screenshot: Return error when stream creation fails

The Shell.Screenshot API expects valid output streams for writing the
completed screenshot, not NULL.

Handle this properly by returning an error instead of passing it on
to the screenshot.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1123

diff --git a/js/ui/screenshot.js b/js/ui/screenshot.js
index 09f5c5109fb24b2bc9d03866dd86e9b3898f9555..78afc4ae47b3f2f04ab2f3e323034046ef383bef 100644 (file)
--- a/js/ui/screenshot.js
+++ b/js/ui/screenshot.js
@@ -84,7 +84,7 @@ var ScreenshotService = class {
         }
     }
 
-    _createStream(filename) {
+    _createStream(filename, invocation) {
         if (filename == '')
             return [Gio.MemoryOutputStream.new_resizable(), null];
 
@@ -94,6 +94,7 @@ var ScreenshotService = class {
                 let stream = file.replace(null, false, Gio.FileCreateFlags.NONE, null);
                 return [stream, file];
             } catch (e) {
+                invocation.return_value(GLib.Variant.new('(bs)', [false, '']));
                 return [null, null];
             }
         }
@@ -104,10 +105,11 @@ var ScreenshotService = class {
                 return [stream, file];
             } catch (e) {
                 if (!e.matches(Gio.IOErrorEnum, Gio.IOErrorEnum.EXISTS))
-                    return [null, null];
+                    break;
             }
         }
 
+        invocation.return_value(GLib.Variant.new('(bs)', [false, '']));
         return [null, null];
     }
 
@@ -169,7 +171,9 @@ var ScreenshotService = class {
         if (!screenshot)
             return;
 
-        let [stream, file] = this._createStream(filename);
+        let [stream, file] = this._createStream(filename, invocation);
+        if (!stream)
+            return;
 
         screenshot.screenshot_area(x, y, width, height, stream,
             (o, res) => {
@@ -190,7 +194,9 @@ var ScreenshotService = class {
         if (!screenshot)
             return;
 
-        let [stream, file] = this._createStream(filename);
+        let [stream, file] = this._createStream(filename, invocation);
+        if (!stream)
+            return;
 
         screenshot.screenshot_window(includeFrame, includeCursor, stream,
             (o, res) => {
@@ -211,7 +217,9 @@ var ScreenshotService = class {
         if (!screenshot)
             return;
 
-        let [stream, file] = this._createStream(filename);
+        let [stream, file] = this._createStream(filename, invocation);
+        if (!stream)
+            return;
 
         screenshot.screenshot(includeCursor, stream,
             (o, res) => {