src/com/facebook/buck/zip/EntryAccounting.java - buck - Git at Google

 /*
  * Copyright 2013-present Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may
  * not use this file except in compliance with the License. You may obtain
  * a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  * License for the specific language governing permissions and limitations
  * under the License.
  */

 package com.facebook.buck.zip;

 import com.facebook.buck.timing.Clock;
 import com.google.common.base.Charsets;
 import com.google.common.base.Preconditions;
 import com.google.common.hash.Hasher;
 import com.google.common.hash.Hashing;

 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.zip.Deflater;
 import java.util.zip.ZipEntry;

 /**
  * A wrapper containing the {@link ZipEntry} and additional book keeping information required to
  * write the entry to a zip file.
  */
 class EntryAccounting {
   private static final int DATA_DESCRIPTOR_FLAG = 1 << 3;
   private static final int UTF8_NAMES_FLAG = 1 << 11;
   private static final int ARBITRARY_SIZE = 1024;
   private static final long DOS_EPOCH_START = (1 << 21) | (1 << 16);

   private final ZipEntry entry;
   private final Method method;
   private Hasher crc = Hashing.crc32().newHasher();
   private long offset;
   /*
    * General purpose bit flag:
    *  Bit 00: encrypted file
    *  Bit 01: compression option
    *  Bit 02: compression option
    *  Bit 03: data descriptor
    *  Bit 04: enhanced deflation
    *  Bit 05: compressed patched data
    *  Bit 06: strong encryption
    *  Bit 07-10: unused
    *  Bit 11: language encoding
    *  Bit 12: reserved
    *  Bit 13: mask header values
    *  Bit 14-15: reserved
    *
    *  The important one is bit 3: the data descriptor.
    *  Defaults to indicate that names are stored as UTF8.
    */
   private int flags = UTF8_NAMES_FLAG;
   private final Deflater deflater = new Deflater(Deflater.DEFAULT_COMPRESSION, true);
   private final byte[] buffer = new byte[ARBITRARY_SIZE];

   public EntryAccounting(Clock clock, ZipEntry entry, long currentOffset) {
     this.entry = Preconditions.checkNotNull(entry);
     this.method = Method.detect(entry.getMethod());
     Preconditions.checkNotNull(clock);
     this.offset = currentOffset;

     if (entry.getTime() == -1) {
       entry.setTime(clock.currentTimeMillis());
     }

     if (entry instanceof CustomZipEntry) {
       deflater.setLevel(((CustomZipEntry) entry).getCompressionLevel());
     }
   }

   public void updateCrc(byte[] b, int off, int len) {
     crc = crc.putBytes(b, off, len);
   }

   /**
    * @return The time of the entry in DOS format.
    */
   public long getTime() {
     // It'd be nice to use a Calendar for this, but (and here's the fun bit), that's a Really Bad
     // Idea since the calendar's internal time representation keeps ticking once set. Instead, do
     // this long way.

     Calendar instance = Calendar.getInstance();
     instance.setTimeInMillis(entry.getTime());

     int year = instance.get(Calendar.YEAR);

     // The DOS epoch begins in 1980. If the year is before that, then default to the start of the
     // epoch (the 1st day of the 1st month)
     if (year < 1980) {
       return DOS_EPOCH_START;
     }
     return (year - 1980) << 25 |
         (instance.get(Calendar.MONTH) + 1) << 21 |
         instance.get(Calendar.DAY_OF_MONTH) << 16 |
         instance.get(Calendar.HOUR_OF_DAY) << 11 |
         instance.get(Calendar.MINUTE) << 5 |
         instance.get(Calendar.SECOND) >> 1;
   }

   private boolean isDeflated() {
     return method == Method.DEFLATE;
   }

   public String getName() {
     return entry.getName();
   }

   public long getSize() {
     return entry.getSize();
   }

   public long getCompressedSize() {
     return entry.getCompressedSize();
   }

   public int getFlags() {
     return flags;
   }

   public long getOffset() {
     return offset;
   }

   public void setOffset(long offset) {
     this.offset = offset;
   }

   public long getCrc() {
     return entry.getCrc();
   }

   public void calculateCrc() {
     entry.setCrc(crc.hash().padToLong());
   }

   public int getCompressionMethod() {
     return method.compressionMethod;
   }

   public int getRequiredExtractVersion() {
     return method.getRequiredExtractVersion();
   }

   public long writeLocalFileHeader(OutputStream out) throws IOException {
     if (method == Method.DEFLATE) {
       flags |= DATA_DESCRIPTOR_FLAG;

       // See http://www.pkware.com/documents/casestudies/APPNOTE.TXT (section 4.4.4)
       // Essentially, we're about to set bits 1 and 2 to indicate to tools such as zipinfo which
       // level of compression we're using. If we've not set a compression level, then we're using
       // the default one, which is right. It turns out. For your viewing pleasure:
       //
       // +----------+-------+-------+
       // | Level    | Bit 1 | Bit 2 |
       // +----------+-------+-------+
       // | Fastest  |   0   |   1   |
       // | Normal   |   0   |   0   |
       // | Best     |   1   |   0   |
       // +----------+-------+-------+
       if (entry instanceof CustomZipEntry) {
         int level = ((CustomZipEntry) entry).getCompressionLevel();
         switch (level) {
           case Deflater.BEST_COMPRESSION:
             flags |= (1 << 1);
             break;

           case Deflater.BEST_SPEED:
             flags |= (1 << 2);
             break;
         }
       }
     }

     try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
       ByteIo.writeInt(stream, ZipEntry.LOCSIG);

       ByteIo.writeShort(stream, getRequiredExtractVersion());
       ByteIo.writeShort(stream, flags);
       ByteIo.writeShort(stream, getCompressionMethod());
       ByteIo.writeInt(stream, getTime());

       // In deflate mode, we don't know the size or CRC of the data.
       if (isDeflated()) {
         ByteIo.writeInt(stream, 0);
         ByteIo.writeInt(stream, 0);
         ByteIo.writeInt(stream, 0);
       } else {
         ByteIo.writeInt(stream, entry.getCrc());
         ByteIo.writeInt(stream, entry.getSize());
         ByteIo.writeInt(stream, entry.getSize());
       }

       byte[] nameBytes = entry.getName().getBytes(Charsets.UTF_8);
       ByteIo.writeShort(stream, nameBytes.length);
       ByteIo.writeShort(stream, 0);
       stream.write(nameBytes);

       byte[] bytes = stream.toByteArray();
       out.write(bytes);
       return bytes.length;
     }
   }

   private byte[] close() throws IOException {
     if (!isDeflated()) {
       return new byte[0];
     }

     try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
       ByteIo.writeInt(out, ZipEntry.EXTSIG);
       ByteIo.writeInt(out, getCrc());
       ByteIo.writeInt(out, getCompressedSize());
       ByteIo.writeInt(out, getSize());

       return out.toByteArray();
     }
   }

   private int deflate(OutputStream out) throws IOException {
     int written = deflater.deflate(buffer, 0, buffer.length);
     if (written > 0) {
       out.write(Arrays.copyOf(buffer, written));
     }
     return written;
   }

   public long write(OutputStream out, byte[] b, int off, int len) throws IOException {
     updateCrc(b, off, len);

     if (!isDeflated()) {
       out.write(b, off, len);
       return len;
     }

     if (len == 0) {
       return 0;
     }

     Preconditions.checkState(!deflater.finished());
     deflater.setInput(b, off, len);

     while (!deflater.needsInput()) {
       deflate(out);
     }
     return 0; // We calculate how many bytes we write when closing deflated entries.
   }

   public long close(OutputStream out) throws IOException {
     if (!isDeflated()) {
       // Nothing left to do.
       return 0;
     }

     deflater.finish();
     while (!deflater.finished()) {
       deflate(out);
     }
     entry.setSize(deflater.getBytesRead());
     entry.setCompressedSize(deflater.getBytesWritten());
     calculateCrc();

     deflater.end();

     byte[] closeBytes = close();
     out.write(closeBytes);

     return entry.getCompressedSize() + closeBytes.length;
   }


   private static enum Method {
     DEFLATE(ZipEntry.DEFLATED, 20, 8),
     STORE(ZipEntry.STORED, 10, 0),
     ;

     private final int zipEntryMethod;
     private final int requiredVersion;
     private final int compressionMethod;

     private Method(int zipEntryMethod, int requiredVersion, int compressionMethod) {
       this.zipEntryMethod = zipEntryMethod;
       this.requiredVersion = requiredVersion;
       this.compressionMethod = compressionMethod;
     }

     public int getRequiredExtractVersion() {
       return requiredVersion;
     }

     public static Method detect(int fromZipMethod) {
       if (fromZipMethod == -1) {
         return DEFLATE;
       }

       for (Method value : values()) {
         if (value.zipEntryMethod == fromZipMethod) {
           return value;
         }
       }

       throw new IllegalArgumentException("Cannot determine zip method from: " + fromZipMethod);
     }
   }
 }
	/*
	* Copyright 2013-present Facebook, Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may
	* not use this file except in compliance with the License. You may obtain
	* a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	* License for the specific language governing permissions and limitations
	* under the License.
	*/

	package com.facebook.buck.zip;

	import com.facebook.buck.timing.Clock;
	import com.google.common.base.Charsets;
	import com.google.common.base.Preconditions;
	import com.google.common.hash.Hasher;
	import com.google.common.hash.Hashing;

	import java.io.ByteArrayOutputStream;
	import java.io.IOException;
	import java.io.OutputStream;
	import java.util.Arrays;
	import java.util.Calendar;
	import java.util.zip.Deflater;
	import java.util.zip.ZipEntry;

	/**
	* A wrapper containing the {@link ZipEntry} and additional book keeping information required to
	* write the entry to a zip file.
	*/
	class EntryAccounting {
	private static final int DATA_DESCRIPTOR_FLAG = 1 << 3;
	private static final int UTF8_NAMES_FLAG = 1 << 11;
	private static final int ARBITRARY_SIZE = 1024;
	private static final long DOS_EPOCH_START = (1 << 21) \| (1 << 16);

	private final ZipEntry entry;
	private final Method method;
	private Hasher crc = Hashing.crc32().newHasher();
	private long offset;
	/*
	* General purpose bit flag:
	* Bit 00: encrypted file
	* Bit 01: compression option
	* Bit 02: compression option
	* Bit 03: data descriptor
	* Bit 04: enhanced deflation
	* Bit 05: compressed patched data
	* Bit 06: strong encryption
	* Bit 07-10: unused
	* Bit 11: language encoding
	* Bit 12: reserved
	* Bit 13: mask header values
	* Bit 14-15: reserved
	*
	* The important one is bit 3: the data descriptor.
	* Defaults to indicate that names are stored as UTF8.
	*/
	private int flags = UTF8_NAMES_FLAG;
	private final Deflater deflater = new Deflater(Deflater.DEFAULT_COMPRESSION, true);
	private final byte[] buffer = new byte[ARBITRARY_SIZE];

	public EntryAccounting(Clock clock, ZipEntry entry, long currentOffset) {
	this.entry = Preconditions.checkNotNull(entry);
	this.method = Method.detect(entry.getMethod());
	Preconditions.checkNotNull(clock);
	this.offset = currentOffset;

	if (entry.getTime() == -1) {
	entry.setTime(clock.currentTimeMillis());
	}

	if (entry instanceof CustomZipEntry) {
	deflater.setLevel(((CustomZipEntry) entry).getCompressionLevel());
	}
	}

	public void updateCrc(byte[] b, int off, int len) {
	crc = crc.putBytes(b, off, len);
	}

	/**
	* @return The time of the entry in DOS format.
	*/
	public long getTime() {
	// It'd be nice to use a Calendar for this, but (and here's the fun bit), that's a Really Bad
	// Idea since the calendar's internal time representation keeps ticking once set. Instead, do
	// this long way.

	Calendar instance = Calendar.getInstance();
	instance.setTimeInMillis(entry.getTime());

	int year = instance.get(Calendar.YEAR);

	// The DOS epoch begins in 1980. If the year is before that, then default to the start of the
	// epoch (the 1st day of the 1st month)
	if (year < 1980) {
	return DOS_EPOCH_START;
	}
	return (year - 1980) << 25 \|
	(instance.get(Calendar.MONTH) + 1) << 21 \|
	instance.get(Calendar.DAY_OF_MONTH) << 16 \|
	instance.get(Calendar.HOUR_OF_DAY) << 11 \|
	instance.get(Calendar.MINUTE) << 5 \|
	instance.get(Calendar.SECOND) >> 1;
	}

	private boolean isDeflated() {
	return method == Method.DEFLATE;
	}

	public String getName() {
	return entry.getName();
	}

	public long getSize() {
	return entry.getSize();
	}

	public long getCompressedSize() {
	return entry.getCompressedSize();
	}

	public int getFlags() {
	return flags;
	}

	public long getOffset() {
	return offset;
	}

	public void setOffset(long offset) {
	this.offset = offset;
	}

	public long getCrc() {
	return entry.getCrc();
	}

	public void calculateCrc() {
	entry.setCrc(crc.hash().padToLong());
	}

	public int getCompressionMethod() {
	return method.compressionMethod;
	}

	public int getRequiredExtractVersion() {
	return method.getRequiredExtractVersion();
	}

	public long writeLocalFileHeader(OutputStream out) throws IOException {
	if (method == Method.DEFLATE) {
	flags \|= DATA_DESCRIPTOR_FLAG;

	// See http://www.pkware.com/documents/casestudies/APPNOTE.TXT (section 4.4.4)
	// Essentially, we're about to set bits 1 and 2 to indicate to tools such as zipinfo which
	// level of compression we're using. If we've not set a compression level, then we're using
	// the default one, which is right. It turns out. For your viewing pleasure:
	//
	// +----------+-------+-------+
	// \| Level \| Bit 1 \| Bit 2 \|
	// +----------+-------+-------+
	// \| Fastest \| 0 \| 1 \|
	// \| Normal \| 0 \| 0 \|
	// \| Best \| 1 \| 0 \|
	// +----------+-------+-------+
	if (entry instanceof CustomZipEntry) {
	int level = ((CustomZipEntry) entry).getCompressionLevel();
	switch (level) {
	case Deflater.BEST_COMPRESSION:
	flags \|= (1 << 1);
	break;

	case Deflater.BEST_SPEED:
	flags \|= (1 << 2);
	break;
	}
	}
	}

	try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
	ByteIo.writeInt(stream, ZipEntry.LOCSIG);

	ByteIo.writeShort(stream, getRequiredExtractVersion());
	ByteIo.writeShort(stream, flags);
	ByteIo.writeShort(stream, getCompressionMethod());
	ByteIo.writeInt(stream, getTime());

	// In deflate mode, we don't know the size or CRC of the data.
	if (isDeflated()) {
	ByteIo.writeInt(stream, 0);
	ByteIo.writeInt(stream, 0);
	ByteIo.writeInt(stream, 0);
	} else {
	ByteIo.writeInt(stream, entry.getCrc());
	ByteIo.writeInt(stream, entry.getSize());
	ByteIo.writeInt(stream, entry.getSize());
	}

	byte[] nameBytes = entry.getName().getBytes(Charsets.UTF_8);
	ByteIo.writeShort(stream, nameBytes.length);
	ByteIo.writeShort(stream, 0);
	stream.write(nameBytes);

	byte[] bytes = stream.toByteArray();
	out.write(bytes);
	return bytes.length;
	}
	}

	private byte[] close() throws IOException {
	if (!isDeflated()) {
	return new byte[0];
	}

	try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
	ByteIo.writeInt(out, ZipEntry.EXTSIG);
	ByteIo.writeInt(out, getCrc());
	ByteIo.writeInt(out, getCompressedSize());
	ByteIo.writeInt(out, getSize());

	return out.toByteArray();
	}
	}

	private int deflate(OutputStream out) throws IOException {
	int written = deflater.deflate(buffer, 0, buffer.length);
	if (written > 0) {
	out.write(Arrays.copyOf(buffer, written));
	}
	return written;
	}

	public long write(OutputStream out, byte[] b, int off, int len) throws IOException {
	updateCrc(b, off, len);

	if (!isDeflated()) {
	out.write(b, off, len);
	return len;
	}

	if (len == 0) {
	return 0;
	}

	Preconditions.checkState(!deflater.finished());
	deflater.setInput(b, off, len);

	while (!deflater.needsInput()) {
	deflate(out);
	}
	return 0; // We calculate how many bytes we write when closing deflated entries.
	}

	public long close(OutputStream out) throws IOException {
	if (!isDeflated()) {
	// Nothing left to do.
	return 0;
	}

	deflater.finish();
	while (!deflater.finished()) {
	deflate(out);
	}
	entry.setSize(deflater.getBytesRead());
	entry.setCompressedSize(deflater.getBytesWritten());
	calculateCrc();

	deflater.end();

	byte[] closeBytes = close();
	out.write(closeBytes);

	return entry.getCompressedSize() + closeBytes.length;
	}


	private static enum Method {
	DEFLATE(ZipEntry.DEFLATED, 20, 8),
	STORE(ZipEntry.STORED, 10, 0),
	;

	private final int zipEntryMethod;
	private final int requiredVersion;
	private final int compressionMethod;

	private Method(int zipEntryMethod, int requiredVersion, int compressionMethod) {
	this.zipEntryMethod = zipEntryMethod;
	this.requiredVersion = requiredVersion;
	this.compressionMethod = compressionMethod;
	}

	public int getRequiredExtractVersion() {
	return requiredVersion;
	}

	public static Method detect(int fromZipMethod) {
	if (fromZipMethod == -1) {
	return DEFLATE;
	}

	for (Method value : values()) {
	if (value.zipEntryMethod == fromZipMethod) {
	return value;
	}
	}

	throw new IllegalArgumentException("Cannot determine zip method from: " + fromZipMethod);
	}
	}
	}