Start cleaning up the Charset implementation.

This was going to be https://issues.apache.org/jira/browse/HARMONY-6461,
but I couldn't resist cleaning up some of the surrounding code, and ended
up cleaning up some of our native code too. In the course of the afternoon
I spent on this, I lost my conviction that the upstream change makes
sense, so I reverted that, leaving this change just pure cleanup.

(Note that the cleanup work is incomplete. This is an improvement, but
there's plenty left to do. I just don't want to get too distracted until
all the Java 6 changes are done.)

Change-Id: I56841db5f6c038bbf7942e83a148dca546519269

1 files changed, 56 insertions, 0 deletions

diff --git a/include/ScopedUtfChars.h b/include/ScopedUtfChars.h
new file mode 100644
index 0000000..8bc3e66
--- /dev/null
+++ b/include/ScopedUtfChars.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SCOPED_UTF_CHARS_H_included
+#define SCOPED_UTF_CHARS_H_included
+
+#include "JNIHelp.h"
+
+// A smart pointer that provides read-only access to a Java string's UTF chars.
+class ScopedUtfChars {
+public:
+    ScopedUtfChars(JNIEnv* env, jstring s)
+    : mEnv(env), mString(s), mUtfChars(NULL)
+    {
+        mUtfChars = env->GetStringUTFChars(s, NULL);
+    }
+
+    ~ScopedUtfChars() {
+        if (mUtfChars) {
+            mEnv->ReleaseStringUTFChars(mString, mUtfChars);
+        }
+    }
+
+    const char* data() const {
+        return mUtfChars;
+    }
+
+    // Element access.
+    const char& operator[](size_t n) const {
+        return mUtfChars[n];
+    }
+
+private:
+    JNIEnv* mEnv;
+    jstring mString;
+    const char* mUtfChars;
+
+    // Disallow copy and assignment.
+    ScopedUtfChars(const ScopedUtfChars&);
+    void operator=(const ScopedUtfChars&);
+};
+
+#endif  // SCOPED_UTF_CHARS_H_included