libcruft-util/io.hpp

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * 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 <windows.h>
#else
#define O_BINARY 0
#endif

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

    template <typename T = std::byte, typename A, typename B>
    std::vector<T> slurp (util::view<A,B> path)
    {
        const std::experimental::filesystem::path src { path.begin (), path.end () };
        return slurp<T> (src);
    }

    template <typename T = std::byte>
    std::vector<T> slurp (FILE *);


    ///////////////////////////////////////////////////////////////////////////
    /// 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
    >
    util::view<IteratorA,IteratorB>
    write (DstT &&dst, const util::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 util::indented<ValueT> &value)
    {
        util::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