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use std::{
convert::TryFrom,
marker::PhantomData,
mem,
ops::{Deref, DerefMut},
};
use crate::{
generated::bpf_map_type::BPF_MAP_TYPE_STACK,
maps::{Map, MapError, MapRef, MapRefMut},
sys::{bpf_map_lookup_and_delete_elem, bpf_map_update_elem},
Pod,
};
#[doc(alias = "BPF_MAP_TYPE_STACK")]
pub struct Stack<T: Deref<Target = Map>, V: Pod> {
inner: T,
_v: PhantomData<V>,
}
impl<T: Deref<Target = Map>, V: Pod> Stack<T, V> {
fn new(map: T) -> Result<Stack<T, V>, MapError> {
let map_type = map.obj.def.map_type;
if map_type != BPF_MAP_TYPE_STACK as u32 {
return Err(MapError::InvalidMapType {
map_type: map_type as u32,
});
}
let expected = 0;
let size = map.obj.def.key_size as usize;
if size != expected {
return Err(MapError::InvalidKeySize { size, expected });
}
let expected = mem::size_of::<V>();
let size = map.obj.def.value_size as usize;
if size != expected {
return Err(MapError::InvalidValueSize { size, expected });
}
let _fd = map.fd_or_err()?;
Ok(Stack {
inner: map,
_v: PhantomData,
})
}
pub fn capacity(&self) -> u32 {
self.inner.obj.def.max_entries
}
}
impl<T: Deref<Target = Map> + DerefMut<Target = Map>, V: Pod> Stack<T, V> {
pub fn pop(&mut self, flags: u64) -> Result<V, MapError> {
let fd = self.inner.fd_or_err()?;
let value = bpf_map_lookup_and_delete_elem::<u32, _>(fd, None, flags).map_err(
|(code, io_error)| MapError::SyscallError {
call: "bpf_map_lookup_and_delete_elem".to_owned(),
code,
io_error,
},
)?;
value.ok_or(MapError::ElementNotFound)
}
pub fn push(&mut self, value: V, flags: u64) -> Result<(), MapError> {
let fd = self.inner.fd_or_err()?;
bpf_map_update_elem(fd, &0, &value, flags).map_err(|(code, io_error)| {
MapError::SyscallError {
call: "bpf_map_update_elem".to_owned(),
code,
io_error,
}
})?;
Ok(())
}
}
impl<V: Pod> TryFrom<MapRef> for Stack<MapRef, V> {
type Error = MapError;
fn try_from(a: MapRef) -> Result<Stack<MapRef, V>, MapError> {
Stack::new(a)
}
}
impl<V: Pod> TryFrom<MapRefMut> for Stack<MapRefMut, V> {
type Error = MapError;
fn try_from(a: MapRefMut) -> Result<Stack<MapRefMut, V>, MapError> {
Stack::new(a)
}
}