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// Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
package org.jetbrains.java.decompiler.main.rels;

import org.jetbrains.java.decompiler.code.CodeConstants;
import org.jetbrains.java.decompiler.code.cfg.ControlFlowGraph;
import org.jetbrains.java.decompiler.main.DecompilerContext;
import org.jetbrains.java.decompiler.main.collectors.CounterContainer;
import org.jetbrains.java.decompiler.main.collectors.VarNamesCollector;
import org.jetbrains.java.decompiler.main.extern.IFernflowerLogger;
import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
import org.jetbrains.java.decompiler.modules.decompiler.flow.FlattenStatementsHelper;
import org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement;
import org.jetbrains.java.decompiler.modules.decompiler.vars.VarProcessor;
import org.jetbrains.java.decompiler.modules.decompiler.vars.VarVersionPair;
import org.jetbrains.java.decompiler.struct.StructClass;
import org.jetbrains.java.decompiler.struct.StructMethod;
import org.jetbrains.java.decompiler.struct.attr.StructLocalVariableTableAttribute;
import org.jetbrains.java.decompiler.struct.gen.MethodDescriptor;
import org.jetbrains.java.decompiler.util.DotExporter;
import org.jetbrains.java.decompiler.util.InterpreterUtil;
import org.jetbrains.java.decompiler.util.VBStyleCollection;

import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.TimeoutException;

public class ClassWrapper {
  // Sometimes when debugging you want to be able to only analyze a specific method.
  // When not null, this skips processing of every method except the one with the name specified.
  private static final String DEBUG_METHOD_FILTER = null;
  private final StructClass classStruct;
  private final Set hiddenMembers = new HashSet<>();
  private final VBStyleCollection staticFieldInitializers = new VBStyleCollection<>();
  private final VBStyleCollection dynamicFieldInitializers = new VBStyleCollection<>();
  private final VBStyleCollection methods = new VBStyleCollection<>();

  public ClassWrapper(StructClass classStruct) {
    this.classStruct = classStruct;
  }

  public void init() {
    DecompilerContext.setProperty(DecompilerContext.CURRENT_CLASS, classStruct);
    DecompilerContext.setProperty(DecompilerContext.CURRENT_CLASS_WRAPPER, this);
    DecompilerContext.getLogger().startClass(classStruct.qualifiedName);

    int maxSec = Integer.parseInt(DecompilerContext.getProperty(IFernflowerPreferences.MAX_PROCESSING_METHOD).toString());
    boolean testMode = DecompilerContext.getOption(IFernflowerPreferences.UNIT_TEST_MODE);

    for (StructMethod mt : classStruct.getMethods()) {
      DecompilerContext.getLogger().startMethod(mt.getName() + " " + mt.getDescriptor());

      MethodDescriptor md = MethodDescriptor.parseDescriptor(mt, null);
      VarProcessor varProc = new VarProcessor(mt, md);
      DecompilerContext.startMethod(varProc);

      VarNamesCollector vc = varProc.getVarNamesCollector();
      CounterContainer counter = DecompilerContext.getCounterContainer();

      RootStatement root = null;

      Throwable error = null;

      if (DEBUG_METHOD_FILTER != null && !DEBUG_METHOD_FILTER.equals(mt.getName())) {
        MethodWrapper methodWrapper = new MethodWrapper(null, varProc, mt, classStruct, counter);
        methods.addWithKey(methodWrapper, InterpreterUtil.makeUniqueKey(mt.getName(), mt.getDescriptor()));
        DecompilerContext.getLogger().endMethod();

        continue;
      }

      try {
        if (mt.containsCode()) {
          if (maxSec == 0 || testMode) {
            root = MethodProcessor.codeToJava(classStruct, mt, md, varProc);
          }
          else {
            MethodProcessor mtProc = new MethodProcessor(classStruct, mt, md, varProc, DecompilerContext.getCurrentContext());

            Thread mtThread = new Thread(mtProc, "Java decompiler");
            long stopAt = System.currentTimeMillis() + maxSec * 1000L;

            mtThread.start();

            while (!mtProc.isFinished()) {
              try {
                synchronized (mtProc.lock) {
                  mtProc.lock.wait(200);
                }
              }
              catch (InterruptedException e) {
                killThread(mtThread);
                throw e;
              }

              if (System.currentTimeMillis() >= stopAt) {
                String message = "Processing time limit exceeded for method " + mt.getName() + ", execution interrupted.";
                DecompilerContext.getLogger().writeMessage(message, IFernflowerLogger.Severity.ERROR);
                killThread(mtThread);
                error = new TimeoutException();
                break;
              }
            }

            if (error == null) {
              root = mtProc.getResult();
            }
          }
        }
        else {
          boolean thisVar = !mt.hasModifier(CodeConstants.ACC_STATIC);

          int paramCount = 0;
          if (thisVar) {
            varProc.getThisVars().put(new VarVersionPair(0, 0), classStruct.qualifiedName);
            paramCount = 1;
          }
          paramCount += md.params.length;

          int varIndex = 0;
          for (int i = 0; i < paramCount; i++) {
            varProc.setVarName(new VarVersionPair(varIndex, 0), vc.getFreeName(varIndex));
            varProc.markParam(new VarVersionPair(varIndex, 0));

            if (thisVar) {
              if (i == 0) {
                varIndex++;
              }
              else {
                varIndex += md.params[i - 1].stackSize;
              }
            }
            else {
              varIndex += md.params[i].stackSize;
            }
          }
        }
      }
      catch (Throwable t) {
        String message = "Method " + mt.getName() + " " + mt.getDescriptor() + " in class " + classStruct.qualifiedName + " couldn't be decompiled.";
        DecompilerContext.getLogger().writeMessage(message, IFernflowerLogger.Severity.WARN, t);
        error = t;
        RootStatement rootStat = MethodProcessor.debugCurrentlyDecompiling.get();
        if (rootStat != null) {
          DotExporter.errorToDotFile(rootStat, mt, "fail");

          try {
            FlattenStatementsHelper flatten = new FlattenStatementsHelper();
            DotExporter.errorToDotFile(flatten.buildDirectGraph(rootStat), mt, "failDigraph");
          } catch (Exception e) {
            // ignore
          }
        }

        ControlFlowGraph graph = MethodProcessor.debugCurrentCFG.get();
        if (graph != null) {
          DotExporter.errorToDotFile(graph, mt, "failCFG");
        }

        DecompileRecord decompileRecord = MethodProcessor.debugCurrentDecompileRecord.get();
        if (decompileRecord != null) {
          DotExporter.toDotFile(decompileRecord, mt, "failRecord", true);
        }
      }

      MethodWrapper methodWrapper = new MethodWrapper(root, varProc, mt, classStruct, counter);
      methodWrapper.decompileError = error;

      methods.addWithKey(methodWrapper, InterpreterUtil.makeUniqueKey(mt.getName(), mt.getDescriptor()));

      if (error == null) {
        // rename vars so that no one has the same name as a field
        VarNamesCollector namesCollector = new VarNamesCollector();
        classStruct.getFields().forEach(f -> namesCollector.addName(f.getName()));
        varProc.refreshVarNames(namesCollector);

        // if debug information present and should be used
        if (DecompilerContext.getOption(IFernflowerPreferences.USE_DEBUG_VAR_NAMES)) {
          StructLocalVariableTableAttribute attr = mt.getLocalVariableAttr();
          if (attr != null) {
            // only param names here
            varProc.setDebugVarNames(root, attr.getMapNames());

            /*
            // the rest is here
            methodWrapper.getOrBuildGraph().iterateExprents(exprent -> {
              List lst = exprent.getAllExprents(true);
              lst.add(exprent);
              lst.stream()
                .filter(e -> e instanceof VarExprent)
                .forEach(e -> {
                  VarExprent varExprent = (VarExprent)e;
                  String name = varExprent.getDebugName(mt);
                  if (name != null) {
                    varProc.setVarName(varExprent.getVarVersionPair(), name);
                  }
                });
              return 0;
            });
            */
          }
        }
      }

      DecompilerContext.getLogger().endMethod();
    }

    DecompilerContext.getLogger().endClass();
  }

  @SuppressWarnings("deprecation")
  private static void killThread(Thread thread) {
    thread.stop();
  }

  public MethodWrapper getMethodWrapper(String name, String descriptor) {
    return methods.getWithKey(InterpreterUtil.makeUniqueKey(name, descriptor));
  }

  public MethodWrapper getMethodWrapper(int index) {
    return methods.get(index);
  }

  public StructClass getClassStruct() {
    return classStruct;
  }

  public VBStyleCollection getMethods() {
    return methods;
  }

  public Set getHiddenMembers() {
    return hiddenMembers;
  }

  public VBStyleCollection getStaticFieldInitializers() {
    return staticFieldInitializers;
  }

  public VBStyleCollection getDynamicFieldInitializers() {
    return dynamicFieldInitializers;
  }

  @Override
  public String toString() {
    return classStruct.qualifiedName;
  }
}