Bug 5410 - XSD regular expressions are interpreted as Java regexes (1/2)

[yangtools.git] / yang / yang-parser-impl / src / main / java / org / opendaylight / yangtools / yang / parser / stmt / rfc6020 / PatternStatementImpl.java

diff --git a/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/rfc6020/PatternStatementImpl.java b/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/rfc6020/PatternStatementImpl.java
index e711624e070a67573fa23d6a241714bf0e419dd2..d899ed879fbc1d8044f239e9ca45663f92f9443a 100644 (file)
--- a/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/rfc6020/PatternStatementImpl.java
+++ b/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/rfc6020/PatternStatementImpl.java
@@ -53,7 +53,7 @@ public class PatternStatementImpl extends AbstractDeclaredStatement<PatternConst
 
         @Override
         public PatternConstraint parseArgumentValue(final StmtContext<?, ?, ?> ctx, final String value) {
-            final String pattern = "^" + Utils.fixUnicodeScriptPattern(value) + '$';
+            final String pattern = getJavaRegexFromXSD(value);
 
             try {
                 Pattern.compile(pattern);
@@ -62,7 +62,58 @@ public class PatternStatementImpl extends AbstractDeclaredStatement<PatternConst
                 return null;
             }
 
-            return new PatternConstraintEffectiveImpl(pattern, Optional.absent(), Optional.absent());
+            return new PatternConstraintEffectiveImpl(pattern, value, Optional.absent(), Optional.absent());
+        }
+
+        static String getJavaRegexFromXSD(final String xsdRegex) {
+            return "^" + Utils.fixUnicodeScriptPattern(escapeChars(xsdRegex)) + '$';
+        }
+
+        /*
+         * As both '^' and '$' are special anchor characters in java regular
+         * expressions which are implicitly present in XSD regular expressions,
+         * we need to escape them in case they are not defined as part of
+         * character ranges i.e. inside regular square brackets.
+         */
+        private static String escapeChars(final String regex) {
+            final StringBuilder result = new StringBuilder(regex.length());
+            int bracket = 0;
+            boolean escape = false;
+            for (int i = 0; i < regex.length(); i++) {
+                final char ch = regex.charAt(i);
+                switch (ch) {
+                case '[':
+                    if (!escape) {
+                        bracket++;
+                    }
+                    escape = false;
+                    result.append(ch);
+                    break;
+                case ']':
+                    if (!escape) {
+                        bracket--;
+                    }
+                    escape = false;
+                    result.append(ch);
+                    break;
+                case '\\':
+                    escape = !escape;
+                    result.append(ch);
+                    break;
+                case '^':
+                case '$':
+                    if (bracket == 0) {
+                        result.append('\\');
+                    }
+                    escape = false;
+                    result.append(ch);
+                    break;
+                default:
+                    escape = false;
+                    result.append(ch);
+                }
+            }
+            return result.toString();
         }
 
         @Override