void fireEvent(int parentStart, PsiFile file, CompositeElement parent) {
  PsiTreeChangeEventImpl e = createEvent(file, myOffset + parentStart);

  if (myOldChild == myNewChild && myNewChild != null) {
    childrenChanged(e, myNewChild, myOldLength);
  }
  else if (myOldChild != null && myNewChild != null) {
    childReplaced(e, myOldChild, myNewChild, parent);
  }
  else if (myOldChild != null) {
    childRemoved(e, myOldChild, parent);
  }
  else if (myNewChild != null) {
    childAdded(e, myNewChild, parent);
  }
}
 

private void fileCreated(@Nonnull VirtualFile vFile) {
  runExternalAction(() -> {
    VirtualFile parent = vFile.getParent();
    PsiDirectory parentDir = getCachedDirectory(parent);
    if (parentDir == null) {
      handleVfsChangeWithoutPsi(vFile);
      return;
    }
    PsiFileSystemItem item = vFile.isDirectory() ? myFileManager.findDirectory(vFile) : myFileManager.findFile(vFile);
    if (item != null && item.getProject() == myManager.getProject()) {
      PsiTreeChangeEventImpl treeEvent = new PsiTreeChangeEventImpl(myManager);
      treeEvent.setParent(parentDir);
      myManager.beforeChildAddition(treeEvent);
      treeEvent.setChild(item);
      myManager.childAdded(treeEvent);
    }
  });
}
 

private void beforeFileDeletion(@Nonnull VFileDeleteEvent event) {
  final VirtualFile vFile = event.getFile();

  VirtualFile parent = vFile.getParent();
  final PsiDirectory parentDir = getCachedDirectory(parent);
  if (parentDir == null) return; // do not notify listeners if parent directory was never accessed via PSI

  runExternalAction(() -> {
    PsiFileSystemItem item = vFile.isDirectory() ? myFileManager.findDirectory(vFile) : myFileManager.getCachedPsiFile(vFile);
    if (item != null) {
      PsiTreeChangeEventImpl treeEvent = new PsiTreeChangeEventImpl(myManager);
      treeEvent.setParent(parentDir);
      treeEvent.setChild(item);
      myManager.beforeChildRemoval(treeEvent);
    }
  });
}
 

@Override
public void registerIndexableSet(@Nonnull IndexableFileSet set, @Nullable Project project) {
  myIndexableSets.add(set);
  myIndexableSetToProjectMap.put(set, project);
  if (project != null) {
    ((PsiManagerImpl)PsiManager.getInstance(project)).addTreeChangePreprocessor(event -> {
      if (event.isGenericChange() && event.getCode() == PsiTreeChangeEventImpl.PsiEventType.CHILDREN_CHANGED) {
        PsiFile file = event.getFile();

        if (file != null) {
          VirtualFile virtualFile = file.getVirtualFile();
          if (virtualFile instanceof VirtualFileWithId) {
            getChangedFilesCollector().getEventMerger().recordTransientStateChangeEvent(virtualFile);
          }
        }
      }
    });
  }
}
 

@Nonnull
static PsiTreeChangeEventImpl createEvent(PsiFile file, int offset) {
  PsiTreeChangeEventImpl e = new PsiTreeChangeEventImpl(file.getManager());
  e.setFile(file);
  e.setOffset(offset);
  return e;
}
 

private void childReplaced(PsiTreeChangeEventImpl e, TreeElement oldChild, TreeElement newChild, CompositeElement parent) {
  e.setParent(parent.getPsi());
  e.setOldChild(oldChild.getPsi());
  e.setChild(newChild.getPsi());
  e.setNewChild(newChild.getPsi());
  e.setOldLength(myOldLength);
  getPsiManagerImpl(e).childReplaced(e);
}
 

@Override
public void childrenChanged(@Nonnull PsiTreeChangeEvent event) {
  if (((PsiTreeChangeEventImpl)event).isGenericChange()) {
    return;
  }
  queueElement(event.getParent(), true, event);
}
 

private void beforeFileMovement(@Nonnull VFileMoveEvent event) {
  final VirtualFile vFile = event.getFile();

  final PsiDirectory oldParentDir = myFileManager.findDirectory(event.getOldParent());
  final PsiDirectory newParentDir = myFileManager.findDirectory(event.getNewParent());
  if (oldParentDir == null && newParentDir == null) return;
  if (myFileTypeManager.isFileIgnored(vFile)) return;

  runExternalAction(() -> {
    PsiTreeChangeEventImpl treeEvent = new PsiTreeChangeEventImpl(myManager);

    boolean isExcluded = vFile.isDirectory() && Registry.is("ide.hide.excluded.files") && myFileIndex.get().isExcluded(vFile);
    if (oldParentDir != null && !isExcluded) {
      PsiElement eventChild = vFile.isDirectory() ? myFileManager.findDirectory(vFile) : myFileManager.findFile(vFile);
      treeEvent.setChild(eventChild);
      if (newParentDir != null) {
        treeEvent.setOldParent(oldParentDir);
        treeEvent.setNewParent(newParentDir);
        myManager.beforeChildMovement(treeEvent);
      }
      else {
        treeEvent.setParent(oldParentDir);
        myManager.beforeChildRemoval(treeEvent);
      }
    }
    else {
      LOG.assertTrue(newParentDir != null); // checked above
      treeEvent.setParent(newParentDir);
      myManager.beforeChildAddition(treeEvent);
    }
  });
}
 

@Override
public void beforeRootsChange(@Nonnull final ModuleRootEvent event) {
  if (event.isCausedByFileTypesChange()) return;
  runExternalAction(() -> {
    depthCounter++;
    if (depthCounter > 1) return;

    PsiTreeChangeEventImpl treeEvent = new PsiTreeChangeEventImpl(myManager);
    treeEvent.setPropertyName(PsiTreeChangeEvent.PROP_ROOTS);
    myManager.beforePropertyChange(treeEvent);
  });
}
 

@Override
public void treeChanged(@NotNull PsiTreeChangeEventImpl event) {
		if (event.getFile() instanceof HeaderPsiFile) {
			ArmaPluginUserData.getInstance().reparseConfigs(event.getFile());
		}
}
 

public GraphQLSchemaChangeListener(Project project) {
    myProject = project;
    psiManager = PsiManager.getInstance(myProject);
    listener = new PsiTreeChangeAdapter() {

        private void checkForSchemaChange(PsiTreeChangeEvent event) {
            if (myProject.isDisposed()) {
                psiManager.removePsiTreeChangeListener(listener);
                return;
            }
            if (event.getFile() instanceof GraphQLFile) {
                if (affectsGraphQLSchema(event)) {
                    signalSchemaChanged();
                }
            }
            if (event.getFile() instanceof JSGraphQLEndpointFile) {
                // always consider the schema changed when editing an endpoint file
                signalSchemaChanged();
            }
            if (event.getParent() instanceof PsiLanguageInjectionHost) {
                GraphQLInjectionSearchHelper graphQLInjectionSearchHelper = ServiceManager.getService(GraphQLInjectionSearchHelper.class);
                if (graphQLInjectionSearchHelper != null && graphQLInjectionSearchHelper.isJSGraphQLLanguageInjectionTarget(event.getParent())) {
                    // change in injection target
                    signalSchemaChanged();
                }
            }
            if (event.getFile() instanceof JsonFile) {
                boolean introspectionJsonUpdated = false;
                if (event.getFile().getUserData(GraphQLSchemaKeys.GRAPHQL_INTROSPECTION_JSON_TO_SDL) != null) {
                    introspectionJsonUpdated = true;
                } else {
                    final VirtualFile virtualFile = event.getFile().getVirtualFile();
                    if (virtualFile != null && Boolean.TRUE.equals(virtualFile.getUserData(GraphQLSchemaKeys.IS_GRAPHQL_INTROSPECTION_JSON))) {
                        introspectionJsonUpdated = true;
                    }
                }
                if(introspectionJsonUpdated) {
                    signalSchemaChanged();
                }
            }
        }

        @Override
        public void propertyChanged(@NotNull PsiTreeChangeEvent event) {
            checkForSchemaChange(event);
        }

        @Override
        public void childAdded(@NotNull PsiTreeChangeEvent event) {
            checkForSchemaChange(event);
        }

        @Override
        public void childRemoved(@NotNull PsiTreeChangeEvent event) {
            checkForSchemaChange(event);
        }

        @Override
        public void childMoved(@NotNull PsiTreeChangeEvent event) {
            checkForSchemaChange(event);
        }

        @Override
        public void childReplaced(@NotNull PsiTreeChangeEvent event) {
            checkForSchemaChange(event);
        }

        @Override
        public void childrenChanged(@NotNull PsiTreeChangeEvent event) {
            if (event instanceof PsiTreeChangeEventImpl) {
                if (!((PsiTreeChangeEventImpl) event).isGenericChange()) {
                    // ignore the generic event which fires for all other cases above
                    // if it's not the generic case, children have been replaced, e.g. using the commenter
                    checkForSchemaChange(event);
                }
            }
        }
    };
    psiManager.addPsiTreeChangeListener(listener);

    // also consider the schema changed when the underlying schema configuration files change
    final MessageBusConnection connection = myProject.getMessageBus().connect();
    connection.subscribe(GraphQLConfigManager.TOPIC, this::signalSchemaChanged);
}
 

@Override
public void treeChanged(@NotNull PsiTreeChangeEventImpl event) {
		if (event.getFile() instanceof HeaderPsiFile) {
			ArmaPluginUserData.getInstance().reparseConfigs(event.getFile());
		}
}
 

private static void childAdded(PsiTreeChangeEventImpl e, TreeElement child, CompositeElement parent) {
  e.setParent(parent.getPsi());
  e.setChild(child.getPsi());
  getPsiManagerImpl(e).childAdded(e);
}
 

private void childRemoved(PsiTreeChangeEventImpl e, TreeElement child, CompositeElement parent) {
  e.setParent(parent.getPsi());
  e.setChild(child.getPsi());
  e.setOldLength(myOldLength);
  getPsiManagerImpl(e).childRemoved(e);
}
 

static void childrenChanged(PsiTreeChangeEventImpl e, TreeElement parent, int oldLength) {
  e.setParent(parent.getPsi());
  e.setOldLength(oldLength);
  getPsiManagerImpl(e).childrenChanged(e);
}
 

private static PsiManagerImpl getPsiManagerImpl(PsiTreeChangeEventImpl e) {
  return (PsiManagerImpl)e.getSource();
}
 

default void firePropertyChangedForUnloadedPsi(@Nonnull PsiTreeChangeEventImpl event, @Nonnull VirtualFile vFile) {
}
 

@Override
public void beforeChildRemoval(@Nonnull final PsiTreeChangeEventImpl event) {
}
 

@Override
public void beforeChildReplacement(@Nonnull final PsiTreeChangeEventImpl event) {
}
 

@Override
public void beforeChildAddition(@Nonnull PsiTreeChangeEventImpl event) {
}
 

private void filesDeleted(@Nonnull List<? extends VFileEvent> events) {
  boolean needToRemoveInvalidFilesAndDirs = false;
  for (VFileEvent event : events) {
    VFileDeleteEvent de = (VFileDeleteEvent)event;
    VirtualFile vFile = de.getFile();
    VirtualFile parent = vFile.getParent();

    final PsiFile psiFile = myFileManager.getCachedPsiFileInner(vFile);
    PsiElement element;
    if (psiFile != null) {
      clearViewProvider(vFile, "PSI fileDeleted");
      element = psiFile;
    }
    else {
      final PsiDirectory psiDir = myFileManager.getCachedDirectory(vFile);
      if (psiDir != null) {
        needToRemoveInvalidFilesAndDirs = true;
        element = psiDir;
      }
      else if (parent != null) {
        handleVfsChangeWithoutPsi(parent);
        return;
      }
      else {
        element = null;
      }
    }
    final PsiDirectory parentDir = getCachedDirectory(parent);
    if (element != null && parentDir != null) {
      runExternalAction(() -> {
        PsiTreeChangeEventImpl treeEvent = new PsiTreeChangeEventImpl(myManager);
        treeEvent.setParent(parentDir);
        treeEvent.setChild(element);
        myManager.childRemoved(treeEvent);
      });
    }
  }
  if (needToRemoveInvalidFilesAndDirs) {
    myFileManager.removeInvalidFilesAndDirs(false);
  }
}