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#ifndef UTIL_FILE_H
#define UTIL_FILE_H
#include "exception.hh"
#include "scoped.hh"
#include "string_piece.hh"
#include <cstddef>
#include <cstdio>
#include <string>
#include <stdint.h>
namespace util {
class scoped_fd {
public:
scoped_fd() : fd_(-1) {}
explicit scoped_fd(int fd) : fd_(fd) {}
~scoped_fd();
#if __cplusplus >= 201103L
scoped_fd(scoped_fd &&from) noexcept : fd_(from.fd_) {
from.fd_ = -1;
}
#endif
void reset(int to = -1) {
scoped_fd other(fd_);
fd_ = to;
}
int get() const { return fd_; }
int operator*() const { return fd_; }
int release() {
int ret = fd_;
fd_ = -1;
return ret;
}
private:
int fd_;
scoped_fd(const scoped_fd &);
scoped_fd &operator=(const scoped_fd &);
};
struct scoped_FILE_closer {
static void Close(std::FILE *file);
};
typedef scoped<std::FILE, scoped_FILE_closer> scoped_FILE;
/* Thrown for any operation where the fd is known. */
class FDException : public ErrnoException {
public:
explicit FDException(int fd) throw();
virtual ~FDException() throw();
// This may no longer be valid if the exception was thrown past open.
int FD() const { return fd_; }
// Guess from NameFromFD.
const std::string &NameGuess() const { return name_guess_; }
private:
int fd_;
std::string name_guess_;
};
// End of file reached.
class EndOfFileException : public Exception {
public:
EndOfFileException() throw();
~EndOfFileException() throw();
};
class UnsupportedOSException : public Exception {};
// Open for read only.
int OpenReadOrThrow(const char *name);
// Create file if it doesn't exist, truncate if it does. Opened for write.
int CreateOrThrow(const char *name);
/** Does the given input file path denote standard input?
*
* Returns true if, and only if, path is either "-" or "/dev/stdin".
*
* Opening standard input as a file may need some special treatment for
* portability. There's a convention that a dash ("-") in place of an input
* file path denotes standard input, but opening "/dev/stdin" may need to be
* special as well.
*/
bool InputPathIsStdin(StringPiece path);
/** Does the given output file path denote standard output?
*
* Returns true if, and only if, path is either "-" or "/dev/stdout".
*
* Opening standard output as a file may need some special treatment for
* portability. There's a convention that a dash ("-") in place of an output
* file path denotes standard output, but opening "/dev/stdout" may need to be
* special as well.
*/
bool OutputPathIsStdout(StringPiece path);
// Return value for SizeFile when it can't size properly.
const uint64_t kBadSize = (uint64_t)-1;
uint64_t SizeFile(int fd);
uint64_t SizeOrThrow(int fd);
void ResizeOrThrow(int fd, uint64_t to);
// It bothers me that fallocate has offset before size while pread has size
// before offset. But best to follow the call.
void HolePunch(int fd, uint64_t offset, uint64_t size);
std::size_t PartialRead(int fd, void *to, std::size_t size);
void ReadOrThrow(int fd, void *to, std::size_t size);
std::size_t ReadOrEOF(int fd, void *to_void, std::size_t size);
void WriteOrThrow(int fd, const void *data_void, std::size_t size);
void WriteOrThrow(FILE *to, const void *data, std::size_t size);
/* These call pread/pwrite in a loop. However, on Windows they call ReadFile/
* WriteFile which changes the file pointer. So it's safe to call ErsatzPRead
* and ErsatzPWrite concurrently (or any combination thereof). But it changes
* the file pointer on windows, so it's not safe to call concurrently with
* anything that uses the implicit file pointer e.g. the Read/Write functions
* above.
*/
void ErsatzPRead(int fd, void *to, std::size_t size, uint64_t off);
void ErsatzPWrite(int fd, const void *data_void, std::size_t size, uint64_t off);
void FSyncOrThrow(int fd);
// Seeking: returns offset
uint64_t SeekOrThrow(int fd, uint64_t off);
uint64_t AdvanceOrThrow(int fd, int64_t off);
uint64_t SeekEnd(int fd);
std::FILE *FDOpenOrThrow(scoped_fd &file);
std::FILE *FDOpenReadOrThrow(scoped_fd &file);
// Temporary files
// Append a / if base is a directory.
void NormalizeTempPrefix(std::string &base);
int MakeTemp(const StringPiece &prefix);
std::FILE *FMakeTemp(const StringPiece &prefix);
// Where should we put temporary files? Handles all the windows/POSIX defaults fun.
std::string DefaultTempDirectory();
// dup an fd.
int DupOrThrow(int fd);
/* Attempt get file name from fd. This won't always work (i.e. on Windows or
* a pipe). The file might have been renamed. It's intended for diagnostics
* and logging only.
*/
std::string NameFromFD(int fd);
} // namespace util
#endif // UTIL_FILE_H
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