// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.io;

using fuchsia.mem;
using zx;

/// The maximal buffer size which can be transmitted for buffered operations.
/// This capacity is currently set somewhat arbitrarily.
const MAX_BUF uint64 = 8192;

protocol File {
    compose File1;
    compose File2;
};

/// File defines the interface of a node which contains a flat layout of data.
protocol File1 {
    compose Node1;

    /// Reads up to `count` bytes at the seek offset.
    /// The seek offset is moved forward by the number of bytes read.
    ///
    /// This method requires the following rights: `OpenFlags.RIGHT_READABLE`, otherwise returns
    /// `ZX_ERR_BAD_HANDLE`.
    ///
    /// Returns `ZX_ERR_OUT_OF_RANGE` if `count` is greater than `MAX_BUF`.
    @selector("fuchsia.io1/File.Read")
    @deprecated("replaced by File2.Read")
    ReadDeprecated(struct {
        count uint64;
    }) -> (struct {
        s zx.status;
        data vector<uint8>:MAX_BUF;
    });

    /// Reads up to `count` bytes at the provided offset.
    /// Does not affect the seek offset.
    ///
    /// This method requires the following rights: `OpenFlags.RIGHT_READABLE`, otherwise returns
    /// `ZX_ERR_BAD_HANDLE`.
    ///
    /// Returns `ZX_ERR_OUT_OF_RANGE` if `count` is greater than `MAX_BUF`.
    @selector("fuchsia.io1/File.ReadAt")
    @deprecated("replaced by File2.ReadAt")
    ReadAtDeprecated(struct {
        count uint64;
        offset uint64;
    }) -> (struct {
        s zx.status;
        data vector<uint8>:MAX_BUF;
    });

    /// Writes data at the seek offset.
    /// The seek offset is moved forward by the number of bytes written.
    ///
    /// This method requires following rights: `OpenFlags.RIGHT_WRITABLE`, otherwise returns
    /// `ZX_ERR_BAD_HANDLE`.
    @selector("fuchsia.io1/File.Write")
    @deprecated("replaced by File2.Write")
    WriteDeprecated(struct {
        data vector<uint8>:MAX_BUF;
    }) -> (struct {
        s zx.status;
        actual uint64;
    });

    /// Writes data to the provided offset.
    /// Does not affect the seek offset.
    ///
    /// This method requires following rights: `OpenFlags.RIGHT_WRITABLE`, otherwise returns
    /// `ZX_ERR_BAD_HANDLE`.
    @selector("fuchsia.io1/File.WriteAt")
    @deprecated("replaced by File2.WriteAt")
    WriteAtDeprecated(struct {
        data vector<uint8>:MAX_BUF;
        offset uint64;
    }) -> (struct {
        s zx.status;
        actual uint64;
    });

    /// Moves the offset at which the next invocation of `Read()` or `Write()` will
    /// occur.
    ///
    /// This method does not require any rights.
    @selector("fuchsia.io1/File.Seek")
    @deprecated("replaced by File2.Seek")
    SeekDeprecated(struct {
        offset int64;
        start SeekOrigin;
    }) -> (struct {
        s zx.status;
        offset uint64;
    });

    /// Shrinks the file size to 'length' bytes.
    ///
    /// This method requires following rights: `OpenFlags.RIGHT_WRITABLE`, otherwise returns
    /// `ZX_ERR_BAD_HANDLE`.
    @selector("fuchsia.io1/File.Truncate")
    @deprecated("replaced by File2.Resize")
    TruncateDeprecatedUseResize(struct {
        length uint64;
    }) -> (struct {
        s zx.status;
    });

    /// Acquires a buffer representing this file, if there is one, with the
    /// requested access rights.
    ///
    /// This method requires following rights:
    ///
    /// - `OpenFlags.RIGHT_WRITABLE` if `flags` includes `VmoFlags.WRITE`.
    /// - `OpenFlags.RIGHT_READABLE` if `flags` includes `VmoFlags.READ` or `VmoFlags.EXECUTE`.
    /// - `OpenFlags.RIGHT_EXECUTABLE` if `flags` includes `VmoFlags.EXECUTE`.
    @selector("fuchsia.io1/File.GetBuffer")
    @deprecated("replaced by File2.GetBackingMemory")
    GetBufferDeprecatedUseGetBackingMemory(struct {
        flags VmoFlags;
    }) -> (resource struct {
        s zx.status;
        buffer box<fuchsia.mem.Buffer>;
    });
};