HelpersFinder.java

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package org.netbeans.modules.ruby;

import java.util.Set;
import org.jrubyparser.ast.Node;
import org.jrubyparser.ast.SymbolNode;
import org.netbeans.modules.csl.api.DeclarationFinder.DeclarationLocation;
import org.netbeans.modules.parsing.spi.indexing.support.QuerySupport.Kind;
import org.netbeans.modules.ruby.elements.IndexedClass;

/**
 * Tries to locate class passed to methods that take a class name as an argument.
 * E.g. tries to find
 * SomeClassHelper for :some_class in the following:
 * <pre>
 * helper :some_class
 * </pre>
 *
 * <i>TODO: should rename as this isn't about helpers only anymore,
 * just can't come up with a good name now</i>.
 * 
 * @author Erno Mononen
 */

final class HelpersFinder {

    private static final MethodInfo[] APPLICABLE_METHODS = {
        new MethodInfo("helper", "Helper"),
        new MethodInfo("cache_sweeper")
    };

    private final RubyIndex index;
    private final SymbolNode closest;
    private final Node root;
    private final AstPath path;

    public HelpersFinder(RubyIndex index, SymbolNode closest, Node root, AstPath path) {
        this.index = index;
        this.closest = closest;
        this.root = root;
        this.path = path;
    }

    private MethodInfo getMethodInfo(Node node) {
        if (!AstUtilities.isCall(node)) {
            return null;
        }
        for (MethodInfo each : APPLICABLE_METHODS) {
            if (AstUtilities.isNodeNameIn(node, each.name)) {
                return each;
            }
        }
        return null;
    }

    private MethodInfo getMethodInfo() {
        MethodInfo result = null;
        // first argument
        for (Node child : closest.childNodes()) {
            result = getMethodInfo(child);
            if (result != null) {
                return result;
            }
        }
        // others
        result = getMethodInfo(path.leafParent());
        if (result == null) {
            result = getMethodInfo(path.leafGrandParent());
        }
        return result;
    }


    private String getClassName(MethodInfo methodInfo) {
        String className = AstUtilities.getName(closest);
        if (className.length() == 0) {
            return null;
        }
        return methodInfo.getClassName(RubyUtils.underlinedNameToCamel(className)); //NOI18N
    }

    DeclarationLocation findHelperLocation() {
        MethodInfo methodInfo = getMethodInfo();
        if (methodInfo == null) {
            return DeclarationLocation.NONE;
        }
        String className = getClassName(methodInfo);
        if (className == null) {
            return DeclarationLocation.NONE;
        }
        Set<IndexedClass> result = index.getClasses(className, Kind.EXACT, true, false, false);
        if (result.isEmpty()) {
            return DeclarationLocation.NONE;
        }
        return RubyDeclarationFinder.getLocation(result);
    }

    private static class MethodInfo {
        /**
         * the name of the method.
         */
        private final String name;
        /**
         * the suffix to add to the class name
         */
        private final String suffix;

        public MethodInfo(String name) {
            this(name, "");
        }

        public MethodInfo(String name, String suffix) {
            this.name = name;
            this.suffix = suffix;
        }

        public String getClassName(String className) {
            return className + suffix;
        }

    }
}