// 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.hardware.block.volume;

using zx;

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

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

const MAX_SLICE_QUERY_REQUESTS uint32 = 16;

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

@transport("Banjo")
@banjo_layout("ddk-protocol")
protocol BlockVolume {
    /// Attempts to extend a virtual partition.
    Extend(struct {
        extent SliceExtent;
    }) -> (struct {
        status zx.status;
    });

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

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

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

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