age-encryption/dist/format.js

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import { base64nopad } from "@scure/base";
import { LineReader, flatten, prepend } from "./io.js";
/**
 * A stanza is a section of an age header. This is part of the low-level
 * {@link Recipient} and {@link Identity} APIs.
 */
export class Stanza {
    /**
     * All space-separated arguments on the first line of the stanza.
     * Each argument is a string that does not contain spaces.
     * The first argument is often a recipient type, which should look like
     * `example.com/...` to avoid collisions.
     */
    args;
    /**
     * The raw body of the stanza. This is automatically base64-encoded and
     * split into lines of 48 characters each.
     */
    body;
    constructor(args, body) {
        this.args = args;
        this.body = body;
    }
}
async function parseNextStanza(hdr) {
    const argsLine = await hdr.readLine();
    if (argsLine === null) {
        throw Error("invalid stanza");
    }
    const args = argsLine.split(" ");
    if (args.length < 2 || args.shift() !== "->") {
        return { next: argsLine };
    }
    for (const arg of args) {
        if (arg.length === 0) {
            throw Error("invalid stanza");
        }
    }
    const bodyLines = [];
    for (;;) {
        const nextLine = await hdr.readLine();
        if (nextLine === null) {
            throw Error("invalid stanza");
        }
        const line = base64nopad.decode(nextLine);
        if (line.length > 48) {
            throw Error("invalid stanza");
        }
        bodyLines.push(line);
        if (line.length < 48) {
            break;
        }
    }
    const body = flatten(bodyLines);
    return { s: new Stanza(args, body) };
}
export async function parseHeader(header) {
    const hdr = new LineReader(header);
    const versionLine = await hdr.readLine();
    if (versionLine !== "age-encryption.org/v1") {
        throw Error("invalid version " + (versionLine ?? "line"));
    }
    const stanzas = [];
    for (;;) {
        const { s, next: macLine } = await parseNextStanza(hdr);
        if (s !== undefined) {
            stanzas.push(s);
            continue;
        }
        if (!macLine.startsWith("--- ")) {
            throw Error("invalid header");
        }
        const MAC = base64nopad.decode(macLine.slice(4));
        const { rest, transcript } = hdr.close();
        const headerNoMAC = transcript.slice(0, transcript.length - 1 - macLine.length + 3);
        return { stanzas, headerNoMAC, MAC, headerSize: transcript.length, rest: prepend(header, rest) };
    }
}
export function encodeHeaderNoMAC(recipients) {
    const lines = [];
    lines.push("age-encryption.org/v1\n");
    for (const s of recipients) {
        lines.push("-> " + s.args.join(" ") + "\n");
        for (let i = 0; i < s.body.length; i += 48) {
            let end = i + 48;
            if (end > s.body.length)
                end = s.body.length;
            lines.push(base64nopad.encode(s.body.subarray(i, end)) + "\n");
        }
        if (s.body.length % 48 === 0)
            lines.push("\n");
    }
    lines.push("---");
    return new TextEncoder().encode(lines.join(""));
}
export function encodeHeader(recipients, MAC) {
    return flatten([
        encodeHeaderNoMAC(recipients),
        new TextEncoder().encode(" " + base64nopad.encode(MAC) + "\n")
    ]);
}