114 lines
3.1 KiB
TypeScript
114 lines
3.1 KiB
TypeScript
/**
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* SDP offer / answer primitives.
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*
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* Pure async wrappers over the spec-standard
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* `pc.createOffer() → pc.setLocalDescription()` pattern (and inverse).
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* Every failure mode is translated into `DriveWebRtcError(PEER_HANDSHAKE_FAILED)`
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* with the original DOMException attached as `cause` so callers never see
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* raw browser errors leak past the package boundary.
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*/
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import {
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DRIVE_WEBRTC_CODES,
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DriveWebRtcError,
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} from "../../error-codes/error-codes.js";
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function throwIfAborted(signal: AbortSignal | undefined, where: string): void {
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if (signal?.aborted === true) {
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throw new DriveWebRtcError(
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DRIVE_WEBRTC_CODES.PEER_HANDSHAKE_FAILED,
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`${where} aborted`
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);
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}
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}
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function wrap(cause: unknown, message: string): DriveWebRtcError {
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return new DriveWebRtcError(
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DRIVE_WEBRTC_CODES.PEER_HANDSHAKE_FAILED,
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message,
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{ cause: cause as Error }
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);
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}
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/**
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* Create an SDP offer on `pc`, apply it as local description, and return it.
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*/
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export async function createOffer(
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pc: RTCPeerConnection,
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signal?: AbortSignal
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): Promise<RTCSessionDescriptionInit> {
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throwIfAborted(signal, "createOffer");
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let offer: RTCSessionDescriptionInit;
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try {
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offer = await pc.createOffer();
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} catch (cause) {
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throw wrap(cause, "RTCPeerConnection.createOffer failed");
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}
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throwIfAborted(signal, "createOffer");
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try {
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await pc.setLocalDescription(offer);
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} catch (cause) {
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throw wrap(
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cause,
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"RTCPeerConnection.setLocalDescription(offer) failed"
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);
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}
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return offer;
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}
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/**
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* Apply a remote offer to `pc`, create an answer, apply it as local
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* description, and return the answer.
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*/
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export async function handleOffer(
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pc: RTCPeerConnection,
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offer: RTCSessionDescriptionInit,
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signal?: AbortSignal
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): Promise<RTCSessionDescriptionInit> {
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throwIfAborted(signal, "handleOffer");
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try {
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await pc.setRemoteDescription(offer);
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} catch (cause) {
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throw wrap(
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cause,
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"RTCPeerConnection.setRemoteDescription(offer) failed"
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);
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}
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throwIfAborted(signal, "handleOffer");
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let answer: RTCSessionDescriptionInit;
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try {
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answer = await pc.createAnswer();
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} catch (cause) {
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throw wrap(cause, "RTCPeerConnection.createAnswer failed");
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}
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throwIfAborted(signal, "handleOffer");
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try {
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await pc.setLocalDescription(answer);
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} catch (cause) {
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throw wrap(
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cause,
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"RTCPeerConnection.setLocalDescription(answer) failed"
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);
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}
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return answer;
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}
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/**
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* Apply a remote answer to an outbound offer we already sent.
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*/
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export async function handleAnswer(
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pc: RTCPeerConnection,
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answer: RTCSessionDescriptionInit,
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signal?: AbortSignal
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): Promise<void> {
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throwIfAborted(signal, "handleAnswer");
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try {
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await pc.setRemoteDescription(answer);
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} catch (cause) {
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throw wrap(
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cause,
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"RTCPeerConnection.setRemoteDescription(answer) failed"
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);
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}
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}
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