Update yang-xpath-api design

[yangtools.git] / yang / yang-xpath-impl / src / main / java / org / opendaylight / yangtools / yang / xpath / impl / InstanceIdentifierParser.java

diff --git a/yang/yang-xpath-impl/src/main/java/org/opendaylight/yangtools/yang/xpath/impl/InstanceIdentifierParser.java b/yang/yang-xpath-impl/src/main/java/org/opendaylight/yangtools/yang/xpath/impl/InstanceIdentifierParser.java
new file mode 100644 (file)
index 0000000..cc6b3d8
--- /dev/null
+++ b/yang/yang-xpath-impl/src/main/java/org/opendaylight/yangtools/yang/xpath/impl/InstanceIdentifierParser.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2019 Pantheon Technologies, s.r.o.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.yangtools.yang.xpath.impl;
+
+import static java.util.Objects.requireNonNull;
+import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.getChild;
+import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.illegalShape;
+import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.verifyToken;
+
+import com.google.common.collect.ImmutableSet;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import javax.xml.xpath.XPathExpressionException;
+import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.tree.ParseTree;
+import org.opendaylight.yangtools.yang.common.QName;
+import org.opendaylight.yangtools.yang.common.YangNamespaceContext;
+import org.opendaylight.yangtools.yang.xpath.api.YangBinaryOperator;
+import org.opendaylight.yangtools.yang.xpath.api.YangExpr;
+import org.opendaylight.yangtools.yang.xpath.api.YangLiteralExpr;
+import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath;
+import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath.Step;
+import org.opendaylight.yangtools.yang.xpath.api.YangQNameExpr;
+import org.opendaylight.yangtools.yang.xpath.api.YangXPathAxis;
+import org.opendaylight.yangtools.yang.xpath.api.YangXPathMathMode;
+import org.opendaylight.yangtools.yang.xpath.api.YangXPathMathSupport;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.EqQuotedStringContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.InstanceIdentifierContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.KeyPredicateContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.KeyPredicateExprContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.LeafListPredicateContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.LeafListPredicateExprContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.NodeIdentifierContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.PathArgumentContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.PosContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.PredicateContext;
+import org.opendaylight.yangtools.yang.xpath.impl.instanceIdentifierParser.QuotedStringContext;
+
+final class InstanceIdentifierParser {
+
+    private final YangNamespaceContext namespaceContext;
+    private final YangXPathMathSupport<?> mathSupport;
+
+    InstanceIdentifierParser(final YangNamespaceContext namespaceContext, final YangXPathMathMode mathMode) {
+        this.namespaceContext = requireNonNull(namespaceContext);
+        this.mathSupport = mathMode.getSupport();
+    }
+
+    YangLocationPath interpretAsInstanceIdentifier(final YangLiteralExpr expr) throws XPathExpressionException {
+        final xpathLexer lexer = new xpathLexer(CharStreams.fromString(expr.getLiteral()));
+        final instanceIdentifierParser parser = new instanceIdentifierParser(new CommonTokenStream(lexer));
+        lexer.removeErrorListeners();
+        parser.removeErrorListeners();
+
+        // FIXME: add listeners
+
+        final InstanceIdentifierContext id = parser.instanceIdentifier();
+        final int length = id.getChildCount();
+        final List<Step> steps = new ArrayList<>(length / 2);
+        for (int i = 1; i < length; i += 2) {
+            steps.add(parsePathArgument(getChild(id, PathArgumentContext.class, i)));
+        }
+
+        return YangLocationPath.of(true, steps);
+    }
+
+    private Step parsePathArgument(final PathArgumentContext expr) {
+        final QName qname = parseQName(getChild(expr, NodeIdentifierContext.class, 0));
+        switch (expr.getChildCount()) {
+            case 1:
+                return YangXPathAxis.CHILD.asStep(qname, ImmutableSet.of());
+            case 2:
+                return YangXPathAxis.CHILD.asStep(qname, parsePredicate(getChild(expr, PredicateContext.class, 1)));
+            default:
+                throw illegalShape(expr);
+        }
+    }
+
+    private Collection<YangExpr> parsePredicate(final PredicateContext expr) {
+        final ParseTree first = expr.getChild(0);
+        if (first instanceof LeafListPredicateContext) {
+            return ImmutableSet.of(YangBinaryOperator.EQUALS.exprWith(YangLocationPath.self(),
+                parseEqStringValue(getChild(((LeafListPredicateContext) first)
+                    .getChild(LeafListPredicateExprContext.class, 0), EqQuotedStringContext.class, 1))));
+        } else if (first instanceof PosContext) {
+            return ImmutableSet.of(YangBinaryOperator.EQUALS.exprWith(Functions.POSITION, mathSupport.createNumber(
+                ((PosContext) first).getToken(instanceIdentifierParser.PositiveIntegerValue, 0).getText())));
+        }
+
+        final int length = expr.getChildCount();
+        final List<YangExpr> ret = new ArrayList<>(length);
+        for (int i = 0; i < length; ++i) {
+            final KeyPredicateExprContext pred = getChild(expr, KeyPredicateContext.class, i)
+                    .getChild(KeyPredicateExprContext.class, 0);
+            ret.add(YangBinaryOperator.EQUALS.exprWith(
+                YangQNameExpr.of(parseQName(getChild(pred, NodeIdentifierContext.class, 0))),
+                parseEqStringValue(getChild(pred, EqQuotedStringContext.class, 1))));
+
+        }
+
+        return ret;
+    }
+
+    private QName parseQName(final NodeIdentifierContext expr) {
+        return namespaceContext.createQName(
+            verifyToken(expr, 0, instanceIdentifierParser.Identifier).getText(),
+            verifyToken(expr, 2, instanceIdentifierParser.Identifier).getText());
+    }
+
+    private static YangLiteralExpr parseEqStringValue(final EqQuotedStringContext expr) {
+        return YangLiteralExpr.of(verifyToken(getChild(expr, QuotedStringContext.class, expr.getChildCount() - 1), 1,
+            instanceIdentifierParser.STRING).getText());
+    }
+}