[Android] Java Bridge with Gin: implement Java methods invocation

content/browser/renderer_host/java/gin_java_method_invocation_helper.cc

+// Copyright 2014 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.
+
+#include "content/browser/renderer_host/java/gin_java_method_invocation_helper.h"
+
+#include <unistd.h>
+
+#include "base/android/event_log.h"
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/float_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+#include "content/browser/renderer_host/java/java_method.h"
+#include "content/browser/renderer_host/java/jni_helper.h"
+#include "content/common/android/gin_java_bridge_value.h"
+#include "content/public/browser/browser_thread.h"
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF8ToJavaString;
+using base::android::ScopedJavaLocalRef;
+
+namespace content {
+
+namespace {
+
+const char kJavaLangString[] = "java/lang/String";
+const char kObjectIsGone[] = "Java object is gone";
+const char kMethodNotFound[] = "Method not found";
+const char kAccessToObjectGetClassIsBlocked[] =
+    "Access to java.lang.Object.getClass is blocked";
+const char kJavaExceptionRaised[] =
+    "Java exception has been raised during method invocation";
+const char kUndefined[] = "undefined";
+
+}  // namespace
+
+GinJavaMethodInvocationHelper::GinJavaMethodInvocationHelper(
+    scoped_ptr<ObjectDelegate> object,
+    const std::string& method_name,
+    const base::ListValue& arguments)
+    : object_(object.Pass()),
+      method_name_(method_name),
+      arguments_(arguments.DeepCopy()) {
+}
+
+GinJavaMethodInvocationHelper::~GinJavaMethodInvocationHelper() {}
+
+void GinJavaMethodInvocationHelper::Init(DispatcherDelegate* dispatcher) {
+  // Build on the UI thread a map of object_id -> WeakRef for Java objects from
+  // |arguments_|.  Then we can use this map on the background thread without
+  // accessing |dispatcher|.
+  BuildObjectRefsFromListValue(dispatcher, arguments_.get());
+}
+
+// As V8ValueConverter has finite recursion depth when serializing
+// JavaScript values, we don't bother about having a recursion threshold here.
+void GinJavaMethodInvocationHelper::BuildObjectRefsFromListValue(
+    DispatcherDelegate* dispatcher,
+    const base::Value* list_value) {
+  DCHECK(list_value->IsType(base::Value::TYPE_LIST));
+  const base::ListValue* list;
+  list_value->GetAsList(&list);
+  for (base::ListValue::const_iterator iter = list->begin();
+       iter != list->end();
+       ++iter) {
+    if (AppendObjectRef(dispatcher, *iter))
+      continue;
+    if ((*iter)->IsType(base::Value::TYPE_LIST)) {
+      BuildObjectRefsFromListValue(dispatcher, *iter);
+    } else if ((*iter)->IsType(base::Value::TYPE_DICTIONARY)) {
+      BuildObjectRefsFromDictionaryValue(dispatcher, *iter);
+    }
+  }
+}
+
+void GinJavaMethodInvocationHelper::BuildObjectRefsFromDictionaryValue(
+    DispatcherDelegate* dispatcher,
+    const base::Value* dict_value) {
+  DCHECK(dict_value->IsType(base::Value::TYPE_DICTIONARY));
+  const base::DictionaryValue* dict;
+  dict_value->GetAsDictionary(&dict);
+  for (base::DictionaryValue::Iterator iter(*dict);
+       !iter.IsAtEnd();
+       iter.Advance()) {
+    if (AppendObjectRef(dispatcher, &iter.value()))
+      continue;
+    if (iter.value().IsType(base::Value::TYPE_LIST)) {
+      BuildObjectRefsFromListValue(dispatcher, &iter.value());
+    } else if (iter.value().IsType(base::Value::TYPE_DICTIONARY)) {
+      BuildObjectRefsFromDictionaryValue(dispatcher, &iter.value());
+    }
+  }
+}
+
+bool GinJavaMethodInvocationHelper::AppendObjectRef(
+    DispatcherDelegate* dispatcher,
+    const base::Value* raw_value) {
+  if (!GinJavaBridgeValue::ContainsGinJavaBridgeValue(raw_value))
+    return false;
+  scoped_ptr<const GinJavaBridgeValue> value(
+      GinJavaBridgeValue::FromValue(raw_value));
+  if (!value->IsType(GinJavaBridgeValue::TYPE_OBJECT_ID))
+    return false;
+  GinJavaBoundObject::ObjectID object_id;
+  if (value->GetAsObjectID(&object_id)) {
+    ObjectRefs::iterator iter = object_refs_.find(object_id);
+    if (iter == object_refs_.end()) {
+      JavaObjectWeakGlobalRef object_ref(
+          dispatcher->GetObjectWeakRef(object_id));
+      if (!object_ref.is_null()) {
+        object_refs_.insert(std::make_pair(object_id, object_ref));
+      }
+    }
+  }
+  return true;
+}
+
+void GinJavaMethodInvocationHelper::Invoke() {
+  JNIEnv* env = AttachCurrentThread();
+  base::android::ScopedJavaLocalRef<jobject> obj(object_->GetLocalRef(env));
+  if (obj.is_null()) {
+    SetInvocationFailure(kObjectIsGone);
+    return;
+  }
+  const JavaMethod* method =
+      object_->FindMethod(method_name_, arguments_->GetSize());
+  if (!method) {
+    SetInvocationFailure(kMethodNotFound);
+    return;
+  }
+
+  if (object_->IsObjectGetClassMethod(method)) {
+    // See frameworks/base/core/java/android/webkit/EventLogTags.logtags
+    base::android::eventLogWriteInt(70151, getuid());

[bulach, 2014/06/09 11:44:33]

any chance we could have those defined here?!

[mnaganov (inactive), 2014/06/11 13:50:44]

I have moved the value into a named constant. There is in fact a method in Java
EventLog class for obtaining a tag code by its name, but then we have to define
tag names here :) Since it's us who actually define the mapping, using the int
code directly is just simpler and faster.

+    SetInvocationFailure(kAccessToObjectGetClassIsBlocked);
+    return;
+  }
+
+  std::vector<jvalue> parameters(method->num_parameters());
+  for (size_t i = 0; i < method->num_parameters(); ++i) {
+    const base::Value* argument;
+    arguments_->Get(i, &argument);
+    parameters[i] = CoerceJavaScriptValueToJavaValue(argument,
+                                                     method->parameter_type(i),
+                                                     true);
+  }
+  InvokeMethod(obj.obj(),
+               method->return_type(),
+               method->id(),
+               &parameters[0]);
+
+  // Now that we're done with the jvalue, release any local references created
+  // by CoerceJavaScriptValueToJavaValue().
+  for (size_t i = 0; i < method->num_parameters(); ++i) {
+    ReleaseJavaValueIfRequired(env, &parameters[i], method->parameter_type(i));
+  }
+}
+
+void GinJavaMethodInvocationHelper::SetInvocationFailure(
+    const char* error_message) {
+  holds_primitive_result_ = true;
+  primitive_result_.reset(new base::ListValue());
+  error_message_ = error_message;
+}
+
+void GinJavaMethodInvocationHelper::SetPrimitiveResult(
+    const base::ListValue& result_wrapper) {
+  holds_primitive_result_ = true;
+  primitive_result_.reset(result_wrapper.DeepCopy());
+}
+
+void GinJavaMethodInvocationHelper::SetObjectResult(
+    const base::android::JavaRef<jobject>& object,
+    const base::android::JavaRef<jclass>& safe_annotation_clazz) {
+  holds_primitive_result_ = false;
+  object_result_.Reset(object);
+  safe_annotation_clazz_.Reset(safe_annotation_clazz);
+}
+
+bool GinJavaMethodInvocationHelper::HoldsPrimitiveResult() {
+  return holds_primitive_result_;
+}
+
+const base::ListValue& GinJavaMethodInvocationHelper::GetPrimitiveResult() {
+  return *primitive_result_.get();
+}
+
+const base::android::JavaRef<jobject>&
+GinJavaMethodInvocationHelper::GetObjectResult() {
+  return object_result_;
+}
+
+const base::android::JavaRef<jclass>&
+GinJavaMethodInvocationHelper::GetSafeAnnotationClass() {
+  return safe_annotation_clazz_;
+}
+
+const std::string& GinJavaMethodInvocationHelper::GetErrorMessage() {
+  return error_message_;
+}
+
+void GinJavaMethodInvocationHelper::InvokeMethod(jobject object,
+                                      const JavaType& return_type,
+                                      jmethodID id,
+                                      jvalue* parameters) {
+  JNIEnv* env = AttachCurrentThread();
+  base::ListValue result_wrapper;
+  switch (return_type.type) {
+    case JavaType::TypeBoolean:
+      result_wrapper.AppendBoolean(
+          env->CallBooleanMethodA(object, id, parameters));
+      break;
+    case JavaType::TypeByte:
+      result_wrapper.AppendInteger(
+          env->CallByteMethodA(object, id, parameters));
+      break;
+    case JavaType::TypeChar:
+      result_wrapper.AppendInteger(
+          env->CallCharMethodA(object, id, parameters));
+      break;
+    case JavaType::TypeShort:
+      result_wrapper.AppendInteger(
+          env->CallShortMethodA(object, id, parameters));
+      break;
+    case JavaType::TypeInt:
+      result_wrapper.AppendInteger(
+          env->CallIntMethodA(object, id, parameters));
+      break;
+    case JavaType::TypeLong:
+      result_wrapper.AppendDouble(
+          env->CallLongMethodA(object, id, parameters));
+      break;
+    case JavaType::TypeFloat: {
+      float result = env->CallFloatMethodA(object, id, parameters);
+      if (base::IsFinite(result)) {
+        result_wrapper.AppendDouble(result);
+      } else {
+        result_wrapper.Append(
+            GinJavaBridgeValue::CreateNonFiniteValue(result).release());
+      }
+      break;
+    }
+    case JavaType::TypeDouble: {
+      double result = env->CallDoubleMethodA(object, id, parameters);
+      if (base::IsFinite(result)) {
+        result_wrapper.AppendDouble(result);
+      } else {
+        result_wrapper.Append(
+            GinJavaBridgeValue::CreateNonFiniteValue(result).release());
+      }
+      break;
+    }
+    case JavaType::TypeVoid:
+      env->CallVoidMethodA(object, id, parameters);
+      result_wrapper.Append(
+          GinJavaBridgeValue::CreateUndefinedValue().release());
+      break;
+    case JavaType::TypeArray:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to not call methods that
+      // return arrays. Spec requires calling the method and converting the
+      // result to a JavaScript array.
+      result_wrapper.Append(
+          GinJavaBridgeValue::CreateUndefinedValue().release());
+      break;
+    case JavaType::TypeString: {
+      jstring java_string = static_cast<jstring>(
+          env->CallObjectMethodA(object, id, parameters));
+      // If an exception was raised, we must clear it before calling most JNI
+      // methods. ScopedJavaLocalRef is liable to make such calls, so we test
+      // first.
+      if (base::android::ClearException(env)) {
+        SetInvocationFailure(kJavaExceptionRaised);
+        return;
+      }
+      ScopedJavaLocalRef<jstring> scoped_java_string(env, java_string);
+      if (!scoped_java_string.obj()) {
+        // LIVECONNECT_COMPLIANCE: Existing behavior is to return undefined.
+        // Spec requires returning a null string.
+        result_wrapper.Append(
+            GinJavaBridgeValue::CreateUndefinedValue().release());
+        break;
+      }
+      result_wrapper.AppendString(
+          base::android::ConvertJavaStringToUTF8(scoped_java_string));
+      break;
+    }
+    case JavaType::TypeObject: {
+      // If an exception was raised, we must clear it before calling most JNI
+      // methods. ScopedJavaLocalRef is liable to make such calls, so we test
+      // first.
+      jobject java_object = env->CallObjectMethodA(object, id, parameters);
+      if (base::android::ClearException(env)) {
+        SetInvocationFailure(kJavaExceptionRaised);
+        return;
+      }
+      ScopedJavaLocalRef<jobject> scoped_java_object(env, java_object);
+      if (!scoped_java_object.obj()) {
+        result_wrapper.Append(base::Value::CreateNullValue());
+        break;
+      }
+      SetObjectResult(scoped_java_object, object_->GetSafeAnnotationClass());
+      return;
+    }
+  }
+  // This is for all cases except JavaType::TypeObject.
+  if (!base::android::ClearException(env)) {
+    SetPrimitiveResult(result_wrapper);
+  } else {
+    SetInvocationFailure(kJavaExceptionRaised);
+  }
+}
+
+void GinJavaMethodInvocationHelper::ReleaseJavaValueIfRequired(JNIEnv* env,
+                                                    jvalue* value,
+                                                    const JavaType& type) {

[bulach, 2014/06/09 11:44:33]

nit: left align, or keep all indented by +4 like the function below

[mnaganov (inactive), 2014/06/11 13:50:44]

Done.

+  if (type.type == JavaType::TypeString ||
+      type.type == JavaType::TypeObject ||
+      type.type == JavaType::TypeArray) {
+    env->DeleteLocalRef(value->l);
+    value->l = NULL;
+  }
+}
+
+jvalue GinJavaMethodInvocationHelper::CoerceJavaScriptValueToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  // Note that in all these conversions, the relevant field of the jvalue must
+  // always be explicitly set, as jvalue does not initialize its fields.
+
+  switch (value->GetType()) {
+    case base::Value::TYPE_INTEGER:
+      return CoerceJavaScriptIntegerToJavaValue(value, target_type,
+                                               coerce_to_string);

[bulach, 2014/06/09 11:44:33]

nit: align

[mnaganov (inactive), 2014/06/11 13:50:44]

Done, thanks!

+    case base::Value::TYPE_DOUBLE: {
+      double double_value;
+      value->GetAsDouble(&double_value);
+      return CoerceJavaScriptDoubleToJavaValue(double_value, target_type,
+                                               coerce_to_string);
+    }
+    case base::Value::TYPE_BOOLEAN:
+      return CoerceJavaScriptBooleanToJavaValue(value, target_type,
+                                                coerce_to_string);
+    case base::Value::TYPE_STRING:
+      return CoerceJavaScriptStringToJavaValue(value, target_type);
+    case base::Value::TYPE_DICTIONARY:
+    case base::Value::TYPE_LIST:
+      return CoerceJavaScriptObjectToJavaValue(value, target_type,
+                                               coerce_to_string);
+    case base::Value::TYPE_NULL:
+      return CoerceJavaScriptNullOrUndefinedToJavaValue(value, target_type,
+                                                        coerce_to_string);
+    case base::Value::TYPE_BINARY:
+      return CoerceGinJavaBridgeValueToJavaValue(value, target_type,
+                                                 coerce_to_string);
+  }
+  NOTREACHED();
+  return jvalue();
+}
+
+jvalue GinJavaMethodInvocationHelper::CoerceGinJavaBridgeValueToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  DCHECK(GinJavaBridgeValue::ContainsGinJavaBridgeValue(value));
+  scoped_ptr<const GinJavaBridgeValue> gin_value(
+      GinJavaBridgeValue::FromValue(value));
+  switch (gin_value->GetType()) {
+    case GinJavaBridgeValue::TYPE_UNDEFINED:
+      return CoerceJavaScriptNullOrUndefinedToJavaValue(
+          value, target_type, coerce_to_string);
+    case GinJavaBridgeValue::TYPE_NONFINITE: {
+      float float_value;
+      gin_value->GetAsNonFinite(&float_value);
+      return CoerceJavaScriptDoubleToJavaValue(
+          float_value, target_type, coerce_to_string);
+    }
+    case GinJavaBridgeValue::TYPE_OBJECT_ID:
+      return CoerceJavaScriptObjectToJavaValue(
+          value, target_type, coerce_to_string);
+    default:
+      NOTREACHED();
+  }
+  return jvalue();
+}
+
+namespace {
+
+double RoundDoubleTowardsZero(const double& x) {
+  if (std::isnan(x)) {
+    return 0.0;
+  }
+  return x > 0.0 ? floor(x) : ceil(x);
+}
+
+// Rounds to jlong using Java's type conversion rules.
+jlong RoundDoubleToLong(const double& x) {
+  double intermediate = RoundDoubleTowardsZero(x);
+  // The int64 limits can not be converted exactly to double values, so we
+  // compare to custom constants. kint64max is 2^63 - 1, but the spacing
+  // between double values in the the range 2^62 to 2^63 is 2^10. The cast is
+  // required to silence a spurious gcc warning for integer overflow.
+  const int64 limit = (GG_INT64_C(1) << 63) - static_cast<uint64>(1 << 10);

[bulach, 2014/06/09 11:44:33]

nit: kLimit

[mnaganov (inactive), 2014/06/11 13:50:44]

Done.

+  DCHECK(limit > 0);
+  const double kLargestDoubleLessThanInt64Max = limit;
+  const double kSmallestDoubleGreaterThanInt64Min = -limit;
+  if (intermediate > kLargestDoubleLessThanInt64Max) {
+    return kint64max;
+  }
+  if (intermediate < kSmallestDoubleGreaterThanInt64Min) {
+    return kint64min;
+  }
+  return static_cast<jlong>(intermediate);
+}
+
+// Rounds to jint using Java's type conversion rules.
+jint RoundDoubleToInt(const double& x) {
+  double intermediate = RoundDoubleTowardsZero(x);
+  // The int32 limits cast exactly to double values.
+  intermediate = std::min(intermediate, static_cast<double>(kint32max));
+  intermediate = std::max(intermediate, static_cast<double>(kint32min));
+  return static_cast<jint>(intermediate);
+}
+
+}  // namespace
+
+jvalue GinJavaMethodInvocationHelper::CoerceJavaScriptIntegerToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  // See http://jdk6.java.net/plugin2/liveconnect/#JS_NUMBER_VALUES.
+
+  // For conversion to numeric types, we need to replicate Java's type
+  // conversion rules. This requires that for integer values, we simply discard
+  // all but the lowest n buts, where n is the number of bits in the target
+  // type.
+  jvalue result;
+  int int_value;
+  value->GetAsInteger(&int_value);
+  switch (target_type.type) {
+    case JavaType::TypeByte:
+      result.b = static_cast<jbyte>(int_value);
+      break;
+    case JavaType::TypeChar:
+      result.c = static_cast<jchar>(int_value);
+      break;
+    case JavaType::TypeShort:
+      result.s = static_cast<jshort>(int_value);
+      break;
+    case JavaType::TypeInt:
+      result.i = int_value;
+      break;
+    case JavaType::TypeLong:
+      result.j = int_value;
+      break;
+    case JavaType::TypeFloat:
+      result.f = int_value;
+      break;
+    case JavaType::TypeDouble:
+      result.d = int_value;
+      break;
+    case JavaType::TypeObject:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to null. Spec
+      // requires handling object equivalents of primitive types.
+      result.l = NULL;
+      break;
+    case JavaType::TypeString:
+      result.l = coerce_to_string
+                     ? ConvertUTF8ToJavaString(AttachCurrentThread(),
+                                               base::Int64ToString(int_value))
+                           .Release()
+                     : NULL;
+      break;
+    case JavaType::TypeBoolean:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to false. Spec
+      // requires converting to false for 0 or NaN, true otherwise.
+      result.z = JNI_FALSE;
+      break;
+    case JavaType::TypeArray:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to null. Spec
+      // requires raising a JavaScript exception.
+      result.l = NULL;
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+      NOTREACHED();
+      break;
+  }
+  return result;
+}
+
+jvalue GinJavaMethodInvocationHelper::CoerceJavaScriptDoubleToJavaValue(
+    double double_value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  // See http://jdk6.java.net/plugin2/liveconnect/#JS_NUMBER_VALUES.
+  // For conversion to numeric types, we need to replicate Java's type
+  // conversion rules.
+  jvalue result;
+  switch (target_type.type) {
+    case JavaType::TypeByte:
+      result.b = static_cast<jbyte>(RoundDoubleToInt(double_value));
+      break;
+    case JavaType::TypeChar:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert double to 0.
+      // Spec requires converting doubles similarly to how we convert doubles to
+      // other numeric types.
+      result.c = 0;
+      break;
+    case JavaType::TypeShort:
+      result.s = static_cast<jshort>(RoundDoubleToInt(double_value));
+      break;
+    case JavaType::TypeInt:
+      result.i = RoundDoubleToInt(double_value);
+      break;
+    case JavaType::TypeLong:
+      result.j = RoundDoubleToLong(double_value);
+      break;
+    case JavaType::TypeFloat:
+      result.f = static_cast<jfloat>(double_value);
+      break;
+    case JavaType::TypeDouble:
+      result.d = double_value;
+      break;
+    case JavaType::TypeObject:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to null. Spec
+      // requires handling object equivalents of primitive types.
+      result.l = NULL;
+      break;
+    case JavaType::TypeString:
+      result.l = coerce_to_string
+                     ? ConvertUTF8ToJavaString(
+                           AttachCurrentThread(),
+                           base::StringPrintf("%.6lg", double_value)).Release()
+                     : NULL;
+      break;
+    case JavaType::TypeBoolean:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to false. Spec
+      // requires converting to false for 0 or NaN, true otherwise.
+      result.z = JNI_FALSE;
+      break;
+    case JavaType::TypeArray:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to null. Spec
+      // requires raising a JavaScript exception.
+      result.l = NULL;
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+      NOTREACHED();
+      break;
+  }
+  return result;
+}
+
+jvalue GinJavaMethodInvocationHelper::CoerceJavaScriptBooleanToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  // See http://jdk6.java.net/plugin2/liveconnect/#JS_BOOLEAN_VALUES.
+  bool boolean_value;
+  value->GetAsBoolean(&boolean_value);
+  jvalue result;
+  switch (target_type.type) {
+    case JavaType::TypeBoolean:
+      result.z = boolean_value ? JNI_TRUE : JNI_FALSE;
+      break;
+    case JavaType::TypeObject:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to NULL. Spec
+      // requires handling java.lang.Boolean and java.lang.Object.
+      result.l = NULL;
+      break;
+    case JavaType::TypeString:
+      result.l = coerce_to_string ?
+          ConvertUTF8ToJavaString(AttachCurrentThread(),
+                                  boolean_value ? "true" : "false").Release() :
+          NULL;
+      break;
+    case JavaType::TypeByte:
+    case JavaType::TypeChar:
+    case JavaType::TypeShort:
+    case JavaType::TypeInt:
+    case JavaType::TypeLong:
+    case JavaType::TypeFloat:
+    case JavaType::TypeDouble: {
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to 0. Spec
+      // requires converting to 0 or 1.
+      jvalue null_value = {0};
+      result = null_value;
+      break;
+    }
+    case JavaType::TypeArray:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to NULL. Spec
+      // requires raising a JavaScript exception.
+      result.l = NULL;
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+      NOTREACHED();
+      break;
+  }
+  return result;
+}
+
+jvalue GinJavaMethodInvocationHelper::CoerceJavaScriptStringToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type) {
+  // See http://jdk6.java.net/plugin2/liveconnect/#JS_STRING_VALUES.
+  jvalue result;
+  switch (target_type.type) {
+    case JavaType::TypeString: {
+      std::string string_result;
+      value->GetAsString(&string_result);
+      result.l = ConvertUTF8ToJavaString(AttachCurrentThread(), string_result)
+                     .Release();
+      break;
+    }
+    case JavaType::TypeObject:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to NULL. Spec
+      // requires handling java.lang.Object.
+      result.l = NULL;
+      break;
+    case JavaType::TypeByte:
+    case JavaType::TypeShort:
+    case JavaType::TypeInt:
+    case JavaType::TypeLong:
+    case JavaType::TypeFloat:
+    case JavaType::TypeDouble: {
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to 0. Spec
+      // requires using valueOf() method of corresponding object type.
+      jvalue null_value = {0};
+      result = null_value;
+      break;
+    }
+    case JavaType::TypeChar:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to 0. Spec
+      // requires using java.lang.Short.decode().
+      result.c = 0;
+      break;
+    case JavaType::TypeBoolean:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to false. Spec
+      // requires converting the empty string to false, otherwise true.
+      result.z = JNI_FALSE;
+      break;
+    case JavaType::TypeArray:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to NULL. Spec
+      // requires raising a JavaScript exception.
+      result.l = NULL;
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+      NOTREACHED();
+      break;
+  }
+  return result;
+}
+
+jvalue GinJavaMethodInvocationHelper::CoerceJavaScriptObjectToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  // This covers both JavaScript objects (including arrays) and Java objects.
+  // See http://jdk6.java.net/plugin2/liveconnect/#JS_OTHER_OBJECTS,
+  // http://jdk6.java.net/plugin2/liveconnect/#JS_ARRAY_VALUES and
+  // http://jdk6.java.net/plugin2/liveconnect/#JS_JAVA_OBJECTS
+  jvalue result;
+  switch (target_type.type) {
+    case JavaType::TypeObject: {
+      if (GinJavaBridgeValue::ContainsGinJavaBridgeValue(value)) {
+        scoped_ptr<const GinJavaBridgeValue> gin_value(
+            GinJavaBridgeValue::FromValue(value));
+        DCHECK(gin_value);
+        DCHECK(gin_value->IsType(GinJavaBridgeValue::TYPE_OBJECT_ID));
+        base::android::ScopedJavaLocalRef<jobject> obj;
+        GinJavaBoundObject::ObjectID object_id;
+        if (gin_value->GetAsObjectID(&object_id)) {
+          ObjectRefs::iterator iter = object_refs_.find(object_id);
+          if (iter != object_refs_.end()) {
+            obj.Reset(iter->second.get(AttachCurrentThread()));
+          }
+        }
+        result.l = obj.Release();
+      } else {
+        // LIVECONNECT_COMPLIANCE: Existing behavior is to pass null. Spec
+        // requires converting if the target type is
+        // netscape.javascript.JSObject, otherwise raising a JavaScript
+        // exception.
+        result.l = NULL;
+      }
+      break;
+    }
+    case JavaType::TypeString:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to
+      // "undefined". Spec requires calling toString() on the Java object.
+      result.l = coerce_to_string
+                     ? ConvertUTF8ToJavaString(AttachCurrentThread(),
+                                               kUndefined).Release()
+                     : NULL;
+      break;
+    case JavaType::TypeByte:
+    case JavaType::TypeShort:
+    case JavaType::TypeInt:
+    case JavaType::TypeLong:
+    case JavaType::TypeFloat:
+    case JavaType::TypeDouble:
+    case JavaType::TypeChar: {
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to 0. Spec
+      // requires raising a JavaScript exception.
+      jvalue null_value = {0};
+      result = null_value;
+      break;
+    }
+    case JavaType::TypeBoolean:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to false. Spec
+      // requires raising a JavaScript exception.
+      result.z = JNI_FALSE;
+      break;
+    case JavaType::TypeArray:
+      if (value->IsType(base::Value::TYPE_DICTIONARY)) {
+        result.l = CoerceJavaScriptDictionaryToArray(value, target_type);
+      } else if (value->IsType(base::Value::TYPE_LIST)) {
+        result.l = CoerceJavaScriptListToArray(value, target_type);
+      } else {
+        result.l = NULL;
+      }
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+      NOTREACHED();
+      break;
+  }
+  return result;
+}
+
+jobject GinJavaMethodInvocationHelper::CoerceJavaScriptListToArray(
+    const base::Value* value,
+    const JavaType& target_type) {
+  DCHECK_EQ(JavaType::TypeArray, target_type.type);
+  const JavaType& target_inner_type = *target_type.inner_type.get();
+  // LIVECONNECT_COMPLIANCE: Existing behavior is to return null for
+  // multi-dimensional arrays. Spec requires handling multi-demensional arrays.
+  if (target_inner_type.type == JavaType::TypeArray) {
+    return NULL;
+  }
+
+  // LIVECONNECT_COMPLIANCE: Existing behavior is to return null for object
+  // arrays. Spec requires handling object arrays.
+  if (target_inner_type.type == JavaType::TypeObject) {
+    return NULL;
+  }
+
+  const base::ListValue* list_value;
+  value->GetAsList(&list_value);
+  // Create the Java array.
+  jsize length = static_cast<jsize>(list_value->GetSize());
+  jobject result = CreateJavaArray(target_inner_type, length);
+  if (!result) {
+    return NULL;
+  }
+  JNIEnv* env = AttachCurrentThread();
+  scoped_ptr<base::Value> null_value(base::Value::CreateNullValue());
+  for (jsize i = 0; i < length; ++i) {
+    const base::Value* value_element = null_value.get();
+    list_value->Get(i, &value_element);
+    jvalue element = CoerceJavaScriptValueToJavaValue(value_element,
+                                                      target_inner_type,
+                                                      false);
+    SetArrayElement(result, target_inner_type, i, element);
+    // CoerceJavaScriptValueToJavaValue() creates new local references to
+    // strings, objects and arrays. Of these, only strings can occur here.
+    // SetArrayElement() causes the array to take its own reference to the
+    // string, so we can now release the local reference.
+    DCHECK_NE(JavaType::TypeObject, target_inner_type.type);
+    DCHECK_NE(JavaType::TypeArray, target_inner_type.type);
+    ReleaseJavaValueIfRequired(env, &element, target_inner_type);
+  }
+
+  return result;
+}
+
+jobject GinJavaMethodInvocationHelper::CoerceJavaScriptDictionaryToArray(
+    const base::Value* value,
+    const JavaType& target_type) {
+  DCHECK_EQ(JavaType::TypeArray, target_type.type);
+
+  const JavaType& target_inner_type = *target_type.inner_type.get();
+  // LIVECONNECT_COMPLIANCE: Existing behavior is to return null for
+  // multi-dimensional arrays. Spec requires handling multi-demensional arrays.
+  if (target_inner_type.type == JavaType::TypeArray) {
+    return NULL;
+  }
+
+  // LIVECONNECT_COMPLIANCE: Existing behavior is to return null for object
+  // arrays. Spec requires handling object arrays.
+  if (target_inner_type.type == JavaType::TypeObject) {
+    return NULL;
+  }
+
+  const base::DictionaryValue* dictionary_value;
+  value->GetAsDictionary(&dictionary_value);
+  const base::Value* length_value;
+  // If the object does not have a length property, return null.
+  if (!dictionary_value->Get("length", &length_value)) {
+    return NULL;
+  }
+
+  // If the length property does not have numeric type, or is outside the valid
+  // range for a Java array length, return null.
+  jsize length = -1;
+  if (length_value->IsType(base::Value::TYPE_INTEGER)) {
+    int int_length;
+    length_value->GetAsInteger(&int_length);
+    if (int_length >= 0 && int_length <= kint32max) {
+      length = static_cast<jsize>(int_length);
+    }
+  } else if (length_value->IsType(base::Value::TYPE_DOUBLE)) {
+    double double_length;
+    length_value->GetAsDouble(&double_length);
+    if (double_length >= 0.0 && double_length <= kint32max) {
+      length = static_cast<jsize>(double_length);
+    }
+  }
+  if (length == -1) {
+    return NULL;
+  }
+
+  jobject result = CreateJavaArray(target_inner_type, length);
+  if (!result) {
+    return NULL;
+  }
+  scoped_ptr<base::Value> null_value(base::Value::CreateNullValue());
+  JNIEnv* env = AttachCurrentThread();
+  for (jsize i = 0; i < length; ++i) {
+    const std::string key(base::IntToString(i));
+    const base::Value* value_element = null_value.get();
+    if (dictionary_value->HasKey(key)) {
+      dictionary_value->Get(key, &value_element);
+    }
+    jvalue element = CoerceJavaScriptValueToJavaValue(value_element,
+                                                      target_inner_type,
+                                                      false);
+    SetArrayElement(result, target_inner_type, i, element);
+    // CoerceJavaScriptValueToJavaValue() creates new local references to
+    // strings, objects and arrays. Of these, only strings can occur here.
+    // SetArrayElement() causes the array to take its own reference to the
+    // string, so we can now release the local reference.
+    DCHECK_NE(JavaType::TypeObject, target_inner_type.type);
+    DCHECK_NE(JavaType::TypeArray, target_inner_type.type);
+    ReleaseJavaValueIfRequired(env, &element, target_inner_type);
+  }
+
+  return result;
+}
+
+// Note that this only handles primitive types and strings.
+jobject GinJavaMethodInvocationHelper::CreateJavaArray(const JavaType& type,
+                                                       jsize length) {
+  JNIEnv* env = AttachCurrentThread();
+  switch (type.type) {
+    case JavaType::TypeBoolean:
+      return env->NewBooleanArray(length);
+    case JavaType::TypeByte:
+      return env->NewByteArray(length);
+    case JavaType::TypeChar:
+      return env->NewCharArray(length);
+    case JavaType::TypeShort:
+      return env->NewShortArray(length);
+    case JavaType::TypeInt:
+      return env->NewIntArray(length);
+    case JavaType::TypeLong:
+      return env->NewLongArray(length);
+    case JavaType::TypeFloat:
+      return env->NewFloatArray(length);
+    case JavaType::TypeDouble:
+      return env->NewDoubleArray(length);
+    case JavaType::TypeString: {
+      ScopedJavaLocalRef<jclass> clazz(
+          base::android::GetClass(env, kJavaLangString));
+      return env->NewObjectArray(length, clazz.obj(), NULL);
+    }
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+    case JavaType::TypeArray:
+    case JavaType::TypeObject:
+      // Not handled.
+      NOTREACHED();
+  }
+  return NULL;
+}
+
+// Sets the specified element of the supplied array to the value of the
+// supplied jvalue. Requires that the type of the array matches that of the
+// jvalue. Handles only primitive types and strings. Note that in the case of a
+// string, the array takes a new reference to the string object.
+void GinJavaMethodInvocationHelper::SetArrayElement(jobject array,
+                                         const JavaType& type,

[bulach, 2014/06/09 11:44:33]

nit: align

[mnaganov (inactive), 2014/06/11 13:50:44]

Done.

+                                         jsize index,
+                                         const jvalue& value) {
+  JNIEnv* env = AttachCurrentThread();
+  switch (type.type) {
+    case JavaType::TypeBoolean:
+      env->SetBooleanArrayRegion(static_cast<jbooleanArray>(array), index, 1,
+                                 &value.z);
+      break;
+    case JavaType::TypeByte:
+      env->SetByteArrayRegion(static_cast<jbyteArray>(array), index, 1,
+                              &value.b);
+      break;
+    case JavaType::TypeChar:
+      env->SetCharArrayRegion(static_cast<jcharArray>(array), index, 1,
+                              &value.c);
+      break;
+    case JavaType::TypeShort:
+      env->SetShortArrayRegion(static_cast<jshortArray>(array), index, 1,
+                               &value.s);
+      break;
+    case JavaType::TypeInt:
+      env->SetIntArrayRegion(static_cast<jintArray>(array), index, 1,
+                             &value.i);
+      break;
+    case JavaType::TypeLong:
+      env->SetLongArrayRegion(static_cast<jlongArray>(array), index, 1,
+                              &value.j);
+      break;
+    case JavaType::TypeFloat:
+      env->SetFloatArrayRegion(static_cast<jfloatArray>(array), index, 1,
+                               &value.f);
+      break;
+    case JavaType::TypeDouble:
+      env->SetDoubleArrayRegion(static_cast<jdoubleArray>(array), index, 1,
+                                &value.d);
+      break;
+    case JavaType::TypeString:
+      env->SetObjectArrayElement(static_cast<jobjectArray>(array), index,
+                                 value.l);
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+    case JavaType::TypeArray:
+    case JavaType::TypeObject:
+      // Not handled.
+      NOTREACHED();
+  }
+  base::android::CheckException(env);
+}
+
+jvalue
+GinJavaMethodInvocationHelper::CoerceJavaScriptNullOrUndefinedToJavaValue(
+    const base::Value* value,
+    const JavaType& target_type,
+    bool coerce_to_string) {
+  bool is_undefined = false;
+  scoped_ptr<const GinJavaBridgeValue> gin_value;
+  if (GinJavaBridgeValue::ContainsGinJavaBridgeValue(value)) {
+    gin_value = GinJavaBridgeValue::FromValue(value);
+    if (gin_value->IsType(GinJavaBridgeValue::TYPE_UNDEFINED)) {
+      is_undefined = true;
+    }
+  }
+  jvalue result;
+  switch (target_type.type) {
+    case JavaType::TypeObject:
+      result.l = NULL;
+      break;
+    case JavaType::TypeString:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert undefined to
+      // "undefined". Spec requires converting undefined to NULL.
+      result.l = (coerce_to_string && is_undefined)
+                     ? ConvertUTF8ToJavaString(AttachCurrentThread(),
+                                               kUndefined).Release()
+                     : NULL;
+      break;
+    case JavaType::TypeByte:
+    case JavaType::TypeChar:
+    case JavaType::TypeShort:
+    case JavaType::TypeInt:
+    case JavaType::TypeLong:
+    case JavaType::TypeFloat:
+    case JavaType::TypeDouble: {
+      jvalue null_value = {0};
+      result = null_value;
+      break;
+    }
+    case JavaType::TypeBoolean:
+      result.z = JNI_FALSE;
+      break;
+    case JavaType::TypeArray:
+      // LIVECONNECT_COMPLIANCE: Existing behavior is to convert to NULL. Spec
+      // requires raising a JavaScript exception.
+      result.l = NULL;
+      break;
+    case JavaType::TypeVoid:
+      // Conversion to void must never happen.
+      NOTREACHED();
+      break;
+  }
+  return result;
+}
+
+}  // namespace content