public abstract class

AbstractJOptimizer

extends AbstractPlugin
implements IJOptimizer
java.lang.Object
   ↳ com.pnfsoftware.jeb.core.AbstractPlugin
     ↳ com.pnfsoftware.jeb.core.units.code.java.AbstractJOptimizer
Known Direct Subclasses

Class Overview

Base class for dexdec (DEX decompiler) AST optimizer plugins. Those plugins can access and modify the AST of a class or method being decompiled. They can be used to implement simple code clean-up and beautification/styling.

Optimizers are usually managed by master optimizers (also called orchestrators). Third-party optimizer plugins can be automatically registered when creating an orchestrator.

Life-cycle information:
- plugins are reused (i.e. the perform() method is called multiple times)
- thread-safety:
-- Python script plugins must be thread-safe: a plugin instance may be executed by multiple threads concurrently
-- Java plugins (including Java script plugins) are not required to be thread-safe: a plugin instance will not be executed by multiple threads concurrently

Summary

Fields
public IJavaClass c Target AST class to be optimized.
public IJavaConstantFactory cf AST constant factory (for convenience - referenced in jctx).
public IDexDecompilerUnit decomp Managing dex decompiler.
public IDexUnit dex Underlying dex code.
public DeferredRequestsCollector drcollector Collector for deferred requests.
public IJavaGlobalContext jctx Java AST global context.
public static final ILogger logger Public logger accessible by the implementing optimizer.
public IJavaMethod m Target AST method to be optimized.
public IJavaOperatorFactory of AST operation factory (for convenience - referenced in jctx).
public IJavaTypeFactory tf AST type factory (for convenience - referenced in jctx).
Public Constructors
AbstractJOptimizer()
Create a standard optimizer.
AbstractJOptimizer(JOptimizerType type)
Create an optimizer.
AbstractJOptimizer(JOptimizerType type, String name)
Create an optimizer.
Public Methods
String getName()
Retrieve the plugin name.
EditablePluginInformation getPluginInformation()
Retrieve basic information about the plugin, such as name, version, author, and organization.
double getPriority()
Get the optimizer priority.
JOptimizerType getType()
Get the optimizer type.
boolean isEnabled()
Determine whether the optimizer is enabled or not.
final int perform(IJavaDecompilableElement elt)
Run the optimizer on the provided target element (method or class).
abstract int perform()
An optimizer must implement this method.
void setEnabled(boolean enabled)
Enable or disable this optimizer.
Protected Methods
void setName(String name)
Set the optimizer name.
void setPriority(double priority)
Set the optimizer priority.
void setType(JOptimizerType type)
Set the optimizer type.
[Expand]
Inherited Methods
From class com.pnfsoftware.jeb.core.AbstractPlugin
From class java.lang.Object
From interface com.pnfsoftware.jeb.core.IPlugin
From interface com.pnfsoftware.jeb.core.units.code.java.IJOptimizer

Fields

public IJavaClass c

Target AST class to be optimized. May be null, in which case m is not.

public IJavaConstantFactory cf

AST constant factory (for convenience - referenced in jctx).

public IDexDecompilerUnit decomp

Managing dex decompiler. May be null.

public IDexUnit dex

Underlying dex code. May be null.

public DeferredRequestsCollector drcollector

Collector for deferred requests. May be null. When non-null, optimizers may file requests to decompile other classes, methods, or fields. It is useful for optimizers needing to examine AST code located in other classes or methods to operate.

How to use in your optimizer: 

 
 // do some work
 // ...
 
 // need access to the AST of some other class (CX) to continue the work
 IJavaClass ast_CX = jctx.getClassFactory().get(csig_CX);
 if(ast_CX == null || !ast_CX.isBuilt()) {
     // the AST of CX is not available at this time
     // if we can, request a decompilation 
     if(drcollector != null) {
         drcollector.request(csig_MX);
     }
     return 0;  // done for now
 }
 
 // in a future call to this optimizer, the above check may pass, allowing further processing
 // ... 
 // ...

public IJavaGlobalContext jctx

Java AST global context. This context holds AST element factory methods as well as references to important factories, such as the constant, type, and operator factories.

public static final ILogger logger

Public logger accessible by the implementing optimizer. Writing to the logger should be favored over writing directly to stdout.

public IJavaMethod m

Target AST method to be optimized. May be null, in which case c is not.

public IJavaOperatorFactory of

AST operation factory (for convenience - referenced in jctx).

public IJavaTypeFactory tf

AST type factory (for convenience - referenced in jctx).

Public Constructors

public AbstractJOptimizer ()

Create a standard optimizer.

public AbstractJOptimizer (JOptimizerType type)

Create an optimizer.

public AbstractJOptimizer (JOptimizerType type, String name)

Create an optimizer.

Public Methods

public String getName ()

Retrieve the plugin name. Should be consistent with the value returned by getPluginInformation().getName().

public EditablePluginInformation getPluginInformation ()

Retrieve basic information about the plugin, such as name, version, author, and organization.

Returns
  • the plugin information

public double getPriority ()

Get the optimizer priority. A higher value means a higher priority. Priorities are used by optimizer orchestrators to determine in which order optimizers should be executed.

Returns
  • the default priority

public JOptimizerType getType ()

Get the optimizer type. Types are used by optimizer orchestrators to determine whether an optimizer should run.

public boolean isEnabled ()

Determine whether the optimizer is enabled or not. This method is used by optimizer orchestrators to determine whether an optimizer can be scheduled for execution.

Returns
  • true if this optimizer is enabled

public final int perform (IJavaDecompilableElement elt)

Run the optimizer on the provided target element (method or class).

Parameters
elt an AST element, such as an IJavaMethod or IJavaClass
Returns
  • number of optimizations performed

public abstract int perform ()

An optimizer must implement this method. This method is called by a master optimizer to perform the optimization on the selected target.

Note that the optimizer is responsible for returning a legal method context, e.g.: the method IR instructions must be consistent with the CFG; the CFG must adhere to certain rules (see #cleanGraph() cleanGraph); if the data flow analysis is no longer valid, it should be invalidated (see resetDFA); etc.

Returns
  • the number of optimizations performed, 0 if none

public void setEnabled (boolean enabled)

Enable or disable this optimizer. This flag is checked by a master optimizer.

Protected Methods

protected void setName (String name)

Set the optimizer name. To be used by the constructor.

Parameters
name if null, a name will be auto-generated

protected void setPriority (double priority)

Set the optimizer priority. To be used by the constructor.

Parameters
priority the new priority (high means higher priority). When optimizers are managed and run by an orchestrator, the optimizers with a higher priority are run before those having a lower priority. The default priority is 0.

protected void setType (JOptimizerType type)

Set the optimizer type. To be used by the constructor.

Parameters
type if null, a standard optimizer is assumed