package org.apache.maven.shared.dependency.analyzer.asm;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *  http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 import java.util.HashSet;

 import java.util.Set;

 import org.objectweb.asm.AnnotationVisitor;

 import org.objectweb.asm.Attribute;

 import org.objectweb.asm.ClassVisitor;

 import org.objectweb.asm.FieldVisitor;

 import org.objectweb.asm.Label;

 import org.objectweb.asm.MethodVisitor;

 import org.objectweb.asm.Type;

 import org.objectweb.asm.signature.SignatureReader;

 import org.objectweb.asm.signature.SignatureVisitor;

 /**

  * Computes the set of classes referenced by visited code.

  * Inspired by <code>org.objectweb.asm.depend.DependencyVisitor</code> in the ASM dependencies example.

  * 

  * @author <a href="mailto:markhobson@gmail.com">Mark Hobson</a>

  * @version $Id: DependencyVisitor.java 1174427 2011-09-22 22:25:17Z hboutemy $

  * @see #getClasses()

  */

 public class DependencyVisitor

     implements AnnotationVisitor, SignatureVisitor, ClassVisitor, FieldVisitor, MethodVisitor

 {

     // fields -----------------------------------------------------------------

     private final Set<String> classes;

     // constructors -----------------------------------------------------------

     public DependencyVisitor()

     {

         classes = new HashSet<String>();

     }

     // ClassVisitor methods ---------------------------------------------------

     /*

      * @see org.objectweb.asm.ClassVisitor#visit(int, int, java.lang.String, java.lang.String, java.lang.String,

      *      java.lang.String[])

      */

     public void visit( final int version, final int access, final String name, final String signature,

                        final String superName, final String[] interfaces )

     {

         if ( signature == null )

         {

             addName( superName );

             addNames( interfaces );

         }

         else

         {

             addSignature( signature );

         }

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitSource(java.lang.String, java.lang.String)

      */

     public void visitSource( final String source, final String debug )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitOuterClass(java.lang.String, java.lang.String, java.lang.String)

      */

     public void visitOuterClass( final String owner, final String name, final String desc )

     {

         // addName(owner);

         // addMethodDesc(desc);

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitAnnotation(java.lang.String, boolean)

      */

     public AnnotationVisitor visitAnnotation( final String desc, final boolean visible )

     {

         addDesc( desc );

         return this;

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitAttribute(org.objectweb.asm.Attribute)

      */

     public void visitAttribute( final Attribute attr )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitInnerClass(java.lang.String, java.lang.String, java.lang.String, int)

      */

     public void visitInnerClass( final String name, final String outerName, final String innerName, final int access )

     {

         // addName( outerName);

         // addName( innerName);

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitField(int, java.lang.String, java.lang.String, java.lang.String,

      *      java.lang.Object)

      */

     public FieldVisitor visitField( final int access, final String name, final String desc, final String signature,

                                     final Object value )

     {

         if ( signature == null )

         {

             addDesc( desc );

         }

         else

         {

             addTypeSignature( signature );

         }

         if ( value instanceof Type )

         {

             addType( (Type) value );

         }

         return this;

     }

     /*

      * @see org.objectweb.asm.ClassVisitor#visitMethod(int, java.lang.String, java.lang.String, java.lang.String,

      *      java.lang.String[])

      */

     public MethodVisitor visitMethod( final int access, final String name, final String desc, final String signature,

                                       final String[] exceptions )

     {

         if ( signature == null )

         {

             addMethodDesc( desc );

         }

         else

         {

             addSignature( signature );

         }

         addNames( exceptions );

         return this;

     }

     // MethodVisitor methods --------------------------------------------------

     /*

      * @see org.objectweb.asm.MethodVisitor#visitAnnotationDefault()

      */

     public AnnotationVisitor visitAnnotationDefault()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitParameterAnnotation(int, java.lang.String, boolean)

      */

     public AnnotationVisitor visitParameterAnnotation( final int parameter, final String desc, final boolean visible )

     {

         addDesc( desc );

         return this;

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitCode()

      */

     public void visitCode()

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitFrame(int, int, java.lang.Object[], int, java.lang.Object[])

      */

     public void visitFrame( final int type, final int nLocal, final Object[] local, final int nStack,

                             final Object[] stack )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitInsn(int)

      */

     public void visitInsn( final int opcode )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitIntInsn(int, int)

      */

     public void visitIntInsn( final int opcode, final int operand )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitVarInsn(int, int)

      */

     public void visitVarInsn( final int opcode, final int var )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitTypeInsn(int, java.lang.String)

      */

     public void visitTypeInsn( final int opcode, final String desc )

     {

         if ( desc.charAt( 0 ) == '[' )

         {

             addDesc( desc );

         }

         else

         {

             addName( desc );

         }

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitFieldInsn(int, java.lang.String, java.lang.String, java.lang.String)

      */

     public void visitFieldInsn( final int opcode, final String owner, final String name, final String desc )

     {

         addName( owner );

         /*

          * NOTE: Merely accessing a field does not impose a direct dependency on its type. For example, the code line

          * <code>java.lang.Object var = bean.field;</code> does not directly depend on the type of the field. A direct

          * dependency is only introduced when the code explicitly references the field's type by means of a variable

          * declaration or a type check/cast. Those cases are handled by other visitor callbacks.

          */

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitMethodInsn(int, java.lang.String, java.lang.String, java.lang.String)

      */

     public void visitMethodInsn( final int opcode, final String owner, final String name, final String desc )

     {

         addName( owner );

         /*

          * NOTE: Merely invoking a method does not impose a direct dependency on its return type nor its parameter

          * types. For example, the code line <code>bean.method(null);</code> only depends on the owner type of the

          * method. A direct dependency is only introduced when the code explicitly references the method's types by

          * means of a variable declaration or a type check/cast. Those cases are handled by other visitor callbacks.

          */

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitJumpInsn(int, org.objectweb.asm.Label)

      */

     public void visitJumpInsn( final int opcode, final Label label )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitLabel(org.objectweb.asm.Label)

      */

     public void visitLabel( final Label label )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitLdcInsn(java.lang.Object)

      */

     public void visitLdcInsn( final Object cst )

     {

         if ( cst instanceof Type )

         {

             addType( (Type) cst );

         }

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitIincInsn(int, int)

      */

     public void visitIincInsn( final int var, final int increment )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitTableSwitchInsn(int, int, org.objectweb.asm.Label,

      *      org.objectweb.asm.Label[])

      */

     public void visitTableSwitchInsn( final int min, final int max, final Label dflt, final Label[] labels )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitLookupSwitchInsn(org.objectweb.asm.Label, int[],

      *      org.objectweb.asm.Label[])

      */

     public void visitLookupSwitchInsn( final Label dflt, final int[] keys, final Label[] labels )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitMultiANewArrayInsn(java.lang.String, int)

      */

     public void visitMultiANewArrayInsn( final String desc, final int dims )

     {

         addDesc( desc );

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitTryCatchBlock(org.objectweb.asm.Label, org.objectweb.asm.Label,

      *      org.objectweb.asm.Label, java.lang.String)

      */

     public void visitTryCatchBlock( final Label start, final Label end, final Label handler, final String type )

     {

         addName( type );

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitLocalVariable(java.lang.String, java.lang.String, java.lang.String,

      *      org.objectweb.asm.Label, org.objectweb.asm.Label, int)

      */

     public void visitLocalVariable( final String name, final String desc, final String signature, final Label start,

                                     final Label end, final int index )

     {

         if ( signature == null )

         {

             addDesc( desc );

         }

         else

         {

             addTypeSignature( signature );

         }

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitLineNumber(int, org.objectweb.asm.Label)

      */

     public void visitLineNumber( final int line, final Label start )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.MethodVisitor#visitMaxs(int, int)

      */

     public void visitMaxs( final int maxStack, final int maxLocals )

     {

         // no-op

     }

     // AnnotationVisitor methods ----------------------------------------------

     /*

      * @see org.objectweb.asm.AnnotationVisitor#visit(java.lang.String, java.lang.Object)

      */

     public void visit( final String name, final Object value )

     {

         if ( value instanceof Type )

         {

             addType( (Type) value );

         }

     }

     /*

      * @see org.objectweb.asm.AnnotationVisitor#visitEnum(java.lang.String, java.lang.String, java.lang.String)

      */

     public void visitEnum( final String name, final String desc, final String value )

     {

         addDesc( desc );

     }

     /*

      * @see org.objectweb.asm.AnnotationVisitor#visitAnnotation(java.lang.String, java.lang.String)

      */

     public AnnotationVisitor visitAnnotation( final String name, final String desc )

     {

         addDesc( desc );

         return this;

     }

     /*

      * @see org.objectweb.asm.AnnotationVisitor#visitArray(java.lang.String)

      */

     public AnnotationVisitor visitArray( final String name )

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.AnnotationVisitor#visitEnd()

      */

     public void visitEnd()

     {

         // no-op

     }

     // SignatureVisitor methods -----------------------------------------------

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitFormalTypeParameter(java.lang.String)

      */

     public void visitFormalTypeParameter( final String name )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitClassBound()

      */

     public SignatureVisitor visitClassBound()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitInterfaceBound()

      */

     public SignatureVisitor visitInterfaceBound()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitSuperclass()

      */

     public SignatureVisitor visitSuperclass()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitInterface()

      */

     public SignatureVisitor visitInterface()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitParameterType()

      */

     public SignatureVisitor visitParameterType()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitReturnType()

      */

     public SignatureVisitor visitReturnType()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitExceptionType()

      */

     public SignatureVisitor visitExceptionType()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitBaseType(char)

      */

     public void visitBaseType( final char descriptor )

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitTypeVariable(java.lang.String)

      */

     public void visitTypeVariable( final String name )

     {

         // TODO: verify

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitArrayType()

      */

     public SignatureVisitor visitArrayType()

     {

         return this;

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitClassType(java.lang.String)

      */

     public void visitClassType( final String name )

     {

         addName( name );

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitInnerClassType(java.lang.String)

      */

     public void visitInnerClassType( final String name )

     {

         addName( name );

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitTypeArgument()

      */

     public void visitTypeArgument()

     {

         // no-op

     }

     /*

      * @see org.objectweb.asm.signature.SignatureVisitor#visitTypeArgument(char)

      */

     public SignatureVisitor visitTypeArgument( final char wildcard )

     {

         return this;

     }

     // public methods ---------------------------------------------------------

     public Set<String> getClasses()

     {

         return classes;

     }

     // private methods --------------------------------------------------------

     private void addName( String name )

     {

         if ( name == null )

         {

             return;

         }

         // decode arrays

         if ( name.startsWith( "[L" ) && name.endsWith( ";" ) )

         {

             name = name.substring( 2, name.length() - 1 );

         }

         // decode internal representation

         name = name.replace( '/', '.' );

         classes.add( name );

     }

     private void addNames( final String[] names )

     {

         if ( names == null )

         {

             return;

         }

         for ( String name : names )

         {

             addName( name );

         }

     }

     private void addDesc( final String desc )

     {

         addType( Type.getType( desc ) );

     }

     private void addMethodDesc( final String desc )

     {

         addType( Type.getReturnType( desc ) );

         Type[] types = Type.getArgumentTypes( desc );

         for ( Type type : types )

         {

             addType( type );

         }

     }

     private void addType( final Type t )

     {

         switch ( t.getSort() )

         {

             case Type.ARRAY:

                 addType( t.getElementType() );

                 break;

             case Type.OBJECT:

                 addName( t.getClassName().replace( '.', '/' ) );

                 break;

         }

     }

     private void addSignature( final String signature )

     {

         if ( signature != null )

         {

             new SignatureReader( signature ).accept( this );

         }

     }

     private void addTypeSignature( final String signature )

     {

         if ( signature != null )

         {

             new SignatureReader( signature ).acceptType( this );

         }

     }

 }