Android: Simplify GEN_JNI.java generation (no behavior change)

Rather than generating a different ${Foo}Jni class for every
target when use_hashed_jni_names=true, also have classes use
org.chromium.base.natives.GEN_JNI.

Then, at the final step, have GEN_JNI forward calls to J.N.$HASH.

Makes a bit more work for R8 (it needs to inline all the GEN_JNI
methods), but move the "hashed functions" logic to live in
one spot at the end of the pipeline.

A byproduct of this is that toggling use_hashed_jni_names no
long requires all libraries to be recompiled (attached bug)

Bug: 1073921
Change-Id: I8df7c751b51d60e878f270c06e2e979dd9dbc821
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2162109Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762036}

base/android/jni_generator/BUILD.gn

@@ -82,12 +82,6 @@ group("jni_generator_tests") {
   ]
 }
 
-java_cpp_template("processor_args_java") {
-  package_path = "org/chromium/jni_generator"
-  sources = [ "ProcessorArgs.template" ]
-  defines = [ "HASH_JNI_NAMES_VALUE=$use_hashed_jni_names" ]
-}
-
 java_annotation_processor("jni_processor") {
   sources = [
     "java/src/org/chromium/jni_generator/JniProcessor.java",
@@ -110,6 +104,4 @@ java_annotation_processor("jni_processor") {
     "//third_party/android_deps:com_squareup_javapoet_java",
     "//third_party/android_deps:javax_annotation_jsr250_api_java",
   ]
-
-  srcjar_deps = [ ":processor_args_java" ]
 }

base/android/jni_generator/ProcessorArgs.template

-// Copyright 2018 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.jni_generator;
-
-class ProcessorArgs {
-    public static final boolean HASH_JNI_NAMES = HASH_JNI_NAMES_VALUE;
-}

base/android/jni_generator/golden/HashedSampleForAnnotationProcessorGenJni.2.golden

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base.natives;
+
+// This file is autogenerated by
+//     base/android/jni_generator/jni_registration_generator.py
+// Please do not change its content.
+
+public class GEN_JNI {
+    public static final boolean TESTING_ENABLED = false;
+    public static final boolean REQUIRE_MOCK = false;
+
+
+    public static void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_foo() {
+        J.N.MygCV2jQ();
+    }
+
+    public static Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_bar(Object sample) {
+        return J.N.MHuqnmXT(sample);
+    }
+
+    public static String org_chromium_example_jni_1generator_SampleForAnnotationProcessor_revString(String stringToReverse) {
+        return J.N.MM5Xkwyy(stringToReverse);
+    }
+
+    public static String[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_sendToNative(String[] strs) {
+        return J.N.MAC2QhR9(strs);
+    }
+
+    public static Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_sendSamplesToNative(Object[] strs) {
+        return J.N.MGhRh4Nd(strs);
+    }
+
+    public static boolean org_chromium_example_jni_1generator_SampleForAnnotationProcessor_hasPhalange() {
+        return J.N.MW0aEs4h();
+    }
+
+    public static int[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_testAllPrimitives(int zint, int[] ints, long zlong, long[] longs, short zshort, short[] shorts, char zchar, char[] chars, byte zbyte, byte[] bytes, double zdouble, double[] doubles, float zfloat, float[] floats, boolean zbool, boolean[] bools) {
+        return J.N.MlVFI4RX(zint, ints, zlong, longs, zshort, shorts, zchar, chars, zbyte, bytes, zdouble, doubles, zfloat, floats, zbool, bools);
+    }
+
+    public static void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_testSpecialTypes(Class clazz, Class[] classes, Throwable throwable, Throwable[] throwables, String string, String[] strings, Object tStruct, Object[] structs, Object obj, Object[] objects) {
+        J.N.MqOnlud7(clazz, classes, throwable, throwables, string, strings, tStruct, structs, obj, objects);
+    }
+
+    public static Throwable org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnThrowable() {
+        return J.N.MuZc76Vt();
+    }
+
+    public static Throwable[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnThrowables() {
+        return J.N.MAD53J7V();
+    }
+
+    public static Class org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnClass() {
+        return J.N.M$ZgOi4g();
+    }
+
+    public static Class[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnClasses() {
+        return J.N.M$hL1577();
+    }
+
+    public static String org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnString() {
+        return J.N.M0k1OjBK();
+    }
+
+    public static String[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnStrings() {
+        return J.N.Mssfs54E();
+    }
+
+    public static Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnStruct() {
+        return J.N.MSzcel_H();
+    }
+
+    public static Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnStructs() {
+        return J.N.MIBrQLK4();
+    }
+
+    public static Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObject() {
+        return J.N.M$hPywjv();
+    }
+
+    public static Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObjects() {
+        return J.N.MPpCU1l5();
+    }
+}

base/android/jni_generator/golden/HashedSampleForAnnotationProcessorGenJni.golden

@@ -2,50 +2,48 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package org.chromium.base.natives;
+package J;
 
 // This file is autogenerated by
 //     base/android/jni_generator/jni_registration_generator.py
 // Please do not change its content.
 
-public class GEN_JNI {
-  public static final boolean TESTING_ENABLED = false;
-  public static final boolean REQUIRE_MOCK = false;
+public class N {
 
-  public static native void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_foo();
 
-  public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_bar(Object sample);
+    public static native void MygCV2jQ();
 
-  public static native String org_chromium_example_jni_1generator_SampleForAnnotationProcessor_revString(String stringToReverse);
+    public static native Object MHuqnmXT(Object sample);
 
-  public static native String[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_sendToNative(String[] strs);
+    public static native String MM5Xkwyy(String stringToReverse);
 
-  public static native Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_sendSamplesToNative(Object[] strs);
+    public static native String[] MAC2QhR9(String[] strs);
 
-  public static native boolean org_chromium_example_jni_1generator_SampleForAnnotationProcessor_hasPhalange();
+    public static native Object[] MGhRh4Nd(Object[] strs);
 
-  public static native int[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_testAllPrimitives(int zint, int[] ints, long zlong, long[] longs, short zshort, short[] shorts, char zchar, char[] chars, byte zbyte, byte[] bytes, double zdouble, double[] doubles, float zfloat, float[] floats, boolean zbool, boolean[] bools);
+    public static native boolean MW0aEs4h();
 
-  public static native void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_testSpecialTypes(Class clazz, Class[] classes, Throwable throwable, Throwable[] throwables, String string, String[] strings, Object tStruct, Object[] structs, Object obj, Object[] objects);
+    public static native int[] MlVFI4RX(int zint, int[] ints, long zlong, long[] longs, short zshort, short[] shorts, char zchar, char[] chars, byte zbyte, byte[] bytes, double zdouble, double[] doubles, float zfloat, float[] floats, boolean zbool, boolean[] bools);
 
-  public static native Throwable org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnThrowable();
+    public static native void MqOnlud7(Class clazz, Class[] classes, Throwable throwable, Throwable[] throwables, String string, String[] strings, Object tStruct, Object[] structs, Object obj, Object[] objects);
 
-  public static native Throwable[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnThrowables();
+    public static native Throwable MuZc76Vt();
 
-  public static native Class org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnClass();
+    public static native Throwable[] MAD53J7V();
 
-  public static native Class[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnClasses();
+    public static native Class M$ZgOi4g();
 
-  public static native String org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnString();
+    public static native Class[] M$hL1577();
 
-  public static native String[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnStrings();
+    public static native String M0k1OjBK();
 
-  public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnStruct();
+    public static native String[] Mssfs54E();
 
-  public static native Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnStructs();
+    public static native Object MSzcel_H();
 
-  public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObject();
+    public static native Object[] MIBrQLK4();
 
-  public static native Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObjects();
+    public static native Object M$hPywjv();
 
+    public static native Object[] MPpCU1l5();
 }

base/android/jni_generator/golden/testGenJniFlagsDisabled.golden

@@ -12,6 +12,7 @@ public class GEN_JNI {
     public static final boolean TESTING_ENABLED = false;
     public static final boolean REQUIRE_MOCK = false;
 
+
     public static native void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_foo();
 
     public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_bar(Object sample);
@@ -47,5 +48,4 @@ public class GEN_JNI {
     public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObject();
 
     public static native Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObjects();
-
 }

base/android/jni_generator/golden/testGenJniFlagsMocksEnabled.golden

@@ -12,6 +12,7 @@ public class GEN_JNI {
     public static final boolean TESTING_ENABLED = true;
     public static final boolean REQUIRE_MOCK = false;
 
+
     public static native void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_foo();
 
     public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_bar(Object sample);
@@ -47,5 +48,4 @@ public class GEN_JNI {
     public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObject();
 
     public static native Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObjects();
-
 }

base/android/jni_generator/golden/testGenJniFlagsMocksRequired.golden

@@ -12,6 +12,7 @@ public class GEN_JNI {
     public static final boolean TESTING_ENABLED = true;
     public static final boolean REQUIRE_MOCK = true;
 
+
     public static native void org_chromium_example_jni_1generator_SampleForAnnotationProcessor_foo();
 
     public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_bar(Object sample);
@@ -47,5 +48,4 @@ public class GEN_JNI {
     public static native Object org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObject();
 
     public static native Object[] org_chromium_example_jni_1generator_SampleForAnnotationProcessor_returnObjects();
-
 }

base/android/jni_generator/golden/testProxyNativesJava.golden

@@ -12,10 +12,10 @@ public class GEN_JNI {
     public static final boolean TESTING_ENABLED = false;
     public static final boolean REQUIRE_MOCK = false;
 
+
     public static native void org_chromium_example_SampleProxyJni_foo(long nativePtr);
 
     public static native int org_chromium_example_SampleProxyJni_bar(int x, int y);
 
     public static native String org_chromium_example_SampleProxyJni_foobar(String x, String y);
-
 }

base/android/jni_generator/java/src/org/chromium/jni_generator/JniProcessor.java

@@ -5,7 +5,6 @@
 package org.chromium.jni_generator;
 
 import com.google.auto.service.AutoService;
-import com.google.common.base.Charsets;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
@@ -26,10 +25,7 @@ import org.chromium.base.annotations.CheckDiscard;
 import org.chromium.base.annotations.MainDex;
 import org.chromium.base.annotations.NativeMethods;
 
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
-import java.util.Base64;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -68,16 +64,14 @@ public class JniProcessor extends AbstractProcessor {
     private static final Class<NativeMethods> JNI_STATIC_NATIVES_CLASS = NativeMethods.class;
     private static final Class<MainDex> MAIN_DEX_CLASS = MainDex.class;
     private static final Class<CheckDiscard> CHECK_DISCARD_CLASS = CheckDiscard.class;
-    private static final Class<NativeLibraryLoadedStatus> JNI_STATUS_CLASS =
-            NativeLibraryLoadedStatus.class;
 
     private static final String CHECK_DISCARD_CRBUG = "crbug.com/993421";
     private static final String NATIVE_WRAPPER_CLASS_POSTFIX = "Jni";
 
-    // The native class name and package name used in debug.
-    private String mNativeClassStr = "GEN_JNI";
-    private String mNativeClassPackage = "org.chromium.base.natives";
-    private ClassName mNativeClassName;
+    private static final ClassName GEN_JNI_CLASS_NAME =
+            ClassName.get("org.chromium.base.natives", "GEN_JNI");
+    private static final ClassName JNI_STATUS_CLASS_NAME =
+            ClassName.get(NativeLibraryLoadedStatus.class);
 
     static final String NATIVE_TEST_FIELD_NAME = "TESTING_ENABLED";
     static final String NATIVE_REQUIRE_MOCK_FIELD_NAME = "REQUIRE_MOCK";
@@ -85,14 +79,6 @@ public class JniProcessor extends AbstractProcessor {
     // Builder for NativeClass which will hold all our native method declarations.
     private TypeSpec.Builder mNativesBuilder;
 
-    // Hash function for native method names.
-    private static MessageDigest sNativeMethodHashFunction;
-
-    // Limits the number characters of the Base64 encoded hash
-    // of the method descriptor used as name of the generated
-    // native method in GEN_JNI (prefixed with "M")
-    private static final int MAX_CHARS_FOR_HASHED_NATIVE_METHODS = 8;
-
     // Types that are non-primitives and should not be
     // casted to objects in native method declarations.
     static final ImmutableSet JNI_OBJECT_TYPE_EXCEPTIONS =
@@ -113,14 +99,6 @@ public class JniProcessor extends AbstractProcessor {
     }
 
     public JniProcessor() {
-        // If non-debug we use shorter names to save space.
-        if (ProcessorArgs.HASH_JNI_NAMES) {
-            // J.N
-            mNativeClassPackage = "J";
-            mNativeClassStr = "N";
-        }
-        mNativeClassName = ClassName.get(mNativeClassPackage, mNativeClassStr);
-
         FieldSpec.Builder testingFlagBuilder =
                 FieldSpec.builder(TypeName.BOOLEAN, NATIVE_TEST_FIELD_NAME)
                         .addModifiers(Modifier.STATIC, Modifier.PUBLIC);
@@ -129,19 +107,12 @@ public class JniProcessor extends AbstractProcessor {
                         .addModifiers(Modifier.STATIC, Modifier.PUBLIC);
 
         // State of mNativesBuilder needs to be preserved between processing rounds.
-        mNativesBuilder = TypeSpec.classBuilder(mNativeClassName)
+        mNativesBuilder = TypeSpec.classBuilder(GEN_JNI_CLASS_NAME)
                                   .addAnnotation(createAnnotationWithValue(
                                           Generated.class, JniProcessor.class.getCanonicalName()))
                                   .addModifiers(Modifier.PUBLIC, Modifier.FINAL)
                                   .addField(testingFlagBuilder.build())
                                   .addField(throwFlagBuilder.build());
-
-        try {
-            sNativeMethodHashFunction = MessageDigest.getInstance("MD5");
-        } catch (NoSuchAlgorithmException e) {
-            // MD5 support is required for all Java platforms so this should never happen.
-            printError(e.getMessage());
-        }
     }
 
     /**
@@ -223,7 +194,8 @@ public class JniProcessor extends AbstractProcessor {
             // provided elsewhere.
             if (!processingEnv.getOptions().containsKey(SKIP_GEN_JNI_ARG)) {
                 JavaFile nativeClassFile =
-                        JavaFile.builder(mNativeClassPackage, mNativesBuilder.build()).build();
+                        JavaFile.builder(GEN_JNI_CLASS_NAME.packageName(), mNativesBuilder.build())
+                                .build();
 
                 nativeClassFile.writeTo(processingEnv.getFiler());
             }
@@ -253,24 +225,9 @@ public class JniProcessor extends AbstractProcessor {
     String getNativeMethodName(String packageName, String className, String oldMethodName) {
         // e.g. org.chromium.base.Foo_Class.bar
         // => org_chromium_base_Foo_1Class_bar()
-        String descriptor = String.format("%s.%s.%s", packageName, className, oldMethodName)
+        return String.format("%s.%s.%s", packageName, className, oldMethodName)
                 .replaceAll("_", "_1")
                 .replaceAll("\\.", "_");
-        if (ProcessorArgs.HASH_JNI_NAMES) {
-            // Must start with a character.
-            byte[] hash = sNativeMethodHashFunction.digest(descriptor.getBytes(Charsets.UTF_8));
-
-            String methodName = "M"
-                    + Base64.getEncoder()
-                              .encodeToString(hash)
-                              .replace("/", "_")
-                              .replace("+", "$")
-                              .replace("=", "");
-
-            return methodName.substring(
-                    0, Math.min(MAX_CHARS_FOR_HASHED_NATIVE_METHODS, methodName.length()));
-        }
-        return descriptor;
     }
 
     /**
@@ -411,18 +368,17 @@ public class JniProcessor extends AbstractProcessor {
                 MethodSpec.methodBuilder("get")
                         .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
                         .returns(nativeInterfaceType)
-                        .beginControlFlow("if ($T.$N)", mNativeClassName, NATIVE_TEST_FIELD_NAME)
+                        .beginControlFlow("if ($T.$N)", GEN_JNI_CLASS_NAME, NATIVE_TEST_FIELD_NAME)
                         .beginControlFlow("if ($N != null)", testTarget)
                         .addStatement("return $N", testTarget)
                         .endControlFlow()
                         .beginControlFlow(
-                                "if ($T.$N)", mNativeClassName, NATIVE_REQUIRE_MOCK_FIELD_NAME)
+                                "if ($T.$N)", GEN_JNI_CLASS_NAME, NATIVE_REQUIRE_MOCK_FIELD_NAME)
                         .addStatement("throw new UnsupportedOperationException($S)",
                                 noMockExceptionString)
                         .endControlFlow()
                         .endControlFlow()
-                        .addStatement("$T.$N($L)", ClassName.get(JNI_STATUS_CLASS), "checkLoaded",
-                                isMainDex)
+                        .addStatement("$T.$N($L)", JNI_STATUS_CLASS_NAME, "checkLoaded", isMainDex)
                         .addStatement("return new $N()", name)
                         .build();
 
@@ -445,7 +401,7 @@ public class JniProcessor extends AbstractProcessor {
                         .addModifiers(Modifier.PUBLIC)
                         .addAnnotation(Override.class)
                         .addParameter(nativeInterfaceType, "instance")
-                        .beginControlFlow("if (!$T.$N)", mNativeClassName, NATIVE_TEST_FIELD_NAME)
+                        .beginControlFlow("if (!$T.$N)", GEN_JNI_CLASS_NAME, NATIVE_TEST_FIELD_NAME)
                         .addStatement(
                                 "throw new RuntimeException($S)", mocksNotEnabledExceptionString)
                         .endControlFlow()
@@ -495,7 +451,7 @@ public class JniProcessor extends AbstractProcessor {
         }
 
         // Make call to native function.
-        builder.addCode("$T.$N(", mNativeClassName, staticNativeMethod);
+        builder.addCode("$T.$N(", GEN_JNI_CLASS_NAME, staticNativeMethod);
 
         // Add params to native call.
         ArrayList<String> paramNames = new ArrayList<>();
@@ -529,10 +485,8 @@ public class JniProcessor extends AbstractProcessor {
     /**
      * Since some types may decay to objects in the native method
      * this method returns a javadoc string that contains the
-     * type information from the old method. The fully qualified
-     * descriptor of the method is also included since the name
-     * may be hashed.
-     */
+     * type information from the old method.
+     **/
     String createNativeMethodJavadocString(ClassName outerType, ExecutableElement oldMethod) {
         ArrayList<String> docLines = new ArrayList<>();
 

base/android/jni_generator/jni_generator.py

@@ -138,6 +138,8 @@ class NativeMethod(object):
       self.name = self.name[0].upper() + self.name[1:]
 
     self.proxy_name = kwargs.get('proxy_name', self.name)
+    # Non-hashed proxy name if applicable.
+    self.proxy_name_orig = None
 
     if self.params:
       assert type(self.params) is list
@@ -469,10 +471,6 @@ class JniParams(object):
       index = signature_line.index(prefix)
     return '"%s"' % signature_line[index + len(prefix):]
 
-  @staticmethod
-  def MakeProxyParamSignature(params):
-    return ', '.join('%s %s' % (p.datatype, p.name) for p in params)
-
   @staticmethod
   def Parse(params, use_proxy_types=False):
     """Parses the params into a list of Param objects."""
@@ -969,22 +967,15 @@ class JNIFromJavaP(object):
 # declaration in another class (org.chromium.base.natives.GEN_JNI)
 # but generates wrapper code so it can be called through the declaring class.
 class ProxyHelpers(object):
-  NATIVE_PROXY_CLASS_NAME = 'GEN_JNI'
-  NATIVE_PROXY_PACKAGE_NAME = 'org/chromium/base/natives'
-
   MAX_CHARS_FOR_HASHED_NATIVE_METHODS = 8
 
   @staticmethod
   def GetClass(use_hash):
-    if use_hash:
-      return 'N'
-    return ProxyHelpers.NATIVE_PROXY_CLASS_NAME
+    return 'N' if use_hash else 'GEN_JNI'
 
   @staticmethod
   def GetPackage(use_hash):
-    if use_hash:
-      return 'J'
-    return ProxyHelpers.NATIVE_PROXY_PACKAGE_NAME
+    return 'J' if use_hash else 'org/chromium/base/natives'
 
   @staticmethod
   def GetQualifiedClass(use_hash):
@@ -1009,9 +1000,8 @@ class ProxyHelpers(object):
   def CreateProxyMethodName(fully_qualified_class, old_name, use_hash=False):
     """Returns the literal method name for the corresponding proxy method"""
     if use_hash:
-      hashed_name = ProxyHelpers.CreateHashedMethodName(fully_qualified_class,
+      return ProxyHelpers.CreateHashedMethodName(fully_qualified_class,
                                                  old_name)
-      return hashed_name
 
     # The annotation processor currently uses a method name
     # org_chromium_example_foo_method_1name escaping _ to _1
@@ -1045,6 +1035,9 @@ class ProxyHelpers(object):
             is_proxy=True,
             proxy_name=unescaped_proxy_name,
             ptr_type=ptr_type)
+        if use_hash:
+          native.proxy_name_orig = ProxyHelpers.CreateProxyMethodName(
+              fully_qualified_class, name, False)
         methods.append(native)
 
     return methods
@@ -1753,8 +1746,7 @@ See SampleForTests.java for more details.
       '--use_proxy_hash',
       action='store_true',
       help='Hashes the native declaration of methods used '
-      'in @JniNatives interface. And uses a shorter name and package'
-      ' than GEN_JNI.')
+      'in @JniNatives interface.')
   parser.add_argument(
       '--feature_list_file',
       default='',

base/android/jni_generator/jni_generator_tests.py

@@ -1792,14 +1792,18 @@ class ProxyTestGenerator(BaseTest):
         golden_file='HashedSampleForAnnotationProcessor_jni.golden')
 
     reg_dict = jni_registration_generator._DictForPath(
-        self._JoinScriptDir(path))
+        self._JoinScriptDir(path), use_proxy_hash=True)
     reg_dict = self._MergeRegistrationForTests([reg_dict])
 
-    proxy_opts = jni_registration_generator.ProxyOptions()
+    proxy_opts = jni_registration_generator.ProxyOptions(use_hash=True)
     self.AssertGoldenTextEquals(
         jni_registration_generator.CreateProxyJavaFromDict(
             reg_dict, proxy_opts),
         golden_file='HashedSampleForAnnotationProcessorGenJni.golden')
+    self.AssertGoldenTextEquals(
+        jni_registration_generator.CreateProxyJavaFromDict(
+            reg_dict, proxy_opts, forwarding=True),
+        golden_file='HashedSampleForAnnotationProcessorGenJni.2.golden')
 
   def testProxyJniExample(self):
     generated_text = self._CreateJniHeaderFromFile(

base/android/jni_generator/jni_registration_generator.py

@@ -27,6 +27,7 @@ MERGEABLE_KEYS = [
     'JNI_NATIVE_METHOD',
     'JNI_NATIVE_METHOD_ARRAY',
     'PROXY_NATIVE_SIGNATURES',
+    'FORWARDING_PROXY_METHODS',
     'PROXY_NATIVE_METHOD_ARRAY',
     'PROXY_NATIVE_METHOD_ARRAY_MAIN_DEX',
     'REGISTER_MAIN_DEX_NATIVES',
@@ -83,10 +84,23 @@ def _Generate(java_file_paths,
 
   with build_utils.AtomicOutput(srcjar_path) as f:
     with zipfile.ZipFile(f, 'w') as srcjar:
+      if proxy_opts.use_hash:
+        # J/N.java
         build_utils.AddToZipHermetic(
             srcjar,
-          '%s.java' % jni_generator.ProxyHelpers.GetQualifiedClass(
-              proxy_opts.use_hash),
+            '%s.java' % jni_generator.ProxyHelpers.GetQualifiedClass(True),
+            data=CreateProxyJavaFromDict(combined_dict, proxy_opts))
+        # org/chromium/base/natives/GEN_JNI.java
+        build_utils.AddToZipHermetic(
+            srcjar,
+            '%s.java' % jni_generator.ProxyHelpers.GetQualifiedClass(False),
+            data=CreateProxyJavaFromDict(
+                combined_dict, proxy_opts, forwarding=True))
+      else:
+        # org/chromium/base/natives/GEN_JNI.java
+        build_utils.AddToZipHermetic(
+            srcjar,
+            '%s.java' % jni_generator.ProxyHelpers.GetQualifiedClass(False),
             data=CreateProxyJavaFromDict(combined_dict, proxy_opts))
 
 
@@ -188,7 +202,7 @@ JNI_REGISTRATION_EXPORT bool ${REGISTRATION_NAME}(JNIEnv* env) {
   registration_dict['REGISTER_MAIN_DEX_PROXY_NATIVES'] = main_dex_call
 
 
-def CreateProxyJavaFromDict(registration_dict, proxy_opts):
+def CreateProxyJavaFromDict(registration_dict, proxy_opts, forwarding=False):
   template = string.Template("""\
 // Copyright 2018 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
@@ -201,25 +215,36 @@ package ${PACKAGE};
 // Please do not change its content.
 
 public class ${CLASS_NAME} {
+${FIELDS}
+${METHODS}
+}
+""")
+
+  is_natives_class = not forwarding and proxy_opts.use_hash
+  class_name = jni_generator.ProxyHelpers.GetClass(is_natives_class)
+  package = jni_generator.ProxyHelpers.GetPackage(is_natives_class)
+
+  if forwarding or not proxy_opts.use_hash:
+    fields = string.Template("""\
     public static final boolean TESTING_ENABLED = ${TESTING_ENABLED};
     public static final boolean REQUIRE_MOCK = ${REQUIRE_MOCK};
-${SIGNATURES}
+""").substitute({
+        'TESTING_ENABLED': str(proxy_opts.enable_mocks).lower(),
+        'REQUIRE_MOCK': str(proxy_opts.require_mocks).lower(),
+    })
+  else:
+    fields = ''
 
-}
-""")
+  if forwarding:
+    methods = registration_dict['FORWARDING_PROXY_METHODS']
+  else:
+    methods = registration_dict['PROXY_NATIVE_SIGNATURES']
 
   return template.substitute({
-      'TESTING_ENABLED':
-      str(proxy_opts.enable_mocks).lower(),
-      'REQUIRE_MOCK':
-      str(proxy_opts.require_mocks).lower(),
-      'CLASS_NAME':
-      jni_generator.ProxyHelpers.GetClass(proxy_opts.use_hash),
-      'PACKAGE':
-      jni_generator.ProxyHelpers.GetPackage(proxy_opts.use_hash).replace(
-          '/', '.'),
-      'SIGNATURES':
-      registration_dict['PROXY_NATIVE_SIGNATURES']
+      'CLASS_NAME': class_name,
+      'FIELDS': fields,
+      'PACKAGE': package.replace('/', '.'),
+      'METHODS': methods
   })
 
 
@@ -310,10 +335,16 @@ class HeaderGenerator(object):
     self._AddClassPathDeclarations()
     self._AddForwardDeclaration()
     self._AddJNINativeMethodsArrays()
-    self._AddProxySignatures()
     self._AddProxyNativeMethodKStrings()
     self._AddRegisterNativesCalls()
     self._AddRegisterNativesFunctions()
+
+    self.registration_dict['PROXY_NATIVE_SIGNATURES'] = ('\n'.join(
+        _MakeProxySignature(n) for n in self.proxy_natives))
+    if self.use_proxy_hash:
+      self.registration_dict['FORWARDING_PROXY_METHODS'] = ('\n'.join(
+          _MakeForwardingProxy(n) for n in self.proxy_natives))
+
     return self.registration_dict
 
   def _SetDictValue(self, key, value):
@@ -412,10 +443,6 @@ ${KMETHODS}
     }
     return template.substitute(values)
 
-  def _AddProxySignatures(self):
-    self.registration_dict['PROXY_NATIVE_SIGNATURES'] = ('\n'.join(
-        _MakeProxySignature(n) for n in self.proxy_natives))
-
   def _AddProxyNativeMethodKStrings(self):
     """Returns KMethodString for wrapped native methods in all_classes """
 
@@ -508,17 +535,45 @@ ${NATIVES}\
     return ''
 
 
-def _MakeProxySignature(proxy_native):
-  signature_template = string.Template("""
-  public static native ${RETURN_TYPE} ${NAME}(${PARAMS});""")
+def _MakeForwardingProxy(proxy_native):
+  template = string.Template("""
+    public static ${RETURN_TYPE} ${ORIG_NAME}(${PARAMS_WITH_TYPES}) {
+        ${MAYBE_RETURN}${PROXY_CLASS}.${NAME}($PARAM_NAMES);
+    }""")
 
-  return signature_template.substitute({
+  params_with_types = ', '.join(
+      '%s %s' % (p.datatype, p.name) for p in proxy_native.params)
+  param_names = ', '.join(p.name for p in proxy_native.params)
+  proxy_class = jni_generator.ProxyHelpers.GetQualifiedClass(True)
+
+  return template.substitute({
       'RETURN_TYPE':
       proxy_native.return_type,
+      'ORIG_NAME':
+      proxy_native.proxy_name_orig,
+      'PARAMS_WITH_TYPES':
+      params_with_types,
+      'MAYBE_RETURN':
+      '' if proxy_native.return_type == 'void' else 'return ',
+      'PROXY_CLASS':
+      proxy_class.replace('/', '.'),
       'NAME':
       proxy_native.proxy_name,
-      'PARAMS':
-      jni_generator.JniParams.MakeProxyParamSignature(proxy_native.params)
+      'PARAM_NAMES':
+      param_names,
+  })
+
+
+def _MakeProxySignature(proxy_native):
+  signature_template = string.Template("""
+    public static native ${RETURN_TYPE} ${NAME}(${PARAMS_WITH_TYPES});""")
+
+  params_with_types = ', '.join(
+      '%s %s' % (p.datatype, p.name) for p in proxy_native.params)
+  return signature_template.substitute({
+      'RETURN_TYPE': proxy_native.return_type,
+      'NAME': proxy_native.proxy_name,
+      'PARAMS_WITH_TYPES': params_with_types,
   })
 
 
@@ -547,7 +602,7 @@ def main(argv):
   arg_parser.add_argument(
       '--srcjar-path',
       required=True,
-      help='Path to output srcjar for GEN_JNI.java (Or J/N.java if proxy'
+      help='Path to output srcjar for GEN_JNI.java (and J/N.java if proxy'
       ' hash is enabled).')
   arg_parser.add_argument(
       '--sources-exclusions',

build/config/android/rules.gni

@@ -1857,12 +1857,8 @@ if (enable_java_templates) {
         "*/R\$*.class",
         "*/Manifest.class",
         "*/Manifest\$*.class",
+        "*/GEN_JNI.class",
       ]
-      if (use_hashed_jni_names) {
-        jar_excluded_patterns += [ "J/N.class" ]
-      } else {
-        jar_excluded_patterns += [ "*/GEN_JNI.class" ]
-      }
     }
   }
 
@@ -1916,7 +1912,7 @@ if (enable_java_templates) {
       defines = []
 
       # Set these even when !use_final_fields so that they have correct default
-      # values withnin junit_binary().
+      # values within junit_binary(), which ignores jar_excluded_patterns.
       if (is_java_debug || dcheck_always_on) {
         defines += [ "_DCHECK_IS_ON" ]
       }