c-resources/CPlusPlus20ForProgrammers-m.../examples/libraries/fmt/test/gtest-extra.cc

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// 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() FMT_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