//! The volume-manager protocol (docs/file-system-development/storage-architecture.md):
//! what a filesystem service says to the volume manager over
//! `/protocol/volume-manager`. Defined through the envelope, so every packet
//! begins with the folded `Header`.
//!
//! One verb. A filesystem the volume manager spawned announces itself with the
//! volume id it was given as argv[1] (folded into `Header.target`); the reply
//! carries that volume's block channel — already range-confined to the
//! filesystem's badge — as the call's returned capability. The filesystem never
//! finds its storage by name and never sees the whole device; establishment is
//! by lineage, exactly as a driver reaches its controller (communication.md
//! "Establishment: two planes"). No channel in the reply means the volume is not
//! ready yet — retryable, never a verdict.

const envelope = @import("envelope");

pub const version: u16 = 1;

/// The filesystem's handshake. Carries only its protocol version; the volume it
/// serves is `Header.target`, and the block channel it needs comes back as the
/// reply's capability.
pub const Hello = extern struct {
    version: u16 = version,
    _padding: u16 = 0,
};

pub const Protocol = envelope.Define(.{
    .name = "volume-manager",
    .version = 1,
    .operations = &.{
        .{ .name = "hello", .request = Hello },
    },
});

pub const Operation = Protocol.Operation;
pub const message_maximum: usize = Protocol.message_maximum;