//! Declare tor client specific errors.

mod hint;

use std::fmt::{self, Display};

use std::sync::Arc;

use futures::task::SpawnError;

#[cfg(feature = "onion-service-client")]

use safelog::DisplayRedacted as _;

use safelog::Sensitive;

use thiserror::Error;

use tor_circmgr::TargetPorts;

use tor_error::{ErrorKind, HasKind};

use crate::TorAddrError;

#[cfg(feature = "onion-service-client")]

use tor_hscrypto::pk::HsId;

pub use hint::HintableError;

/// Main high-level error type for the Arti Tor client

///

/// If you need to handle different types of errors differently, use the

/// [`kind`](`tor_error::HasKind::kind`) trait method to check what kind of

/// error it is.

///

/// Note that although this type implements that standard

/// [`Error`](trait@std::error::Error) trait, the output of that trait's methods are

/// not covered by semantic versioning.  Specifically: you should not rely on

/// the specific output of `Display`, `Debug`, or `Error::source()` when run on

/// this type; it may change between patch versions without notification.

#[derive(Error, Clone, Debug)]

pub struct Error {

    /// The actual error.

    ///

    /// This field is exposed via the `detail()` method only if the

    /// `error_detail` feature is enabled. Using it will void your semver

    /// guarantee.

    #[source]

    detail: Box<ErrorDetail>,

}

impl From<ErrorDetail> for Error {

}

/// Declare an enum as `pub` if `error_details` is enabled, and as `pub(crate)` otherwise.

#[cfg(feature = "error_detail")]

macro_rules! pub_if_error_detail {

    {  $(#[$meta:meta])* enum $e:ident $tt:tt } => {

        $(#[$meta])* pub enum $e $tt

    }

}

/// Declare an enum as `pub` if `error_details` is enabled, and as `pub(crate)` otherwise.

#[cfg(not(feature = "error_detail"))]

macro_rules! pub_if_error_detail {

    {  $(#[$meta:meta])* enum $e:ident $tt:tt } => {

        $(#[$meta])* pub(crate) enum $e $tt }

}

// Hello, macro-fans!  There are some other solutions that we considered here

// but didn't use.

//

// 1. For one, `pub_if_error_detail!{} enum ErrorDetail { ... }` would be neat,

// but Rust doesn't allow macros to appear in that position.

//

// 2. We could also declare `ErrorDetail` here as `pub` unconditionally, and

// rely on `mod err` being private to keep it out of the user's hands.  Then we

// could conditionally re-export `ErrorDetail` in `lib`:

//

// ```

// mod err {

//    pub enum ErrorDetail { ... }

// }

//

// #[cfg(feature = "error_detail")]

// pub use err::ErrorDetail;

// ```

//

// But if we did that, the compiler would no longer warn us if we

// _unconditionally_ exposed the ErrorDetail type from somewhere else in this

// crate.  That doesn't seem too safe.

//

// 3. At one point we had a macro more like:

// ```

// macro_rules! declare_error_detail { { $vis: $vis } } =>

//  => { ... $vis enum ErrorDetail {...} }

// ```

// There's nothing wrong with that in principle, but it's no longer needed,

// since we used to use $vis in several places but now it's only used in one.

// Also, it's good to make macro declarations small, and rust-analyzer seems to

// handle understand format a little bit better.

pub_if_error_detail! {

// We cheat with the indentation, a bit.  Happily rustfmt doesn't seem to mind.

/// Represents errors that can occur while doing Tor operations.

///

/// This enumeration is the inner view of a

/// [`arti_client::Error`](crate::Error): we don't expose it unless the

/// `error_detail` feature is enabled.

///

/// The details of this enumeration are not stable: using the `error_detail`

/// feature will void your semver guarantee.

///

/// Instead of looking at the type, you should try to use the

/// [`kind`](`tor_error::HasKind::kind`) trait method to distinguish among

/// different kinds of [`Error`](struct@crate::Error).  If that doesn't provide enough information

/// for your use case, please let us know.

#[cfg_attr(docsrs, doc(cfg(feature = "error_detail")))]

#[cfg_attr(test, derive(strum::EnumDiscriminants))]

#[cfg_attr(test, strum_discriminants(vis(pub(crate))))]

#[derive(Error, Clone, Debug)]

#[non_exhaustive]

enum ErrorDetail {

    /// Error setting up the memory quota tracker

    #[error("Error setting up the memory quota tracker")]

    MemquotaSetup(#[from] tor_memquota::StartupError),

    /// Memory quota error while starting up Arti

    #[error("Memory quota error during startup")]

    MemquotaDuringStartup(#[from] tor_memquota::Error),

    /// Error setting up the channel manager

    // TODO: should "chanmgr setup error" be its own type in tor-chanmgr

    #[error("Error setting up the channel manager")]

    ChanMgrSetup(#[source] tor_chanmgr::Error),

    /// Error setting up the guard manager

    // TODO: should "guardmgr setup error" be its own type in tor-guardmgr?

    #[error("Error setting up the guard manager")]

    GuardMgrSetup(#[source] tor_guardmgr::GuardMgrError),

    /// Error setting up the guard manager

    // TODO: should "vanguardmgr setup error" be its own type in tor-guardmgr?

    #[cfg(all(

        feature = "vanguards",

        any(feature = "onion-service-client", feature = "onion-service-service")

    ))]

    #[error("Error setting up the vanguard manager")]

    VanguardMgrSetup(#[source] tor_guardmgr::VanguardMgrError),

    /// Error setting up the circuit manager

    // TODO: should "circmgr setup error" be its own type in tor-circmgr?

    #[error("Error setting up the circuit manager")]

    CircMgrSetup(#[source] tor_circmgr::Error),

    /// Error setting up the bridge descriptor manager

    #[error("Error setting up the bridge descriptor manager")]

    #[cfg(feature = "bridge-client")]

    BridgeDescMgrSetup(#[from] tor_dirmgr::bridgedesc::StartupError),

    /// Error setting up the directory manager

    // TODO: should "dirmgr setup error" be its own type in tor-dirmgr?

    #[error("Error setting up the directory manager")]

    DirMgrSetup(#[source] tor_dirmgr::Error),

    /// Error setting up the state manager.

    #[error("Error setting up the persistent state manager")]

    StateMgrSetup(#[source] tor_persist::Error),

    /// Error setting up the hidden service client connector.

    #[error("Error setting up the hidden service client connector")]

    #[cfg(feature = "onion-service-client")]

    HsClientConnectorSetup(#[from] tor_hsclient::StartupError),

    /// Error setting up onion service.

    #[cfg(feature= "onion-service-service")]

    #[error("Error setting up onion service")]

    OnionServiceSetup(#[source] tor_hsservice::StartupError),

    /// Failed to obtain exit circuit

    #[error("Failed to obtain exit circuit for ports {exit_ports}")]

    ObtainExitCircuit {

        /// The ports that we wanted a circuit for.

        exit_ports: Sensitive<TargetPorts>,

        /// What went wrong

        #[source]

        cause: tor_circmgr::Error,

    },

    /// Failed to obtain hidden service circuit

    #[cfg(feature = "onion-service-client")]

    #[error("Failed to obtain hidden service circuit to {}", hsid.display_redacted())]

    ObtainHsCircuit {

        /// The service we were trying to connect to

        hsid: HsId,

        /// What went wrong

        #[source]

        cause: tor_hsclient::ConnError,

    },

    /// Directory manager was unable to bootstrap a working directory.

    #[error("Unable to bootstrap a working directory")]

    DirMgrBootstrap(#[source] tor_dirmgr::Error),

    /// A protocol error while launching a stream

    #[error("Protocol error while launching a {kind} stream")]

    StreamFailed {

        /// What kind of stream we were trying to launch.

        kind: &'static str,

        /// The error that occurred.

        #[source]

        cause: tor_circmgr::Error

    },

    /// An error while interfacing with the persistent data layer.

    #[error("Error while trying to access persistent state")]

    StateAccess(#[source] tor_persist::Error),

    /// We asked an exit to do something, and waited too long for an answer.

    #[error("Timed out while waiting for answer from exit")]

    ExitTimeout,

    /// Onion services are not compiled in, but we were asked to connect to one.

    #[error("Rejecting .onion address; feature onion-service-client not compiled in")]

    OnionAddressNotSupported,

    /// Onion services are not enabled, but we were asked to connect to one.

    ///

    /// This error occurs when Arti is built with onion service support, but

    /// onion services are disabled via our stream preferences.

    ///

    /// To enable onion services, set `allow_onion_addrs` to `true` in the

    /// `address_filter` configuration section.  Alternatively, set

    /// `connect_to_onion_services` in your `StreamPrefs` object.

    #[cfg(feature = "onion-service-client")]

    #[error("Rejecting .onion address; allow_onion_addrs disabled in stream preferences")]

    OnionAddressDisabled,

    /// Error when trying to find the IP address of a hidden service

    #[error("A .onion address cannot be resolved to an IP address")]

    OnionAddressResolveRequest,

    /// Unusable target address.

    ///

    /// `TorAddrError::InvalidHostname` should not appear here;

    /// use `ErrorDetail::InvalidHostname` instead.

    // TODO this is a violation of the "make invalid states unrepresentable" principle,

    // but maybe that doesn't matter too much here?

    #[error("Could not parse target address")]

    Address(crate::address::TorAddrError),

    /// Hostname not valid.

    #[error("Rejecting hostname as invalid")]

    InvalidHostname,

    /// Address was local, and we don't permit connecting to those over Tor.

    #[error("Cannot connect to a local-only address without enabling allow_local_addrs")]

    LocalAddress,

    /// Building configuration for the client failed.

    #[error("Problem with configuration")]

    Configuration(#[from] tor_config::ConfigBuildError),

    /// Unable to change configuration.

    #[error("Unable to change configuration")]

    Reconfigure(#[from] tor_config::ReconfigureError),

    /// Problem creating or launching a pluggable transport.

    #[cfg(feature="pt-client")]

    #[error("Problem with a pluggable transport")]

    PluggableTransport(#[from] tor_ptmgr::err::PtError),

    /// We encountered a problem while inspecting or creating a directory.

    #[error("Problem accessing filesystem")]

    FsMistrust(#[from] fs_mistrust::Error),

    /// Unable to spawn task

    #[error("Unable to spawn {spawning}")]

    Spawn {

        /// What we were trying to spawn.

        spawning: &'static str,

        /// What happened when we tried to spawn it.

        #[source]

        cause: Arc<SpawnError>

    },

    /// Attempted to use an unbootstrapped `TorClient` for something that

    /// requires bootstrapping to have completed.

    #[error("Cannot {action} with unbootstrapped client")]

    BootstrapRequired {

        /// What we were trying to do that required bootstrapping.

        action: &'static str

    },

    /// Attempted to use a `TorClient` for something when it did not

    /// have a valid directory.

    #[error("Tried to {action} without a valid directory")]

    NoDir {

        /// The underlying error.

        #[source]

        error: tor_netdir::Error,

        /// What we were trying to do that needed a directory.

        action: &'static str,

    },

    /// A key store access failed.

    #[error("Error while trying to access a key store")]

    Keystore(#[from] tor_keymgr::Error),

    /// Attempted to use a `TorClient` for something that

    /// requires the keystore to be enabled in the configuration.

    #[error("Cannot {action} without enabling storage.keystore")]

    KeystoreRequired {

        /// What we were trying to do that required the keystore to be enabled.

        action: &'static str

    },

    /// Encountered a malformed client specifier.

    #[error("Bad client specifier")]

    BadClientSpecifier(#[from] tor_keymgr::ArtiPathSyntaxError),

    /// We tried to parse an onion address, but we found that it was invalid.

    ///

    /// This error occurs if we are asked to connect to an invalid .onion address.

    #[cfg(feature = "onion-service-client")]

    #[error("Invalid onion address")]

    BadOnionAddress(#[from] tor_hscrypto::pk::HsIdParseError),

    /// We were unable to launch an onion service, even though we

    /// we are configured to be able to do so.

    #[cfg(feature= "onion-service-service")]

    #[error("Unable to launch onion service")]

    LaunchOnionService(#[source] tor_hsservice::StartupError),

    /// We found that at least one required protocol was missing.

    #[error("Arti is missing a required protocol feature")]

    MissingProtocol(#[source] tor_netdoc::doc::netstatus::ProtocolSupportError),

    /// A programming problem, either in our code or the code calling it.

    #[error("Programming problem")]

    Bug(#[from] tor_error::Bug),

}

// End of the use of $vis to refer to visibility according to `error_detail`

}

#[cfg(feature = "error_detail")]

impl Error {

    /// Return the underlying error detail object for this error.

    ///

    /// In general, it's not a good idea to use this function.  Our

    /// `arti_client::ErrorDetail` objects are unstable, and matching on them is

    /// probably not the best way to achieve whatever you're trying to do.

    /// Instead, we recommend using  the [`kind`](`tor_error::HasKind::kind`)

    /// trait method if your program needs to distinguish among different types

    /// of errors.

    ///

    /// (If the above function don't meet your needs, please let us know!)

    ///

    /// This function is only available when `arti-client` is built with the

    /// `error_detail` feature.  Using this function will void your semver

    /// guarantees.

}

impl Error {

    /// Consume this error and return the underlying error detail object.

}

impl ErrorDetail {

    /// Construct a new `Error` from a `SpawnError`.

}

impl Display for Error {

}

impl tor_error::HasKind for Error {

}

impl tor_error::HasKind for ErrorDetail {

        use ErrorDetail as E;

        use ErrorKind as EK;

            #[cfg(feature = "onion-service-client")]

            #[cfg(all(

                feature = "vanguards",

                any(feature = "onion-service-client", feature = "onion-service-service")

            ))]

            #[cfg(feature = "bridge-client")]

            #[cfg(feature = "onion-service-client")]

            #[cfg(feature = "onion-service-service")]

            #[cfg(feature = "pt-client")]

            #[cfg(feature = "onion-service-client")]

            #[cfg(feature = "onion-service-client")]

            #[cfg(feature = "onion-service-service")]

        }

}

impl From<TorAddrError> for Error {

}

impl From<tor_keymgr::Error> for Error {

}

impl From<TorAddrError> for ErrorDetail {

        use ErrorDetail as E;

        use TorAddrError as TAE;

        }

}

/// Verbose information about an error, meant to provide detail or justification

/// for user-facing errors, rather than the normal short message for

/// developer-facing errors.

///

/// User-facing code may attempt to produce this by calling [`Error::hint`].

/// Not all errors may wish to provide verbose messages. `Some(ErrorHint)` will be

/// returned if hinting is supported for the error. Err(()) will be returned otherwise.

/// Which errors support hinting, and the hint content, have no SemVer warranty and may

/// change in patch versions without warning. Callers should handle both cases,

/// falling back on the original error message in case of Err.

///

/// Since the internal machinery for constructing and displaying hints may change over time,

/// no data members are currently exposed. In the future we may wish to offer an unstable

/// API locked behind a feature, like we do with ErrorDetail.

#[derive(Clone, Debug)]

pub struct ErrorHint<'a> {

    /// The pieces of the message to display to the user

    inner: ErrorHintInner<'a>,

}

/// An inner enumeration, describing different kinds of error hint that we know how to give.

#[derive(Clone, Debug)]

enum ErrorHintInner<'a> {

    /// There is a misconfigured filesystem permission, reported by `fs-mistrust`.

    ///

    /// Tell the user to make their file more private, or to disable `fs-mistrust`.

    BadPermission {

        /// The location of the file.

        filename: &'a std::path::Path,

        /// The access bits set on the file.

        bits: u32,

        /// The access bits that, according to fs-mistrust, should not be set.

        badbits: u32,

    },

    /// At least one required protocol was missing.

    MissingProtocols {

        /// The list of missing required protocols

        required: &'a tor_protover::Protocols,

    },

}

// TODO: Perhaps we want to lower this logic to fs_mistrust crate, and have a

// separate `ErrorHint` type for each crate that can originate a hint.  But I'd

// rather _not_ have that turn into something that forces us to give a Hint for

// every intermediate crate.

impl<'a> Display for ErrorHint<'a> {

        use fs_mistrust::anon_home::PathExt as _;

            ErrorHintInner::BadPermission {

            } => {

                    "Permissions are set too permissively on {}: currently {}",

                        "* Untrusted users could modify its contents and override our behavior.",

                    "You can fix this by further restricting the permissions of your filesystem, using:\n\

                         chmod {} {}",

                    "You can suppress this message by setting storage.permissions.dangerously_trust_everyone=true,\n\

                    or setting ARTI_FS_DISABLE_PERMISSION_CHECKS=yes in your environment."

            }

                    "The consensus directory says that we need to support certain protocols which we do not implement."

                    "The best solution is to upgrade to a more recent version of Arti."

            }

        }

}

impl Error {

    /// Return a hint object explaining how to solve this error, if we have one.

    ///

    /// Most errors won't have obvious hints, but some do.  For the ones that

    /// do, we can return an [`ErrorHint`].

    ///

    /// Right now, `ErrorHint` is completely opaque: the only supported option

    /// is to format it for human consumption.

}

#[cfg(test)]

mod test {

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

    #![allow(clippy::bool_assert_comparison)]

    #![allow(clippy::clone_on_copy)]

    #![allow(clippy::dbg_macro)]

    #![allow(clippy::mixed_attributes_style)]

    #![allow(clippy::print_stderr)]

    #![allow(clippy::print_stdout)]

    #![allow(clippy::single_char_pattern)]

    #![allow(clippy::unwrap_used)]

    #![allow(clippy::unchecked_time_subtraction)]

    #![allow(clippy::useless_vec)]

    #![allow(clippy::needless_pass_by_value)]

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

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

    use super::*;

    /// This code makes sure that our errors implement all the traits we want.

    #[test]

    fn traits_ok() {

        // I had intended to use `assert_impl`, but that crate can't check whether

        // a type is 'static.

        fn assert<

            T: Send + Sync + Clone + std::fmt::Debug + Display + std::error::Error + 'static,

        >() {

        }

        fn check() {

            assert::<Error>();

            assert::<ErrorDetail>();

        }

        check(); // doesn't do anything, but avoids "unused function" warnings.

    }

}