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Merged
jeromeludmann merged 1 commit into from
Apr 4, 2026
+87 −106
Merged

perf(core/parsers): optimize core parser #30

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10 changes: 6 additions & 4 deletions core/client.ts
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
import { type ClientError, type ErrorArgs, toClientError } from "./errors.ts";
import { EventEmitter, type EventEmitterOptions } from "./events.ts";
import { Hooks } from "./hooks.ts";
import { escapeTagValue, Parser, type Raw } from "./parsers.ts";
import { escapeTagValue, parseChunk, type Raw } from "./parsers.ts";
import { loadPlugins, type Plugin } from "./plugins.ts";
import {
type AnyCommand,
Expand Down Expand Up @@ -98,7 +98,7 @@ export class CoreClient<

private decoder = new TextDecoder();
private encoder = new TextEncoder();
private parser = new Parser();
private chunk = "";
private buffer: Uint8Array;

constructor(
Expand Down Expand Up @@ -211,9 +211,11 @@ export class CoreClient<
const chunks = await this.read(conn);
if (chunks === null) break;

const messageGenerator = this.parser.parseMessages(chunks);
const input = this.chunk ? this.chunk + chunks : chunks;
const [messages, remainder] = parseChunk(input);
this.chunk = remainder;

for (const msg of messageGenerator) {
for (const msg of messages) {
this.emit(`raw:${msg.command}`, msg);
}
}
Expand Down
70 changes: 39 additions & 31 deletions core/parsers.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -51,15 +51,20 @@ export type Raw = Message<string[]> & {

/** Parses an IRC prefix string (e.g. `nick!user@host`) into a {@link Source}. */
export function parseSource(prefix: string): Source {
const source = {} as Source;
const [name, user, host] = prefix.split(/[@!]+/);

source.name = name;
if (user !== undefined && host !== undefined) {
source.mask = { user, host };
const bangIdx = prefix.indexOf("!");
const atIdx = prefix.indexOf("@");

if (bangIdx !== -1 && atIdx > bangIdx) {
return {
name: prefix.slice(0, bangIdx),
mask: {
user: prefix.slice(bangIdx + 1, atIdx),
host: prefix.slice(atIdx + 1),
},
};
}

return source;
return { name: prefix };
}

const UNESCAPE_MAP: Record<string, string> = {
Expand Down Expand Up @@ -121,11 +126,15 @@ function parseMessage(raw: string): Raw {
msg.tags = {};
while (start < end) {
let pos = raw.indexOf(";", start);
if (pos === -1) pos = end;
const [key, rawValue] = raw.slice(start, pos).split("=");
msg.tags[key] = rawValue !== undefined
? unescapeTagValue(rawValue)
: undefined;
if (pos === -1 || pos > end) pos = end;
const eqIdx = raw.indexOf("=", start);
if (eqIdx !== -1 && eqIdx < pos) {
msg.tags[raw.slice(start, eqIdx)] = unescapeTagValue(
raw.slice(eqIdx + 1, pos),
);
} else {
msg.tags[raw.slice(start, pos)] = undefined;
}
start = pos + 1;
}
}
Expand Down Expand Up @@ -165,25 +174,24 @@ function parseMessage(raw: string): Raw {
return msg;
}

/** Stateful parser that handles incremental IRC message chunks split across TCP reads. */
export class Parser {
private chunk = "";
/**
* Parses raw IRC messages from `input` and returns parsed messages with any
* incomplete trailing chunk.
*
* `input` is a string of raw messages each ending with `\r\n`. If the last
* raw message does not end with `\r\n`, it is returned as the remainder to
* be prepended to the next call.
*/
export function parseChunk(input: string): [Raw[], string] {
const results: Raw[] = [];

/**
* Parses `chunks` of raw messages and provides a `Generator<Raw>`.
*
* `chunks` is a string of raw messages each ending with `\r\n`. If the last
* raw message of the `batch` does not end with `\r\n`, it means the message
* is not complete and will be temporarily stored in the `Parser` instance to
* be processed on the next call.
*/
*parseMessages(chunks: string): Generator<Raw> {
this.chunk += chunks;
const batch = this.chunk.split("\r\n");
this.chunk = batch.pop()!;

for (const raw of batch) {
yield parseMessage(raw);
}
let start = 0;
let end: number;

while ((end = input.indexOf("\r\n", start)) !== -1) {
results.push(parseMessage(input.slice(start, end)));
start = end + 2; // skip \r\n
}

return [results, start < input.length ? input.slice(start) : ""];
}
113 changes: 42 additions & 71 deletions core/parsers_test.ts
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Original file line number Diff line number Diff line change
@@ -1,59 +1,47 @@
import { assertEquals } from "@std/assert";
import { describe } from "../testing/helpers.ts";
import { escapeTagValue, Parser, unescapeTagValue } from "./parsers.ts";
import { escapeTagValue, parseChunk, unescapeTagValue } from "./parsers.ts";

describe("core/parsers", (test) => {
test("parse message without prefix", () => {
const parser = new Parser();
const [msgs] = parseChunk("PING :QimVSbibZg\r\n");

const msg = Array.from(parser.parseMessages("PING :QimVSbibZg\r\n"));

assertEquals(msg, [{
assertEquals(msgs, [{
command: "ping",
params: ["QimVSbibZg"],
}]);
});

test("parse message with server prefix", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages(
":serverhost NOTICE * :*** Looking up your hostname...\r\n",
),
const [msgs] = parseChunk(
":serverhost NOTICE * :*** Looking up your hostname...\r\n",
);

assertEquals(msg, [{
assertEquals(msgs, [{
command: "notice",
params: ["*", "*** Looking up your hostname..."],
source: { name: "serverhost" },
}]);
});

test("parse message with user prefix", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages(":someone!user@host JOIN #channel\r\n"),
const [msgs] = parseChunk(
":someone!user@host JOIN #channel\r\n",
);

assertEquals(msg, [{
assertEquals(msgs, [{
command: "join",
params: ["#channel"],
source: { mask: { host: "host", user: "user" }, name: "someone" },
}]);
});

test("parse message with tags", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages(
"@aaa=bbb;ccc;example.com/ddd=eee :someone!user@host JOIN #channel\r\n",
),
const [msgs] = parseChunk(
"@aaa=bbb;ccc;example.com/ddd=eee :someone!user@host JOIN #channel\r\n",
);

assertEquals(msg, [{
assertEquals(msgs, [{
command: "join",
params: ["#channel"],
source: { mask: { host: "host", user: "user" }, name: "someone" },
Expand All @@ -62,67 +50,51 @@ describe("core/parsers", (test) => {
});

test("parse message with tags but no source", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages("@time=2026-03-24T12:00:00Z PING :server\r\n"),
const [msgs] = parseChunk(
"@time=2026-03-24T12:00:00Z PING :server\r\n",
);

assertEquals(msg, [{
assertEquals(msgs, [{
command: "ping",
params: ["server"],
tags: { "time": "2026-03-24T12:00:00Z" },
}]);
});

test("parse message with empty tag value", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages("@key= :nick!u@h PRIVMSG #chan :text\r\n"),
const [msgs] = parseChunk(
"@key= :nick!u@h PRIVMSG #chan :text\r\n",
);

assertEquals(msg[0].tags, { "key": "" });
assertEquals(msgs[0].tags, { "key": "" });
});

test("parse message with multiple escaped tags", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages(
"@a=1\\s2;b=x\\:y;c :nick!u@h PRIVMSG #chan :text\r\n",
),
const [msgs] = parseChunk(
"@a=1\\s2;b=x\\:y;c :nick!u@h PRIVMSG #chan :text\r\n",
);

assertEquals(msg[0].tags, { "a": "1 2", "b": "x;y", "c": undefined });
assertEquals(msgs[0].tags, { "a": "1 2", "b": "x;y", "c": undefined });
});

test("parse tags split across chunks", () => {
const parser = new Parser();

const raw1 = Array.from(
parser.parseMessages("@time=2026-03-24T12:00:00Z :nick!u@h PRI"),
const [msgs1, chunk] = parseChunk(
"@time=2026-03-24T12:00:00Z :nick!u@h PRI",
);
assertEquals(raw1, []);
assertEquals(msgs1, []);

const raw2 = Array.from(
parser.parseMessages("VMSG #chan :hello\r\n"),
);
assertEquals(raw2.length, 1);
assertEquals(raw2[0].tags, { "time": "2026-03-24T12:00:00Z" });
assertEquals(raw2[0].params, ["#chan", "hello"]);
const [msgs2] = parseChunk(chunk + "VMSG #chan :hello\r\n");
assertEquals(msgs2.length, 1);
assertEquals(msgs2[0].tags, { "time": "2026-03-24T12:00:00Z" });
assertEquals(msgs2[0].params, ["#chan", "hello"]);
});

test("parse message with escaped tag values", () => {
const parser = new Parser();

const msg = Array.from(
parser.parseMessages(
"@msg=hello\\sworld\\:test\\\\end :nick!u@h PRIVMSG #chan :text\r\n",
),
const [msgs] = parseChunk(
"@msg=hello\\sworld\\:test\\\\end :nick!u@h PRIVMSG #chan :text\r\n",
);

assertEquals(msg[0].tags, { "msg": "hello world;test\\end" });
assertEquals(msgs[0].tags, { "msg": "hello world;test\\end" });
});

test("unescape tag values", () => {
Expand Down Expand Up @@ -150,16 +122,14 @@ describe("core/parsers", (test) => {
});

test("parse chunks of raw messages", () => {
const parser = new Parser();

const raw1 = Array.from(
parser.parseMessages(":serverhost NOTICE Auth :*** Looking up"),
const [raw1, chunk1] = parseChunk(
":serverhost NOTICE Auth :*** Looking up",
);
assertEquals(raw1, []);

const raw2 = Array.from(parser.parseMessages(
" your hostname...\r\n:serverhost 001 nick :Wel",
));
const [raw2, chunk2] = parseChunk(
chunk1 + " your hostname...\r\n:serverhost 001 nick :Wel",
);
assertEquals(raw2, [
{
source: { name: "serverhost" },
Expand All @@ -168,9 +138,9 @@ describe("core/parsers", (test) => {
},
]);

const raw3 = Array.from(parser.parseMessages(
"come to the server\r\n:nick!user@host JOIN #channel\r\n",
));
const [raw3, chunk3] = parseChunk(
chunk2 + "come to the server\r\n:nick!user@host JOIN #channel\r\n",
);
assertEquals(raw3, [
{
source: { name: "serverhost" },
Expand All @@ -183,10 +153,11 @@ describe("core/parsers", (test) => {
params: ["#channel"],
},
]);
assertEquals(chunk3, "");

const raw4 = Array.from(parser.parseMessages(
const [raw4] = parseChunk(
"PING serverhost\r\n:nick!user@host PRIVMSG #channel ::!@ ;\r\n",
));
);
assertEquals(raw4, [
{
command: "ping",
Expand Down
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