FileDownloader now works in Emscripten

CMakeLists.txt

@@ -106,6 +106,7 @@ set(sources "src/main.cpp"
             "include/Helpers/StringHelpers.cpp"
             "include/Helpers/Serializers.cpp"
             "include/Helpers/FileDownloader.cpp"
+            "include/Helpers/FileDownloaderEmscripten.cpp"
             "include/Helpers/VersionNumber.cpp"
         )
 
@@ -197,7 +198,7 @@ if(EMSCRIPTEN)
     endif()
 
     target_compile_options(infinipaint PRIVATE -Wall -fdiagnostics-color -sUSE_SDL=0 -include functional -fexceptions)
-    target_link_options(infinipaint PRIVATE --emrun -sUSE_SDL=0 -sFULL_ES2 -sUSE_WEBGL2=1 --embed-file data -sALLOW_MEMORY_GROWTH -sEXPORTED_RUNTIME_METHODS=ccall -sEXPORTED_FUNCTIONS=[_main,_malloc,_free] -sMAXIMUM_MEMORY=4GB -sSINGLE_FILE -lidbfs.js -fexceptions)
+    target_link_options(infinipaint PRIVATE --emrun -sUSE_SDL=0 -sFULL_ES2 -sUSE_WEBGL2=1 -sFETCH --embed-file data -sALLOW_MEMORY_GROWTH -sEXPORTED_RUNTIME_METHODS=ccall -sEXPORTED_FUNCTIONS=[_main,_malloc,_free] -sMAXIMUM_MEMORY=4GB -sSINGLE_FILE -lidbfs.js -fexceptions)
     if(EMSCRIPTEN_SINGLE_HTML_FILE)
         target_link_options(infinipaint PRIVATE --shell-file emscripteninstall/singlefilereleaseshell.html)
         set(CMAKE_EXECUTABLE_SUFFIX ".html")

include/Helpers/FileDownloader.cpp

@@ -1,6 +1,7 @@
-#include "FileDownloader.hpp"
 #ifndef __EMSCRIPTEN__
 
+#include "FileDownloader.hpp"
+
 #include <curl/multi.h>
 #include <iostream>
 #include <curl/curl.h>

include/Helpers/FileDownloader.hpp

@@ -1,12 +1,15 @@
 #pragma once
-#ifndef __EMSCRIPTEN__
-
-#include <curl/curl.h>
 #include <memory>
 #include <functional>
 #include <atomic>
-#include <thread>
-#include <mutex>
+
+#ifndef __EMSCRIPTEN__
+    #include <mutex>
+    #include <thread>
+    #include <curl/curl.h>
+#else
+    #include <emscripten/fetch.h>
+#endif
 
 class FileDownloader {
     public:
@@ -24,28 +27,30 @@ class FileDownloader {
         static std::shared_ptr<DownloadData> download_data_from_url(std::string_view url);
         static void cleanup();
     private:
-        static void add_new_handlers_to_multi();
-        static void download_thread_update();
 
         struct DownloadHandler {
-            CURL* eHandle;
+            #ifndef __EMSCRIPTEN__
+                CURL* eHandle;
+            #endif
             std::shared_ptr<DownloadData> data;
         };
 
-        static std::mutex newDownloadsMutex;
-        static std::vector<DownloadHandler> newDownloads;
-        static std::atomic<bool> shutdownThread;
-        static CURLM* mHandle;
         static std::vector<DownloadHandler> currentDownloads;
-        static std::unique_ptr<std::thread> downloadThread;
 
-        static void save_to_string(CURL* curl, std::string* str);
-        static void disable_ssl_verification(CURL* curl);
+        #ifndef __EMSCRIPTEN__
+            static std::mutex newDownloadsMutex;
+            static std::vector<DownloadHandler> newDownloads;
+            static std::atomic<bool> shutdownThread;
+            static CURLM* mHandle;
+            static std::unique_ptr<std::thread> downloadThread;
 
-        static timeval get_timeout(CURLM* mCurl);
-        static int wait_if_needed(CURLM* mCurl, timeval& timeout);
-
-        static size_t write_to_string(void* contents, size_t size, size_t nmemb, void* userp);
+            static void save_to_string(CURL* curl, std::string* str);
+            static void disable_ssl_verification(CURL* curl);
+            static size_t write_to_string(void* contents, size_t size, size_t nmemb, void* userp);
+            static void add_new_handlers_to_multi();
+            static void download_thread_update();
+        #else
+            static void download_succeeded(emscripten_fetch_t *fetch);
+            static void download_failed(emscripten_fetch_t *fetch);
+        #endif
 };
-
-#endif

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

src/main.cpp

@@ -391,9 +391,7 @@ SDL_AppResult SDL_AppInit(void **appstate, int argc, char **argv) {
 
     init_logs(mS);
 
-#ifndef __EMSCRIPTEN__
     FileDownloader::init();
-#endif
 
 #ifdef NDEBUG
     try {
@@ -779,9 +777,7 @@ void SDL_AppQuit(void *appstate, SDL_AppResult result) {
 
     delete (&mS);
 
-#ifndef __EMSCRIPTEN__
     FileDownloader::cleanup();
-#endif
 
     SDL_Quit();
 }