph/src/seastar/fmt/test/gtest-extra.cc

   1 // Formatting library for C++ - custom Google Test assertions
   2 //
   3 // Copyright (c) 2012 - present, Victor Zverovich
   4 // All rights reserved.
   5 //
   6 // For the license information refer to format.h.
   7
   8 #include "gtest-extra.h"
   9
  10 #if FMT_USE_FILE_DESCRIPTORS
  11
  12 using fmt::file;
  13
  14 void OutputRedirect::flush() {
  15 #if EOF != -1
  16 # error "FMT_RETRY assumes return value of -1 indicating failure"
  17 #endif
  18   int result = 0;
  19   FMT_RETRY(result, fflush(file_));
  20   if (result != 0)
  21     throw fmt::system_error(errno, "cannot flush stream");
  22 }
  23
  24 void OutputRedirect::restore() {
  25   if (original_.descriptor() == -1)
  26     return;  // Already restored.
  27   flush();
  28   // Restore the original file.
  29   original_.dup2(FMT_POSIX(fileno(file_)));
  30   original_.close();
  31 }
  32
  33 OutputRedirect::OutputRedirect(FILE *f) : file_(f) {
  34   flush();
  35   int fd = FMT_POSIX(fileno(f));
  36   // Create a file object referring to the original file.
  37   original_ = file::dup(fd);
  38   // Create a pipe.
  39   file write_end;
  40   file::pipe(read_end_, write_end);
  41   // Connect the passed FILE object to the write end of the pipe.
  42   write_end.dup2(fd);
  43 }
  44
  45 OutputRedirect::~OutputRedirect() FMT_NOEXCEPT {
  46   try {
  47     restore();
  48   } catch (const std::exception &e) {
  49     std::fputs(e.what(), stderr);
  50   }
  51 }
  52
  53 std::string OutputRedirect::restore_and_read() {
  54   // Restore output.
  55   restore();
  56
  57   // Read everything from the pipe.
  58   std::string content;
  59   if (read_end_.descriptor() == -1)
  60     return content;  // Already read.
  61   enum { BUFFER_SIZE = 4096 };
  62   char buffer[BUFFER_SIZE];
  63   std::size_t count = 0;
  64   do {
  65     count = read_end_.read(buffer, BUFFER_SIZE);
  66     content.append(buffer, count);
  67   } while (count != 0);
  68   read_end_.close();
  69   return content;
  70 }
  71
  72 std::string read(file &f, std::size_t count) {
  73   std::string buffer(count, '\0');
  74   std::size_t n = 0, offset = 0;
  75   do {
  76     n = f.read(&buffer[offset], count - offset);
  77     // We can't read more than size_t bytes since count has type size_t.
  78     offset += n;
  79   } while (offset < count && n != 0);
  80   buffer.resize(offset);
  81   return buffer;
  82 }
  83
  84 #endif  // FMT_USE_FILE_DESCRIPTORS
  85
  86 std::string format_system_error(int error_code, fmt::string_view message) {
  87   fmt::memory_buffer out;
  88   format_system_error(out, error_code, message);
  89   return to_string(out);
  90 }