Improve Android and Linux accessibility reliability

packages/accessibility-android-sys/resources/AxDump.java

@@ -0,0 +1,194 @@
+import android.accessibilityservice.AccessibilityServiceInfo;
+import android.app.UiAutomation;
+import android.os.HandlerThread;
+import android.os.SystemClock;
+import android.view.accessibility.AccessibilityNodeInfo;
+import android.graphics.Rect;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+/**
+ * Persistent accessibility dump server for ADB. Runs under app_process with
+ * shell permissions, connects a UiAutomation once, then serves repeated
+ * hierarchy dumps over stdin/stdout: read the line "dump", write the tree
+ * as uiautomator-compatible XML terminated by "###END###".
+ *
+ * This avoids the ~2s per-call cost of `uiautomator dump`, which spawns a
+ * fresh JVM, connects UiAutomation, dumps once, and exits.
+ */
+public final class AxDump {
+    private AxDump() {}
+
+    /**
+     * Hidden {@code AccessibilityNodeInfo.getSourceNodeId()}: a per-window
+     * stable identity for the underlying view (virtual descendant id packed
+     * with the accessibility view id). Survives text/label changes and moves,
+     * so hosts can tell "same control, new state" from "replaced control".
+     */
+    private static Method sourceNodeId;
+
+    static {
+        try {
+            sourceNodeId = AccessibilityNodeInfo.class.getDeclaredMethod("getSourceNodeId");
+            sourceNodeId.setAccessible(true);
+        } catch (Exception ignored) {
+            sourceNodeId = null;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        HandlerThread thread = new HandlerThread("axdump");
+        thread.start();
+
+        UiAutomation automation = connect(thread);
+        AccessibilityServiceInfo info = automation.getServiceInfo();
+        if (info != null) {
+            info.flags |= AccessibilityServiceInfo.FLAG_INCLUDE_NOT_IMPORTANT_VIEWS
+                | AccessibilityServiceInfo.FLAG_REPORT_VIEW_IDS;
+            automation.setServiceInfo(info);
+        }
+
+        System.out.println("axdump ready");
+        System.out.flush();
+
+        BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
+        String line;
+        while ((line = stdin.readLine()) != null) {
+            line = line.trim();
+            if (line.equals("quit")) {
+                break;
+            }
+            if (!line.equals("dump")) {
+                continue;
+            }
+            long started = SystemClock.uptimeMillis();
+            AccessibilityNodeInfo root = automation.getRootInActiveWindow();
+            StringBuilder out = new StringBuilder(16 * 1024);
+            if (root == null) {
+                out.append("error: no active window root\n");
+            } else {
+                out.append("<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>");
+                out.append("<hierarchy rotation=\"0\">");
+                emit(root, 0, out);
+                out.append("</hierarchy>\n");
+            }
+            out.append("###END### ").append(SystemClock.uptimeMillis() - started).append("ms\n");
+            System.out.print(out);
+            System.out.flush();
+        }
+        // Unregister the UiTestAutomationService before exiting: a bare
+        // System.exit can leave the registration alive in the accessibility
+        // manager long enough that the next AxDump start dies with
+        // "UiAutomationService ... already registered!".
+        try {
+            Method disconnect = UiAutomation.class.getDeclaredMethod("disconnect");
+            disconnect.setAccessible(true);
+            disconnect.invoke(automation);
+        } catch (Exception ignored) {
+        }
+        System.exit(0);
+    }
+
+    private static UiAutomation connect(HandlerThread thread) throws Exception {
+        // UiAutomationConnection and IUiAutomationConnection are hidden APIs:
+        // reach them purely reflectively so android.jar can compile this.
+        Class<?> connectionClass = Class.forName("android.app.UiAutomationConnection");
+        Object connection = connectionClass.getDeclaredConstructor().newInstance();
+        Class<?> interfaceClass = Class.forName("android.app.IUiAutomationConnection");
+        Constructor<UiAutomation> constructor = UiAutomation.class.getDeclaredConstructor(
+            android.os.Looper.class, interfaceClass);
+        constructor.setAccessible(true);
+        UiAutomation automation = constructor.newInstance(thread.getLooper(), connection);
+        Method connect;
+        try {
+            connect = UiAutomation.class.getDeclaredMethod("connect", int.class);
+            connect.setAccessible(true);
+            connect.invoke(automation, 0);
+        } catch (NoSuchMethodException e) {
+            connect = UiAutomation.class.getDeclaredMethod("connect");
+            connect.setAccessible(true);
+            connect.invoke(automation);
+        }
+        return automation;
+    }
+
+    private static void emit(AccessibilityNodeInfo node, int index, StringBuilder out) {
+        if (node == null || !node.isVisibleToUser()) {
+            // uiautomator dump prunes invisible subtrees (unrealized/off-screen
+            // list rows report clamped, inverted bounds); match that.
+            return;
+        }
+        Rect bounds = new Rect();
+        node.getBoundsInScreen(bounds);
+        out.append("<node index=\"").append(index).append('"');
+        attr(out, "text", node.getText());
+        attr(out, "resource-id", node.getViewIdResourceName());
+        attr(out, "class", node.getClassName());
+        attr(out, "package", node.getPackageName());
+        attr(out, "content-desc", node.getContentDescription());
+        flag(out, "checkable", node.isCheckable());
+        flag(out, "checked", node.isChecked());
+        flag(out, "clickable", node.isClickable());
+        flag(out, "enabled", node.isEnabled());
+        flag(out, "focusable", node.isFocusable());
+        flag(out, "focused", node.isFocused());
+        flag(out, "scrollable", node.isScrollable());
+        flag(out, "long-clickable", node.isLongClickable());
+        flag(out, "password", node.isPassword());
+        flag(out, "selected", node.isSelected());
+        if (sourceNodeId != null) {
+            try {
+                Object id = sourceNodeId.invoke(node);
+                if (id instanceof Long) {
+                    out.append(" ax-node-id=\"").append(((Long) id).longValue()).append('"');
+                }
+            } catch (Exception ignored) {
+            }
+        }
+        out.append(" bounds=\"")
+            .append('[').append(bounds.left).append(',').append(bounds.top).append(']')
+            .append('[').append(bounds.right).append(',').append(bounds.bottom).append(']')
+            .append('"');
+        int count = node.getChildCount();
+        if (count == 0) {
+            out.append(" />");
+            return;
+        }
+        out.append('>');
+        for (int i = 0; i < count; i++) {
+            emit(node.getChild(i), i, out);
+        }
+        out.append("</node>");
+    }
+
+    private static void attr(StringBuilder out, String name, CharSequence value) {
+        out.append(' ').append(name).append("=\"");
+        if (value != null) {
+            String text = value.toString();
+            for (int i = 0; i < text.length(); i++) {
+                char c = text.charAt(i);
+                switch (c) {
+                    case '&': out.append("&amp;"); break;
+                    case '<': out.append("&lt;"); break;
+                    case '>': out.append("&gt;"); break;
+                    case '"': out.append("&quot;"); break;
+                    case '\'': out.append("&apos;"); break;
+                    default:
+                        if (c < 0x20 && c != '\t') {
+                            out.append(' ');
+                        } else {
+                            out.append(c);
+                        }
+                }
+            }
+        }
+        out.append('"');
+    }
+
+    private static void flag(StringBuilder out, String name, boolean value) {
+        out.append(' ').append(name).append("=\"").append(value).append('"');
+    }
+}