1 /*
2  * Copyright (C) 2023 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #pragma once
17 
18 #include <nativehelper/JNIHelp.h>
19 #include <binder/Parcel.h>
20 
21 namespace android {
22     static jclass gParcelClazz;
23     static jfieldID gParcelDataFieldID;
24     static jmethodID gParcelObtainMethodID;
25 
FindClassOrDie(JNIEnv * env,const char * class_name)26     static inline jclass FindClassOrDie(JNIEnv* env, const char* class_name) {
27         jclass clazz = env->FindClass(class_name);
28         LOG_ALWAYS_FATAL_IF(clazz == NULL, "Unable to find class %s", class_name);
29         return clazz;
30     }
31 
GetFieldIDOrDie(JNIEnv * env,jclass clazz,const char * field_name,const char * field_signature)32     static inline jfieldID GetFieldIDOrDie(JNIEnv* env, jclass clazz, const char* field_name,
33                                            const char* field_signature) {
34         jfieldID res = env->GetFieldID(clazz, field_name, field_signature);
35         LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to find field %s with signature %s", field_name,
36                             field_signature);
37         return res;
38     }
39 
GetStaticMethodIDOrDie(JNIEnv * env,jclass clazz,const char * method_name,const char * method_signature)40     static inline jmethodID GetStaticMethodIDOrDie(JNIEnv* env, jclass clazz,
41                                                    const char* method_name,
42                                                    const char* method_signature) {
43         jmethodID res = env->GetStaticMethodID(clazz, method_name, method_signature);
44         LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to find method %s with signature %s", method_name,
45                             method_signature);
46         return res;
47     }
48 
nativeObtainParcel(JNIEnv * env)49     static jobject nativeObtainParcel(JNIEnv* env) {
50         jobject parcel = env->CallStaticObjectMethod(gParcelClazz, gParcelObtainMethodID);
51         if (parcel == nullptr) {
52             jniThrowException(env, "java/lang/IllegalArgumentException", "Obtain parcel failed.");
53         }
54         return parcel;
55     }
56 
nativeGetParcelData(JNIEnv * env,jobject obj)57     static Parcel* nativeGetParcelData(JNIEnv* env, jobject obj) {
58         Parcel* parcel = reinterpret_cast<Parcel*>(env->GetLongField(obj, gParcelDataFieldID));
59         if (parcel && parcel->objectsCount() != 0) {
60             jniThrowException(env, "java/lang/IllegalArgumentException", "Invalid parcel object.");
61         }
62         parcel->setDataPosition(0);
63         return parcel;
64     }
65 
loadParcelClass(JNIEnv * env)66     static void loadParcelClass(JNIEnv* env) {
67         gParcelClazz = FindClassOrDie(env, "android/os/Parcel");
68         gParcelDataFieldID = GetFieldIDOrDie(env, gParcelClazz, "mNativePtr", "J");
69         gParcelObtainMethodID =
70                 GetStaticMethodIDOrDie(env, gParcelClazz, "obtain", "()Landroid/os/Parcel;");
71     }
72 
73 }