AAPT2: Accept Java unicode identifiers
Test: make aapt2_tests
Change-Id: I75a0e52d43b1785001bfe120eea7484f7bb4682b
diff --git a/tools/aapt2/text/Unicode.h b/tools/aapt2/text/Unicode.h
new file mode 100644
index 0000000..2707187
--- /dev/null
+++ b/tools/aapt2/text/Unicode.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 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 AAPT_TEXT_UNICODE_H
+#define AAPT_TEXT_UNICODE_H
+
+#include "androidfw/StringPiece.h"
+
+namespace aapt {
+namespace text {
+
+// Returns true if the Unicode codepoint has the XID_Start property, meaning it can be used as the
+// first character of a programming language identifier.
+// http://unicode.org/reports/tr31/#Default_Identifier_Syntax
+//
+// XID_Start is a Unicode Derived Core Property. It is a variation of the ID_Start
+// Derived Core Property, accounting for a few characters that, when normalized, yield valid
+// characters in the ID_Start set.
+bool IsXidStart(char32_t codepoint);
+
+// Returns true if the Unicode codepoint has the XID_Continue property, meaning it can be used in
+// any position of a programming language identifier, except the first.
+// http://unicode.org/reports/tr31/#Default_Identifier_Syntax
+//
+// XID_Continue is a Unicode Derived Core Property. It is a variation of the ID_Continue
+// Derived Core Property, accounting for a few characters that, when normalized, yield valid
+// characters in the ID_Continue set.
+bool IsXidContinue(char32_t codepoint);
+
+// Returns true if the UTF8 string can be used as a Java identifier.
+// NOTE: This does not check against the set of reserved Java keywords.
+bool IsJavaIdentifier(const android::StringPiece& str);
+
+// Returns true if the UTF8 string can be used as the entry name of a resource name.
+// This is the `entry` part of package:type/entry.
+bool IsValidResourceEntryName(const android::StringPiece& str);
+
+} // namespace text
+} // namespace aapt
+
+#endif // AAPT_TEXT_UNICODE_H