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use std::convert::{TryFrom, TryInto};
use std::pin::Pin;
use bytes::Bytes;
use futures::Future;
use log::debug;
use safecast::{TryCastFrom, TryCastInto};
use tc_error::*;
use tc_transact::{Transact, Transaction};
use tcgeneric::*;
use crate::cluster::Cluster;
use crate::object::InstanceExt;
use crate::route::Public;
use crate::scalar::*;
use crate::state::*;
use crate::txn::*;
mod hosted;
use hosted::Hosted;
const HYPOTHETICAL: PathLabel = path_label(&["transact", "hypothetical"]);
type ExeScope<'a> = crate::scalar::Scope<'a, State>;
pub struct Kernel {
actor: Actor,
hosted: Hosted,
}
impl Kernel {
pub fn new<I: IntoIterator<Item = InstanceExt<Cluster>>>(clusters: I) -> Self {
Self {
actor: Actor::new(Link::default().into()),
hosted: clusters.into_iter().collect(),
}
}
pub async fn get(&self, txn: &Txn, path: &[PathSegment], key: Value) -> TCResult<State> {
if path.is_empty() {
if key.is_none() {
Ok(Value::from(Bytes::copy_from_slice(self.actor.public_key().as_bytes())).into())
} else {
Err(TCError::method_not_allowed(TCPath::from(path)))
}
} else if let Some(class) = StateType::from_path(path) {
let err = format!("Cannot cast into {} from {}", class, key);
State::Scalar(Scalar::Value(key))
.into_type(class)
.ok_or_else(|| TCError::unsupported(err))
} else if let Some((suffix, cluster)) = self.hosted.get(path) {
debug!(
"GET {}: {} from cluster {}",
TCPath::from(suffix),
key,
cluster
);
cluster.get(&txn, suffix, key).await
} else if &path[0] == "error" && path.len() == 2 {
let message = String::try_cast_from(key, |v| {
TCError::bad_request("cannot cast into error message string from", v)
})?;
if let Some(err_type) = error_type(&path[1]) {
Err(TCError::new(err_type, message))
} else {
Err(TCError::not_found(TCPath::from(path)))
}
} else {
Err(TCError::not_found(TCPath::from(path)))
}
}
pub async fn put(
&self,
txn: &Txn,
path: &[PathSegment],
key: Value,
value: State,
) -> TCResult<()> {
if path.is_empty() {
if key.is_none() {
if Link::can_cast_from(&value) {
return Ok(());
}
}
Err(TCError::method_not_allowed(TCPath::from(path)))
} else if let Some(class) = StateType::from_path(path) {
Err(TCError::method_not_allowed(class))
} else if let Some((suffix, cluster)) = self.hosted.get(path) {
debug!(
"PUT {}: {} <- {} to cluster {}",
TCPath::from(suffix),
key,
value,
cluster
);
execute(txn, cluster, |txn, cluster| async move {
cluster.put(&txn, suffix, key, value).await
})
.await
} else {
Err(TCError::not_found(TCPath::from(path)))
}
}
pub async fn post(&self, txn: &Txn, path: &[PathSegment], data: State) -> TCResult<State> {
if path.is_empty() {
if Map::try_from(data)?.is_empty() {
Ok(State::default())
} else {
Err(TCError::method_not_allowed(TCPath::from(path)))
}
} else if path == &HYPOTHETICAL[..] {
let txn = txn.clone().claim(&self.actor, TCPathBuf::default()).await?;
let context = Map::<State>::default();
if PostOp::can_cast_from(&data) {
OpDef::call(data.opt_cast_into().unwrap(), txn, context).await
} else {
data.resolve(&ExeScope::new(&State::default(), context), &txn)
.await
}
} else if let Some((suffix, cluster)) = self.hosted.get(path) {
let params: Map<State> = data.try_into()?;
debug!(
"POST {}: {} to cluster {}",
TCPath::from(suffix),
params,
cluster
);
if suffix.is_empty() && params.is_empty() {
cluster.post(&txn, suffix, params).await
} else {
execute(txn, cluster, |txn, cluster| async move {
cluster.post(&txn, suffix, params).await
})
.await
}
} else {
Err(TCError::not_found(TCPath::from(path)))
}
}
}
fn execute<
'a,
R: Send,
Fut: Future<Output = TCResult<R>> + Send,
F: FnOnce(Txn, &'a InstanceExt<Cluster>) -> Fut + Send + 'a,
>(
txn: &'a Txn,
cluster: &'a InstanceExt<Cluster>,
handler: F,
) -> Pin<Box<dyn Future<Output = TCResult<R>> + Send + 'a>> {
Box::pin(async move {
if let Some(owner_link) = txn.owner() {
let link = txn.link(cluster.path().to_vec().into());
if txn.is_owner(cluster.path()) {
debug!("{} owns this transaction, no need to notify", link);
} else {
txn.put(owner_link.clone(), Value::default(), link.into())
.await?;
}
handler(txn.clone(), cluster).await
} else {
let txn = cluster.claim(&txn).await?;
let state = handler(txn.clone(), cluster).await?;
let owner = cluster.owner(txn.id()).await?;
owner.commit(&txn).await?;
cluster.commit(txn.id()).await;
Ok(state)
}
})
}
fn error_type(err_type: &Id) -> Option<ErrorType> {
match err_type.as_str() {
"bad_gateway" => Some(ErrorType::BadGateway),
"bad_request" => Some(ErrorType::BadRequest),
"conflict" => Some(ErrorType::Conflict),
"forbidden" => Some(ErrorType::Forbidden),
"internal" => Some(ErrorType::Internal),
"method_not_allowed" => Some(ErrorType::MethodNotAllowed),
"not_found" => Some(ErrorType::NotFound),
"not_implemented" => Some(ErrorType::NotImplemented),
"timeout" => Some(ErrorType::Timeout),
"unauthorized" => Some(ErrorType::Unauthorized),
_ => None,
}
}