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APP/nexus-remote/node_modules/webrtc-adapter/src/js/common_shim.js

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+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree.
+ */
+/* eslint-env node */
+'use strict';
+
+import SDPUtils from 'sdp';
+import * as utils from './utils';
+
+export function shimRTCIceCandidate(window) {
+  // foundation is arbitrarily chosen as an indicator for full support for
+  // https://w3c.github.io/webrtc-pc/#rtcicecandidate-interface
+  if (!window.RTCIceCandidate || (window.RTCIceCandidate && 'foundation' in
+      window.RTCIceCandidate.prototype)) {
+    return;
+  }
+
+  const NativeRTCIceCandidate = window.RTCIceCandidate;
+  window.RTCIceCandidate = function RTCIceCandidate(args) {
+    // Remove the a= which shouldn't be part of the candidate string.
+    if (typeof args === 'object' && args.candidate &&
+        args.candidate.indexOf('a=') === 0) {
+      args = JSON.parse(JSON.stringify(args));
+      args.candidate = args.candidate.substring(2);
+    }
+
+    if (args.candidate && args.candidate.length) {
+      // Augment the native candidate with the parsed fields.
+      const nativeCandidate = new NativeRTCIceCandidate(args);
+      const parsedCandidate = SDPUtils.parseCandidate(args.candidate);
+      for (const key in parsedCandidate) {
+        if (!(key in nativeCandidate)) {
+          Object.defineProperty(nativeCandidate, key,
+            {value: parsedCandidate[key]});
+        }
+      }
+
+      // Override serializer to not serialize the extra attributes.
+      nativeCandidate.toJSON = function toJSON() {
+        return {
+          candidate: nativeCandidate.candidate,
+          sdpMid: nativeCandidate.sdpMid,
+          sdpMLineIndex: nativeCandidate.sdpMLineIndex,
+          usernameFragment: nativeCandidate.usernameFragment,
+        };
+      };
+      return nativeCandidate;
+    }
+    return new NativeRTCIceCandidate(args);
+  };
+  window.RTCIceCandidate.prototype = NativeRTCIceCandidate.prototype;
+
+  // Hook up the augmented candidate in onicecandidate and
+  // addEventListener('icecandidate', ...)
+  utils.wrapPeerConnectionEvent(window, 'icecandidate', e => {
+    if (e.candidate) {
+      Object.defineProperty(e, 'candidate', {
+        value: new window.RTCIceCandidate(e.candidate),
+        writable: 'false'
+      });
+    }
+    return e;
+  });
+}
+
+export function shimRTCIceCandidateRelayProtocol(window) {
+  if (!window.RTCIceCandidate || (window.RTCIceCandidate && 'relayProtocol' in
+      window.RTCIceCandidate.prototype)) {
+    return;
+  }
+
+  // Hook up the augmented candidate in onicecandidate and
+  // addEventListener('icecandidate', ...)
+  utils.wrapPeerConnectionEvent(window, 'icecandidate', e => {
+    if (e.candidate) {
+      const parsedCandidate = SDPUtils.parseCandidate(e.candidate.candidate);
+      if (parsedCandidate.type === 'relay') {
+        // This is a libwebrtc-specific mapping of local type preference
+        // to relayProtocol.
+        e.candidate.relayProtocol = {
+          0: 'tls',
+          1: 'tcp',
+          2: 'udp',
+        }[parsedCandidate.priority >> 24];
+      }
+    }
+    return e;
+  });
+}
+
+export function shimMaxMessageSize(window, browserDetails) {
+  if (!window.RTCPeerConnection) {
+    return;
+  }
+
+  if (!('sctp' in window.RTCPeerConnection.prototype)) {
+    Object.defineProperty(window.RTCPeerConnection.prototype, 'sctp', {
+      get() {
+        return typeof this._sctp === 'undefined' ? null : this._sctp;
+      }
+    });
+  }
+
+  const sctpInDescription = function(description) {
+    if (!description || !description.sdp) {
+      return false;
+    }
+    const sections = SDPUtils.splitSections(description.sdp);
+    sections.shift();
+    return sections.some(mediaSection => {
+      const mLine = SDPUtils.parseMLine(mediaSection);
+      return mLine && mLine.kind === 'application'
+          && mLine.protocol.indexOf('SCTP') !== -1;
+    });
+  };
+
+  const getRemoteFirefoxVersion = function(description) {
+    // TODO: Is there a better solution for detecting Firefox?
+    const match = description.sdp.match(/mozilla...THIS_IS_SDPARTA-(\d+)/);
+    if (match === null || match.length < 2) {
+      return -1;
+    }
+    const version = parseInt(match[1], 10);
+    // Test for NaN (yes, this is ugly)
+    return version !== version ? -1 : version;
+  };
+
+  const getCanSendMaxMessageSize = function(remoteIsFirefox) {
+    // Every implementation we know can send at least 64 KiB.
+    // Note: Although Chrome is technically able to send up to 256 KiB, the
+    //       data does not reach the other peer reliably.
+    //       See: https://bugs.chromium.org/p/webrtc/issues/detail?id=8419
+    let canSendMaxMessageSize = 65536;
+    if (browserDetails.browser === 'firefox') {
+      if (browserDetails.version < 57) {
+        if (remoteIsFirefox === -1) {
+          // FF < 57 will send in 16 KiB chunks using the deprecated PPID
+          // fragmentation.
+          canSendMaxMessageSize = 16384;
+        } else {
+          // However, other FF (and RAWRTC) can reassemble PPID-fragmented
+          // messages. Thus, supporting ~2 GiB when sending.
+          canSendMaxMessageSize = 2147483637;
+        }
+      } else if (browserDetails.version < 60) {
+        // Currently, all FF >= 57 will reset the remote maximum message size
+        // to the default value when a data channel is created at a later
+        // stage. :(
+        // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
+        canSendMaxMessageSize =
+          browserDetails.version === 57 ? 65535 : 65536;
+      } else {
+        // FF >= 60 supports sending ~2 GiB
+        canSendMaxMessageSize = 2147483637;
+      }
+    }
+    return canSendMaxMessageSize;
+  };
+
+  const getMaxMessageSize = function(description, remoteIsFirefox) {
+    // Note: 65536 bytes is the default value from the SDP spec. Also,
+    //       every implementation we know supports receiving 65536 bytes.
+    let maxMessageSize = 65536;
+
+    // FF 57 has a slightly incorrect default remote max message size, so
+    // we need to adjust it here to avoid a failure when sending.
+    // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1425697
+    if (browserDetails.browser === 'firefox'
+         && browserDetails.version === 57) {
+      maxMessageSize = 65535;
+    }
+
+    const match = SDPUtils.matchPrefix(description.sdp,
+      'a=max-message-size:');
+    if (match.length > 0) {
+      maxMessageSize = parseInt(match[0].substring(19), 10);
+    } else if (browserDetails.browser === 'firefox' &&
+                remoteIsFirefox !== -1) {
+      // If the maximum message size is not present in the remote SDP and
+      // both local and remote are Firefox, the remote peer can receive
+      // ~2 GiB.
+      maxMessageSize = 2147483637;
+    }
+    return maxMessageSize;
+  };
+
+  const origSetRemoteDescription =
+      window.RTCPeerConnection.prototype.setRemoteDescription;
+  window.RTCPeerConnection.prototype.setRemoteDescription =
+    function setRemoteDescription() {
+      this._sctp = null;
+      // Chrome decided to not expose .sctp in plan-b mode.
+      // As usual, adapter.js has to do an 'ugly worakaround'
+      // to cover up the mess.
+      if (browserDetails.browser === 'chrome' && browserDetails.version >= 76) {
+        const {sdpSemantics} = this.getConfiguration();
+        if (sdpSemantics === 'plan-b') {
+          Object.defineProperty(this, 'sctp', {
+            get() {
+              return typeof this._sctp === 'undefined' ? null : this._sctp;
+            },
+            enumerable: true,
+            configurable: true,
+          });
+        }
+      }
+
+      if (sctpInDescription(arguments[0])) {
+        // Check if the remote is FF.
+        const isFirefox = getRemoteFirefoxVersion(arguments[0]);
+
+        // Get the maximum message size the local peer is capable of sending
+        const canSendMMS = getCanSendMaxMessageSize(isFirefox);
+
+        // Get the maximum message size of the remote peer.
+        const remoteMMS = getMaxMessageSize(arguments[0], isFirefox);
+
+        // Determine final maximum message size
+        let maxMessageSize;
+        if (canSendMMS === 0 && remoteMMS === 0) {
+          maxMessageSize = Number.POSITIVE_INFINITY;
+        } else if (canSendMMS === 0 || remoteMMS === 0) {
+          maxMessageSize = Math.max(canSendMMS, remoteMMS);
+        } else {
+          maxMessageSize = Math.min(canSendMMS, remoteMMS);
+        }
+
+        // Create a dummy RTCSctpTransport object and the 'maxMessageSize'
+        // attribute.
+        const sctp = {};
+        Object.defineProperty(sctp, 'maxMessageSize', {
+          get() {
+            return maxMessageSize;
+          }
+        });
+        this._sctp = sctp;
+      }
+
+      return origSetRemoteDescription.apply(this, arguments);
+    };
+}
+
+export function shimSendThrowTypeError(window) {
+  if (!(window.RTCPeerConnection &&
+      'createDataChannel' in window.RTCPeerConnection.prototype)) {
+    return;
+  }
+
+  // Note: Although Firefox >= 57 has a native implementation, the maximum
+  //       message size can be reset for all data channels at a later stage.
+  //       See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
+
+  function wrapDcSend(dc, pc) {
+    const origDataChannelSend = dc.send;
+    dc.send = function send() {
+      const data = arguments[0];
+      const length = data.length || data.size || data.byteLength;
+      if (dc.readyState === 'open' &&
+          pc.sctp && length > pc.sctp.maxMessageSize) {
+        throw new TypeError('Message too large (can send a maximum of ' +
+          pc.sctp.maxMessageSize + ' bytes)');
+      }
+      return origDataChannelSend.apply(dc, arguments);
+    };
+  }
+  const origCreateDataChannel =
+    window.RTCPeerConnection.prototype.createDataChannel;
+  window.RTCPeerConnection.prototype.createDataChannel =
+    function createDataChannel() {
+      const dataChannel = origCreateDataChannel.apply(this, arguments);
+      wrapDcSend(dataChannel, this);
+      return dataChannel;
+    };
+  utils.wrapPeerConnectionEvent(window, 'datachannel', e => {
+    wrapDcSend(e.channel, e.target);
+    return e;
+  });
+}
+
+
+/* shims RTCConnectionState by pretending it is the same as iceConnectionState.
+ * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
+ * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
+ * since DTLS failures would be hidden. See
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
+ * for the Firefox tracking bug.
+ */
+export function shimConnectionState(window) {
+  if (!window.RTCPeerConnection ||
+      'connectionState' in window.RTCPeerConnection.prototype) {
+    return;
+  }
+  const proto = window.RTCPeerConnection.prototype;
+  Object.defineProperty(proto, 'connectionState', {
+    get() {
+      return {
+        completed: 'connected',
+        checking: 'connecting'
+      }[this.iceConnectionState] || this.iceConnectionState;
+    },
+    enumerable: true,
+    configurable: true
+  });
+  Object.defineProperty(proto, 'onconnectionstatechange', {
+    get() {
+      return this._onconnectionstatechange || null;
+    },
+    set(cb) {
+      if (this._onconnectionstatechange) {
+        this.removeEventListener('connectionstatechange',
+          this._onconnectionstatechange);
+        delete this._onconnectionstatechange;
+      }
+      if (cb) {
+        this.addEventListener('connectionstatechange',
+          this._onconnectionstatechange = cb);
+      }
+    },
+    enumerable: true,
+    configurable: true
+  });
+
+  ['setLocalDescription', 'setRemoteDescription'].forEach((method) => {
+    const origMethod = proto[method];
+    proto[method] = function() {
+      if (!this._connectionstatechangepoly) {
+        this._connectionstatechangepoly = e => {
+          const pc = e.target;
+          if (pc._lastConnectionState !== pc.connectionState) {
+            pc._lastConnectionState = pc.connectionState;
+            const newEvent = new Event('connectionstatechange', e);
+            pc.dispatchEvent(newEvent);
+          }
+          return e;
+        };
+        this.addEventListener('iceconnectionstatechange',
+          this._connectionstatechangepoly);
+      }
+      return origMethod.apply(this, arguments);
+    };
+  });
+}
+
+export function removeExtmapAllowMixed(window, browserDetails) {
+  /* remove a=extmap-allow-mixed for webrtc.org < M71 */
+  if (!window.RTCPeerConnection) {
+    return;
+  }
+  if (browserDetails.browser === 'chrome' && browserDetails.version >= 71) {
+    return;
+  }
+  if (browserDetails.browser === 'safari' &&
+      browserDetails._safariVersion >= 13.1) {
+    return;
+  }
+  const nativeSRD = window.RTCPeerConnection.prototype.setRemoteDescription;
+  window.RTCPeerConnection.prototype.setRemoteDescription =
+  function setRemoteDescription(desc) {
+    if (desc && desc.sdp && desc.sdp.indexOf('\na=extmap-allow-mixed') !== -1) {
+      const sdp = desc.sdp.split('\n').filter((line) => {
+        return line.trim() !== 'a=extmap-allow-mixed';
+      }).join('\n');
+      // Safari enforces read-only-ness of RTCSessionDescription fields.
+      if (window.RTCSessionDescription &&
+          desc instanceof window.RTCSessionDescription) {
+        arguments[0] = new window.RTCSessionDescription({
+          type: desc.type,
+          sdp,
+        });
+      } else {
+        desc.sdp = sdp;
+      }
+    }
+    return nativeSRD.apply(this, arguments);
+  };
+}
+
+export function shimAddIceCandidateNullOrEmpty(window, browserDetails) {
+  // Support for addIceCandidate(null or undefined)
+  // as well as addIceCandidate({candidate: "", ...})
+  // https://bugs.chromium.org/p/chromium/issues/detail?id=978582
+  // Note: must be called before other polyfills which change the signature.
+  if (!(window.RTCPeerConnection && window.RTCPeerConnection.prototype)) {
+    return;
+  }
+  const nativeAddIceCandidate =
+      window.RTCPeerConnection.prototype.addIceCandidate;
+  if (!nativeAddIceCandidate || nativeAddIceCandidate.length === 0) {
+    return;
+  }
+  window.RTCPeerConnection.prototype.addIceCandidate =
+    function addIceCandidate() {
+      if (!arguments[0]) {
+        if (arguments[1]) {
+          arguments[1].apply(null);
+        }
+        return Promise.resolve();
+      }
+      // Firefox 68+ emits and processes {candidate: "", ...}, ignore
+      // in older versions.
+      // Native support for ignoring exists for Chrome M77+.
+      // Safari ignores as well, exact version unknown but works in the same
+      // version that also ignores addIceCandidate(null).
+      if (((browserDetails.browser === 'chrome' && browserDetails.version < 78)
+           || (browserDetails.browser === 'firefox'
+               && browserDetails.version < 68)
+           || (browserDetails.browser === 'safari'))
+          && arguments[0] && arguments[0].candidate === '') {
+        return Promise.resolve();
+      }
+      return nativeAddIceCandidate.apply(this, arguments);
+    };
+}
+
+// Note: Make sure to call this ahead of APIs that modify
+// setLocalDescription.length
+export function shimParameterlessSetLocalDescription(window, browserDetails) {
+  if (!(window.RTCPeerConnection && window.RTCPeerConnection.prototype)) {
+    return;
+  }
+  const nativeSetLocalDescription =
+      window.RTCPeerConnection.prototype.setLocalDescription;
+  if (!nativeSetLocalDescription || nativeSetLocalDescription.length === 0) {
+    return;
+  }
+  window.RTCPeerConnection.prototype.setLocalDescription =
+    function setLocalDescription() {
+      let desc = arguments[0] || {};
+      if (typeof desc !== 'object' || (desc.type && desc.sdp)) {
+        return nativeSetLocalDescription.apply(this, arguments);
+      }
+      // The remaining steps should technically happen when SLD comes off the
+      // RTCPeerConnection's operations chain (not ahead of going on it), but
+      // this is too difficult to shim. Instead, this shim only covers the
+      // common case where the operations chain is empty. This is imperfect, but
+      // should cover many cases. Rationale: Even if we can't reduce the glare
+      // window to zero on imperfect implementations, there's value in tapping
+      // into the perfect negotiation pattern that several browsers support.
+      desc = {type: desc.type, sdp: desc.sdp};
+      if (!desc.type) {
+        switch (this.signalingState) {
+          case 'stable':
+          case 'have-local-offer':
+          case 'have-remote-pranswer':
+            desc.type = 'offer';
+            break;
+          default:
+            desc.type = 'answer';
+            break;
+        }
+      }
+      if (desc.sdp || (desc.type !== 'offer' && desc.type !== 'answer')) {
+        return nativeSetLocalDescription.apply(this, [desc]);
+      }
+      const func = desc.type === 'offer' ? this.createOffer : this.createAnswer;
+      return func.apply(this)
+        .then(d => nativeSetLocalDescription.apply(this, [d]));
+    };
+}