terminal/snapshot: setup the snapshot main

src/terminal/main.zig

@@ -21,6 +21,7 @@ pub const modes = @import("modes.zig");
 pub const page = @import("page.zig");
 pub const parse_table = @import("parse_table.zig");
 pub const search = @import("search.zig");
+pub const snapshot = @import("snapshot/main.zig");
 pub const sgr = @import("sgr.zig");
 pub const size = @import("size.zig");
 pub const size_report = @import("size_report.zig");

src/terminal/snapshot/main.zig

@@ -0,0 +1,50 @@
+//! Terminal snapshot binary representation and codecs.
+//!
+//! This is NOT a full transport-ready format to implement generic replay
+//! software such as multiplexers, recorders (e.g. asciinema), etc. The goal
+//! of this package is to provide a documented, binary-compatible representation
+//! for a terminal state.
+//!
+//! We call this a "snapshot." The snapshot is purposely laid out in a way
+//! that prioritizes making a terminal functional as quickly as possible.
+//! To do that, it sends down the terminal state, viewport, etc. followed
+//! by a "READY" event. At the READY state, the terminal is functional and
+//! could in theory begin processing pty bytes. After the READY state the
+//! binary format continues transmitting history and extra assets such as
+//! images and so on.
+//!
+//! ## Snapshot Format
+//!
+//! This documents snapshot format 0. Version 0 is the work-in-progress
+//! format that we intended to continue to break until we can promise
+//! binary compatibility.
+//!
+//! A snapshot is one envelope followed by a sequence of records. The envelope
+//! occurs once at byte zero. Every record is independently framed as a fixed
+//! header followed by the number of payload bytes declared by that header.
+//!
+//! ```text
+//! +------------------+
+//! | Envelope         |
+//! +------------------+
+//! | Record 1 header  |
+//! +------------------+
+//! | Record 1 payload |
+//! +------------------+
+//! | Record 2 header  |
+//! +------------------+
+//! | Record 2 payload |
+//! +------------------+
+//! | ...              |
+//! +------------------+
+//! ```
+//!
+//! Records have a strict order: TERMINAL, the primary SCREEN and its
+//! PAGE records, an optional alternate SCREEN and its PAGE records,
+//! CONTINUATION, READY, and FINISH.
+
+pub const envelope = @import("envelope.zig");
+pub const hyperlink = @import("hyperlink.zig");
+pub const page = @import("page.zig");
+pub const record = @import("record.zig");
+pub const style = @import("style.zig");