/* * Copyright (C) 2018 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef LIBTEXTCLASSIFIER_UTILS_JAVA_STRING_UTILS_H_ #define LIBTEXTCLASSIFIER_UTILS_JAVA_STRING_UTILS_H_ #include <jni.h> #include <memory> #include <string> #include "utils/base/logging.h" namespace libtextclassifier3 { bool JByteArrayToString(JNIEnv* env, const jbyteArray& array, std::string* result); bool JStringToUtf8String(JNIEnv* env, const jstring& jstr, std::string* result); // A deleter to be used with std::unique_ptr to release Java string chars. class StringCharsReleaser { public: StringCharsReleaser() : env_(nullptr) {} StringCharsReleaser(JNIEnv* env, jstring jstr) : env_(env), jstr_(jstr) {} StringCharsReleaser(const StringCharsReleaser& orig) = default; // Copy assignment to allow move semantics in StringCharsReleaser. StringCharsReleaser& operator=(const StringCharsReleaser& rhs) { // As the releaser and its state are thread-local, it's enough to only // ensure the envs are consistent but do nothing. TC3_CHECK_EQ(env_, rhs.env_); return *this; } // The delete operator. void operator()(const char* chars) const { if (env_ != nullptr) { env_->ReleaseStringUTFChars(jstr_, chars); } } private: // The env_ stashed to use for deletion. Thread-local, don't share! JNIEnv* const env_; // The referenced jstring. jstring jstr_; }; // A smart pointer that releases string chars when it goes out of scope. // of scope. // Note that this class is not thread-safe since it caches JNIEnv in // the deleter. Do not use the same jobject across different threads. using ScopedStringChars = std::unique_ptr<const char, StringCharsReleaser>; // Returns a scoped pointer to the array of Unicode characters of a string. ScopedStringChars GetScopedStringChars(JNIEnv* env, jstring string, jboolean* is_copy = nullptr); } // namespace libtextclassifier3 #endif // LIBTEXTCLASSIFIER_UTILS_JAVA_STRING_UTILS_H_