Pull FileData segment reading out to separate method for LFH

Allows library consumers to handle edge cases more easily

Author: Col-E

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>software.coley</groupId>
     <artifactId>lljzip</artifactId>
-    <version>2.7.2</version>
+    <version>2.8.0</version>
 
     <name>LL Java ZIP</name>
     <description>Lower level ZIP support for Java</description>

src/main/java/software/coley/lljzip/format/model/JvmLocalFileHeader.java

@@ -31,17 +31,9 @@ public void setOffsets(@Nonnull NavigableSet<Long> offsets) {
 		this.offsets = offsets;
 	}
 
+	@Nonnull
 	@Override
-	public void read(@Nonnull MemorySegment data, long offset) throws ZipParseException {
-		try {
-			super.read(data, offset);
-		} catch (ZipParseException ex) {
-			// If the error was that the data couldn't be read, that's OK because we're going to try reading
-			// that in a slightly different way below.
-			if (ex.getType() != ZipParseException.Type.IOOBE_FILE_DATA)
-				throw ex;
-		}
-
+	protected MemorySegmentData readFileData(@Nonnull MemorySegment data, long headerOffset) {
 		// JVM file data reading does NOT use the compressed/uncompressed fields.
 		// Instead, it scans data until the next header.
 		long relativeDataOffsetStart = MIN_FIXED_SIZE + getFileNameLength() + getExtraFieldLength();
@@ -86,13 +78,7 @@ public void read(@Nonnull MemorySegment data, long offset) throws ZipParseExcept
 		this.relativeDataOffsetEnd = relativeDataOffsetEnd;
 		long fileDataLength = relativeDataOffsetEnd - relativeDataOffsetStart;
 
-		try {
-			fileData = MemorySegmentData.of(MemorySegmentUtil.readLongSlice(data, offset, relativeDataOffsetStart, fileDataLength));
-		} catch (IndexOutOfBoundsException ex) {
-			throw new ZipParseException(ex, ZipParseException.Type.IOOBE_FILE_DATA);
-		} catch (Throwable t) {
-			throw new ZipParseException(t, ZipParseException.Type.OTHER);
-		}
+		fileData = MemorySegmentData.of(MemorySegmentUtil.readLongSlice(data, offset, relativeDataOffsetStart, fileDataLength));
 
 		// Update sizes where possible
 		if (getCompressionMethod() == ZipCompressions.STORED) {
@@ -105,6 +91,7 @@ public void read(@Nonnull MemorySegment data, long offset) throws ZipParseExcept
 		// If we have a size, we can assume we found some data.
 		// Whether its valid, who really knows?
 		foundData = fileDataLength != 0;
+		return fileData;
 	}
 
 	@Override

src/main/java/software/coley/lljzip/format/model/LocalFileHeader.java

@@ -101,16 +101,32 @@ public void read(@Nonnull MemorySegment data, long offset) throws ZipParseExcept
 		} catch (Throwable t) {
 			throw new ZipParseException(t, ZipParseException.Type.OTHER);
 		}
-		long fileDataLength = (compressionMethod == STORED) ? uncompressedSize : compressedSize;
 		try {
-			fileData = MemorySegmentData.of(readLongSlice(data, offset, MIN_FIXED_SIZE + fileNameLength + extraFieldLength, fileDataLength));
+			fileData = readFileData(data, offset);
 		} catch (IndexOutOfBoundsException ex) {
 			throw new ZipParseException(ex, ZipParseException.Type.IOOBE_FILE_DATA);
 		} catch (Throwable t) {
 			throw new ZipParseException(t, ZipParseException.Type.OTHER);
 		}
 	}
 
+	/**
+	 * @param data
+	 * 		Data to read from.
+	 * @param headerOffset
+	 * 		Initial offset in data to where the local file header starts at.
+	 *
+	 * @return File data segment.
+	 */
+	@Nonnull
+	protected MemorySegmentData readFileData(@Nonnull MemorySegment data, long headerOffset) {
+		long localOffset = MIN_FIXED_SIZE + getFileNameLength() + getExtraFieldLength();
+		long fileDataLength = (compressionMethod == STORED) ? uncompressedSize : compressedSize;
+		if (localOffset + fileDataLength > data.byteSize())
+			throw new IndexOutOfBoundsException("LFH FileData: Reads beyond file bounds");
+		return MemorySegmentData.of(readLongSlice(data, headerOffset, localOffset, fileDataLength));
+	}
+
 	/**
 	 * Should match {@link CentralDirectoryFileHeader#getFileNameLength()} but is not a strict requirement.
 	 * If they do not match, the central directory file name length should be trusted instead.

src/test/java/software/coley/lljzip/PatchingTests.java

@@ -3,21 +3,30 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
+import software.coley.lljzip.format.ZipPatterns;
+import software.coley.lljzip.format.model.LocalFileHeader;
 import software.coley.lljzip.format.model.ZipArchive;
+import software.coley.lljzip.format.read.NaiveLocalFileZipReader;
+import software.coley.lljzip.format.read.SimpleZipPartAllocator;
 import software.coley.lljzip.format.transform.IdentityZipPartMapper;
 import software.coley.lljzip.format.transform.JvmClassDirectoryMapper;
 import software.coley.lljzip.format.write.ZipOutputStreamZipWriter;
+import software.coley.lljzip.util.MemorySegmentUtil;
+import software.coley.lljzip.util.data.MemorySegmentData;
 
+import javax.annotation.Nonnull;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.lang.foreign.MemorySegment;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
 import static org.junit.jupiter.api.Assertions.*;
+import static software.coley.lljzip.util.MemorySegmentUtil.readLongSlice;
 
 /**
  * Tests for patching the <i>"trick"</i> jars, and making them compatible with standard Java ZIP apis.
@@ -85,6 +94,33 @@ public void testTrickJarPatched(String name) {
 		}
 	}
 
+	@Test
+	@SuppressWarnings("resource")
+	public void testNaiveWithForwardScanningData() {
+		NaiveLocalFileZipReader strategy = new NaiveLocalFileZipReader(new SimpleZipPartAllocator() {
+			@Nonnull
+			@Override
+			public LocalFileHeader newLocalFileHeader() {
+				return new LocalFileHeader() {
+					@Nonnull
+					@Override
+					protected MemorySegmentData readFileData(@Nonnull MemorySegment data, long headerOffset) {
+						long localOffset = MIN_FIXED_SIZE + getFileNameLength() + getExtraFieldLength();
+						long nextStart = MemorySegmentUtil.indexOfQuad(data, headerOffset + localOffset, ZipPatterns.LOCAL_FILE_HEADER_QUAD);
+						long fileDataLength = nextStart > headerOffset ?
+								nextStart - (headerOffset + localOffset) :
+								data.byteSize() - (headerOffset + localOffset);
+						return MemorySegmentData.of(readLongSlice(data, headerOffset, localOffset, fileDataLength));
+					}
+				};
+			}
+		});
+
+		Path path = Paths.get("src/test/resources/resource-pack-trick-data-ioobe-no-end.zip");
+		ZipArchive zip = assertDoesNotThrow(() -> ZipIO.read(path, strategy));
+		assertNotNull(zip.getLocalFileByName("pack.mcmeta"), "IOOBE not patched");
+	}
+
 	@Test
 	@SuppressWarnings("resource")
 	public void testTrailingSlashTransform() {