1 /*
2  * Copyright (C) 2011 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 
17 #pragma once
18 
19 #ifdef __cplusplus
20 
21 #include <string>
22 #include <vector>
23 
24 #include "JNIHelp.h"
25 #include "ScopedLocalRef.h"
26 
27 template <typename StringVisitor>
28 jobjectArray toStringArray(JNIEnv* env, size_t count, StringVisitor&& visitor) {
29     jclass stringClass = env->FindClass("java/lang/String");
30     ScopedLocalRef<jobjectArray> result(env, env->NewObjectArray(count, stringClass, NULL));
31     env->DeleteLocalRef(stringClass);
32     if (result == nullptr) {
33         return nullptr;
34     }
35     for (size_t i = 0; i < count; ++i) {
36         ScopedLocalRef<jstring> s(env, env->NewStringUTF(visitor(i)));
37         if (env->ExceptionCheck()) {
38             return nullptr;
39         }
40         env->SetObjectArrayElement(result.get(), i, s.get());
41         if (env->ExceptionCheck()) {
42             return nullptr;
43         }
44     }
45     return result.release();
46 }
47 
48 inline jobjectArray toStringArray(JNIEnv* env, const std::vector<std::string>& strings) {
49     return toStringArray(env, strings.size(), [&strings](size_t i) { return strings[i].c_str(); });
50 }
51 
52 inline jobjectArray toStringArray(JNIEnv* env, const char* const* strings) {
53     size_t count = 0;
54     for (; strings[count] != nullptr; ++count) {}
55     return toStringArray(env, count, [&strings](size_t i) { return strings[i]; });
56 }
57 
58 template <typename Counter, typename Getter>
59 jobjectArray toStringArray(JNIEnv* env, Counter* counter, Getter* getter) {
60     return toStringArray(env, counter(), [getter](size_t i) { return getter(i); });
61 }
62 
63 #endif  // __cplusplus
64 
65