sys.h

#ifndef WREPORT_SYS_H
#define WREPORT_SYS_H

 
#include <string>
#include <memory>
#include <iterator>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
 
namespace wreport {
namespace sys {

std::unique_ptr<struct stat> stat(const std::string& pathname);

void stat(const std::string& pathname, struct stat& st);

bool isdir(const std::string& pathname);

bool isblk(const std::string& pathname);

bool ischr(const std::string& pathname);

bool isfifo(const std::string& pathname);

bool islnk(const std::string& pathname);

bool isreg(const std::string& pathname);

bool issock(const std::string& pathname);

time_t timestamp(const std::string& file);

time_t timestamp(const std::string& file, time_t def);

size_t size(const std::string& file);

size_t size(const std::string& file, size_t def);

ino_t inode(const std::string& file);

ino_t inode(const std::string& file, ino_t def);

bool access(const std::string& s, int m);

bool exists(const std::string& s);

std::string getcwd();

void chdir(const std::string& dir);

void chroot(const std::string& dir);

mode_t umask(mode_t mask);

std::string abspath(const std::string& pathname);

class MMap
{
    void* addr;
    size_t length;
 
public:
    MMap(const MMap&) = delete;
    MMap(MMap&&);
    MMap(void* addr, size_t length);
    ~MMap();
 
    MMap& operator=(const MMap&) = delete;
    MMap& operator=(MMap&&);
 
    size_t size() const { return length; }
 
    void munmap();
 
    template<typename T>
    operator const T*() const { return reinterpret_cast<const T*>(addr); }
 
    template<typename T>
    operator T*() const { return reinterpret_cast<T*>(addr); }
};

class FileDescriptor
{
protected:
    int fd = -1;
 
public:
    FileDescriptor();
    FileDescriptor(FileDescriptor&& o);
    FileDescriptor(int fd);
    virtual ~FileDescriptor();
 
    // We can copy at the FileDescriptor level because the destructor does not
    // close fd
    FileDescriptor(const FileDescriptor& o) = default;
    FileDescriptor& operator=(const FileDescriptor& o) = default;

    [[noreturn]] virtual void throw_error(const char* desc);

    [[noreturn]] virtual void throw_runtime_error(const char* desc);

    bool is_open() const;

    void close();
 
    void fstat(struct stat& st);
    void fchmod(mode_t mode);
 
    void futimens(const struct ::timespec ts[2]);
 
    void fsync();
    void fdatasync();
 
    int dup();
 
    size_t read(void* buf, size_t count);

    bool read_all_or_retry(void* buf, size_t count);

    void read_all_or_throw(void* buf, size_t count);
 
    size_t write(const void* buf, size_t count);
 
    template<typename Container>
    size_t write(const Container& c)
    {
        return write(c.data(), c.size() * sizeof(Container::value_type));
    }

    void write_all_or_retry(const void* buf, size_t count);
 
    template<typename Container>
    void write_all_or_retry(const Container& c)
    {
        write_all_or_retry(c.data(), c.size() * sizeof(typename Container::value_type));
    }

    void write_all_or_throw(const void* buf, size_t count);
 
    template<typename Container>
    void write_all_or_throw(const Container& c)
    {
        write_all_or_throw(c.data(), c.size() * sizeof(typename Container::value_type));
    }
 
    off_t lseek(off_t offset, int whence=SEEK_SET);
 
    size_t pread(void* buf, size_t count, off_t offset);
    size_t pwrite(const void* buf, size_t count, off_t offset);
 
    template<typename Container>
    size_t pwrite(const Container& c, off_t offset)
    {
        return pwrite(c.data(), c.size() * sizeof(typename Container::value_type), offset);
    }
 
    void ftruncate(off_t length);
 
    MMap mmap(size_t length, int prot, int flags, off_t offset=0);

    bool ofd_setlk(struct ::flock&);

    bool ofd_setlkw(struct ::flock&, bool retry_on_signal=true);

    bool ofd_getlk(struct ::flock&);

    int getfl();

    void setfl(int flags);
 
    operator int() const { return fd; }
};
 

class PreserveFileTimes
{
protected:
    FileDescriptor fd;
    struct ::timespec ts[2];
 
public:
    PreserveFileTimes(FileDescriptor fd);
    ~PreserveFileTimes();
};
 
 

class NamedFileDescriptor : public FileDescriptor
{
protected:
    std::string pathname;
 
public:
    NamedFileDescriptor(int fd, const std::string& pathname);
    NamedFileDescriptor(NamedFileDescriptor&&);
    NamedFileDescriptor& operator=(NamedFileDescriptor&&);
 
    // We can copy at the NamedFileDescriptor level because the destructor does not
    // close fd
    NamedFileDescriptor(const NamedFileDescriptor& o) = default;
    NamedFileDescriptor& operator=(const NamedFileDescriptor& o) = default;
 
    [[noreturn]] virtual void throw_error(const char* desc);
    [[noreturn]] virtual void throw_runtime_error(const char* desc);

    const std::string& name() const { return pathname; }
};
 

struct ManagedNamedFileDescriptor : public NamedFileDescriptor
{
    using NamedFileDescriptor::NamedFileDescriptor;
 
    ManagedNamedFileDescriptor(ManagedNamedFileDescriptor&&) = default;
    ManagedNamedFileDescriptor(const ManagedNamedFileDescriptor&) = delete;

    ~ManagedNamedFileDescriptor();
 
    ManagedNamedFileDescriptor& operator=(const ManagedNamedFileDescriptor&) = delete;
    ManagedNamedFileDescriptor& operator=(ManagedNamedFileDescriptor&&);
};
 

struct Path : public ManagedNamedFileDescriptor
{
    struct iterator
    {
        using iterator_category = std::input_iterator_tag;
        using value_type = struct dirent;
        using difference_type = int;
        using pointer = struct dirent*;
        using reference = struct dirent&;
 
        Path* path = nullptr;
        DIR* dir = nullptr;
        struct dirent* cur_entry = nullptr;
 
        // End iterator
        iterator();
        // Start iteration on dir
        iterator(Path& dir);
        iterator(iterator&) = delete;
        iterator(iterator&& o)
            : dir(o.dir), cur_entry(o.cur_entry)
        {
            o.dir = nullptr;
            o.cur_entry = nullptr;
        }
        ~iterator();
        iterator& operator=(iterator&) = delete;
        iterator& operator=(iterator&&) = delete;
 
        bool operator==(const iterator& i) const;
        bool operator!=(const iterator& i) const;
        struct dirent& operator*() const { return *cur_entry; }
        struct dirent* operator->() const { return cur_entry; }
        void operator++();

        bool isdir() const;

        bool isblk() const;

        bool ischr() const;

        bool isfifo() const;

        bool islnk() const;

        bool isreg() const;

        bool issock() const;

        Path open_path(int flags=0) const;
    };
 
    using ManagedNamedFileDescriptor::ManagedNamedFileDescriptor;

    Path(const char* pathname, int flags=0, mode_t mode=0777);
    Path(const std::string& pathname, int flags=0, mode_t mode=0777);
    Path(Path& parent, const char* pathname, int flags=0, mode_t mode=0777);
    Path(const Path&) = delete;
    Path(Path&&) = default;
    Path& operator=(const Path&) = delete;
    Path& operator=(Path&&) = default;

    void open(int flags, mode_t mode=0777);
 
    DIR* fdopendir();

    iterator begin();

    iterator end();
 
    int openat(const char* pathname, int flags, mode_t mode=0777);

    int openat_ifexists(const char* pathname, int flags, mode_t mode=0777);
 
    bool faccessat(const char* pathname, int mode, int flags=0);
 
    void fstatat(const char* pathname, struct stat& st);

    bool fstatat_ifexists(const char* pathname, struct stat& st);

    void lstatat(const char* pathname, struct stat& st);

    bool lstatat_ifexists(const char* pathname, struct stat& st);
 
    void unlinkat(const char* pathname);
 
    void mkdirat(const char* pathname, mode_t mode=0777);

    void rmdirat(const char* pathname);
 
    void symlinkat(const char* target, const char* linkpath);
 
    std::string readlinkat(const char* pathname);

    void rmtree();
 
    static std::string mkdtemp(const std::string& prefix);
    static std::string mkdtemp(const char* prefix);
    static std::string mkdtemp(char* pathname_template);
};
 

class File : public ManagedNamedFileDescriptor
{
public:
    using ManagedNamedFileDescriptor::ManagedNamedFileDescriptor;
 
    File(File&&) = default;
    File(const File&) = delete;

    File(const std::string& pathname);

    File(const std::string& pathname, int flags, mode_t mode=0777);
 
    File& operator=(const File&) = delete;
    File& operator=(File&&) = default;

    void open(int flags, mode_t mode=0777);

    bool open_ifexists(int flags, mode_t mode=0777);
 
    static File mkstemp(const std::string& prefix);
    static File mkstemp(const char* prefix);
    static File mkstemp(char* pathname_template);
};
 

class Tempfile : public File
{
protected:
    bool m_unlink_on_exit = true;
 
public:
    Tempfile();
    Tempfile(const std::string& prefix);
    Tempfile(const char* prefix);
    ~Tempfile();

    void unlink_on_exit(bool val);

    void unlink();
};
 

class Tempdir : public Path
{
protected:
    bool m_rmtree_on_exit = true;
 
public:
    Tempdir();
    Tempdir(const std::string& prefix);
    Tempdir(const char* prefix);
    ~Tempdir();

    void rmtree_on_exit(bool val);
};
 

std::string read_file(const std::string &file);

void write_file(const std::string& file, const std::string& data, mode_t mode=0777);

void write_file(const std::string& file, const void* data, size_t size, mode_t mode=0777);

void write_file_atomically(const std::string& file, const std::string& data, mode_t mode=0777);

void write_file_atomically(const std::string& file, const void* data, size_t size, mode_t mode=0777);
 
#if 0
// Create a temporary directory based on a template.
std::string mkdtemp(std::string templ);

void mkFilePath(const std::string& file);
#endif

bool unlink_ifexists(const std::string& file);

bool rename_ifexists(const std::string& src, const std::string& dst);

bool mkdir_ifmissing(const char* pathname, mode_t mode=0777);
 
bool mkdir_ifmissing(const std::string& pathname, mode_t mode=0777);

bool makedirs(const std::string& pathname, mode_t=0777);

std::string which(const std::string& name);

void unlink(const std::string& pathname);

void rmdir(const std::string& pathname);

void rmtree(const std::string& pathname);

bool rmtree_ifexists(const std::string& pathname);

void rename(const std::string& src_pathname, const std::string& dst_pathname);

void touch(const std::string& pathname, time_t ts);

void clock_gettime(::clockid_t clk_id, struct ::timespec& ts);

unsigned long long timesec_elapsed(const struct ::timespec& begin, const struct ::timespec& until);

struct Clock
{
    ::clockid_t clk_id;
    struct ::timespec ts;

    Clock(::clockid_t clk_id);

    unsigned long long elapsed();
};


void getrlimit(int resource, struct ::rlimit& rlim);

void setrlimit(int resource, const struct ::rlimit& rlim);

struct OverrideRlimit
{
    int resource;
    struct ::rlimit orig;
 
    OverrideRlimit(int resource, rlim_t rlim);
    ~OverrideRlimit();

    void set(rlim_t rlim);
};
 
}
}
 
#endif