WebRTC refactor. Data channels, STUN/TURN support.

A big refactor to the WebRTC module. API is now considered quite stable.

Highlights:

- Renamed `WebRTCPeer` to `WebRTCPeerConnection`.
- `WebRTCPeerConnection` no longer act as `PacketPeer`, it only handle the connection itself (a bit like `TCP_Server`)
- Added new `WebRTCDataChannel` class which inherits from `PacketPeer` to handle data transfer.
- Add `WebRTCPeerConnection.initialize` method to create a new connection with the desired configuration provided as dictionary ([see MDN docs](https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/RTCPeerConnection#RTCConfiguration_dictionary)).
- Add `WebRTCPeerConnection.create_data_channel` method to create a data channel for the given connection. The connection must be in `STATE_NEW` as specified by the standard ([see MDN docs for options](https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/createDataChannel#RTCDataChannelInit_dictionary)).
- Add a `data_channel_received` signal to `WebRTCPeerConnection` for in-band (not negotiated) channels.
- Renamed `WebRTCPeerConnection` `offer_created` signal to `session_description_created`.
- Renamed `WebRTCPeerConnection` `new_ice_candidate` signal to `ice_candidate_created`

1 files changed, 352 insertions, 0 deletions

diff --git a/modules/webrtc/webrtc_data_channel_js.cpp b/modules/webrtc/webrtc_data_channel_js.cpp
new file mode 100644
index 0000000000..2e7c64aa72
--- /dev/null
+++ b/modules/webrtc/webrtc_data_channel_js.cpp
@@ -0,0 +1,352 @@
+/*************************************************************************/
+/*  webrtc_data_channel_js.cpp                                           */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifdef JAVASCRIPT_ENABLED
+
+#include "webrtc_data_channel_js.h"
+#include "emscripten.h"
+
+extern "C" {
+EMSCRIPTEN_KEEPALIVE void _emrtc_on_ch_error(void *obj) {
+	WebRTCDataChannelJS *peer = static_cast<WebRTCDataChannelJS *>(obj);
+	peer->_on_error();
+}
+
+EMSCRIPTEN_KEEPALIVE void _emrtc_on_ch_open(void *obj) {
+	WebRTCDataChannelJS *peer = static_cast<WebRTCDataChannelJS *>(obj);
+	peer->_on_open();
+}
+
+EMSCRIPTEN_KEEPALIVE void _emrtc_on_ch_close(void *obj) {
+	WebRTCDataChannelJS *peer = static_cast<WebRTCDataChannelJS *>(obj);
+	peer->_on_close();
+}
+
+EMSCRIPTEN_KEEPALIVE void _emrtc_on_ch_message(void *obj, uint8_t *p_data, uint32_t p_size, bool p_is_string) {
+	WebRTCDataChannelJS *peer = static_cast<WebRTCDataChannelJS *>(obj);
+	peer->_on_message(p_data, p_size, p_is_string);
+}
+}
+
+void WebRTCDataChannelJS::_on_open() {
+	in_buffer.resize(16);
+}
+
+void WebRTCDataChannelJS::_on_close() {
+	close();
+}
+
+void WebRTCDataChannelJS::_on_error() {
+	close();
+}
+
+void WebRTCDataChannelJS::_on_message(uint8_t *p_data, uint32_t p_size, bool p_is_string) {
+	if (in_buffer.space_left() < p_size + 5) {
+		ERR_EXPLAIN("Buffer full! Dropping data");
+		ERR_FAIL();
+	}
+
+	uint8_t is_string = p_is_string ? 1 : 0;
+	in_buffer.write((uint8_t *)&p_size, 4);
+	in_buffer.write((uint8_t *)&is_string, 1);
+	in_buffer.write(p_data, p_size);
+	queue_count++;
+}
+
+void WebRTCDataChannelJS::close() {
+	in_buffer.resize(0);
+	queue_count = 0;
+	_was_string = false;
+	/* clang-format off */
+	EM_ASM({
+		var dict = Module.IDHandler.get($0);
+		if (!dict) return;
+		var channel = dict["channel"];
+		channel.onopen = null;
+		channel.onclose = null;
+		channel.onerror = null;
+		channel.onmessage = null;
+		channel.close();
+	}, _js_id);
+	/* clang-format on */
+}
+
+Error WebRTCDataChannelJS::poll() {
+	return OK;
+}
+
+WebRTCDataChannelJS::ChannelState WebRTCDataChannelJS::get_ready_state() const {
+	/* clang-format off */
+	return (ChannelState) EM_ASM_INT({
+		var dict = Module.IDHandler.get($0);
+		if (!dict) return 3; // CLOSED
+		var channel = dict["channel"];
+		switch(channel.readyState) {
+			case "connecting":
+				return 0;
+			case "open":
+				return 1;
+			case "closing":
+				return 2;
+			case "closed":
+				return 3;
+		}
+		return 3; // CLOSED
+	}, _js_id);
+	/* clang-format on */
+}
+
+int WebRTCDataChannelJS::get_available_packet_count() const {
+	return queue_count;
+}
+
+Error WebRTCDataChannelJS::get_packet(const uint8_t **r_buffer, int &r_buffer_size) {
+	ERR_FAIL_COND_V(get_ready_state() != STATE_OPEN, ERR_UNCONFIGURED);
+
+	if (queue_count == 0)
+		return ERR_UNAVAILABLE;
+
+	uint32_t to_read = 0;
+	uint32_t left = 0;
+	uint8_t is_string = 0;
+	r_buffer_size = 0;
+
+	in_buffer.read((uint8_t *)&to_read, 4);
+	--queue_count;
+	left = in_buffer.data_left();
+
+	if (left < to_read + 1) {
+		in_buffer.advance_read(left);
+		return FAILED;
+	}
+
+	in_buffer.read(&is_string, 1);
+	_was_string = is_string == 1;
+	in_buffer.read(packet_buffer, to_read);
+	*r_buffer = packet_buffer;
+	r_buffer_size = to_read;
+
+	return OK;
+}
+
+Error WebRTCDataChannelJS::put_packet(const uint8_t *p_buffer, int p_buffer_size) {
+	ERR_FAIL_COND_V(get_ready_state() != STATE_OPEN, ERR_UNCONFIGURED);
+
+	int is_bin = _write_mode == WebRTCDataChannel::WRITE_MODE_BINARY ? 1 : 0;
+
+	/* clang-format off */
+	EM_ASM({
+		var dict = Module.IDHandler.get($0);
+		var channel = dict["channel"];
+		var bytes_array = new Uint8Array($2);
+		var i = 0;
+
+		for(i=0; i<$2; i++) {
+			bytes_array[i] = getValue($1+i, 'i8');
+		}
+
+		if ($3) {
+			channel.send(bytes_array.buffer);
+		} else {
+			var string = new TextDecoder("utf-8").decode(bytes_array);
+			channel.send(string);
+		}
+	}, _js_id, p_buffer, p_buffer_size, is_bin);
+	/* clang-format on */
+
+	return OK;
+}
+
+int WebRTCDataChannelJS::get_max_packet_size() const {
+	return 1200;
+}
+
+void WebRTCDataChannelJS::set_write_mode(WriteMode p_mode) {
+	_write_mode = p_mode;
+}
+
+WebRTCDataChannel::WriteMode WebRTCDataChannelJS::get_write_mode() const {
+	return _write_mode;
+}
+
+bool WebRTCDataChannelJS::was_string_packet() const {
+	return _was_string;
+}
+
+String WebRTCDataChannelJS::get_label() const {
+	return _label;
+}
+
+/* clang-format off */
+#define _JS_GET(PROP)				\
+EM_ASM_INT({					\
+	var dict = Module.IDHandler.get($0);	\
+	if (!dict || !dict["channel"]) {	\
+		return 0;			\
+	};					\
+	return dict["channel"].PROP;		\
+}, _js_id)
+/* clang-format on */
+
+bool WebRTCDataChannelJS::is_ordered() const {
+	return _JS_GET(ordered);
+}
+
+int WebRTCDataChannelJS::get_id() const {
+	return _JS_GET(id);
+}
+
+int WebRTCDataChannelJS::get_max_packet_life_time() const {
+	return _JS_GET(maxPacketLifeTime);
+}
+
+int WebRTCDataChannelJS::get_max_retransmits() const {
+	return _JS_GET(maxRetransmits);
+}
+
+String WebRTCDataChannelJS::get_protocol() const {
+	return _protocol;
+}
+
+bool WebRTCDataChannelJS::is_negotiated() const {
+	return _JS_GET(negotiated);
+}
+
+WebRTCDataChannelJS::WebRTCDataChannelJS() {
+	queue_count = 0;
+	_was_string = false;
+	_write_mode = WRITE_MODE_BINARY;
+	_js_id = 0;
+}
+
+WebRTCDataChannelJS::WebRTCDataChannelJS(int js_id) {
+	queue_count = 0;
+	_was_string = false;
+	_write_mode = WRITE_MODE_BINARY;
+	_js_id = js_id;
+
+	/* clang-format off */
+	EM_ASM({
+		var c_ptr = $0;
+		var dict = Module.IDHandler.get($1);
+		if (!dict) return;
+		var channel = dict["channel"];
+		dict["ptr"] = c_ptr;
+
+		channel.binaryType = "arraybuffer";
+		channel.onopen = function (evt) {
+			ccall("_emrtc_on_ch_open",
+				"void",
+				["number"],
+				[c_ptr]
+			);
+		};
+		channel.onclose = function (evt) {
+			ccall("_emrtc_on_ch_close",
+				"void",
+				["number"],
+				[c_ptr]
+			);
+		};
+		channel.onerror = function (evt) {
+			ccall("_emrtc_on_ch_error",
+				"void",
+				["number"],
+				[c_ptr]
+			);
+		};
+		channel.onmessage = function(event) {
+			var buffer;
+			var is_string = 0;
+			if (event.data instanceof ArrayBuffer) {
+				buffer = new Uint8Array(event.data);
+			} else if (event.data instanceof Blob) {
+				console.error("Blob type not supported");
+				return;
+			} else if (typeof event.data === "string") {
+				is_string = 1;
+				var enc = new TextEncoder("utf-8");
+				buffer = new Uint8Array(enc.encode(event.data));
+			} else {
+				console.error("Unknown message type");
+				return;
+			}
+			var len = buffer.length*buffer.BYTES_PER_ELEMENT;
+			var out = Module._malloc(len);
+			Module.HEAPU8.set(buffer, out);
+			ccall("_emrtc_on_ch_message",
+				"void",
+				["number", "number", "number", "number"],
+				[c_ptr, out, len, is_string]
+			);
+			Module._free(out);
+		}
+
+	}, this, js_id);
+	// Parse label
+	char *str;
+	str = (char *)EM_ASM_INT({
+		var dict = Module.IDHandler.get($0);
+		if (!dict || !dict["channel"]) return 0;
+		var str = dict["channel"].label;
+		var len = lengthBytesUTF8(str)+1;
+		var ptr = _malloc(str);
+		stringToUTF8(str, ptr, len+1);
+		return ptr;
+	}, js_id);
+	if(str != NULL) {
+		_label.parse_utf8(str);
+		EM_ASM({ _free($0) }, str);
+	}
+	str = (char *)EM_ASM_INT({
+		var dict = Module.IDHandler.get($0);
+		if (!dict || !dict["channel"]) return 0;
+		var str = dict["channel"].protocol;
+		var len = lengthBytesUTF8(str)+1;
+		var ptr = _malloc(str);
+		stringToUTF8(str, ptr, len+1);
+		return ptr;
+	}, js_id);
+	if(str != NULL) {
+		_protocol.parse_utf8(str);
+		EM_ASM({ _free($0) }, str);
+	}
+	/* clang-format on */
+}
+
+WebRTCDataChannelJS::~WebRTCDataChannelJS() {
+	close();
+	/* clang-format off */
+	EM_ASM({
+		Module.IDHandler.remove($0);
+	}, _js_id);
+	/* clang-format on */
+};
+#endif