FileDownloader now works in Emscripten

include/Helpers/FileDownloaderEmscripten.cpp

@@ -0,0 +1,49 @@
+#ifdef __EMSCRIPTEN__
+#include "FileDownloader.hpp"
+#include <cstdio>
+
+std::vector<FileDownloader::DownloadHandler> FileDownloader::currentDownloads;
+
+void FileDownloader::download_succeeded(emscripten_fetch_t *fetch) {
+    DownloadData* downData = static_cast<DownloadData*>(fetch->userData);
+    downData->str = std::string(fetch->data, fetch->numBytes);
+    downData->status = DownloadData::Status::SUCCESS;
+    std::erase_if(currentDownloads, [fetch](DownloadHandler& d) {
+        return (DownloadData*)fetch->userData == d.data.get();
+    });
+    emscripten_fetch_close(fetch);
+}
+
+void FileDownloader::download_failed(emscripten_fetch_t *fetch) {
+    DownloadData* downData = static_cast<DownloadData*>(fetch->userData);
+    downData->status = DownloadData::Status::FAILURE;
+    std::erase_if(currentDownloads, [fetch](DownloadHandler& d) {
+        return (DownloadData*)fetch->userData == d.data.get();
+    });
+    emscripten_fetch_close(fetch);
+}
+
+void FileDownloader::init() {
+}
+
+std::shared_ptr<FileDownloader::DownloadData> FileDownloader::download_data_from_url(std::string_view url) {
+    DownloadHandler& newDownload = currentDownloads.emplace_back();
+    newDownload.data = std::make_shared<DownloadData>();
+    newDownload.data->status = DownloadData::Status::IN_PROGRESS;
+
+    emscripten_fetch_attr_t attr;
+    emscripten_fetch_attr_init(&attr);
+    std::strcpy(attr.requestMethod, "GET");
+    attr.attributes = EMSCRIPTEN_FETCH_LOAD_TO_MEMORY;
+    attr.onsuccess = download_succeeded;
+    attr.onerror = download_failed;
+    attr.userData = static_cast<void*>(newDownload.data.get());
+    emscripten_fetch(&attr, url.data());
+
+    return newDownload.data;
+}
+
+void FileDownloader::cleanup() {
+}
+
+#endif