Struct HashMap

pub struct HashMap<K: Copy + Default, V: Copy + Default> { /* private fields */ }

A hashmap that exposes an idiomatic Rust interface to an underlying BPF hashmap.

Implementations

impl<K: Copy + Default, V: Copy + Default> HashMap<K, V>

pub fn with_capacity(entries: u32) -> Result<Self, Error>

Creates a new BPF hashmap with entries elements.

Arguments

• entries - The number of elements in the hashmap.

Example

use bpf_api::collections::HashMap;

let hashmap = HashMap::<u32, u32>::with_capacity(10).expect("Failed to create hashmap");

pub fn get(&self, key: K) -> Result<V, Error>

Retrieves the value for a given key.

Arguments

• key - The key associated with the value to be retrieved.

Example

use bpf_api::collections::HashMap;

let hashmap = HashMap::<u32, u32>::with_capacity(10).expect("Failed to create hashmap");
assert!(matches!(hashmap.get(1000), Err(_)));

pub fn insert(&self, key: K, val: V) -> Result<(), Error>

Sets the value for a given key.

Arguments

• key - The key associated with the value to be set.
• value - The new value.

Example

use bpf_api::collections::HashMap;

let hashmap = HashMap::<u32, u32>::with_capacity(10).expect("Failed to create hashmap");
assert!(matches!(hashmap.get(1000), Err(_)));
assert!(matches!(hashmap.insert(1000, 0xdeadbeef), Ok(_)));
assert!(matches!(hashmap.get(1000), Ok(0xdeadbeef)));

pub fn remove(&self, key: K) -> Result<(), Error>

Deletes an entry from the hash map given a key.

Arguments

• key - The key of the entry to be deleted.

Example

use bpf_api::collections::HashMap;

let hashmap = HashMap::<u32, u32>::with_capacity(10).expect("Failed to create hashmap");
assert!(matches!(hashmap.get(1000), Err(_)));
assert!(matches!(hashmap.insert(1000, 0xdeadbeef), Ok(_)));
assert!(matches!(hashmap.get(1000), Ok(0xdeadbeef)));
assert!(matches!(hashmap.remove(1000), Ok(_)));
assert!(matches!(hashmap.remove(1000), Err(_)));

pub fn get_identifier(&self) -> u32

Retrieve the BPF identifier for this map. This is the underlying file descriptor that’s used in eBPF programs.

Example

use bpf_api::collections::HashMap;

let hashmap = HashMap::<u32, u32>::with_capacity(10).expect("Failed to create hashmap");
hashmap.get_identifier();