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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::{OpenOptions, OpenOptionsError, OpenOptionsResult},
};
#[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<FdHandles, 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(FdHandles(count))
}
}
}
struct FdHandles(u64);
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> {
let handles_to_aquire = 1;
match self.aquire_handles(handles_to_aquire) {
Ok(FdHandles(aquired_handles)) => {
if aquired_handles != handles_to_aquire {
let err = Error::InsufficientHandles {
required: handles_to_aquire,
received: aquired_handles,
};
return sender
.reply(OpenOptionsResult::new(
message,
Err(OpenOptionsError::from(err)),
))
.map_err(|_| Error::SendingReply)
.map_err(PluginError::from);
}
let file_result = message
.as_std()
.open(message.path())
.map(|file| {
crate::file::FileGuard::new(
file,
Guard::new(aquired_handles, self.currently_held_count.clone()),
)
})
.map_err(Error::from)
.map_err(OpenOptionsError::from);
let res = OpenOptionsResult::new(message, file_result);
sender
.reply(res)
.map_err(|_| Error::SendingReply)
.map_err(PluginError::from)
}
Err(err @ Error::InsufficientHandles { .. }) => sender
.reply(OpenOptionsResult::new(
message,
Err(OpenOptionsError::from(err)),
))
.map_err(|_| Error::SendingReply)
.map_err(PluginError::from),
Err(other) => Err(PluginError::from(other)),
}
}
}
|
