// 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 ddk.protocol.block.volume;

using zircon.device.block;
using zx;

/// Information about the parent device of the current volume.
struct ParentVolumeInfo {
    /// The size of a single slice, in bytes.
    uint64 slice_size;
    /// The number of addressable slices within a volume.
    uint64 virtual_slice_count;
    /// The total number of slices which are allocatable.
    uint64 physical_slice_count_total;
    /// The total number of slices which are allocated.
    uint64 physical_slice_count_used;
};

/// Describes an region within a Volume. Both units are in "slices".
struct SliceExtent {
    uint64 offset;
    uint64 length;
};

const uint32 MAX_SLICE_QUERY_REQUESTS = 16;

/// Information about an extent of virtual slices.
struct SliceRegion {
    /// True if the virtual slices are allocated, false otherwise.
    bool allocated;
    /// The number of contiguous virtual slices.
    uint64 count;
};

[Layout="ddk-protocol"]
protocol BlockVolume {
    /// Attempts to extend a virtual partition.
    Extend(SliceExtent extent) -> (zx.status status);

    /// Shrinks a virtual Partition.
    Shrink(SliceExtent extent) -> (zx.status status);

    /// Acquire slice size information about the parent volume.
    Query() -> (zx.status status, ParentVolumeInfo info);

    /// Returns the number of contiguous slices from a collection
    /// of start offsets.
    QuerySlices(vector<uint64>:MAX_SLICE_QUERY_REQUESTS start) -> (zx.status status, vector<SliceRegion>:MAX_SLICE_QUERY_REQUESTS responses);

    /// Destroys the current partition, removing it from the Volume Manager, and
    /// freeing all underlying storage.
    Destroy() -> (zx.status status);
};