/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jshell;

import com.sun.source.tree.ClassTree;

import com.sun.source.tree.IdentifierTree;

import com.sun.source.tree.ImportTree;

import com.sun.source.tree.MemberSelectTree;

import com.sun.source.tree.MethodTree;

import com.sun.source.tree.PackageTree;

import com.sun.source.tree.Tree;

import com.sun.source.tree.VariableTree;

import com.sun.source.util.TreeScanner;

import com.sun.tools.javac.util.DefinedBy;

import com.sun.tools.javac.util.DefinedBy.Api;

import java.util.Collection;

import java.util.HashSet;

import java.util.Set;

import javax.lang.model.element.Name;

/**

 * Search a compiler API parse tree for dependencies.

 */

class TreeDependencyScanner extends TreeScanner<Void, Set<String>> {

    private final Set<String> decl = new HashSet<>();

    private final Set<String> body = new HashSet<>();

    public void scan(Tree node) {

        scan(node, decl);

    }

    public Collection<String> declareReferences() {

        return decl;

    }

    public Collection<String> bodyReferences() {

        return body;

    }

    private void add(Set<String> p, Name name) {

        p.add(name.toString());

    }

    // -- Differentiate declaration references from body references ---

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitClass(ClassTree node, Set<String> p) {

        scan(node.getModifiers(), p);

        scan(node.getTypeParameters(), p);

        scan(node.getExtendsClause(), p);

        scan(node.getImplementsClause(), p);

        scan(node.getMembers(), body);

        return null;

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitMethod(MethodTree node, Set<String> p) {

        scan(node.getModifiers(), p);

        scan(node.getReturnType(), p);

        scan(node.getTypeParameters(), p);

        scan(node.getParameters(), p);

        scan(node.getReceiverParameter(), p);

        scan(node.getThrows(), p);

        scan(node.getBody(), body);

        scan(node.getDefaultValue(), body);

        return null;

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitVariable(VariableTree node, Set<String> p) {

        scan(node.getModifiers(), p);

        scan(node.getType(), p);

        scan(node.getNameExpression(), p);

        scan(node.getInitializer(), body);

        return null;

    }

    // --- Ignore these ---

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitPackage(PackageTree node, Set<String> p) {

        return null;

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitImport(ImportTree node, Set<String> p) {

        return null;

    }

    // -- Actual Symbol names ---

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitMemberSelect(MemberSelectTree node, Set<String> p) {

        add(p, node.getIdentifier());

        return super.visitMemberSelect(node, p);

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Void visitIdentifier(IdentifierTree node, Set<String> p) {

        add(p, node.getName());

        return super.visitIdentifier(node, p);

    }

}