fmt-11.0.2/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_FCNTL
  11
  12 using fmt::file;
  13
  14 output_redirect::output_redirect(FILE* f, bool flush) : file_(f) {
  15   if (flush) this->flush();
  16   int fd = FMT_POSIX(fileno(f));
  17   // Create a file object referring to the original file.
  18   original_ = file::dup(fd);
  19   // Create a pipe.
  20   auto pipe = fmt::pipe();
  21   read_end_ = std::move(pipe.read_end);
  22   // Connect the passed FILE object to the write end of the pipe.
  23   pipe.write_end.dup2(fd);
  24 }
  25
  26 output_redirect::~output_redirect() noexcept {
  27   try {
  28     restore();
  29   } catch (const std::exception& e) {
  30     std::fputs(e.what(), stderr);
  31   }
  32 }
  33
  34 void output_redirect::flush() {
  35   int result = 0;
  36   do {
  37     result = fflush(file_);
  38   } while (result == EOF && errno == EINTR);
  39   if (result != 0) throw fmt::system_error(errno, "cannot flush stream");
  40 }
  41
  42 void output_redirect::restore() {
  43   if (original_.descriptor() == -1) return;  // Already restored.
  44   flush();
  45   // Restore the original file.
  46   original_.dup2(FMT_POSIX(fileno(file_)));
  47   original_.close();
  48 }
  49
  50 std::string output_redirect::restore_and_read() {
  51   // Restore output.
  52   restore();
  53
  54   // Read everything from the pipe.
  55   std::string content;
  56   if (read_end_.descriptor() == -1) return content;  // Already read.
  57   enum { BUFFER_SIZE = 4096 };
  58   char buffer[BUFFER_SIZE];
  59   size_t count = 0;
  60   do {
  61     count = read_end_.read(buffer, BUFFER_SIZE);
  62     content.append(buffer, count);
  63   } while (count != 0);
  64   read_end_.close();
  65   return content;
  66 }
  67
  68 std::string read(file& f, size_t count) {
  69   std::string buffer(count, '\0');
  70   size_t n = 0, offset = 0;
  71   do {
  72     n = f.read(&buffer[offset], count - offset);
  73     // We can't read more than size_t bytes since count has type size_t.
  74     offset += n;
  75   } while (offset < count && n != 0);
  76   buffer.resize(offset);
  77   return buffer;
  78 }
  79
  80 #endif  // FMT_USE_FCNTL