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|
use std::sync::{atomic::AtomicU64, Arc};
use async_trait::async_trait;
use tedge_api::{
plugin::{Handle, Plugin},
PluginError,
};
use crate::{
error::Error,
guard::Guard,
message::{
Copy, CopyError, CopyResult, MessageResult, OpenOptions, OpenOptionsError,
OpenOptionsResult, Rename, RenameError, RenameResult,
},
};
#[derive(Debug)]
pub struct FdManPlugin {
max_fds: u64,
currently_held_count: Arc<AtomicU64>,
}
impl FdManPlugin {
pub fn new(max_fds: u64) -> Self {
Self {
max_fds,
currently_held_count: Arc::new(AtomicU64::from(0)),
}
}
fn aquire_handles(&self, count: u64) -> Result<Guard, Error> {
let old_value = self
.currently_held_count
.fetch_add(count, std::sync::atomic::Ordering::SeqCst);
if old_value >= self.max_fds {
self.currently_held_count
.fetch_sub(count, std::sync::atomic::Ordering::SeqCst);
Err(Error::InsufficientHandles {
required: count,
received: (old_value - self.max_fds),
})
} else {
Ok(Guard::new(count, self.currently_held_count.clone()))
}
}
}
impl tedge_api::plugin::PluginDeclaration for FdManPlugin {
type HandledMessages = (OpenOptions,);
}
#[async_trait]
impl Plugin for FdManPlugin {}
#[async_trait::async_trait]
impl Handle<OpenOptions> for FdManPlugin {
async fn handle_message(
&self,
message: OpenOptions,
sender: tedge_api::address::ReplySenderFor<OpenOptions>,
) -> Result<(), PluginError> {
async fn inner(guard: Guard, message: OpenOptions) -> OpenOptionsResult {
let file_result = message
.as_std()
.open(message.path())
.map(|file| crate::file::FileGuard::new(file, guard))
.map_err(Error::from)
.map_err(OpenOptionsError::from);
OpenOptionsResult::new(message, file_result)
}
HandleWithGuard::new(self, message, sender)
.with_handles(1, inner)
.await
}
}
#[async_trait::async_trait]
impl Handle<Copy> for FdManPlugin {
async fn handle_message(
&self,
message: Copy,
sender: tedge_api::address::ReplySenderFor<Copy>,
) -> Result<(), PluginError> {
async fn inner(guard: Guard, message: Copy) -> CopyResult {
let copy_res = tokio::fs::copy(message.src(), message.dst())
.await
.map_err(Error::from)
.map_err(CopyError::from);
drop(guard); // We can now drop the guard, as the copy process is done
CopyResult::new(message, copy_res)
}
HandleWithGuard::new(self, message, sender)
.with_handles(2, inner)
.await
}
}
#[async_trait::async_trait]
impl Handle<Rename> for FdManPlugin {
async fn handle_message(
&self,
message: Rename,
sender: tedge_api::address::ReplySenderFor<Rename>,
) -> Result<(), PluginError> {
async fn inner(guard: Guard, message: Rename) -> RenameResult {
let rename_res = tokio::fs::rename(message.src(), message.dst())
.await
.map_err(Error::from)
.map_err(RenameError::from);
drop(guard); // We can now drop the guard, as the copy process is done
RenameResult::new(message, rename_res)
}
HandleWithGuard::new(self, message, sender)
.with_handles(2, inner)
.await
}
}
struct HandleWithGuard<'a, M, Res, RT, Err>
where
M: tedge_api::Message + tedge_api::message::AcceptsReplies<Reply = Res>,
Res: tedge_api::Message + MessageResult<M, RT, Err>,
Err: From<Error> + std::error::Error,
{
plugin: &'a FdManPlugin,
message: M,
sender: tedge_api::address::ReplySenderFor<M>,
_pd_res: std::marker::PhantomData<Res>,
_pd_rt: std::marker::PhantomData<RT>,
_pd_err: std::marker::PhantomData<Err>,
}
impl<'a, M, Res, RT, Err> HandleWithGuard<'a, M, Res, RT, Err>
where
M: tedge_api::Message + tedge_api::message::AcceptsReplies<Reply = Res>,
Res: tedge_api::Message + MessageResult<M, RT, Err>,
Err: From<Error> + std::error::Error,
{
fn new(
plugin: &'a FdManPlugin,
message: M,
sender: tedge_api::address::ReplySenderFor<M>,
) -> Self {
Self {
plugin,
message,
sender,
_pd_res: std::marker::PhantomData,
_pd_rt: std::marker::PhantomData,
_pd_err: std::marker::PhantomData,
}
}
async fn with_handles<F, Fut>(self, handles_to_aquire: u64, fun: F) -> Result<(), PluginError>
where
F: Fn(Guard, M) -> Fut,
Fut: std::future::Future<Output = Res>,
{
match self.plugin.aquire_handles(handles_to_aquire) {
Ok(guard) => {
let res: Res = fun(guard, self.message).await;
self.sender
.reply(res)
.map_err(|_| Error::SendingReply)
.map_err(PluginError::from)
}
Err(err @ Error::InsufficientHandles { .. }) => self
.sender
.reply(Res::new(self.message, Err(Err::from(err))))
.map_err(|_| Error::SendingReply)
.map_err(PluginError::from),
Err(other) => Err(PluginError::from(other)),
}
}
}
|
