base/android/jni_string.cc

   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/strings/utf_string_conversions.h"
  10
  11 namespace {
  12
  13 // Internal version that does not use a scoped local pointer.
  14 jstring 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 }  // namespace
  22
  23 namespace base {
  24 namespace android {
  25
  26 void ConvertJavaStringToUTF8(JNIEnv* env, jstring str, std::string* result) {
  27   if (!str) {
  28     LOG(WARNING) << "ConvertJavaStringToUTF8 called with null string.";
  29     result->clear();
  30     return;
  31   }
  32   const jsize length = env->GetStringLength(str);
  33   if (!length) {
  34     result->clear();
  35     CheckException(env);
  36     return;
  37   }
  38   // JNI's GetStringUTFChars() returns strings in Java "modified" UTF8, so
  39   // instead get the String in UTF16 and convert using chromium's conversion
  40   // function that yields plain (non Java-modified) UTF8.
  41   const jchar* chars = env->GetStringChars(str, NULL);
  42   DCHECK(chars);
  43   UTF16ToUTF8(chars, length, result);
  44   env->ReleaseStringChars(str, chars);
  45   CheckException(env);
  46 }
  47
  48 std::string ConvertJavaStringToUTF8(JNIEnv* env, jstring str) {
  49   std::string result;
  50   ConvertJavaStringToUTF8(env, str, &result);
  51   return result;
  52 }
  53
  54 std::string ConvertJavaStringToUTF8(const JavaRef<jstring>& str) {
  55   return ConvertJavaStringToUTF8(AttachCurrentThread(), str.obj());
  56 }
  57
  58 ScopedJavaLocalRef<jstring> ConvertUTF8ToJavaString(
  59     JNIEnv* env,
  60     const base::StringPiece& str) {
  61   // JNI's NewStringUTF expects "modified" UTF8 so instead create the string
  62   // via our own UTF16 conversion utility.
  63   // Further, Dalvik requires the string passed into NewStringUTF() to come from
  64   // a trusted source. We can't guarantee that all UTF8 will be sanitized before
  65   // it gets here, so constructing via UTF16 side-steps this issue.
  66   // (Dalvik stores strings internally as UTF16 anyway, so there shouldn't be
  67   // a significant performance hit by doing it this way).
  68   return ScopedJavaLocalRef<jstring>(env, ConvertUTF16ToJavaStringImpl(
  69       env, UTF8ToUTF16(str)));
  70 }
  71
  72 void ConvertJavaStringToUTF16(JNIEnv* env, jstring str, string16* result) {
  73   if (!str) {
  74     LOG(WARNING) << "ConvertJavaStringToUTF16 called with null string.";
  75     result->clear();
  76     return;
  77   }
  78   const jsize length = env->GetStringLength(str);
  79   if (!length) {
  80     result->clear();
  81     CheckException(env);
  82     return;
  83   }
  84   const jchar* chars = env->GetStringChars(str, NULL);
  85   DCHECK(chars);
  86   // GetStringChars isn't required to NULL-terminate the strings
  87   // it returns, so the length must be explicitly checked.
  88   result->assign(chars, length);
  89   env->ReleaseStringChars(str, chars);
  90   CheckException(env);
  91 }
  92
  93 string16 ConvertJavaStringToUTF16(JNIEnv* env, jstring str) {
  94   string16 result;
  95   ConvertJavaStringToUTF16(env, str, &result);
  96   return result;
  97 }
  98
  99 string16 ConvertJavaStringToUTF16(const JavaRef<jstring>& str) {
 100   return ConvertJavaStringToUTF16(AttachCurrentThread(), str.obj());
 101 }
 102
 103 ScopedJavaLocalRef<jstring> ConvertUTF16ToJavaString(
 104     JNIEnv* env,
 105     const base::StringPiece16& str) {
 106   return ScopedJavaLocalRef<jstring>(env,
 107                                      ConvertUTF16ToJavaStringImpl(env, str));
 108 }
 109
 110 }  // namespace android
 111 }  // namespace base