Create zip reader impl delegating to java.util.zip.ZipFile

Author: Col-E

src/main/java/software/coley/lljzip/ZipIO.java

@@ -3,10 +3,7 @@
 import software.coley.lljzip.format.model.CentralDirectoryFileHeader;
 import software.coley.lljzip.format.model.EndOfCentralDirectory;
 import software.coley.lljzip.format.model.ZipArchive;
-import software.coley.lljzip.format.read.ForwardScanZipReader;
-import software.coley.lljzip.format.read.JvmZipReader;
-import software.coley.lljzip.format.read.NaiveLocalFileZipReader;
-import software.coley.lljzip.format.read.ZipReader;
+import software.coley.lljzip.format.read.*;
 import software.coley.lljzip.util.BufferData;
 import software.coley.lljzip.util.ByteData;
 import software.coley.lljzip.util.FileMapUtil;
@@ -15,6 +12,7 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.zip.ZipFile;
 
 /**
  * IO wrappers for reading {@link ZipArchive} contents.
@@ -64,7 +62,7 @@ public static ZipArchive readStandard(byte[] data) throws IOException {
 	 * @param data
 	 * 		Zip path.
 	 *
-	 * @return Archive from bytes.
+	 * @return Archive from path.
 	 *
 	 * @throws IOException
 	 * 		When the archive bytes cannot be read from, usually indicating a malformed zip.
@@ -109,7 +107,7 @@ public static ZipArchive readNaive(byte[] data) throws IOException {
 	 * @param data
 	 * 		Zip path.
 	 *
-	 * @return Archive from bytes.
+	 * @return Archive from path.
 	 *
 	 * @throws IOException
 	 * 		When the archive bytes cannot be read from, usually indicating a malformed zip.
@@ -157,7 +155,7 @@ public static ZipArchive readJvm(byte[] data) throws IOException {
 	 * @param path
 	 * 		Zip path.
 	 *
-	 * @return Archive from bytes.
+	 * @return Archive from path.
 	 *
 	 * @throws IOException
 	 * 		When the archive bytes cannot be read from, usually indicating a malformed zip.
@@ -166,6 +164,22 @@ public static ZipArchive readJvm(Path path) throws IOException {
 		return read(path, new JvmZipReader());
 	}
 
+	/**
+	 * Creates an archive using the {@link AdaptingZipReader} which delegates work to {@link ZipFile}.
+	 *
+	 * @param path
+	 * 		Zip path.
+	 *
+	 * @return Archive from path.
+	 *
+	 * @throws IOException
+	 */
+	public static ZipArchive readAdaptingIO(Path path) throws IOException {
+		ZipArchive archive = new ZipArchive();
+		AdaptingZipReader.fill(archive, path.toFile());
+		return archive;
+	}
+
 	/**
 	 * @param data
 	 * 		Zip bytes.
@@ -189,7 +203,7 @@ public static ZipArchive read(byte[] data, ZipReader strategy) throws IOExceptio
 	 * @param strategy
 	 * 		Zip reader implementation.
 	 *
-	 * @return Archive from bytes.
+	 * @return Archive from path.
 	 *
 	 * @throws IOException
 	 * 		When the archive bytes cannot be read from, usually indicating a malformed zip.

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

@@ -251,7 +251,7 @@ public void setFileName(ByteData fileName) {
 	 */
 	public String getFileNameAsString() {
 		String fileNameCache = this.fileNameCache;
-		if (fileNameCache == null) {
+		if (fileNameCache == null && fileName != null) {
 			return this.fileNameCache = ByteDataUtil.toString(fileName.get());
 		}
 		return fileNameCache;
@@ -278,7 +278,7 @@ public void setExtraField(ByteData extraField) {
 	 */
 	public String getExtraFieldAsString() {
 		String fileCommentCache = this.extraFieldCache;
-		if (fileCommentCache == null) {
+		if (fileCommentCache == null && extraField != null) {
 			return this.extraFieldCache = ByteDataUtil.toString(extraField.get());
 		}
 		return fileCommentCache;

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

@@ -0,0 +1,64 @@
+package software.coley.lljzip.format.model;
+
+import software.coley.lljzip.util.BufferData;
+import software.coley.lljzip.util.NoopByteData;
+import software.coley.lljzip.util.lazy.LazyByteData;
+import software.coley.lljzip.util.lazy.LazyInt;
+import software.coley.lljzip.util.lazy.LazyLong;
+
+import javax.annotation.Nonnull;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+
+/**
+ * Local file header implementation that pulls values from {@link ZipEntry}.
+ *
+ * @author Matt Coley
+ */
+public class AdaptingLocalFileHeader extends LocalFileHeader {
+	private static final int BUFFER_SIZE = 2048;
+
+	/**
+	 * @param archive
+	 * 		Containing archive holding the entry.
+	 * @param entry
+	 * 		Entry to adapt.
+	 *
+	 * @throws IOException
+	 * 		When the entry cannot be read from the archive.
+	 */
+	public AdaptingLocalFileHeader(@Nonnull ZipFile archive, @Nonnull ZipEntry entry) throws IOException {
+		InputStream inputStream = archive.getInputStream(entry);
+		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+		byte[] buffer = new byte[BUFFER_SIZE];
+		int read;
+		while ((read = inputStream.read(buffer)) != -1)
+			outputStream.write(buffer, 0, read);
+		byte[] entryData = outputStream.toByteArray();
+		String entryName = entry.getName();
+		byte[] extra = entry.getExtra();
+		versionNeededToExtract = new LazyInt(() -> 0);
+		generalPurposeBitFlag = new LazyInt(() -> 0);
+		lastModFileTime = new LazyInt(() -> 0);
+		lastModFileDate = new LazyInt(() -> 0);
+		fileNameLength = new LazyInt(entryName::length);
+		fileName = new LazyByteData(() -> BufferData.wrap(entryName.getBytes()));
+		fileDataLength = new LazyLong(() -> entryData.length);
+		fileData = new LazyByteData(() -> BufferData.wrap(entryData));
+		compressionMethod = new LazyInt(() -> 0);
+		uncompressedSize = new LazyLong(() -> entryData.length);
+		compressedSize = new LazyLong(() -> entryData.length);
+		crc32 = new LazyInt(() -> (int) entry.getCrc());
+		if (extra != null) {
+			extraFieldLength = new LazyInt(() -> extra.length);
+			extraField = new LazyByteData(() -> BufferData.wrap(extra));
+		} else {
+			extraFieldLength = new LazyInt(() -> 0);
+			extraField = new LazyByteData(() -> NoopByteData.INSTANCE);
+		}
+		data = NoopByteData.INSTANCE;
+	}
+}

src/main/java/software/coley/lljzip/format/read/AdaptingZipReader.java

@@ -0,0 +1,69 @@
+package software.coley.lljzip.format.read;
+
+import software.coley.lljzip.format.model.AdaptingLocalFileHeader;
+import software.coley.lljzip.format.model.ZipArchive;
+import software.coley.lljzip.util.ByteData;
+import software.coley.lljzip.util.ByteDataUtil;
+
+import javax.annotation.Nonnull;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.Enumeration;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+
+/**
+ * A zip reader implementation delegating all the work to {@link ZipFile}.
+ * <p/>
+ * This will write temporary files to disk in order to satisfy constructor requirements if you use
+ * the standard {@link ZipReader} methods. Instead directly call {@link #fill(ZipArchive, File)} or
+ * {@link #fill(ZipArchive, ZipFile)}.
+ *
+ * @author Matt Coley
+ */
+public class AdaptingZipReader implements ZipReader {
+	@Override
+	public void read(@Nonnull ZipArchive zip, @Nonnull ByteData data) throws IOException {
+		// Java's ZipFile requires the data be on-disk
+		File temp = File.createTempFile("lljzip", ".tempzip");
+		try {
+			Files.write(temp.toPath(), ByteDataUtil.toByteArray(data));
+			fill(zip, temp);
+		} finally {
+			temp.delete();
+		}
+	}
+
+	/**
+	 * @param to
+	 * 		Archive to fill.
+	 * @param from
+	 * 		Archive to adapt from.
+	 *
+	 * @throws IOException
+	 * 		When the zip file cannot be read.
+	 */
+	public static void fill(@Nonnull ZipArchive to, @Nonnull File from) throws IOException {
+		try (ZipFile zipFile = new ZipFile(from)) {
+			fill(to, zipFile);
+		}
+	}
+
+	/**
+	 * @param to
+	 * 		Archive to fill.
+	 * @param from
+	 * 		Archive to adapt from.
+	 *
+	 * @throws IOException
+	 * 		When the zip file cannot be read.
+	 */
+	public static void fill(@Nonnull ZipArchive to, @Nonnull ZipFile from) throws IOException {
+		Enumeration<? extends ZipEntry> zipEntries = from.entries();
+		while (zipEntries.hasMoreElements()) {
+			ZipEntry entry = zipEntries.nextElement();
+			to.addPart(new AdaptingLocalFileHeader(from, entry));
+		}
+	}
+}