[updater] reuse diffs from sibling patches

When building several patches for different OS/Arch pairs of IDE distributions, we could reuse diffs since IDE distributions contains a lot of exactly the same files.

Fixes IJI-319

GitOrigin-RevId: 7a74330a8467121106de5b74e7443dc96d0ebfb7

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

@@ -1,4 +1,4 @@
-// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.updater;
 
 import java.io.File;
@@ -20,7 +20,7 @@ import static com.intellij.updater.Runner.LOG;
 public final class PatchFileCreator {
   private static final String PATCH_INFO_FILE_NAME = ".patch-info";
 
-  public static Patch create(PatchSpec spec, File patchFile, UpdaterUI ui) throws IOException {
+  public static Patch create(PatchSpec spec, File patchFile, UpdaterUI ui, Path cacheDir) throws IOException {
     LOG.info("Creating the patch file '" + patchFile + "'...");
     ui.startProcess("Creating the patch file '" + patchFile + "'...");
 
@@ -40,11 +40,27 @@ public final class PatchFileCreator {
       if (action instanceof UpdateAction && !action.isCritical()) {
         int _i = i;
         tasks.put(action, executor.submit(() -> {
+          Path cached = null;
+          if (cacheDir != null) {
+            String cachedName = getCachedFileName((UpdateAction)action, newerDir);
+            if (cachedName != null) {
+              cached = cacheDir.resolve(cachedName);
+              if (Files.exists(cached) && Files.isRegularFile(cached)) {
+                LOG.info("Reusing diff for " + action.getPath() + " : " + cachedName);
+                return cached;
+              }
+            }
+          }
           Path temp = Utils.getTempFile("diff_" + _i).toPath();
           try (ZipOutputStream out = new ZipOutputStream(Files.newOutputStream(temp))) {
             out.setLevel(0);
             action.buildPatchFile(olderDir, newerDir, out);
           }
+          if (cached != null) {
+            Files.createDirectories(cached.getParent());
+            Files.copy(temp, cached);
+            LOG.info("Caching diff for " + action.getPath() + " : " + cached.getFileName());
+          }
           return temp;
         }));
       }
@@ -93,6 +109,24 @@ public final class PatchFileCreator {
     return patchInfo;
   }
 
+  private static String getCachedFileName(UpdateAction action, File newerDir) {
+    if (action.isMove()) return null;
+    if (!Digester.isFile(action.getChecksum())) return null;
+    // Single file diff is a zip file with single entry corresponding to target file name, so entry name should be part of caching key
+    // Also both source and target digests are part of key
+    try {
+      return "diff-v1-" +
+             action.getPath().replaceAll("[^A-Za-z0-9_\\-]","_") +
+             '-' +
+             Long.toHexString(action.getChecksum()) +
+             '-' +
+             Long.toHexString(Digester.digestRegularFile(action.getFile(newerDir), false));
+    }
+    catch (IOException ignored) {
+      return null;
+    }
+  }
+
   public static PreparationResult prepareAndValidate(File patchFile,
                                                      File toDir,
                                                      UpdaterUI ui) throws IOException, OperationCancelledException {

updater/src/com/intellij/updater/Runner.java

@@ -145,6 +145,8 @@ public final class Runner {
       String timeoutStr = getArgument(args, "timeout");
       int timeout = timeoutStr != null ? Integer.parseInt(timeoutStr) : 0;
 
+      String cacheDir = getArgument(args, "cache-dir");
+
       PatchSpec spec = new PatchSpec()
         .setOldVersionDescription(oldVersionDesc)
         .setNewVersionDescription(newVersionDesc)
@@ -164,7 +166,7 @@ public final class Runner {
         .setWarnings(warnings)
         .setTimeout(timeout);
 
-      boolean success = create(spec);
+      boolean success = create(spec, cacheDir != null ? Paths.get(cacheDir) : null);
       System.exit(success ? 0 : 1);
     }
     else if (args.length >= 2 && ("install".equals(args[0]) || "apply".equals(args[0])) ||
@@ -289,6 +291,8 @@ public final class Runner {
       "                  patch will only be applied if it is guaranteed that the patched version will match exactly\n" +
       "                  the source of the patch. This means that unexpected files will be deleted and all existing files\n" +
       "                  will be validated\n" +
+      "    --cache-dir=<dir>: Sets directory where diffs can be cached.\n" +
+      "                  Useful when building several patches on folders with common files.\n" +
       "    --root=<dir>: Sets dir as the root directory of the patch. The root directory is the directory where the patch should be\n" +
       "                  applied to. For example on Mac, you can diff the two .app folders and set Contents as the root.\n" +
       "                  The root directory is relative to <old_folder> and uses forwards-slashes as separators.\n" +
@@ -302,13 +306,13 @@ public final class Runner {
       "  <folder>: The folder where product was installed. For example: c:/Program Files/JetBrains/IntelliJ IDEA 2017.3.4");
   }
 
-  private static boolean create(PatchSpec spec) {
+  private static boolean create(PatchSpec spec, Path cacheDir) {
     ConsoleUpdaterUI ui = new ConsoleUpdaterUI();
     boolean success = false;
 
     try {
       File tempPatchFile = Utils.getTempFile("patch");
-      PatchFileCreator.create(spec, tempPatchFile, ui);
+      PatchFileCreator.create(spec, tempPatchFile, ui, cacheDir);
 
       LOG.info("Packing JAR file: " + spec.getPatchFile());
       ui.startProcess("Packing JAR file '" + spec.getPatchFile() + "'...");

updater/testSrc/com/intellij/updater/PatchApplyingRevertingTest.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.updater;
 
 import com.intellij.openapi.util.io.FileUtil;
@@ -15,7 +15,10 @@ import java.io.RandomAccessFile;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Paths;
-import java.util.*;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 import java.util.zip.ZipFile;
@@ -664,7 +667,7 @@ public abstract class PatchApplyingRevertingTest extends PatchTestCase {
   @Override
   protected Patch createPatch() throws IOException {
     assertFalse(myFile.exists());
-    Patch patch = PatchFileCreator.create(myPatchSpec, myFile, TEST_UI);
+    Patch patch = PatchFileCreator.create(myPatchSpec, myFile, TEST_UI, null);
     assertTrue(myFile.exists());
     return patch;
   }