R3944Realms/ModernFix-fix
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Allow ZipPackIndex to work with any byte channel

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embeddedt 2026-06-04 20:57:13 -04:00
parent 0ecee529d7
commit f1492cc829
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GPG Key ID: A69433EC199B5613
1 changed files with 24 additions and 10 deletions
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34
src/main/java/org/embeddedt/modernfix/resources/ZipPackIndex.java
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@ -13,7 +13,9 @@ import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.nio.channels.SeekableByteChannel;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.util.*;
@ -106,8 +108,16 @@ public class ZipPackIndex {
this.root = buildTree();
}
private static SeekableByteChannel obtainChannel(Path filePath) throws IOException {
try {
return FileChannel.open(filePath, StandardOpenOption.READ);
} catch (Exception e) {
return Files.newByteChannel(filePath);
}
}
private static ByteBuffer readCentralDirectory(Path filePath) throws IOException {
try (FileChannel channel = FileChannel.open(filePath, StandardOpenOption.READ)) {
try (SeekableByteChannel channel = obtainChannel(filePath)) {
long fileSize = channel.size();
if (fileSize < EOCD_SIZE) return null;
@ -117,7 +127,8 @@ public class ZipPackIndex {
long tailStart = fileSize - tailSize;
while (tail.hasRemaining()) {
int n = channel.read(tail, tailStart + tail.position());
channel.position(tailStart + tail.position());
int n = channel.read(tail);
if (n < 0) {
break;
}
@ -151,19 +162,22 @@ public class ZipPackIndex {
}
// Try memory-mapping first; fall back to a heap copy if the OS refuses.
try {
ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, cdOffset, cdSize);
buf.order(ByteOrder.LITTLE_ENDIAN);
return buf;
} catch (Exception ignored) {
// mmap unavailable (e.g. some Linux mount flags, container restrictions);
// read the central directory into a heap buffer instead.
if (channel instanceof FileChannel fc) {
try {
ByteBuffer buf = fc.map(FileChannel.MapMode.READ_ONLY, cdOffset, cdSize);
buf.order(ByteOrder.LITTLE_ENDIAN);
return buf;
} catch (Exception ignored) {
// mmap unavailable (e.g. some Linux mount flags, container restrictions);
// read the central directory into a heap buffer instead.
}
}
ByteBuffer buf = ByteBuffer.allocate((int) cdSize);
buf.order(ByteOrder.LITTLE_ENDIAN);
while (buf.hasRemaining()) {
int n = channel.read(buf, cdOffset + buf.position());
channel.position(cdOffset + buf.position());
int n = channel.read(buf);
if (n < 0) throw new IOException("Truncated central directory during heap read");
}
buf.flip();