add ability to avoid backing up the tool before applying to patch. This makes Toolbox App apply patches ~30% faster

updater/src/META-INF/MANIFEST.MF

@@ -1,3 +1,3 @@
 Manifest-Version: 1.0
 Main-Class: com.intellij.updater.Bootstrap
-Patcher-Version: 2.1
+Patcher-Version: 3.0

updater/src/com/intellij/updater/Patch.java

@@ -311,7 +311,9 @@ public class Patch {
       if (each.shouldApply(toDir, options)) actionsToProcess.add(each);
     }
 
-    forEach(actionsToProcess, "Backing up files...", ui, true, action -> action.backup(toDir, backupDir));
+    if (backupDir != null) {
+      forEach(actionsToProcess, "Backing up files...", ui, true, action -> action.backup(toDir, backupDir));
+    }
 
     List<PatchAction> appliedActions = new ArrayList<>();
     boolean shouldRevert = false;
@@ -342,7 +344,9 @@ public class Patch {
     }
 
     if (shouldRevert) {
-      revert(appliedActions, backupDir, rootDir, ui);
+      if (backupDir != null) {
+        revert(appliedActions, backupDir, rootDir, ui);
+      }
       appliedActions.clear();
 
       if (cancelled) throw new OperationCancelledException();

updater/src/com/intellij/updater/PatchFileCreator.java

@@ -27,6 +27,11 @@ import java.util.zip.ZipOutputStream;
 
 public class PatchFileCreator {
   private static final String PATCH_INFO_FILE_NAME = ".patch-info";
+  /**
+   * This property allows applying patches without creating backups. In this case a callee is responsible for that.
+   * Example: JetBrains Toolbox App copies a tool it wants to update and then applies the patch.
+   */
+  private static final String NO_BACKUP_PROPERTY = "no.backup";
 
   public static Patch create(PatchSpec spec, File patchFile, UpdaterUI ui) throws IOException, OperationCancelledException {
     Patch patchInfo = new Patch(spec, ui);
@@ -72,7 +77,12 @@ public class PatchFileCreator {
   public static boolean apply(PreparationResult preparationResult,
                               Map<String, ValidationResult.Option> options,
                               UpdaterUI ui) throws IOException, OperationCancelledException {
-    return apply(preparationResult, options, Utils.createTempDir(), ui).applied;
+    File backupDir = shouldSkipBackups() ? null : Utils.createTempDir();
+    return apply(preparationResult, options, backupDir, ui).applied;
+  }
+
+  private static boolean shouldSkipBackups() {
+    return Boolean.parseBoolean(System.getProperty(NO_BACKUP_PROPERTY, "false"));
   }
 
   public static Patch.ApplicationResult apply(PreparationResult preparationResult,

updater/src/com/intellij/updater/UpdateAction.java

@@ -51,7 +51,8 @@ public class UpdateAction extends BaseUpdateAction {
   protected void doApply(ZipFile patchFile, File backupDir, File toFile) throws IOException {
     Runner.logger().info("Update action. File: " + toFile.getAbsolutePath());
 
-    File source = getSource(backupDir);
+    //in case no backup is required
+    File source = backupDir == null ? toFile : getSource(backupDir);
     if (!isMove()) {
       try (InputStream in = Utils.findEntryInputStream(patchFile, getPath())) {
         if (in == null) {

updater/src/com/intellij/updater/UpdateZipAction.java

@@ -135,9 +135,11 @@ public class UpdateZipAction extends BaseUpdateAction {
   @Override
   protected void doApply(final ZipFile patchFile, File backupDir, File toFile) throws IOException {
     File temp = Utils.getTempFile(toFile.getName());
+    //in case no backup is required
+    File source = backupDir == null ? toFile : getSource(backupDir);
 
     try (ZipOutputWrapper out = new ZipOutputWrapper(new FileOutputStream(temp), 0)) {
-      processZipFile(getSource(backupDir), (entry, in) -> {
+      processZipFile(source, (entry, in) -> {
         String path = entry.getName();
         if (myFilesToUpdate.contains(path)) {
           try (OutputStream entryOut = out.zipStream(path)) {