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1 /*
2  * Copyright (C) 2010 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef SCOPED_JAVA_UNICODE_STRING_H_included
18 #define SCOPED_JAVA_UNICODE_STRING_H_included
19 
20 #include <nativehelper/JNIHelp.h>
21 #include "unicode/unistr.h"
22 
23 // A smart pointer that provides access to an ICU UnicodeString given a JNI
24 // jstring. We give ICU a direct pointer to the characters on the Java heap.
25 // It's clever enough to copy-on-write if necessary.
26 class ScopedJavaUnicodeString {
27  public:
ScopedJavaUnicodeString(JNIEnv * env,jstring s)28   ScopedJavaUnicodeString(JNIEnv* env, jstring s) : mEnv(env), mString(s) {
29     if (s == NULL) {
30       jniThrowNullPointerException(mEnv, NULL);
31     } else {
32       mChars = env->GetStringChars(mString, NULL);
33       const int32_t charCount = env->GetStringLength(mString);
34       mUnicodeString.setTo(false, mChars, charCount);
35     }
36   }
37 
~ScopedJavaUnicodeString()38   ~ScopedJavaUnicodeString() {
39     if (mString != NULL) {
40       mEnv->ReleaseStringChars(mString, mChars);
41     }
42   }
43 
valid()44   bool valid() const {
45     return (mString != NULL);
46   }
47 
unicodeString()48   const icu::UnicodeString& unicodeString() const {
49     return mUnicodeString;
50   }
51 
unicodeString()52   icu::UnicodeString& unicodeString() {
53     return mUnicodeString;
54   }
55 
56  private:
57   JNIEnv* mEnv;
58   jstring mString;
59   const jchar* mChars;
60   icu::UnicodeString mUnicodeString;
61 
62   // Disallow copy and assignment.
63   ScopedJavaUnicodeString(const ScopedJavaUnicodeString&);
64   void operator=(const ScopedJavaUnicodeString&);
65 };
66 
67 #endif  // SCOPED_JAVA_UNICODE_STRING_H_included
68