src/storage/blobfs/compression/decompressor_sandbox/decompressor.fidl

// Copyright 2020 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.blobfs.internal;

using zx;

/// Used to transport the Blobfs CompressionAlgorithm enum.
type CompressionAlgorithm = strict enum {
    UNCOMPRESSED = 1;
    LZ4 = 2;
    ZSTD = 3;
    ZSTD_SEEKABLE = 4;
    /// For decompressing an entire chunked archive from start to finish.
    CHUNKED = 5;
    /// Used for decompressing only part of a chunked archive.
    CHUNKED_PARTIAL = 6;
};

/// A range of bytes.
type Range = struct {
    /// Offset in bytes from the start of the VMO.
    offset uint64;
    /// The number of bytes starting at the offset.
    size uint64;
};

/// A request sent to the decompressor.
type DecompressRequest = struct {
    /// The bytes where the decompressed result will be placed.
    decompressed Range;
    /// The bytes from the compressed input to extract from.
    compressed Range;

    /// Algorithm to use for decompression.
    algorithm CompressionAlgorithm;
};

/// A response from the decompressor after handling a `DecompressRangeRequest`.
type DecompressResponse = struct {
    /// Decompressed size in bytes.
    size uint64;
    /// Operation status.
    status zx.status;

    /// Padding out to the same length as `DecompressRangeRequest`. Values must be zero.
    reserved array<int8, 24>;
};

@discoverable
protocol DecompressorCreator {
    /// Takes the server end of a fifo for `DecompressRangeRequest` objects to
    /// handle requests and put `DecopmressRangeResponse` responses on. Data
    /// for requests is read from `compressed_vmo` and results written to
    /// `decompressed_vmo`.
    Create(resource struct {
        server_end zx.handle:FIFO;
        compressed_vmo zx.handle:VMO;
        decompressed_vmo zx.handle:VMO;
    }) -> (struct {
        status zx.status;
    });
};