libcruft-util/io.hpp

/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
 */

#ifndef __UTIL_IO_HPP
#define __UTIL_IO_HPP

#include "platform.hpp"
#include "posix/fd.hpp"

#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <experimental/filesystem>
#include <vector>
#include <streambuf>

#ifdef PLATFORM_WIN32
#include "win32/windows.hpp"
#else
#define O_BINARY 0
#endif

namespace cruft {
    ///////////////////////////////////////////////////////////////////////////
    /// Reads an entire file into memory in one operation.
    template <typename T = std::byte>
    std::vector<T>
    slurp (const std::experimental::filesystem::path&);


    ///------------------------------------------------------------------------
    /// Read the entire contents of a FILE object into memory.
    ///
    /// * This may trigger an arbitrary number of read calls.
    /// * This may block indefinitely depending on the contents of the fd.
    template <typename T = std::byte>
    std::vector<T>
    slurp (FILE *);


    ///------------------------------------------------------------------------
    /// Read the entire contents of a file-descriptor into memory in one
    /// operation.
    ///
    /// * This may trigger an arbitrary number of read calls.
    /// * This may block indefinitely depending on the contents of the fd.
    template <typename T = std::byte>
    std::vector<T>
    slurp (cruft::posix::fd&);


    ///////////////////////////////////////////////////////////////////////////
    /// writes all data from the provided view into the file-like-object
    ///
    /// writing will continually iterate until the entire buffer has been
    /// dispatched so as to avoid issues with partial writes. will block until
    /// such time as the entire buffer has written.
    ///
    /// an exception may be thrown in the event forward progress is impossible.
    /// in this event the progress may not be reported to the caller. in the
    /// future an exception member variable may expose the information.
    template <
        typename DstT,
        typename IteratorA,
        typename IteratorB
    >
    cruft::view<IteratorA,IteratorB>
    write (DstT &&dst, const cruft::view<IteratorA, IteratorB> &src)
    {
        auto remain = src;
        while (!remain.empty ())
            remain = remain.consume (dst.write (remain));
        return src;
    }


    ///////////////////////////////////////////////////////////////////////////
    class indenter : public std::streambuf {
    protected:
        std::streambuf* m_dest;
        bool            m_line_start;
        std::string     m_indent;
        std::ostream*   m_owner;

    protected:
        virtual int overflow (int ch) override;

    public:
        explicit indenter (std::streambuf* _dest, size_t _indent = 4);
        explicit indenter (std::ostream&   _dest, size_t _indent = 4);

        virtual ~indenter ();
    };

    //-------------------------------------------------------------------------
    // a wrapper type that implicitly indents a single value when passed to an
    // ostream operator.
    template <typename ValueT>
    struct indented {
        explicit indented (const ValueT &_data):
            data (_data)
        { ; }

        const ValueT &data;
    };


    //-------------------------------------------------------------------------
    template <typename ValueT>
    std::ostream&
    operator<< (std::ostream &os, const cruft::indented<ValueT> &value)
    {
        cruft::indenter scoped_indent (os);
        return os << value.data;

    }


    //-------------------------------------------------------------------------
    class scoped_cwd {
        public:
            scoped_cwd ();
            ~scoped_cwd ();

        protected:
            std::string m_original;
    };


    //-------------------------------------------------------------------------
    class path_error : public std::runtime_error {
    public:
        explicit path_error (const std::experimental::filesystem::path &path);

        const std::experimental::filesystem::path& path (void) const noexcept;

    private:
        const std::experimental::filesystem::path m_path;
    };

    class stream_error : public std::exception {
    public:
        virtual const char* what (void) const noexcept
        { return "error on C stream"; }
    };
}

#ifdef PLATFORM_WIN32
#include "io_win32.hpp"
#else
#include "io_posix.hpp"
#endif

#endif