JavaASTCreateMethodRef.py

#?description=Show how the Java AST API can be used to modify and create elements in a decompiled syntax tree
#?shortcut=
import time
from com.pnfsoftware.jeb.client.api import IScript
from com.pnfsoftware.jeb.core.units.code.java import IJavaSourceUnit
"""
Sample script for JEB Decompiler.

Open an APK/DEX, decompile any class or method; in the Decompiled view, position the caret somewhere in a method.
Execute the script.

The script shows how to use the Java factory to create an external method reference (also available for fields),
create a new statement (here, a call to 'new String("...")'), and replace an arbitrary selected statement
(index 0 in the currently selected method) by the new statement.
"""
class JavaASTCreateMethodRef(IScript):

  def run(self, ctx):
    # retrieve the currently active UI fragment (make sure to select a Decompiled Java fragment)
    f = ctx.getFocusedFragment()
    assert f, 'Need a focused fragment'

    unit = f.getUnit()
    assert isinstance(unit, IJavaSourceUnit), 'Need a java unit'

    # a DEX-style address: TYPENAME->METHODNAME(PARAMTYPES)RETTYPE+OFFSET
    addr = f.getActiveAddress()

    # IDexDecompilerUnit
    dexdec = unit.getParent()

    pos = addr.find('+')
    if pos >= 0: addr = addr[:pos]

    # retrieve the already decompiled IJavaMethod on caret
    _m = dexdec.getMethod(addr)

    # method body...
    _blk = _m.getBody()
    # we pick the first statement
    _stm0 = _blk.get(0)
    print('Will replace statement: "%s"' % _stm0)

    # IJavaFactories
    self.jfactory = unit.getFactories()

    # now, replace that first method statement by a call to 'new String("...")'
    if self.replaceStatement(_blk, _stm0):
      unit.notifyGenericChange()


  def replaceStatement(self, parent, e):
    m = self.jfactory.createMethodReference('Ljava/lang/String;-><init>(Ljava/lang/String;)V', False)
    t = self.jfactory.getTypeFactory().createType('Ljava/lang/String;')
    args = [self.jfactory.getConstantFactory().createString('FOOBAR__' + str(time.time()))]
    stm = self.jfactory.createNew(t, m, args)
    return parent.replaceSubElement(e, stm)