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

   1 /*
   2  * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.yangtools.yang.parser.stmt.rfc6020;
   9
  10 import com.google.common.base.Optional;
  11 import java.util.regex.Pattern;
  12 import java.util.regex.PatternSyntaxException;
  13 import javax.annotation.Nonnull;
  14 import org.opendaylight.yangtools.yang.model.api.YangStmtMapping;
  15 import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
  16 import org.opendaylight.yangtools.yang.model.api.stmt.DescriptionStatement;
  17 import org.opendaylight.yangtools.yang.model.api.stmt.ErrorAppTagStatement;
  18 import org.opendaylight.yangtools.yang.model.api.stmt.ErrorMessageStatement;
  19 import org.opendaylight.yangtools.yang.model.api.stmt.ModifierStatement;
  20 import org.opendaylight.yangtools.yang.model.api.stmt.PatternStatement;
  21 import org.opendaylight.yangtools.yang.model.api.stmt.ReferenceStatement;
  22 import org.opendaylight.yangtools.yang.model.api.type.PatternConstraint;
  23 import org.opendaylight.yangtools.yang.parser.spi.SubstatementValidator;
  24 import org.opendaylight.yangtools.yang.parser.spi.meta.AbstractDeclaredStatement;
  25 import org.opendaylight.yangtools.yang.parser.spi.meta.AbstractStatementSupport;
  26 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
  27 import org.opendaylight.yangtools.yang.parser.stmt.rfc6020.effective.type.PatternConstraintEffectiveImpl;
  28 import org.opendaylight.yangtools.yang.parser.stmt.rfc6020.effective.type.PatternEffectiveStatementImpl;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 public class PatternStatementImpl extends AbstractDeclaredStatement<PatternConstraint> implements PatternStatement {
  33     private static final SubstatementValidator SUBSTATEMENT_VALIDATOR = SubstatementValidator.builder(YangStmtMapping
  34             .PATTERN)
  35             .addOptional(YangStmtMapping.DESCRIPTION)
  36             .addOptional(YangStmtMapping.ERROR_APP_TAG)
  37             .addOptional(YangStmtMapping.ERROR_MESSAGE)
  38             .addOptional(YangStmtMapping.REFERENCE)
  39             .build();
  40     private static final Logger LOG = LoggerFactory.getLogger(PatternStatementImpl.class);
  41
  42     protected PatternStatementImpl(final StmtContext<PatternConstraint, PatternStatement, ?> context) {
  43         super(context);
  44     }
  45
  46     public static class Definition
  47             extends
  48             AbstractStatementSupport<PatternConstraint, PatternStatement, EffectiveStatement<PatternConstraint, PatternStatement>> {
  49
  50         public Definition() {
  51             super(YangStmtMapping.PATTERN);
  52         }
  53
  54         @Override
  55         public PatternConstraint parseArgumentValue(final StmtContext<?, ?, ?> ctx, final String value) {
  56             final String pattern = getJavaRegexFromXSD(value);
  57
  58             try {
  59                 Pattern.compile(pattern);
  60             } catch (final PatternSyntaxException e) {
  61                 LOG.debug("Pattern \"{}\" failed to compile at {}", pattern, ctx.getStatementSourceReference(), e);
  62                 return null;
  63             }
  64
  65             return new PatternConstraintEffectiveImpl(pattern, value, Optional.absent(), Optional.absent());
  66         }
  67
  68         static String getJavaRegexFromXSD(final String xsdRegex) {
  69             return "^" + Utils.fixUnicodeScriptPattern(escapeChars(xsdRegex)) + '$';
  70         }
  71
  72         /*
  73          * As both '^' and '$' are special anchor characters in java regular
  74          * expressions which are implicitly present in XSD regular expressions,
  75          * we need to escape them in case they are not defined as part of
  76          * character ranges i.e. inside regular square brackets.
  77          */
  78         private static String escapeChars(final String regex) {
  79             final StringBuilder result = new StringBuilder(regex.length());
  80             int bracket = 0;
  81             boolean escape = false;
  82             for (int i = 0; i < regex.length(); i++) {
  83                 final char ch = regex.charAt(i);
  84                 switch (ch) {
  85                 case '[':
  86                     if (!escape) {
  87                         bracket++;
  88                     }
  89                     escape = false;
  90                     result.append(ch);
  91                     break;
  92                 case ']':
  93                     if (!escape) {
  94                         bracket--;
  95                     }
  96                     escape = false;
  97                     result.append(ch);
  98                     break;
  99                 case '\\':
 100                     escape = !escape;
 101                     result.append(ch);
 102                     break;
 103                 case '^':
 104                 case '$':
 105                     if (bracket == 0) {
 106                         result.append('\\');
 107                     }
 108                     escape = false;
 109                     result.append(ch);
 110                     break;
 111                 default:
 112                     escape = false;
 113                     result.append(ch);
 114                 }
 115             }
 116             return result.toString();
 117         }
 118
 119         @Override
 120         public PatternStatement createDeclared(final StmtContext<PatternConstraint, PatternStatement, ?> ctx) {
 121             return new PatternStatementImpl(ctx);
 122         }
 123
 124         @Override
 125         public EffectiveStatement<PatternConstraint, PatternStatement> createEffective(
 126                 final StmtContext<PatternConstraint, PatternStatement, EffectiveStatement<PatternConstraint, PatternStatement>> ctx) {
 127             return new PatternEffectiveStatementImpl(ctx);
 128         }
 129
 130         @Override
 131         protected SubstatementValidator getSubstatementValidator() {
 132             return SUBSTATEMENT_VALIDATOR;
 133         }
 134     }
 135
 136     @Override
 137     public ErrorAppTagStatement getErrorAppTagStatement() {
 138         return firstDeclared(ErrorAppTagStatement.class);
 139     }
 140
 141     @Override
 142     public ErrorMessageStatement getErrorMessageStatement() {
 143         return firstDeclared(ErrorMessageStatement.class);
 144     }
 145
 146     @Override
 147     public DescriptionStatement getDescription() {
 148         return firstDeclared(DescriptionStatement.class);
 149     }
 150
 151     @Override
 152     public ModifierStatement getModifierStatement() {
 153         return firstDeclared(ModifierStatement.class);
 154     }
 155
 156     @Override
 157     public ReferenceStatement getReference() {
 158         return firstDeclared(ReferenceStatement.class);
 159     }
 160
 161     @Nonnull
 162     @Override
 163     public PatternConstraint getValue() {
 164         return argument();
 165     }
 166 }