// 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.minfs;

using zx;
using fuchsia.storage.metrics;

/// Describes metrics about the running Minfs instance.
[ForDeprecatedCBindings]
struct Metrics {
    fuchsia.storage.metrics.FsMetrics fs_metrics;

    /// Minfs initializes entire VMOs at once.
    /// The following fields track this information.
    uint64 initialized_vmos;
    /// Top-level direct blocks only
    uint32 init_dnum_count;
    /// Top-level indirect blocks only
    uint32 init_inum_count;
    uint32 init_dinum_count;
    uint64 init_user_data_size;
    uint64 init_user_data_ticks;

    /// Minfs looks up Vnodes by ino internally (using "VnodeGet").
    /// The following fields track this information.
    uint64 vnodes_opened_cache_hit;

    /// The number of bytes in dirty cache for which we have not issued writes yet.
    /// The number is filesystem block aligned.
    uint64 dirty_bytes;
};

struct MountState {
    /// True if the fileystem is operational in readonly state. There may have been
    /// writes during mount or during replaying journal.
    bool readonly_after_initialization;

    /// True if the mounted filesystem is collecting metrics.
    bool collect_metrics;

    /// True if the mounted filesystem is in verbose mode.
    bool verbose;

    /// True if the journalled writes were allowed during mount.
    bool repair_filesystem;

    /// True if the journaling is enabled.
    bool use_journal;

    /// True is dirty cache is enabled for minfs.
    bool dirty_cache_enabled;
};

/// Describes a contiguous run of allocated blocks.
[ForDeprecatedCBindings]
struct BlockRegion {
    uint64 offset;
    uint64 length;
};

[ForDeprecatedCBindings]
protocol Minfs {
    /// Acquires metrics about the currently running filesystem.
    GetMetrics() -> (zx.status status, Metrics? metrics);

    /// Toggle the metrics collection system on or off.
    ToggleMetrics(bool enable) -> (zx.status status);

    /// Retrieve information about allocated regions on the filesystem.
    GetAllocatedRegions() -> (zx.status status, zx.handle:VMO? regions, uint64 count);

    /// Get mount state.
    GetMountState() -> (zx.status status, MountState? mount_state);
};