content: /*
   * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package openjdk.tools.javac.code;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import openjdk.tools.javac.code.Kinds.Kind;
  import openjdk.tools.javac.code.Scope.WriteableScope;
  import openjdk.tools.javac.code.Symbol;
  import openjdk.tools.javac.code.Symbol.ClassSymbol;
  import openjdk.tools.javac.code.Symbol.Completer;
  import openjdk.tools.javac.code.Symbol.CompletionFailure;
  import openjdk.tools.javac.util.Context;
  
  /** When a CompletionFailure is thrown when user code is running, it shouldn't be
   *  thrown out to the client code, but rather skipped, and then rethrown later if javac
   *  itself will complete the Symbol.
   *
   *  On all places where javac invokes client code (e.g. TaskListeners, annotation
   *  Processors), the {@code userCodeHandler} should be set using
   *  {@link DeferredCompletionFailureHandler#setHandler}, and the original handler
   *  should be restored when the control returns back to javac.
   *
   *  Implementations of API methods should use {@link Symbol#apiComplete()} instead of
   *  {@link Symbol#complete}, as the {@code apiComplete} method will invoke
   *  {@link DeferredCompletionFailureHandler#handleAPICompletionFailure }, which will
   *  catch the CompletionFailure and will either rethrow it or skip it, depending on
   *  the context.
   */
  public class DeferredCompletionFailureHandler {
  
      protected static final Context.Key<DeferredCompletionFailureHandler> deferredCompletionFailureHandlerKey = new Context.Key<>();
  
      public static DeferredCompletionFailureHandler instance(Context context) {
          DeferredCompletionFailureHandler instance = context.get(deferredCompletionFailureHandlerKey);
          if (instance == null)
              instance = new DeferredCompletionFailureHandler(context);
          return instance;
      }
  
      public final Handler userCodeHandler = new Handler() {
          private final Map<ClassSymbol, FlipSymbolDescription> class2Flip = new HashMap<>();
  
          public void install() {
              class2Flip.values().forEach(f -> f.flip());
          }
          public void handleAPICompletionFailure(CompletionFailure cf) {
              //ignore
          }
          public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
              class2Flip.put(sym, new FlipSymbolDescription(sym, new DeferredCompleter(origCompleter) {
                  @Override public void complete(Symbol sym) throws CompletionFailure {
                      class2Flip.remove(sym);
                      super.complete(sym);
                  }
              }));
          }
          public void classSymbolRemoved(ClassSymbol sym) {
              class2Flip.remove(sym);
          }
          public void uninstall() {
              class2Flip.values().forEach(f -> f.flip());
          }
      };
  
      public final Handler speculativeCodeHandler = new Handler() {
          private final Map<ClassSymbol, FlipSymbolDescription> class2Flip = new HashMap<>();
  
          public void install() {
          }
          public void handleAPICompletionFailure(CompletionFailure cf) {
              throw cf;
          }
          public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
              class2Flip.put(sym, new FlipSymbolDescription(sym, new DeferredCompleter(origCompleter)));
          }
          public void classSymbolRemoved(ClassSymbol sym) {
              class2Flip.remove(sym);
          }
          public void uninstall() {
              class2Flip.values().forEach(f -> f.flip());
              class2Flip.clear();
          }
      };
  
      public final Handler javacCodeHandler = new Handler() {
          public void install() {
          }
          public void handleAPICompletionFailure(CompletionFailure cf) {
              throw cf;
          }
          public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {}
          public void classSymbolRemoved(ClassSymbol sym) {}
          public void uninstall() {
          }
      };
  
      private Handler handler = javacCodeHandler;
  
      protected DeferredCompletionFailureHandler(Context context) {
          context.put(deferredCompletionFailureHandlerKey, this);
      }
  
      public Handler setHandler(Handler h) {
          if (h == handler) return handler;
  
          handler.uninstall();
          Handler prev = handler;
          handler = h;
          handler.install();
          return prev;
      }
  
      public void handleAPICompletionFailure(CompletionFailure cf) {
          handler.handleAPICompletionFailure(cf);
      }
  
      public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
          handler.classSymbolCompleteFailed(sym, origCompleter);
      }
  
      public void classSymbolRemoved(ClassSymbol sym) {
          handler.classSymbolRemoved(sym);
      }
  
      public boolean isDeferredCompleter(Completer c) {
          return c instanceof DeferredCompleter;
      }
  
      public interface Handler {
          public void install();
          public void handleAPICompletionFailure(CompletionFailure cf);
          public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter);
          public void classSymbolRemoved(ClassSymbol sym);
          public void uninstall();
      }
  
      private class DeferredCompleter implements Completer {
  
          private final Completer origCompleter;
  
          public DeferredCompleter(Completer origCompleter) {
              this.origCompleter = origCompleter;
          }
  
          @Override
          public void complete(Symbol sym) throws CompletionFailure {
              origCompleter.complete(sym);
          }
      }
  
      private static class FlipSymbolDescription {
          public final ClassSymbol sym;
          public Type type;
          public Kind kind;
          public WriteableScope members;
          public Completer completer;
  
          public FlipSymbolDescription(ClassSymbol sym, Completer completer) {
              this.sym = sym;
              this.type = sym.type;
              this.kind = sym.kind;
              this.members = null;
              this.completer = completer;
          }
  
          public void flip() {
              Type prevType = sym.type;
              sym.type = type;
              this.type = prevType;
              Kind prevKind = sym.kind;
              sym.kind = kind;
              this.kind = prevKind;
              Completer prevCompleter = sym.completer;
              sym.completer = completer;
              this.completer = prevCompleter;
              WriteableScope prevMembers = sym.members_field;
              sym.members_field = members;
              this.members = prevMembers;
          }
  
      }
  }
  