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