file-descriptor.hh

Go to the documentation of this file.

#pragma once
 
#include "lix/libutil/error.hh"
#include "lix/libutil/generator.hh"
 
namespace nix {
 
struct Sink;
struct Source;

std::string readLine(int fd);

void writeLine(int fd, std::string s);

std::string readFile(int fd);

void readFull(int fd, char * buf, size_t count);
void writeFull(int fd, std::string_view s, bool allowInterrupts = true);

std::string drainFD(int fd, bool block = true, const size_t reserveSize=0);
 
 
/*
 * Will attempt to guess *A* path associated that might lead to the same file as used by this
 * file descriptor.
 *
 * The returned string should NEVER be used as a valid path.
 */
std::string guessOrInventPathFromFD(int fd);
 
Generator<Bytes> drainFDSource(int fd, bool block = true);
 
class AutoCloseFD
{
    int fd;
public:
    AutoCloseFD();
    explicit AutoCloseFD(int fd);
    AutoCloseFD(const AutoCloseFD & fd) = delete;
    AutoCloseFD(AutoCloseFD&& fd);
    ~AutoCloseFD();
    AutoCloseFD& operator =(const AutoCloseFD & fd) = delete;
    AutoCloseFD& operator =(AutoCloseFD&& fd) noexcept(false);
    int get() const;
 
    /*
     * Will attempt to guess *A* path associated that might lead to the same file as used by this
     * file descriptor.
     *
     * The returned string should NEVER be used as a valid path.
     */
    std::string guessOrInventPath() const { return guessOrInventPathFromFD(fd); }
 
    explicit operator bool() const;
    int release();
    void close();
    void fsync();
    void reset() { *this = {}; }
};
 
class Pipe
{
public:
    AutoCloseFD readSide, writeSide;
    void create();
    void close();
};

void closeExtraFDs();

void closeOnExec(int fd);
 
MakeError(EndOfFile, Error);
 
}