From bea7af4e8ac2b74f9590ac9fede8a25cf6758fb5 Mon Sep 17 00:00:00 2001
From: Taylor Richards <taylor@icculus.org>
Date: Fri, 8 Dec 2017 01:14:58 -0500
Subject: [PATCH] support persistent file storage for Emscripten

---
 src/cfile/cfile.cpp          | 24 ++++++++++++++++++++++--
 src/freespace2/freespace.cpp | 17 +++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/src/cfile/cfile.cpp b/src/cfile/cfile.cpp
index 4505ab3..f14d3d7 100644
--- a/src/cfile/cfile.cpp
+++ b/src/cfile/cfile.cpp
@@ -224,6 +224,10 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
+
 #include "pstypes.h"
 #include "cfile.h"
 #include "encrypt.h"
@@ -1547,8 +1551,24 @@ int cfile_init_paths()
 	SDL_free(u_path);
 	u_path = NULL;
 #else
-	SDL_snprintf(Cfile_user_dir, SDL_arraysize(Cfile_user_dir), "/persist/");
-	mkdir("/.prefs", 0777);
+	SDL_snprintf(Cfile_user_dir, SDL_arraysize(Cfile_user_dir), "/%s/%s/", Osreg_company_name, Osreg_app_name);
+
+	EM_ASM({
+		const base_path = UTF8ToString($0);
+		FS.mkdir(base_path);
+		FS.mount(IDBFS, {}, base_path);
+
+		Module.syncdone = 0;
+
+		FS.syncfs(true, function(err) {
+			if (err && err.code !== 'EEXIST') {
+				console.log('FS.syncfs() load error: ' + err);
+				assert(err);
+			}
+
+			Module.syncdone = 1;
+		});
+	}, Osreg_company_name);
 #endif
 
 	// see if CF_TYPE_DATA exists for user and if not populate user path
diff --git a/src/freespace2/freespace.cpp b/src/freespace2/freespace.cpp
index 79b9342..bded2b0 100644
--- a/src/freespace2/freespace.cpp
+++ b/src/freespace2/freespace.cpp
@@ -5295,6 +5295,14 @@ void game_process_event( int current_state, int event )
 			break;
 
 		case GS_EVENT_GAME_INIT:
+#ifdef __EMSCRIPTEN__
+			// keep looping through until the persistent storage has sync'd
+			if (emscripten_run_script_int("Module.syncdone") == 0) {
+				// this event got popped, so add it back into the queue
+				gameseq_post_event(GS_EVENT_GAME_INIT);
+				break;
+			}
+#endif
 #if defined(FS2_DEMO) || defined(OEM_BUILD) || defined(FS1_DEMO)
 			gameseq_set_state(GS_STATE_INITIAL_PLAYER_SELECT);
 #else			
@@ -6885,6 +6893,15 @@ void game_shutdown(void)
 	psnet_close();
 	os_cleanup();
 
+#ifdef __EMSCRIPTEN__
+	// sync files to persistent storage
+	EM_ASM(
+		FS.syncfs(function(err) {
+			assert(!err);
+		});
+	);
+#endif
+
 	// HACKITY HACK HACK
 	// if this flag is set, we should be firing up the launcher when exiting freespace
 	extern int Multi_update_fireup_launcher_on_exit;
-- 
2.39.2