#![cfg_attr(docsrs, feature(doc_cfg))]

#![doc = include_str!("../README.md")]

// @@ begin lint list maintained by maint/add_warning @@

#![allow(renamed_and_removed_lints)] // @@REMOVE_WHEN(ci_arti_stable)

#![allow(unknown_lints)] // @@REMOVE_WHEN(ci_arti_nightly)

#![warn(missing_docs)]

#![warn(noop_method_call)]

#![warn(unreachable_pub)]

#![warn(clippy::all)]

#![deny(clippy::await_holding_lock)]

#![deny(clippy::cargo_common_metadata)]

#![deny(clippy::cast_lossless)]

#![deny(clippy::checked_conversions)]

#![warn(clippy::cognitive_complexity)]

#![deny(clippy::debug_assert_with_mut_call)]

#![deny(clippy::exhaustive_enums)]

#![deny(clippy::exhaustive_structs)]

#![deny(clippy::expl_impl_clone_on_copy)]

#![deny(clippy::fallible_impl_from)]

#![deny(clippy::implicit_clone)]

#![deny(clippy::large_stack_arrays)]

#![warn(clippy::manual_ok_or)]

#![deny(clippy::missing_docs_in_private_items)]

#![warn(clippy::needless_borrow)]

#![warn(clippy::needless_pass_by_value)]

#![warn(clippy::option_option)]

#![deny(clippy::print_stderr)]

#![deny(clippy::print_stdout)]

#![warn(clippy::rc_buffer)]

#![deny(clippy::ref_option_ref)]

#![warn(clippy::semicolon_if_nothing_returned)]

#![warn(clippy::trait_duplication_in_bounds)]

#![deny(clippy::unchecked_time_subtraction)]

#![deny(clippy::unnecessary_wraps)]

#![warn(clippy::unseparated_literal_suffix)]

#![deny(clippy::unwrap_used)]

#![deny(clippy::mod_module_files)]

#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness

#![allow(clippy::uninlined_format_args)]

#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945

#![allow(clippy::result_large_err)] // temporary workaround for arti#587

#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best

#![allow(clippy::needless_lifetimes)] // See arti#1765

#![allow(mismatched_lifetime_syntaxes)] // temporary workaround for arti#2060

#![allow(clippy::collapsible_if)] // See arti#2342

#![deny(clippy::unused_async)]

#![deny(clippy::string_slice)] // See arti#2571

//! <!-- @@ end lint list maintained by maint/add_warning @@ -->

// TODO #1645 (either remove this, or decide to have it everywhere)

#![cfg_attr(not(all(feature = "experimental", feature = "full")), allow(unused))]

mod err;

#[cfg(not(target_arch = "wasm32"))]

mod fs;

mod fs_mistrust_error_ext;

mod handle;

pub mod hsnickname;

mod load_store;

pub mod slug;

#[cfg(feature = "testing")]

mod testing;

#[cfg(feature = "state-dir")]

pub mod state_dir;

use serde::{Deserialize, Serialize, de::DeserializeOwned};

use std::sync::Arc;

/// Wrapper type for Results returned from this crate.

type Result<T> = std::result::Result<T, crate::Error>;

pub use err::{Error, ErrorSource};

#[cfg(not(target_arch = "wasm32"))]

pub use fs::FsStateMgr;

pub use fs_mistrust_error_ext::FsMistrustErrorExt;

pub use handle::{DynStorageHandle, StorageHandle};

pub use serde_json::Value as JsonValue;

#[cfg(feature = "testing")]

pub use testing::TestingStateMgr;

/// An object that can manage persistent state.

///

/// State is implemented as a simple key-value store, where the values

/// are objects that can be serialized and deserialized.

///

/// # Warnings

///

/// Current implementations may place additional limits on the types

/// of objects that can be stored.  This is not a great example of OO

/// design: eventually we should probably clarify that more.

pub trait StateMgr: Clone {

    /// Try to load the object with key `key` from the store.

    ///

    /// Return None if no such object exists.

    fn load<D>(&self, key: &str) -> Result<Option<D>>

    where

        D: DeserializeOwned;

    /// Try to save `val` with key `key` in the store.

    ///

    /// Replaces any previous value associated with `key`.

    fn store<S>(&self, key: &str, val: &S) -> Result<()>

    where

        S: Serialize;

    /// Return true if this is a read-write state manager.

    ///

    /// If it returns false, then attempts to `store` will fail with

    /// an error of kind [`BadApiUsage`](tor_error::ErrorKind::BadApiUsage)

    fn can_store(&self) -> bool;

    /// Try to become a read-write state manager if possible, without

    /// blocking.

    ///

    /// This function will return an error only if something really

    /// unexpected went wrong.  It may return `Ok(_)` even if we don't

    /// acquire the lock: check the return value or call

    /// `[StateMgr::can_store()`] to see if the lock is held.

    fn try_lock(&self) -> Result<LockStatus>;

    /// Release any locks held and become a read-only state manager

    /// again. If no locks were held, do nothing.

    fn unlock(&self) -> Result<()>;

    /// Make a new [`StorageHandle`] to store values of particular type

    /// at a particular key.

    fn create_handle<T>(self, key: impl Into<String>) -> DynStorageHandle<T>

    where

        Self: Send + Sync + Sized + 'static,

        T: Serialize + DeserializeOwned + 'static,

    {

        Arc::new(handle::StorageHandleImpl::new(self, key.into()))

    }

}

/// A possible outcome from calling [`StateMgr::try_lock()`]

#[allow(clippy::exhaustive_enums)]

#[derive(Debug, Copy, Clone, Eq, PartialEq)]

#[must_use]

pub enum LockStatus {

    /// We didn't have the lock and were unable to acquire it.

    NoLock,

    /// We already held the lock, and didn't have anything to do.

    AlreadyHeld,

    /// We successfully acquired the lock for the first time.

    NewlyAcquired,

}

impl LockStatus {

    /// Return true if this status indicates that we hold the lock.

}

/// A wrapper type for types whose representation may change in future versions of Arti.

///

/// This uses `#[serde(untagged)]` to attempt deserializing as a type `T` first, and falls back

/// to a generic JSON value representation if that fails.

#[derive(Clone, Serialize, Deserialize, Debug, PartialEq, Eq)]

#[serde(untagged)]

#[allow(clippy::exhaustive_enums)]

pub enum Futureproof<T> {

    /// A successfully-deserialized `T`.

    Understandable(T),

    /// A generic JSON value, representing a failure to deserialize a `T`.

    Unknown(JsonValue),

}

impl<T> Futureproof<T> {

    /// Convert the `Futureproof` into an `Option<T>`, throwing away an `Unknown` value.

        }

}

impl<T> From<T> for Futureproof<T> {

}