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Introduce textual checkpoint format. It's basically one base64-encoded line per checkpoint.

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The BuildCheckpoints tool now generates and sanity checks both formats.
This commit is contained in:
Andreas Schildbach
2014-09-07 00:19:08 +02:00
parent 34214533c9
commit 3e5e3496ea
2 changed files with 104 additions and 15 deletions
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68
core/src/main/java/com/google/bitcoin/core/CheckpointManager.java
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@@ -19,14 +19,23 @@ package com.google.bitcoin.core;
import com.google.bitcoin.store.BlockStore;
import com.google.bitcoin.store.BlockStoreException;
import com.google.bitcoin.store.FullPrunedBlockStore;
import com.google.common.base.Charsets;
import com.google.common.hash.HashCode;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import com.google.common.io.BaseEncoding;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
@@ -62,6 +71,8 @@ import static com.google.common.base.Preconditions.*;
public class CheckpointManager {
private static final Logger log = LoggerFactory.getLogger(CheckpointManager.class);
private static final String BINARY_MAGIC = "CHECKPOINTS 1";
private static final String TEXTUAL_MAGIC = "TXT CHECKPOINTS 1";
private static final int MAX_SIGNATURES = 256;
// Map of block header time to data.
@@ -70,19 +81,33 @@ public class CheckpointManager {
protected final NetworkParameters params;
protected final Sha256Hash dataHash;
public static final BaseEncoding BASE64 = BaseEncoding.base64().omitPadding();
public CheckpointManager(NetworkParameters params, InputStream inputStream) throws IOException {
this.params = checkNotNull(params);
checkNotNull(inputStream);
inputStream = new BufferedInputStream(inputStream);
inputStream.mark(1);
int first = inputStream.read();
inputStream.reset();
if (first == BINARY_MAGIC.charAt(0))
dataHash = readBinary(inputStream);
else if (first == TEXTUAL_MAGIC.charAt(0))
dataHash = readTextual(inputStream);
else
throw new IOException("Unsupported format.");
}
private Sha256Hash readBinary(InputStream inputStream) throws IOException {
DataInputStream dis = null;
try {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
DigestInputStream digestInputStream = new DigestInputStream(inputStream, digest);
dis = new DataInputStream(digestInputStream);
digestInputStream.on(false);
String magic = "CHECKPOINTS 1";
byte[] header = new byte[magic.length()];
byte[] header = new byte[BINARY_MAGIC.length()];
dis.readFully(header);
if (!Arrays.equals(header, magic.getBytes("US-ASCII")))
if (!Arrays.equals(header, BINARY_MAGIC.getBytes("US-ASCII")))
throw new IOException("Header bytes did not match expected version");
int numSignatures = checkPositionIndex(dis.readInt(), MAX_SIGNATURES, "Num signatures out of range");
for (int i = 0; i < numSignatures; i++) {
@@ -102,8 +127,9 @@ public class CheckpointManager {
buffer.position(0);
checkpoints.put(block.getHeader().getTimeSeconds(), block);
}
dataHash = new Sha256Hash(digest.digest());
Sha256Hash dataHash = new Sha256Hash(digest.digest());
log.info("Read {} checkpoints, hash is {}", checkpoints.size(), dataHash);
return dataHash;
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e); // Cannot happen.
} catch (ProtocolException e) {
@@ -114,6 +140,40 @@ public class CheckpointManager {
}
}
private Sha256Hash readTextual(InputStream inputStream) throws IOException {
Hasher hasher = Hashing.sha256().newHasher();
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(inputStream, Charsets.US_ASCII));
String magic = reader.readLine();
if (!TEXTUAL_MAGIC.equals(magic))
throw new IOException("unexpected magic: " + magic);
int numSigs = Integer.parseInt(reader.readLine());
for (int i = 0; i < numSigs; i++)
reader.readLine(); // Skip sigs for now.
int numCheckpoints = Integer.parseInt(reader.readLine());
checkState(numCheckpoints > 0);
// Hash numCheckpoints in a way compatible to the binary format.
hasher.putBytes(ByteBuffer.allocate(4).order(ByteOrder.BIG_ENDIAN).putInt(numCheckpoints).array());
final int size = StoredBlock.COMPACT_SERIALIZED_SIZE;
ByteBuffer buffer = ByteBuffer.allocate(size);
for (int i = 0; i < numCheckpoints; i++) {
byte[] bytes = BASE64.decode(reader.readLine());
hasher.putBytes(bytes);
buffer.position(0);
buffer.put(bytes);
buffer.position(0);
StoredBlock block = StoredBlock.deserializeCompact(params, buffer);
checkpoints.put(block.getHeader().getTimeSeconds(), block);
}
HashCode hash = hasher.hash();
log.info("Read {} checkpoints, hash is {}", checkpoints.size(), hash);
return new Sha256Hash(hash.asBytes());
} finally {
if (reader != null) reader.close();
}
}
/**
* Returns a {@link StoredBlock} representing the last checkpoint before the given time, for example, normally
* you would want to know the checkpoint before the earliest wallet birthday.