RFR: 8326712: Robot tests fail on XWayland

[Alexander Zvegintsev]

On Thu, 27 Jun 2024 18:15:53 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Most of the headful test failures on XWayland are due to screen capture is not working.
>> 
>> Wayland, unlike X11, does not allow arbitrary applications to capture the screen contents directly.
>> Instead, screen capture functionality is managed by the compositor, which can enforce stricter controls and permissions, requiring explicit user approval for screen capture operations.
>> 
>> This issue is already resolved in OpenJDK ([base issue](https://bugs.openjdk.org/browse/JDK-8280982), there are  subsequent fixes) by using the [ScreenCast XDG portal](https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.ScreenCast.html).
>> 
>> The XDG ScreenCast portal is utilized for capturing screen data as it provides a secure and standardized method for applications to access screen content.
>> Additionally, it allows for the reuse of user permissions without requiring repeated confirmations, streamlining the user experience and enhancing convenience.
>> 
>> 
>> <hr>
>> 
>> So this changeset is a copy of the OpenJDK fixes with the addition of the JavaFX customization. 
>> For ease of review, you can skip the changes in the first two commits:
>> - First commit is a direct copy of files from OpenJDK
>> - Second commit removes the `gtk-` prefix before the `gtk_...` and `g_...` function calls (in AWT all gtk functions are dynamically loaded, we don't need that in JavaFX).
>> 
>> properties added:
>> 
>> - `javafx.robot.screenshotMethod`, accepts `gtk`(existing gtk method) and `dbusScreencast`(added by this changeset, used by default for Wayland)
>> - `javafx.robot.screenshotDebug` prints debug info if it is set to `true`
>> 
>> <hr>
>> 
>> What are the remaining issues?
>> 
>> 1.
>> 
>> After applying this fix, system tests will pass except for the `SwingNodeJDialogTest` test.
>> 
>> This interop test calls `java.awt.Robot#getPixelColor` which internally `gtk->g_main_context_iteration(NULL, TRUE);` causes a blocking of javafx gtk loop, so the test hangs.
>> So a change is required on OpenJDK side to fix this issue.
>> 
>> 2.
>> 
>> Even after solving the `#1`, the `SwingNodeJDialogTest.testNodeRemovalBeforeShow` case is still failing.
>> 
>> 3.
>> 
>> Internally the ScreenCast session keeps open for [2s](https://github.com/openjdk/jdk/blob/d457609f700bbb1fed233f1a04501c995852e5ac/src/java.desktop/unix/classes/sun/awt/screencast/ScreencastHelper.java#L62).
>> This is to reduce overhead in case of frequent consecutive screen captures.
>> 
>> There is a crash when an AWT ScreenCast session o...
>
> modules/javafx.graphics/src/main/java/com/sun/glass/ui/gtk/GtkRobot.java line 39:
> 
>> 37: import java.security.PrivilegedAction;
>> 38: 
>> 39: @SuppressWarnings("removal")
> 
> Maybe this can go on the individual elements that use the security manager? To do this, you might need to create a local "tmp" variable and then assign that to `screenshotMethod`.
> (either way, don't worry about the files you copied from AWT)

Done for all cases.

> modules/javafx.graphics/src/main/java/com/sun/glass/ui/gtk/screencast/TokenStorage.java line 117:
> 
>> 115: 
>> 116:         // use secondary path only if it already exists and writable
>> 117:         Path path = Files.isWritable(secondaryPath)
> 
> If both exist and are writable, then wouldn't you want to default to the primary path? If so, then I think the test should be something like `Files.isWritable(secondaryPath) && !Files.isWritable(primaryPath)`.

Sure, it sounds reasonable, updated.

-------------

PR Review Comment: https://git.openjdk.org/jfx/pull/1490#discussion_r1658305497
PR Review Comment: https://git.openjdk.org/jfx/pull/1490#discussion_r1658306065