jni_string.cc revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/android/jni_string.h"
6
7#include "base/android/jni_android.h"
8#include "base/logging.h"
9#include "base/utf_string_conversions.h"
10
11namespace {
12
13// Internal version that does not use a scoped local pointer.
14jstring ConvertUTF16ToJavaStringImpl(JNIEnv* env,
15                                     const base::StringPiece16& str) {
16  jstring result = env->NewString(str.data(), str.length());
17  base::android::CheckException(env);
18  return result;
19}
20
21}
22
23namespace base {
24namespace android {
25
26std::string ConvertJavaStringToUTF8(JNIEnv* env, jstring str) {
27  // JNI's GetStringUTFChars() returns strings in Java-modified UTF8, so we
28  // instead get the String in UTF16 and convert using our own utility function.
29  return UTF16ToUTF8(ConvertJavaStringToUTF16(env, str));
30}
31
32std::string ConvertJavaStringToUTF8(const JavaRef<jstring>& str) {
33  return ConvertJavaStringToUTF8(AttachCurrentThread(), str.obj());
34}
35
36ScopedJavaLocalRef<jstring> ConvertUTF8ToJavaString(
37    JNIEnv* env,
38    const base::StringPiece& str) {
39  // JNI's NewStringUTF expects "modified" UTF8 so instead create the string
40  // via our own UTF16 conversion utility.
41  // Further, Dalvik requires the string passed into NewStringUTF() to come from
42  // a trusted source. We can't guarantee that all UTF8 will be sanitized before
43  // it gets here, so constructing via UTF16 side-steps this issue.
44  // (Dalvik stores strings internally as UTF16 anyway, so there shouldn't be
45  // a significant performance hit by doing it this way).
46  return ScopedJavaLocalRef<jstring>(env, ConvertUTF16ToJavaStringImpl(
47      env, UTF8ToUTF16(str)));
48}
49
50string16 ConvertJavaStringToUTF16(JNIEnv* env, jstring str) {
51  if (!str) {
52    LOG(WARNING) << " ConvertJavaStringToUTF16 called with null string.";
53    return string16();
54  }
55  const jchar* chars = env->GetStringChars(str, NULL);
56  DCHECK(chars);
57  // GetStringChars isn't required to NULL-terminate the strings
58  // it returns, so the length must be explicitly checked.
59  string16 result(chars, env->GetStringLength(str));
60  env->ReleaseStringChars(str, chars);
61  CheckException(env);
62  return result;
63}
64
65string16 ConvertJavaStringToUTF16(const JavaRef<jstring>& str) {
66  return ConvertJavaStringToUTF16(AttachCurrentThread(), str.obj());
67}
68
69ScopedJavaLocalRef<jstring> ConvertUTF16ToJavaString(
70    JNIEnv* env,
71    const base::StringPiece16& str) {
72  return ScopedJavaLocalRef<jstring>(env,
73                                     ConvertUTF16ToJavaStringImpl(env, str));
74}
75
76}  // namespace android
77}  // namespace base
78