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Preserve timestamps when stripping jar signatures #67

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Merged
jpenilla merged 1 commit into from
Nov 4, 2026
Merged

Preserve timestamps when stripping jar signatures #67

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90 changes: 39 additions & 51 deletions src/main/java/io/papermc/codebook/pages/StripSignaturesPage.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,22 +25,21 @@
import io.papermc.codebook.exceptions.UnexpectedException;
import io.papermc.codebook.util.IOUtil;
import jakarta.inject.Inject;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Iterator;
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;
import org.checkerframework.checker.nullness.qual.Nullable;

public final class StripSignaturesPage extends CodeBookPage {

private static final Map<String, String> CREATE_FS_ARGS = Map.of("create", "true");
private static final String DIGEST_SUFFIX = "-digest";
private static final int DIGEST_SUFFIX_LENGTH = DIGEST_SUFFIX.length();

Expand All @@ -55,18 +54,19 @@ public StripSignaturesPage(@InputJar final Path inputJar, @TempDir final Path te

@Override
public void exec() {
try (final FileSystem inputFs = FileSystems.newFileSystem(this.inputJar)) {
final Path inputRoot = inputFs.getPath("/");
final @Nullable Manifest strippedManifest = stripManifestDigestEntries(inputRoot);
if (strippedManifest == null && !containsSignatureFiles(inputRoot)) {
try (final ZipFile inputZip = new ZipFile(this.inputJar.toFile())) {
final @Nullable Manifest strippedManifest = stripManifestDigestEntries(inputZip);
if (strippedManifest == null && !containsSignatureFiles(inputZip)) {
return;
}

final Path strippedJar = this.tempDir.resolve("unsigned-" + this.inputJar.getFileName());
IOUtil.deleteIfExists(strippedJar);

try (final FileSystem outputFs = FileSystems.newFileSystem(strippedJar, CREATE_FS_ARGS)) {
copyContents(inputRoot, outputFs.getPath("/"), strippedManifest);
try (final ZipOutputStream outputZip =
new ZipOutputStream(new BufferedOutputStream(Files.newOutputStream(strippedJar)))) {
outputZip.setComment(inputZip.getComment());
copyContents(inputZip, outputZip, strippedManifest);
}

this.bind(InputJar.KEY).to(strippedJar);
Expand All @@ -75,49 +75,47 @@ public void exec() {
}
}

private static boolean containsSignatureFiles(final Path inputRoot) throws IOException {
try (final var paths = Files.walk(inputRoot)) {
for (final Path path : (Iterable<Path>) paths::iterator) {
if (isSignatureFile(pathName(inputRoot.relativize(path)))) {
return true;
}
}
}
return false;
private static boolean containsSignatureFiles(final ZipFile inputZip) {
return inputZip.stream().anyMatch(entry -> isSignatureFile(entry.getName()));
}

private static void copyContents(
final Path inputRoot, final Path outputRoot, final @Nullable Manifest strippedManifest) throws IOException {
try (final var paths = Files.walk(inputRoot)) {
for (final Path sourcePath : (Iterable<Path>) paths::iterator) {
final Path relativePath = inputRoot.relativize(sourcePath);
final String entryName = pathName(relativePath);
if (entryName.isEmpty() || isSignatureFile(entryName)) {
continue;
}
final ZipFile inputZip, final ZipOutputStream outputZip, final @Nullable Manifest strippedManifest)
throws IOException {
final var entries = inputZip.entries();
while (entries.hasMoreElements()) {
final ZipEntry entry = entries.nextElement();
if (isSignatureFile(entry.getName())) {
continue;
}

final Path outputPath = outputRoot.resolve(relativePath.toString());
if (Files.isDirectory(sourcePath)) {
Files.createDirectories(outputPath);
} else if (strippedManifest != null && isManifestFile(entryName)) {
IOUtil.createParentDirectories(outputPath);
writeManifest(outputPath, strippedManifest);
} else {
IOUtil.createParentDirectories(outputPath);
Files.copy(sourcePath, outputPath);
final boolean rewriteManifest = strippedManifest != null && isManifestFile(entry.getName());
final ZipEntry outputEntry = new ZipEntry(entry);
if (outputEntry.getMethod() == ZipEntry.DEFLATED || rewriteManifest) {
// Recalculate compression metadata, including for a previously STORED manifest.
outputEntry.setMethod(ZipEntry.DEFLATED);
outputEntry.setCompressedSize(-1);
}
outputZip.putNextEntry(outputEntry);
if (rewriteManifest) {
strippedManifest.write(outputZip);
} else {
try (final InputStream input = inputZip.getInputStream(entry)) {
input.transferTo(outputZip);
}
}
outputZip.closeEntry();
}
}

private static @Nullable Manifest stripManifestDigestEntries(final Path inputRoot) throws IOException {
final Path manifestPath = inputRoot.resolve("META-INF/MANIFEST.MF");
if (Files.notExists(manifestPath)) {
private static @Nullable Manifest stripManifestDigestEntries(final ZipFile inputZip) throws IOException {
final ZipEntry manifestEntry = inputZip.getEntry("META-INF/MANIFEST.MF");
if (manifestEntry == null) {
return null;
}

final Manifest manifest;
try (final InputStream input = Files.newInputStream(manifestPath)) {
try (final InputStream input = inputZip.getInputStream(manifestEntry)) {
manifest = new Manifest(input);
}

Expand Down Expand Up @@ -155,14 +153,4 @@ private static boolean isSignatureFile(final String entryName) {
private static boolean isManifestFile(final String entryName) {
return entryName.equals("META-INF/MANIFEST.MF");
}

private static String pathName(final Path relativePath) {
return relativePath.toString().replace('\\', '/');
}

private static void writeManifest(final Path outputPath, final Manifest manifest) throws IOException {
try (final OutputStream output = Files.newOutputStream(outputPath)) {
manifest.write(output);
}
}
}