Accessibility focus on wrong component fix (#793)

* Introduce a way to initialize CAccessible for Accessible to build proper context -> accessible mapping

* Add test for getCAccessible call

skiko/src/awtMain/kotlin/org/jetbrains/skiko/Accessibility.kt

+package org.jetbrains.skiko
+
+import javax.accessibility.Accessible
+
+/**
+ * See [nativeInitializeAccessible] doc for details
+ */
+internal external fun initializeCAccessible(accessible: Accessible)
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skiko/src/awtMain/kotlin/org/jetbrains/skiko/HardwareLayer.kt

@@ -2,7 +2,10 @@ package org.jetbrains.skiko
 
 import kotlinx.coroutines.*
 import kotlinx.coroutines.channels.Channel
-import java.awt.*
+import java.awt.Canvas
+import java.awt.Component
+import java.awt.Graphics
+import java.awt.KeyboardFocusManager
 import java.awt.event.FocusEvent
 import java.awt.event.InputMethodEvent
 import java.beans.PropertyChangeEvent
@@ -134,3 +137,29 @@ internal fun layerFrameLimiter(
         }
     )
 }
+
+/**
+ * This method should be called on custom [Accessible] creation (or its context if context is created lazily).
+ *
+ * JDK's accessibility support (at least for MacOS) builds mapping AccessibleContext -> Accessible.
+ * Some [Accessible] are built only when focus is settled and
+ * since we have a hack [requestNativeFocusOnAccessible], wrong mapping can be built
+ * (ComponentAccessibleContext -> SkiaLayer instead of ComponentAccessibleContext -> ComponentAccessible).
+ *
+ * This method forces JDK's accessibility support to cache mapping ComponentAccessibleContext -> ComponentAccessible,
+ * if it is called on ComponentAccessibleContext creation.
+ *
+ * Related to the [issue](https://youtrack.jetbrains.com/issue/COMPOSE-176).
+ */
+@Suppress("unused")
+fun nativeInitializeAccessible(accessible: Accessible) {
+    when (hostOs) {
+        OS.MacOS -> {
+            initializeCAccessible(accessible)
+        }
+
+        else -> {
+            // TODO: do we need something for Windows?
+        }
+    }
+}
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skiko/src/awtMain/kotlin/org/jetbrains/skiko/MetalApi.kt

 package org.jetbrains.skiko
 
+import javax.accessibility.Accessible
+
 /**
  * Provides [MetalAdapter] that holds pointer to native [MTLDevice](https://developer.apple.com/documentation/metal/mtldevice)
  * chosen using [adapterPriority]

skiko/src/awtMain/objectiveC/macos/Accessibility.mm

+#import <jawt.h>
+#import <jawt_md.h>
+
+extern "C" {
+JNIEXPORT void JNICALL Java_org_jetbrains_skiko_AccessibilityKt_initializeCAccessible(
+    JNIEnv *env, jobject obj, jobject accessible)
+{
+    @autoreleasepool {
+        jclass accClass = env->FindClass("sun/lwawt/macosx/CAccessible");
+        if (accClass == NULL) {
+            return;
+        }
+
+        jmethodID getCAccessibleMethod = env->GetStaticMethodID(
+            accClass, "getCAccessible",
+            "(Ljavax/accessibility/Accessible;)Lsun/lwawt/macosx/CAccessible;"
+        );
+        if (getCAccessibleMethod == NULL) {
+            return;
+        }
+
+        jobject result = env->CallStaticObjectMethod(accClass, getCAccessibleMethod, accessible);
+        if (result == NULL) {
+            return;
+        }
+    }
+}
+
+} // extern "C"
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skiko/src/awtTest/kotlin/org/jetbrains/skiko/AccessibilityKtTest.kt

+package org.jetbrains.skiko
+
+import org.junit.Assume.assumeTrue
+import java.util.*
+import javax.accessibility.Accessible
+import javax.accessibility.AccessibleContext
+import javax.accessibility.AccessibleRole
+import javax.accessibility.AccessibleStateSet
+import kotlin.test.Test
+
+class AccessibilityKtTest {
+    private companion object {
+        init {
+            Library.load()
+        }
+    }
+
+    @Test
+    fun `getCAccessible is available`() {
+        assumeTrue(hostOs == OS.MacOS)
+
+        val context = object : AccessibleContext() {
+            override fun getAccessibleRole(): AccessibleRole {
+                return AccessibleRole.PANEL
+            }
+
+            override fun getAccessibleStateSet(): AccessibleStateSet {
+                return AccessibleStateSet()
+            }
+
+            override fun getAccessibleIndexInParent(): Int {
+                return 0
+            }
+
+            override fun getAccessibleChildrenCount(): Int {
+                return 0
+            }
+
+            override fun getAccessibleChild(i: Int): Accessible? {
+                return null
+            }
+
+            override fun getLocale(): Locale {
+                return Locale.getDefault()
+            }
+
+        }
+        val accessible = Accessible {
+            context
+        }
+
+        initializeCAccessible(accessible)
+    }
+}
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