From a8f3a108a0d7e705bdedfa65a206fd0fcaf4c6fa Mon Sep 17 00:00:00 2001
From: Sylvain Beucler <beuc@beuc.net>
Date: Mon, 18 Nov 2019 15:56:50 +0100
Subject: [PATCH] Better error handling

---
 launcher/game/web.rpy |  1 +
 renpy/display/core.py |  2 +-
 renpy/loader.py       | 49 ++++++++++++++++++++++++++-----------------
 3 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/launcher/game/web.rpy b/launcher/game/web.rpy
index e7acc18328..9ac0f0df9f 100644
--- a/launcher/game/web.rpy
+++ b/launcher/game/web.rpy
@@ -87,6 +87,7 @@ init python:
         # Filter out downloadable resources
         MIN_REMOTE_SIZE=100*1024
         # TODO: configurable min_size? use archives to better describe web distribution?
+        # TODO: predict/include title screen's resources for a smooth start (no black blink)
         shutil.move(
             os.path.join(destination, 'game.zip'),
             os.path.join(destination, 'game-old.zip'))
diff --git a/renpy/display/core.py b/renpy/display/core.py
index 812dd099e1..b3f4ac8619 100644
--- a/renpy/display/core.py
+++ b/renpy/display/core.py
@@ -2791,7 +2791,7 @@ def idle_frame(self, can_block, expensive):
             elif step == 2:
 
                 if renpy.emscripten or os.environ.get('RENPY_SIMULATE_DOWNLOAD', False):
-                    renpy.loader.ReloadRequest.load_downloaded_resources()
+                    renpy.loader.ReloadRequest.process_downloaded_resources()
 
                 step += 1
 
diff --git a/renpy/loader.py b/renpy/loader.py
index 233aa81979..4b36ad9c25 100644
--- a/renpy/loader.py
+++ b/renpy/loader.py
@@ -45,27 +45,34 @@
     xhrs: {},
 
     dl_new: function(path) {
-	var xhr = new XMLHttpRequest();
-	xhr.responseType = 'arraybuffer';
-	xhr.onload = function() {
-	    // Create file reusing XHR's buffer (no-copy)
-	    try { FS.unlink(path); } catch {}
-	    FS.writeFile(path, new Uint8Array(xhr.response), {canOwn:true});
-	}
-	xhr.open('GET', path);
-	xhr.send();
-	RenPyWeb.xhrs[RenPyWeb.xhr_id] = xhr;
-	var ret = RenPyWeb.xhr_id;
-	RenPyWeb.xhr_id++;
-	return ret;
+        var xhr = new XMLHttpRequest();
+        xhr.responseType = 'arraybuffer';
+        xhr.onerror = function() {
+            console.log("Network error", xhr);
+        }
+        xhr.onload = function() {
+            if (xhr.status == 200 || xhr.status == 304 || xhr.status == 206 || (xhr.status == 0 && xhr.response)) {
+                // Create file reusing XHR's buffer (no-copy)
+                try { FS.unlink(path); } catch {}
+                FS.writeFile(path, new Uint8Array(xhr.response), {canOwn:true});
+            } else {
+                console.log("Download error", xhr);
+            }
+        }
+        xhr.open('GET', path);
+        xhr.send();
+        RenPyWeb.xhrs[RenPyWeb.xhr_id] = xhr;
+        var ret = RenPyWeb.xhr_id;
+        RenPyWeb.xhr_id++;
+        return ret;
     },
 
     dl_get: function(xhr_id) {
-	return RenPyWeb.xhrs[xhr_id];
+        return RenPyWeb.xhrs[xhr_id];
     },
 
     dl_free: function(xhr_id) {
-	delete RenPyWeb.xhrs[xhr_id];
+        delete RenPyWeb.xhrs[xhr_id];
         // Note: xhr.response kept alive until file is deleted
     },
 }
@@ -145,7 +152,7 @@ def download_completed(self):
         return self.xhr is not None and self.xhr.readyState == 4
 
     @staticmethod
-    def load_downloaded_resources():
+    def process_downloaded_resources():
         postponed = []
         reloaded = False
 
@@ -153,13 +160,17 @@ def load_downloaded_resources():
             # TODO: support images and sounds
             if hasattr(rr, 'image'):
                 if rr.download_completed():
-                    if rr.xhr.status == 0:
-                        raise IOError("Download error: " + rr.xhr.statusText)
+                    fullpath = os.path.join(renpy.config.gamedir,rr.image.filename)
+                    if not os.path.exists(fullpath):
+                        # don't rethrow exception in Ren'Py's error handler
+                        ReloadRequest.all.remove(rr)
+                        # show Ren'Py's error handler
+                        raise IOError("Download error: {}: {}".format(
+                            rr.image.filename, (rr.xhr.statusText or "network error")))
                     #print("reloading", rr.image.filename)
                     ce = renpy.display.im.cache.cache.get(rr.image)
                     renpy.display.im.cache.kill(ce)
                     renpy.display.im.cache.get(rr.image, render=True)
-                    fullpath = os.path.join(renpy.config.gamedir,rr.image.filename)
                     #print("unlink", fullpath)
                     os.unlink(fullpath)
                     reloaded = True