On Thu, 8 Apr 2021 20:43:57 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> The functions from FileSystemJava are called from different threads the >> root problem manifests because the JNI FindClass function behaves >> differently when called from a context that is the ancestor of a java >> frame compared to when called in isolation. >> >> A segmentation fault is observed when local storage of a webview is >> accessed. At that time a new native thread is spun up and that sets up >> the local storage, by calling into the JVM via >> WTF::FileSystem::makeAllDirectories. At that point GetFileSystemClass is >> invoked to get a referenc to the java implementation of the FileSystem. >> As this is is called from a new native thread (no java context >> available), JNI uses the system classloader to locate the class. This >> fails if the JavaFX modules are not on the boot module/class path. >> >> Instead on relying on fetching the class reference everytime it is >> needed, this change fetches it once when the JavaFX library is loaded >> and stores it in the WTF namespace. >> >> In addition to this it was observed, that there is no attachment to the >> JVM done when calling into the filesystem. No fault was observed, but >> the JNI specs indicate, that the JNIEnv interface is only valid when >> attached. > > The fix looks OK to me, although I'd like @arun-Joseph to comfirm. > > The test needs one change in how the resource (the `.html` file) is located, > and I added a couple minor comments on the test. I'll test it after that. To follow up on my earlier comment, if I move `LocalStorageAccess.html` to `tests/system/src/testapp7/resources/mymod/myapp7/` and remove the `/` from the program that loads it, the test is able to load the resource. And I verified that the test fails without your fix and passes with your fix. ------------- PR: https://git.openjdk.java.net/jfx/pull/458
