1 files changed, 80 insertions, 0 deletions
diff --git a/src/fmt/test/gtest-extra.cc b/src/fmt/test/gtest-extra.cc
new file mode 100644
index 000000000..542e4b5e6
--- /dev/null
+++ b/src/fmt/test/gtest-extra.cc
@@ -0,0 +1,80 @@
+// Formatting library for C++ - custom Google Test assertions
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "gtest-extra.h"
+
+#if FMT_USE_FCNTL
+
+using fmt::file;
+
+output_redirect::output_redirect(FILE* f) : file_(f) {
+  flush();
+  int fd = FMT_POSIX(fileno(f));
+  // Create a file object referring to the original file.
+  original_ = file::dup(fd);
+  // Create a pipe.
+  file write_end;
+  file::pipe(read_end_, write_end);
+  // Connect the passed FILE object to the write end of the pipe.
+  write_end.dup2(fd);
+}
+
+output_redirect::~output_redirect() noexcept {
+  try {
+    restore();
+  } catch (const std::exception& e) {
+    std::fputs(e.what(), stderr);
+  }
+}
+
+void output_redirect::flush() {
+  int result = 0;
+  do {
+    result = fflush(file_);
+  } while (result == EOF && errno == EINTR);
+  if (result != 0) throw fmt::system_error(errno, "cannot flush stream");
+}
+
+void output_redirect::restore() {
+  if (original_.descriptor() == -1) return;  // Already restored.
+  flush();
+  // Restore the original file.
+  original_.dup2(FMT_POSIX(fileno(file_)));
+  original_.close();
+}
+
+std::string output_redirect::restore_and_read() {
+  // Restore output.
+  restore();
+
+  // Read everything from the pipe.
+  std::string content;
+  if (read_end_.descriptor() == -1) return content;  // Already read.
+  enum { BUFFER_SIZE = 4096 };
+  char buffer[BUFFER_SIZE];
+  size_t count = 0;
+  do {
+    count = read_end_.read(buffer, BUFFER_SIZE);
+    content.append(buffer, count);
+  } while (count != 0);
+  read_end_.close();
+  return content;
+}
+
+std::string read(file& f, size_t count) {
+  std::string buffer(count, '\0');
+  size_t n = 0, offset = 0;
+  do {
+    n = f.read(&buffer[offset], count - offset);
+    // We can't read more than size_t bytes since count has type size_t.
+    offset += n;
+  } while (offset < count && n != 0);
+  buffer.resize(offset);
+  return buffer;
+}
+
+#endif  // FMT_USE_FCNTL