[HTML5] Libraries refactor for linting.

Initial work to make liniting easier.

This includes:
- Rename http_request.js to library_godot_http_request.js.
- Rename externs.js to engine.externs.js.
- New library_godot_runtime.js (GodotRuntime) wraps around emscripten
  functions.
- Refactor of XMLHttpRequest handler in engine/preloader.js.
- Few fixes to bugs spotted by early stage linting.

1 files changed, 143 insertions, 0 deletions

diff --git a/platform/javascript/js/libs/library_godot_http_request.js b/platform/javascript/js/libs/library_godot_http_request.js
new file mode 100644
index 0000000000..6f80f3b958
--- /dev/null
+++ b/platform/javascript/js/libs/library_godot_http_request.js
@@ -0,0 +1,143 @@
+/*************************************************************************/
+/*  http_request.js                                                      */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 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.                */
+/*************************************************************************/
+
+const GodotHTTPRequest = {
+	$GodotHTTPRequest__deps: ['$GodotRuntime'],
+	$GodotHTTPRequest: {
+		requests: [],
+
+		getUnusedRequestId: function() {
+			var idMax = GodotHTTPRequest.requests.length;
+			for (var potentialId = 0; potentialId < idMax; ++potentialId) {
+				if (GodotHTTPRequest.requests[potentialId] instanceof XMLHttpRequest) {
+					continue;
+				}
+				return potentialId;
+			}
+			GodotHTTPRequest.requests.push(null)
+			return idMax;
+		},
+
+		setupRequest: function(xhr) {
+			xhr.responseType = 'arraybuffer';
+		},
+	},
+
+	godot_xhr_new: function() {
+		var newId = GodotHTTPRequest.getUnusedRequestId();
+		GodotHTTPRequest.requests[newId] = new XMLHttpRequest;
+		GodotHTTPRequest.setupRequest(GodotHTTPRequest.requests[newId]);
+		return newId;
+	},
+
+	godot_xhr_reset: function(xhrId) {
+		GodotHTTPRequest.requests[xhrId] = new XMLHttpRequest;
+		GodotHTTPRequest.setupRequest(GodotHTTPRequest.requests[xhrId]);
+	},
+
+	godot_xhr_free: function(xhrId) {
+		GodotHTTPRequest.requests[xhrId].abort();
+		GodotHTTPRequest.requests[xhrId] = null;
+	},
+
+	godot_xhr_open: function(xhrId, method, url, p_user, p_password) {
+		const user = p_user > 0 ? GodotRuntime.parseString(p_user) : null;
+		const password = p_password > 0 ? GodotRuntime.parseString(p_password) : null;
+		GodotHTTPRequest.requests[xhrId].open(GodotRuntime.parseString(method), GodotRuntime.parseString(url), true, user, password);
+	},
+
+	godot_xhr_set_request_header: function(xhrId, header, value) {
+		GodotHTTPRequest.requests[xhrId].setRequestHeader(GodotRuntime.parseString(header), GodotRuntime.parseString(value));
+	},
+
+	godot_xhr_send_null: function(xhrId) {
+		GodotHTTPRequest.requests[xhrId].send();
+	},
+
+	godot_xhr_send_string: function(xhrId, strPtr) {
+		if (!strPtr) {
+			GodotRuntime.error("Failed to send string per XHR: null pointer");
+			return;
+		}
+		GodotHTTPRequest.requests[xhrId].send(GodotRuntime.parseString(strPtr));
+	},
+
+	godot_xhr_send_data: function(xhrId, ptr, len) {
+		if (!ptr) {
+			GodotRuntime.error("Failed to send data per XHR: null pointer");
+			return;
+		}
+		if (len < 0) {
+			GodotRuntime.error("Failed to send data per XHR: buffer length less than 0");
+			return;
+		}
+		GodotHTTPRequest.requests[xhrId].send(HEAPU8.subarray(ptr, ptr + len));
+	},
+
+	godot_xhr_abort: function(xhrId) {
+		GodotHTTPRequest.requests[xhrId].abort();
+	},
+
+	godot_xhr_get_status: function(xhrId) {
+		return GodotHTTPRequest.requests[xhrId].status;
+	},
+
+	godot_xhr_get_ready_state: function(xhrId) {
+		return GodotHTTPRequest.requests[xhrId].readyState;
+	},
+
+	godot_xhr_get_response_headers_length: function(xhrId) {
+		var headers = GodotHTTPRequest.requests[xhrId].getAllResponseHeaders();
+		return headers === null ? 0 : GodotRuntime.strlen(headers);
+	},
+
+	godot_xhr_get_response_headers: function(xhrId, dst, len) {
+		var str = GodotHTTPRequest.requests[xhrId].getAllResponseHeaders();
+		if (str === null)
+			return;
+		GodotRuntime.stringToHeap(str, dst, len);
+	},
+
+	godot_xhr_get_response_length: function(xhrId) {
+		var body = GodotHTTPRequest.requests[xhrId].response;
+		return body === null ? 0 : body.byteLength;
+	},
+
+	godot_xhr_get_response: function(xhrId, dst, len) {
+		var buf = GodotHTTPRequest.requests[xhrId].response;
+		if (buf === null)
+			return;
+		buf = new Uint8Array(buf).subarray(0, len);
+		HEAPU8.set(buf, dst);
+	},
+};
+
+autoAddDeps(GodotHTTPRequest, "$GodotHTTPRequest");
+mergeInto(LibraryManager.library, GodotHTTPRequest);