tools/aapt2/jni/ScopedUtfChars.h

/*
 * Copyright (C) 2010 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 SCOPED_UTF_CHARS_H_included
#define SCOPED_UTF_CHARS_H_included

#include <string.h>
#include <jni.h>

#include "android-base/logging.h"

// This file was copied with some minor modifications from libnativehelper.
// As soon as libnativehelper can be compiled for Windows, this file should be
// replaced with libnativehelper's implementation.
class ScopedUtfChars {
 public:
  ScopedUtfChars(JNIEnv* env, jstring s) : env_(env), string_(s) {
    CHECK(s != nullptr);
    utf_chars_ = env->GetStringUTFChars(s, nullptr);
  }

  ScopedUtfChars(ScopedUtfChars&& rhs) :
      env_(rhs.env_), string_(rhs.string_), utf_chars_(rhs.utf_chars_) {
    rhs.env_ = nullptr;
    rhs.string_ = nullptr;
    rhs.utf_chars_ = nullptr;
  }

  ~ScopedUtfChars() {
    if (utf_chars_) {
      env_->ReleaseStringUTFChars(string_, utf_chars_);
    }
  }

  ScopedUtfChars& operator=(ScopedUtfChars&& rhs) {
    if (this != &rhs) {
      // Delete the currently owned UTF chars.
      this->~ScopedUtfChars();

      // Move the rhs ScopedUtfChars and zero it out.
      env_ = rhs.env_;
      string_ = rhs.string_;
      utf_chars_ = rhs.utf_chars_;
      rhs.env_ = nullptr;
      rhs.string_ = nullptr;
      rhs.utf_chars_ = nullptr;
    }
    return *this;
  }

  const char* c_str() const {
    return utf_chars_;
  }

  size_t size() const {
    return strlen(utf_chars_);
  }

  const char& operator[](size_t n) const {
    return utf_chars_[n];
  }

 private:
  JNIEnv* env_;
  jstring string_;
  const char* utf_chars_;

  DISALLOW_COPY_AND_ASSIGN(ScopedUtfChars);
};

#endif  // SCOPED_UTF_CHARS_H_included