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 #ifndef SRC_ANDROID_SDK_NATIVEHELPER_SCOPED_STRING_CHARS_H_ 18 #define SRC_ANDROID_SDK_NATIVEHELPER_SCOPED_STRING_CHARS_H_ 19 20 // Copied from 21 // https://cs.android.com/android/platform/superproject/main/+/main:libnativehelper/header_only_include/nativehelper/scoped_string_chars.h;drc=4be05051ef76b2c24d8385732a892401eb45d911 22 23 #include <stddef.h> 24 25 #include <jni.h> 26 27 #include "src/android_sdk/nativehelper/nativehelper_utils.h" 28 29 // A smart pointer that provides access to a jchar* given a JNI jstring. 30 // Unlike GetStringChars, we throw NullPointerException rather than abort if 31 // passed a null jstring, and get will return nullptr. 32 // This makes the correct idiom very simple: 33 // 34 // ScopedStringChars name(env, java_name); 35 // if (name.get() == nullptr) { 36 // return nullptr; 37 // } 38 class ScopedStringChars { 39 public: ScopedStringChars(JNIEnv * env,jstring s)40 ScopedStringChars(JNIEnv* env, jstring s) : env_(env), string_(s), size_(0) { 41 if (s == nullptr) { 42 chars_ = nullptr; 43 jniThrowNullPointerException(env); 44 } else { 45 chars_ = env->GetStringChars(string_, nullptr); 46 if (chars_ != nullptr) { 47 size_ = env->GetStringLength(string_); 48 } 49 } 50 } 51 ~ScopedStringChars()52 ~ScopedStringChars() { 53 if (chars_ != nullptr) { 54 env_->ReleaseStringChars(string_, chars_); 55 } 56 } 57 get()58 const jchar* get() const { return chars_; } 59 size()60 size_t size() const { return size_; } 61 62 const jchar& operator[](size_t n) const { return chars_[n]; } 63 64 private: 65 JNIEnv* const env_; 66 const jstring string_; 67 const jchar* chars_; 68 size_t size_; 69 70 DISALLOW_COPY_AND_ASSIGN(ScopedStringChars); 71 }; 72 73 #endif // SRC_ANDROID_SDK_NATIVEHELPER_SCOPED_STRING_CHARS_H_ 74