text: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "base/android/jni_string.h"
  
  #include "base/android/jni_android.h"
  #include "base/logging.h"
  #include "base/strings/utf_string_conversions.h"
  
  namespace {
  
  // Internal version that does not use a scoped local pointer.
  jstring ConvertUTF16ToJavaStringImpl(JNIEnv* env,
                                       const base::StringPiece16& str) {
    jstring result = env->NewString(str.data(), str.length());
    base::android::CheckException(env);
    return result;
  }
  
  }
  
  namespace base {
  namespace android {
  
  void ConvertJavaStringToUTF8(JNIEnv* env, jstring str, std::string* result) {
    if (!str) {
      LOG(WARNING) << "ConvertJavaStringToUTF8 called with null string.";
      result->clear();
      return;
    }
    // JNI's GetStringUTFChars() returns strings in Java "modified" UTF8, so
    // instead get the String in UTF16 and convert using chromium's conversion
    // function that yields plain (non Java-modified) UTF8.
    const jchar* chars = env->GetStringChars(str, NULL);
    DCHECK(chars);
    UTF16ToUTF8(chars, env->GetStringLength(str), result);
    env->ReleaseStringChars(str, chars);
    CheckException(env);
  }
  
  std::string ConvertJavaStringToUTF8(JNIEnv* env, jstring str) {
    std::string result;
    ConvertJavaStringToUTF8(env, str, &result);
    return result;
  }
  
  std::string ConvertJavaStringToUTF8(const JavaRef<jstring>& str) {
    return ConvertJavaStringToUTF8(AttachCurrentThread(), str.obj());
  }
  
  ScopedJavaLocalRef<jstring> ConvertUTF8ToJavaString(
      JNIEnv* env,
      const base::StringPiece& str) {
    // JNI's NewStringUTF expects "modified" UTF8 so instead create the string
    // via our own UTF16 conversion utility.
    // Further, Dalvik requires the string passed into NewStringUTF() to come from
    // a trusted source. We can't guarantee that all UTF8 will be sanitized before
    // it gets here, so constructing via UTF16 side-steps this issue.
    // (Dalvik stores strings internally as UTF16 anyway, so there shouldn't be
    // a significant performance hit by doing it this way).
    return ScopedJavaLocalRef<jstring>(env, ConvertUTF16ToJavaStringImpl(
        env, UTF8ToUTF16(str)));
  }
  
  void ConvertJavaStringToUTF16(JNIEnv* env, jstring str, string16* result) {
    if (!str) {
      LOG(WARNING) << "ConvertJavaStringToUTF16 called with null string.";
      result->clear();
      return;
    }
    const jchar* chars = env->GetStringChars(str, NULL);
    DCHECK(chars);
    // GetStringChars isn't required to NULL-terminate the strings
    // it returns, so the length must be explicitly checked.
    result->assign(chars, env->GetStringLength(str));
    env->ReleaseStringChars(str, chars);
    CheckException(env);
  }
  
  string16 ConvertJavaStringToUTF16(JNIEnv* env, jstring str) {
    string16 result;
    ConvertJavaStringToUTF16(env, str, &result);
    return result;
  }
  
  string16 ConvertJavaStringToUTF16(const JavaRef<jstring>& str) {
    return ConvertJavaStringToUTF16(AttachCurrentThread(), str.obj());
  }
  
  ScopedJavaLocalRef<jstring> ConvertUTF16ToJavaString(
      JNIEnv* env,
      const base::StringPiece16& str) {
    return ScopedJavaLocalRef<jstring>(env,
                                       ConvertUTF16ToJavaStringImpl(env, str));
  }
  
  }  // namespace android
  }  // namespace base
  