Struct HostFunctions 

pub struct HostFunctions;

Host functions that plugins can import and call.

These functions are implemented by the Orbis runtime and available to all plugins. Plugins should declare these in an unsafe extern "C" block:

unsafe extern "C" {
    fn log(level: i32, ptr: i32, len: i32);
    fn state_get(key_ptr: i32, key_len: i32) -> i32;
    fn state_set(key_ptr: i32, key_len: i32, value_ptr: i32, value_len: i32) -> i32;
    fn state_remove(key_ptr: i32, key_len: i32) -> i32;
}

Implementations

impl HostFunctions

pub const LOG: &'static str = "log"

Log a message from the plugin.

Parameters

• level: Log level (0=ERROR, 1=WARN, 2=INFO, 3=DEBUG, 4=TRACE)
• ptr: Pointer to UTF-8 message bytes (as i32 in WASM)
• len: Length of message in bytes

Example

unsafe extern "C" {
    fn log(level: i32, ptr: i32, len: i32);
}

fn log_info(msg: &str) {
    unsafe {
        log(2, msg.as_ptr() as i32, msg.len() as i32);
    }
}

pub const STATE_GET: &'static str = "state_get"

Get a value from plugin state.

Parameters

• key_ptr: Pointer to UTF-8 key bytes (as i32 in WASM)
• key_len: Length of key in bytes

Returns

Pointer to JSON-serialized value (with 4-byte length prefix), or 0 if key not found.

Example

unsafe extern "C" {
    fn state_get(key_ptr: i32, key_len: i32) -> i32;
}

fn get_counter() -> Option<i64> {
    let key = "counter";
    let ptr = unsafe {
        state_get(key.as_ptr() as i32, key.len() as i32)
    };
     
    if ptr == 0 {
        return None;
    }
     
    // Read length and data, deserialize JSON
    // ...
    Some(0)
}

pub const STATE_SET: &'static str = "state_set"

Set a value in plugin state.

Parameters

• key_ptr: Pointer to UTF-8 key bytes (as i32 in WASM)
• key_len: Length of key in bytes
• value_ptr: Pointer to JSON-serialized value bytes (as i32 in WASM)
• value_len: Length of value in bytes

Returns

1 on success, 0 on failure.

Example

unsafe extern "C" {
    fn state_set(key_ptr: i32, key_len: i32, value_ptr: i32, value_len: i32) -> i32;
}

fn set_counter(value: i64) -> bool {
    let key = "counter";
    let value_json = serde_json::to_string(&value).unwrap();
     
    let result = unsafe {
        state_set(
            key.as_ptr() as i32,
            key.len() as i32,
            value_json.as_ptr() as i32,
            value_json.len() as i32,
        )
    };
     
    result == 1
}

pub const STATE_REMOVE: &'static str = "state_remove"

Remove a value from plugin state.

Parameters

• key_ptr: Pointer to UTF-8 key bytes
• key_len: Length of key in bytes

Returns

1 on success, 0 on failure.

Example

unsafe extern "C" {
    fn state_remove(key_ptr: i32, key_len: i32) -> i32;
}

fn clear_counter() -> bool {
    let key = "counter";
    let result = unsafe {
        state_remove(key.as_ptr() as i32, key.len() as i32)
    };
     
    result == 1
}