Struct ProviderStreamControl 

#[repr(C)]
pub struct ProviderStreamControl {
    pub is_cancelled: extern "C" fn(user_data: *mut c_void, chunk_kind: u32) -> i32,
    pub wait_cancelled_ms: extern "C" fn(user_data: *mut c_void, timeout_ms: u32) -> i32,
    pub user_data: *mut c_void,
}

The plugin’s synchronous control surface over the host, passed to a v2 streaming request fn.

The fields are plain fn pointers plus an opaque pointer, so the struct is Copy and needs no deallocation. The host owns it for the duration of the request and it must not be retained.

is_cancelled is the cheap check a plugin’s request loop makes between chunks (poll it, do not block on it). wait_cancelled_ms is the blocking variant for a plugin whose loop is not able to poll — an SSE frame read, a sleep between retries — and it must return promptly on cancellation rather than waiting out the full timeout.

// Inside a v2 request fn, before handing a delta to `emit`:
if control.is_cancelled(control.user_data, ProviderChunkKind::Content as u32) != 0 {
    return 1; // stop producing; the host is already gone
}

Fields

is_cancelled: extern "C" fn(user_data: *mut c_void, chunk_kind: u32) -> i32

is_cancelled(control_user_data, chunk_kind: u32) -> i32. Nonzero when the caller has gone away. chunk_kind lets the host still admit the structural chunks a partial message needs: pass ProviderChunkKind::Content (0) for model output and ProviderChunkKind::Structural (1) otherwise. Never blocking, never frees anything.

wait_cancelled_ms: extern "C" fn(user_data: *mut c_void, timeout_ms: u32) -> i32

wait_cancelled_ms(control_user_data, timeout_ms) -> i32. Blocks up to timeout_ms waiting for cancellation, returning nonzero the moment it is observed. timeout_ms == 0 is a non-blocking poll (same as is_cancelled with ProviderChunkKind::Content). Safe to call from the request thread: it only touches the host’s cancellation latch, which is always present in the snapshot and never holds another lock.

user_data: *mut c_void

Host-owned opaque handle, passed back unchanged to both fields above.

Trait Implementations

impl Clone for ProviderStreamControl

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ProviderStreamControl