Add a wrapper for IInputMethodPrivilegedOperations

This is a mechanical refactoring to split out boilerplate code around
IPCs from InputMethodManager to another file.

Bug: 114418674
Bug: 113177698
Test: atest CtsInputMethodTestCases CtsInputMethodServiceHostTestCases
Change-Id: I9ca251482867daea84c2777f74fd9b8a2b0f29cd

2 files changed, 203 insertions, 49 deletions

diff --git a/core/java/android/inputmethodservice/InputMethodService.java b/core/java/android/inputmethodservice/InputMethodService.java
index ea7d42ee79a9..d3abe7f38808 100644
--- a/core/java/android/inputmethodservice/InputMethodService.java
+++ b/core/java/android/inputmethodservice/InputMethodService.java
@@ -42,7 +42,6 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
-import android.os.RemoteException;
 import android.os.ResultReceiver;
 import android.os.SystemClock;
 import android.provider.Settings;
@@ -82,6 +81,7 @@ import android.widget.TextView;
 
 import com.android.internal.inputmethod.IInputContentUriToken;
 import com.android.internal.inputmethod.IInputMethodPrivilegedOperations;
+import com.android.internal.inputmethod.InputMethodPrivilegedOperations;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
@@ -346,7 +346,7 @@ public class InputMethodService extends AbstractInputMethodService {
     private static final int BACK_DISPOSITION_MAX = BACK_DISPOSITION_ADJUST_NOTHING;
 
     InputMethodManager mImm;
-    private IInputMethodPrivilegedOperations mPrivOps;
+    private InputMethodPrivilegedOperations mPrivOps = new InputMethodPrivilegedOperations();
 
     @UnsupportedAppUsage
     int mTheme = 0;
@@ -457,11 +457,7 @@ public class InputMethodService extends AbstractInputMethodService {
         @Override
         public final void initializeInternal(IBinder token,
                 IInputMethodPrivilegedOperations privilegedOperations) {
-            if (mToken != null) {
-                throw new IllegalStateException("initializeInternal() must be called at most once."
-                        + " privOps=" + privilegedOperations);
-            }
-            mPrivOps = privilegedOperations;
+            mPrivOps.set(privilegedOperations);
             attachToken(token);
         }
 
@@ -540,12 +536,7 @@ public class InputMethodService extends AbstractInputMethodService {
         public void dispatchStartInputWithToken(@Nullable InputConnection inputConnection,
                 @NonNull EditorInfo editorInfo, boolean restarting,
                 @NonNull IBinder startInputToken) {
-            try {
-                mPrivOps.reportStartInput(startInputToken);
-            } catch (RemoteException e) {
-                throw e.rethrowFromSystemServer();
-            }
-
+            mPrivOps.reportStartInput(startInputToken);
             // This needs to be dispatched to interface methods rather than doStartInput().
             // Otherwise IME developers who have overridden those interface methods will lose
             // notifications.
@@ -607,14 +598,7 @@ public class InputMethodService extends AbstractInputMethodService {
     }
 
     private void setImeWindowStatus(int visibilityFlags, int backDisposition) {
-        if (mPrivOps == null) {
-            return;
-        }
-        try {
-            mPrivOps.setImeWindowStatus(visibilityFlags, backDisposition);
-        } catch (RemoteException e) {
-            throw e.rethrowFromSystemServer();
-        }
+        mPrivOps.setImeWindowStatus(visibilityFlags, backDisposition);
     }
 
     /**
@@ -1223,14 +1207,7 @@ public class InputMethodService extends AbstractInputMethodService {
     }
 
     private void reportFullscreenMode() {
-        if (mPrivOps == null) {
-            return;
-        }
-        try {
-            mPrivOps.reportFullscreenMode(mIsFullscreen);
-        } catch (RemoteException e) {
-            throw e.rethrowFromSystemServer();
-        }
+        mPrivOps.reportFullscreenMode(mIsFullscreen);
     }
 
     /**
@@ -1945,14 +1922,7 @@ public class InputMethodService extends AbstractInputMethodService {
      * <p>TODO: We probably need to reconsider how IME should be handled.</p>
      */
     private void clearLastInputMethodWindowForTransition() {
-        if (mPrivOps == null) {
-            return;
-        }
-        try {
-            mPrivOps.clearLastInputMethodWindowForTransition();
-        } catch (RemoteException e) {
-            throw e.rethrowFromSystemServer();
-        }
+        mPrivOps.clearLastInputMethodWindowForTransition();
     }
 
     /**
@@ -2885,23 +2855,15 @@ public class InputMethodService extends AbstractInputMethodService {
      */
     private void exposeContentInternal(@NonNull InputContentInfo inputContentInfo,
             @NonNull EditorInfo editorInfo) {
-        if (mPrivOps == null) {
-            return;
-        }
-        final IInputContentUriToken uriToken;
         final Uri contentUri = inputContentInfo.getContentUri();
-        try {
-            uriToken = mPrivOps.createInputContentUriToken(contentUri, editorInfo.packageName);
-            if (uriToken == null) {
-                return;
-            }
-        } catch (RemoteException e) {
+        final IInputContentUriToken uriToken =
+                mPrivOps.createInputContentUriToken(contentUri, editorInfo.packageName);
+        if (uriToken == null) {
             Log.e(TAG, "createInputContentAccessToken failed. contentUri=" + contentUri.toString()
-                    + " packageName=" + editorInfo.packageName, e);
+                    + " packageName=" + editorInfo.packageName);
             return;
         }
         inputContentInfo.setUriToken(uriToken);
-        return;
     }
 
     private static int mapToImeWindowStatus(boolean isInputViewShown) {
diff --git a/core/java/com/android/internal/inputmethod/InputMethodPrivilegedOperations.java b/core/java/com/android/internal/inputmethod/InputMethodPrivilegedOperations.java
new file mode 100644
index 000000000000..45719f057ed6
--- /dev/null
+++ b/core/java/com/android/internal/inputmethod/InputMethodPrivilegedOperations.java
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.inputmethod;
+
+import android.annotation.AnyThread;
+import android.annotation.Nullable;
+import android.net.Uri;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Log;
+
+import com.android.internal.annotations.GuardedBy;
+
+/**
+ * A utility class to take care of boilerplate code around IPCs.
+ */
+public final class InputMethodPrivilegedOperations {
+    private static final String TAG = "InputMethodPrivilegedOperations";
+
+    private static final class OpsHolder {
+        @Nullable
+        @GuardedBy("this")
+        private IInputMethodPrivilegedOperations mPrivOps;
+
+        /**
+         * Sets {@link IInputMethodPrivilegedOperations}.
+         *
+         * <p>This method can be called only once.</p>
+         *
+         * @param privOps Binder interface to be set
+         */
+        @AnyThread
+        public synchronized void set(IInputMethodPrivilegedOperations privOps) {
+            if (mPrivOps != null) {
+                throw new IllegalStateException(
+                        "IInputMethodPrivilegedOperations must be set at most once."
+                                + " privOps=" + privOps);
+            }
+            mPrivOps = privOps;
+        }
+
+        /**
+         * A simplified version of {@link android.os.Debug#getCaller()}.
+         *
+         * @return method name of the caller.
+         */
+        @AnyThread
+        private static String getCallerMethodName() {
+            final StackTraceElement[] callStack = Thread.currentThread().getStackTrace();
+            if (callStack.length <= 4) {
+                return "<bottom of call stack>";
+            }
+            return callStack[4].getMethodName();
+        }
+
+        @AnyThread
+        @Nullable
+        public synchronized IInputMethodPrivilegedOperations getAndWarnIfNull() {
+            if (mPrivOps == null) {
+                Log.e(TAG, getCallerMethodName() + " is ignored."
+                        + " Call it within attachToken() and InputMethodService.onDestroy()");
+            }
+            return mPrivOps;
+        }
+    }
+    private final OpsHolder mOps = new OpsHolder();
+
+    /**
+     * Sets {@link IInputMethodPrivilegedOperations}.
+     *
+     * <p>This method can be called only once.</p>
+     *
+     * @param privOps Binder interface to be set
+     */
+    @AnyThread
+    public void set(IInputMethodPrivilegedOperations privOps) {
+        mOps.set(privOps);
+    }
+
+    /**
+     * Calls {@link IInputMethodPrivilegedOperations#setImeWindowStatus(int, int)}.
+     *
+     * @param vis visibility flags
+     * @param backDisposition disposition flags
+     * @see android.inputmethodservice.InputMethodService#IME_ACTIVE
+     * @see android.inputmethodservice.InputMethodService#IME_VISIBLE
+     * @see android.inputmethodservice.InputMethodService#BACK_DISPOSITION_DEFAULT
+     * @see android.inputmethodservice.InputMethodService#BACK_DISPOSITION_ADJUST_NOTHING
+     */
+    @AnyThread
+    public void setImeWindowStatus(int vis, int backDisposition) {
+        final IInputMethodPrivilegedOperations ops = mOps.getAndWarnIfNull();
+        if (ops == null) {
+            return;
+        }
+        try {
+            ops.setImeWindowStatus(vis, backDisposition);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Calls {@link IInputMethodPrivilegedOperations#reportStartInput(IBinder)}.
+     *
+     * @param startInputToken {@link IBinder} token to distinguish startInput session
+     */
+    @AnyThread
+    public void reportStartInput(IBinder startInputToken) {
+        final IInputMethodPrivilegedOperations ops = mOps.getAndWarnIfNull();
+        if (ops == null) {
+            return;
+        }
+        try {
+            ops.reportStartInput(startInputToken);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Calls {@link IInputMethodPrivilegedOperations#clearLastInputMethodWindowForTransition()}.
+     */
+    @AnyThread
+    public void clearLastInputMethodWindowForTransition() {
+        final IInputMethodPrivilegedOperations ops = mOps.getAndWarnIfNull();
+        if (ops == null) {
+            return;
+        }
+        try {
+            ops.clearLastInputMethodWindowForTransition();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Calls {@link IInputMethodPrivilegedOperations#createInputContentUriToken(Uri, String)}.
+     *
+     * @param contentUri Content URI to which a temporary read permission should be granted
+     * @param packageName Indicates what package needs to have a temporary read permission
+     * @return special Binder token that should be set to
+     *         {@link android.view.inputmethod.InputContentInfo#setUriToken(IInputContentUriToken)}
+     */
+    @AnyThread
+    public IInputContentUriToken createInputContentUriToken(Uri contentUri, String packageName) {
+        final IInputMethodPrivilegedOperations ops = mOps.getAndWarnIfNull();
+        if (ops == null) {
+            return null;
+        }
+        try {
+            return ops.createInputContentUriToken(contentUri, packageName);
+        } catch (RemoteException e) {
+            // For historical reasons, this error was silently ignored.
+            // Note that the caller already logs error so we do not need additional Log.e() here.
+            // TODO(team): Check if it is safe to rethrow error here.
+            return null;
+        }
+    }
+
+    /**
+     * Calls {@link IInputMethodPrivilegedOperations#reportFullscreenMode(boolean)}.
+     *
+     * @param fullscreen {@code true} if the IME enters full screen mode
+     */
+    @AnyThread
+    public void reportFullscreenMode(boolean fullscreen) {
+        final IInputMethodPrivilegedOperations ops = mOps.getAndWarnIfNull();
+        if (ops == null) {
+            return;
+        }
+        try {
+            ops.reportFullscreenMode(fullscreen);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+}