Merge "Laoutlib_creator: keep original of delegate methods."

Consequently this tool:

- parses the input JAR,

- modifies some of the classes directly using some bytecode manipulation,

- filters some packages and removes some that we don't want to end in the output JAR,

- filters some packages and removes those we don't want in the output JAR,

- injects some new classes,

- and generates a modified JAR file that is suitable for the Android plugin

- generates a modified JAR file that is suitable for the Android plugin

  for Eclipse to perform rendering.

The ASM library is used to do the bytecode modification using its visitor pattern API.

To do that, the analyzer is created with a list of base classes to keep -- everything

that derives from these is kept. Currently the one such class is android.view.View:

since we want to render layouts, anything that is sort of the view needs to be kept.

since we want to render layouts, anything that is sort of a view needs to be kept.

The analyzer is also given a list of class names to keep in the output.

This is done using shell-like glob patterns that filter on the fully-qualified

- the classes to inject in the output JAR -- these classes are directly implemented

  in layoutlib_create and will be used to interface with the renderer in Eclipse.

- specific methods to override (see method stubs details below).

- specific methods for which to delegate calls.

- specific methods to remove based on their return type.

- specific classes to rename.

The code of the methods is then kept as-is, except for native methods which are

replaced by a stub. Methods that are to be overridden are also replaced by a stub.

The transformed class is then fed through the DelegateClassAdapter to implement

method delegates. 

Finally fields are also visited and changed from protected/private to public.

method was native. We do not currently provide the parameters. The listener

can however specify the return value of the overridden method.

An extension being worked on is to actually replace these listeners by

direct calls to a delegate class, complete with parameters.

This strategy is now obsolete and replaced by the method delegates.

- Strategies

by a call to a specific OveriddeMethod.invokeX(). The bridge then registers

a listener on the method signature and can provide an implementation.

This strategy is now obsolete and replaced by the method delegates.

See strategy 5 below.

3- Renaming classes

bridge will provide its own implementation.

5- Method Delegates

This strategy is used to override method implementations.

Given a method SomeClass.MethodName(), 1 or 2 methods are generated:

a- A copy of the original method named SomeClass.MethodName_Original().

   The content is the original method as-is from the reader.

   This step is omitted if the method is native, since it has no Java implementation.

b- A brand new implementation of SomeClass.MethodName() which calls to a

   non-existing static method named SomeClass_Delegate.MethodName().

   The implementation of this 'delegate' method is done in layoutlib_brigde.

The delegate method is a static method.

If the original method is non-static, the delegate method receives the original 'this'

as its first argument. If the original method is an inner non-static method, it also

receives the inner 'this' as the second argument.

- References -

--------------

     * Returns The list of methods to stub out. Each entry must be in the form

     * "package.package.OuterClass$InnerClass#MethodName".

     * The list can be empty but must not be null.

     * <p/>

     * This usage is deprecated. Please use method 'delegates' instead.

     */

    public String[] getOverriddenMethods() {

        return OVERRIDDEN_METHODS;

    /**

     * The list of methods to stub out. Each entry must be in the form

     *  "package.package.OuterClass$InnerClass#MethodName".

     *  This usage is deprecated. Please use method 'delegates' instead.

     */

    private final static String[] OVERRIDDEN_METHODS = new String[] {

    };

 */

public class DelegateClassAdapter extends ClassAdapter {

    /** Suffix added to original methods. */

    private static final String ORIGINAL_SUFFIX = "_Original";

    private static String CONSTRUCTOR = "<init>";

    private static String CLASS_INIT = "<clinit>";

    public final static String ALL_NATIVES = "<<all_natives>>";

    private final String mClassName;

        boolean useDelegate = (isNative && mDelegateMethods.contains(ALL_NATIVES)) ||

                              mDelegateMethods.contains(name);

        if (useDelegate) {

            // remove native

            access = access & ~Opcodes.ACC_NATIVE;

        if (!useDelegate) {

            // Not creating a delegate for this method, pass it as-is from the reader

            // to the writer.

            return super.visitMethod(access, name, desc, signature, exceptions);

        }

        MethodVisitor mw = super.visitMethod(access, name, desc, signature, exceptions);

        if (useDelegate) {

            DelegateMethodAdapter a = new DelegateMethodAdapter(mLog, mw, mClassName,

                                                                name, desc, isStatic);

            if (CONSTRUCTOR.equals(name) || CLASS_INIT.equals(name)) {

                // We don't currently support generating delegates for constructors.

                throw new UnsupportedOperationException(

                    String.format(

                        "Delegate doesn't support overriding constructor %1$s:%2$s(%3$s)",  //$NON-NLS-1$

                        mClassName, name, desc));

            }

        }

        if (isNative) {

            // Remove native flag

            access = access & ~Opcodes.ACC_NATIVE;

            MethodVisitor mwDelegate = super.visitMethod(access, name, desc, signature, exceptions);

            DelegateMethodAdapter2 a = new DelegateMethodAdapter2(

                    mLog, null /*mwOriginal*/, mwDelegate, mClassName, name, desc, isStatic);

            // A native has no code to visit, so we need to generate it directly.

                a.generateCode();

            } else {

                return a;

            }

            a.generateDelegateCode();

            return mwDelegate;

        }

        return mw;

        // Given a non-native SomeClass.MethodName(), we want to generate 2 methods:

        // - A copy of the original method named SomeClass.MethodName_Original().

        //   The content is the original method as-is from the reader.

        // - A brand new implementation of SomeClass.MethodName() which calls to a

        //   non-existing method named SomeClass_Delegate.MethodName().

        //   The implementation of this 'delegate' method is done in layoutlib_brigde.

        int accessDelegate = access;

        // change access to public for the original one

        access &= ~(Opcodes.ACC_PROTECTED | Opcodes.ACC_PRIVATE);

        access |= Opcodes.ACC_PUBLIC;

        MethodVisitor mwOriginal = super.visitMethod(access, name + ORIGINAL_SUFFIX,

                                                     desc, signature, exceptions);

        MethodVisitor mwDelegate = super.visitMethod(accessDelegate, name,

                                                     desc, signature, exceptions);

        DelegateMethodAdapter2 a = new DelegateMethodAdapter2(

                mLog, mwOriginal, mwDelegate, mClassName, name, desc, isStatic);

        return a;

    }

}

                generatePop();

                generateInvoke();

                mMessageGenerated = true;

                //$FALL-THROUGH$

            default:

                mParentVisitor.visitInsn(opcode);

            }