[HTML5] Replace XMLHttpRequest with Fetch.

This has some advantages:
- Streaming/chunked response support.
- Broader headers support.

platform/javascript/js/libs/library_godot_fetch.js

@@ -0,0 +1,258 @@
+/*************************************************************************/
+/*  library_godot_fetch.js                                               */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 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 GodotFetch = {
+	$GodotFetch__deps: ['$GodotRuntime'],
+	$GodotFetch: {
+
+		onread: function (id, result) {
+			const obj = IDHandler.get(id);
+			if (!obj) {
+				return;
+			}
+			if (result.value) {
+				obj.chunks.push(result.value);
+			}
+			obj.reading = false;
+			obj.done = result.done;
+		},
+
+		onresponse: function (id, response) {
+			const obj = IDHandler.get(id);
+			if (!obj) {
+				return;
+			}
+			let size = -1;
+			let compressed = false;
+			let chunked = false;
+			response.headers.forEach(function (value, header) {
+				const v = value.toLowerCase().trim();
+				const h = header.toLowerCase().trim();
+				if (h === 'content-encoding') {
+					compressed = true;
+					size = -1;
+				} else if (h === 'content-length') {
+					const len = Number.parseInt(value, 10);
+					if (!Number.isNaN(len) && !compressed) {
+						size = len;
+					}
+				} else if (h === 'transfer-encoding' && v === 'chunked') {
+					chunked = true;
+				}
+			});
+			obj.bodySize = size;
+			obj.status = response.status;
+			obj.response = response;
+			obj.reader = response.body.getReader();
+			obj.chunked = chunked;
+		},
+
+		onerror: function (id, err) {
+			GodotRuntime.error(err);
+			const obj = IDHandler.get(id);
+			if (!obj) {
+				return;
+			}
+			obj.error = err;
+		},
+
+		create: function (method, url, headers, body) {
+			const obj = {
+				request: null,
+				response: null,
+				reader: null,
+				error: null,
+				done: false,
+				reading: false,
+				status: 0,
+				chunks: [],
+				bodySize: -1,
+			};
+			const id = IDHandler.add(obj);
+			const init = {
+				method: method,
+				headers: headers,
+				body: body,
+			};
+			obj.request = fetch(url, init);
+			obj.request.then(GodotFetch.onresponse.bind(null, id)).catch(GodotFetch.onerror.bind(null, id));
+			return id;
+		},
+
+		free: function (id) {
+			const obj = IDHandler.get(id);
+			if (!obj) {
+				return;
+			}
+			IDHandler.remove(id);
+			if (!obj.request) {
+				return;
+			}
+			// Try to abort
+			obj.request.then(function (response) {
+				response.abort();
+			}).catch(function (e) { /* nothing to do */ });
+		},
+
+		read: function (id) {
+			const obj = IDHandler.get(id);
+			if (!obj) {
+				return;
+			}
+			if (obj.reader && !obj.reading) {
+				if (obj.done) {
+					obj.reader = null;
+					return;
+				}
+				obj.reading = true;
+				obj.reader.read().then(GodotFetch.onread.bind(null, id)).catch(GodotFetch.onerror.bind(null, id));
+			}
+		},
+	},
+
+	godot_js_fetch_create__sig: 'iii',
+	godot_js_fetch_create: function (p_method, p_url, p_headers, p_headers_size, p_body, p_body_size) {
+		const method = GodotRuntime.parseString(p_method);
+		const url = GodotRuntime.parseString(p_url);
+		const headers = GodotRuntime.parseStringArray(p_headers, p_headers_size);
+		const body = p_body_size ? GodotRuntime.heapSlice(HEAP8, p_body, p_body_size) : null;
+		return GodotFetch.create(method, url, headers.map(function (hv) {
+			const idx = hv.indexOf(':');
+			if (idx <= 0) {
+				return [];
+			}
+			return [
+				hv.slice(0, idx).trim(),
+				hv.slice(idx + 1).trim(),
+			];
+		}).filter(function (v) {
+			return v.length === 2;
+		}), body);
+	},
+
+	godot_js_fetch_state_get__sig: 'ii',
+	godot_js_fetch_state_get: function (p_id) {
+		const obj = IDHandler.get(p_id);
+		if (!obj) {
+			return -1;
+		}
+		if (obj.error) {
+			return -1;
+		}
+		if (!obj.response) {
+			return 0;
+		}
+		if (obj.reader) {
+			return 1;
+		}
+		if (obj.done) {
+			return 2;
+		}
+		return -1;
+	},
+
+	godot_js_fetch_http_status_get__sig: 'ii',
+	godot_js_fetch_http_status_get: function (p_id) {
+		const obj = IDHandler.get(p_id);
+		if (!obj || !obj.response) {
+			return 0;
+		}
+		return obj.status;
+	},
+
+	godot_js_fetch_read_headers__sig: 'iii',
+	godot_js_fetch_read_headers: function (p_id, p_parse_cb, p_ref) {
+		const obj = IDHandler.get(p_id);
+		if (!obj || !obj.response) {
+			return 1;
+		}
+		const cb = GodotRuntime.get_func(p_parse_cb);
+		const arr = [];
+		obj.response.headers.forEach(function (v, h) {
+			arr.push(`${h}:${v}`);
+		});
+		const c_ptr = GodotRuntime.allocStringArray(arr);
+		cb(arr.length, c_ptr, p_ref);
+		GodotRuntime.freeStringArray(c_ptr, arr.length);
+		return 0;
+	},
+
+	godot_js_fetch_read_chunk__sig: 'ii',
+	godot_js_fetch_read_chunk: function (p_id, p_buf, p_buf_size) {
+		const obj = IDHandler.get(p_id);
+		if (!obj || !obj.response) {
+			return 0;
+		}
+		let to_read = p_buf_size;
+		const chunks = obj.chunks;
+		while (to_read && chunks.length) {
+			const chunk = obj.chunks[0];
+			if (chunk.length > to_read) {
+				GodotRuntime.heapCopy(HEAP8, chunk.slice(0, to_read), p_buf);
+				chunks[0] = chunk.slice(to_read);
+				to_read = 0;
+			} else {
+				GodotRuntime.heapCopy(HEAP8, chunk, p_buf);
+				to_read -= chunk.length;
+				chunks.pop();
+			}
+		}
+		if (!chunks.length) {
+			GodotFetch.read(p_id);
+		}
+		return p_buf_size - to_read;
+	},
+
+	godot_js_fetch_body_length_get__sig: 'ii',
+	godot_js_fetch_body_length_get: function (p_id) {
+		const obj = IDHandler.get(p_id);
+		if (!obj || !obj.response) {
+			return -1;
+		}
+		return obj.bodySize;
+	},
+
+	godot_js_fetch_is_chunked__sig: 'ii',
+	godot_js_fetch_is_chunked: function (p_id) {
+		const obj = IDHandler.get(p_id);
+		if (!obj || !obj.response) {
+			return -1;
+		}
+		return obj.chunked ? 1 : 0;
+	},
+
+	godot_js_fetch_free__sig: 'vi',
+	godot_js_fetch_free: function (id) {
+		GodotFetch.free(id);
+	},
+};
+
+autoAddDeps(GodotFetch, '$GodotFetch');
+mergeInto(LibraryManager.library, GodotFetch);