Audit log reporting

client/src/AuditLog.java

@@ -5,6 +5,10 @@
 import snowblossom.util.proto.*;
 import com.google.protobuf.ByteString;
 
+import java.util.LinkedList;
+import java.util.HashMap;
+import java.util.HashSet;
+
 public class AuditLog
 {
   public static String init(SnowBlossomClient client, String msg)
@@ -89,5 +93,138 @@ public static String recordLog(SnowBlossomClient client, ByteString msg)
 
   }
 
+  public static AuditLogReport getAuditReport(SnowBlossomClient client, AddressSpecHash audit_log_hash)
+  {
+    RequestAddress req_addr = RequestAddress.newBuilder().setAddressSpecHash( audit_log_hash.getBytes() ).build();
+    HistoryList history_list = client.getStub().getAddressHistory( req_addr );
+    TransactionHashList mempool_list = client.getStub().getMempoolTransactionList(req_addr);
+
+    if (history_list.getNotEnabled()) throw new RuntimeException("Node does not support history.  Unable to log.");
+
+    HashMap<ChainHash, Integer> tx_height_map = new HashMap<>();
+    LinkedList<ByteString> addr_list = new LinkedList<>();
+    for( HistoryEntry he : history_list.getEntriesList())
+    {
+
+      tx_height_map.put(new ChainHash(he.getTxHash()), he.getBlockHeight());
+      addr_list.add(he.getTxHash());
+    }
+    for (ByteString tx_hash : mempool_list.getTxHashesList())
+    {
+      addr_list.add(tx_hash);
+    }
+
+    HashMap<ChainHash, Transaction> tx_map = new HashMap<>();
+    HashSet<ChainHash> spent_tx = new HashSet<>();
+    for(ByteString tx_hash : addr_list)
+    {
+      Transaction tx = client.getStub().getTransaction( RequestTransaction.newBuilder().setTxHash(tx_hash).build() );
+      tx_map.put(new ChainHash(tx_hash), tx);
+
+      if (acceptableAuditTransaction(audit_log_hash, tx))
+      {
+        TransactionInner tx_inner = TransactionUtil.getInner(tx);
+        for(TransactionInput input : tx_inner.getInputsList())
+        {
+          spent_tx.add( new ChainHash(input.getSrcTxId()));
+        }
+      }
+
+    }
+
+    AuditLogReport.Builder report = AuditLogReport.newBuilder();
+
+    for(ChainHash tx_hash : tx_map.keySet())
+    {
+      if (!spent_tx.contains(tx_hash))
+      {
+        AuditLogChain chain = getAuditChain(audit_log_hash, tx_hash, tx_map, tx_height_map);
+        if (chain != null)
+        {
+          report.addChains(chain);
+        }
+      }
+    }
+
+    return report.build();
+  }
+
+  public static AuditLogChain getAuditChain(AddressSpecHash audit_log_hash, ChainHash head, 
+    HashMap<ChainHash, Transaction> tx_map, HashMap<ChainHash, Integer> tx_height_map)
+  {
+    AuditLogChain.Builder chain = AuditLogChain.newBuilder();
+    int chain_len = 0;
+    ChainHash curr = head;
+    while(curr != null)
+    {
+      Transaction tx = tx_map.get(curr);
+      if (acceptableAuditTransaction(audit_log_hash, tx_map.get(curr)))
+      {
+        chain_len++;
+        TransactionInner inner = TransactionUtil.getInner(tx);
+        AuditLogItem.Builder item = AuditLogItem.newBuilder();
+        item.setTxHash(curr.getBytes());
+        item.setLogMsg( inner.getExtra() );
+        if (tx_height_map.containsKey(curr))
+        {
+          item.setConfirmedHeight(tx_height_map.get(curr));
+        }
+        chain.addItems(item.build());
+
+        int acceptable_sources = 0;
+        ChainHash prev = null;
+        for(TransactionInput input : inner.getInputsList())
+        {
+          if (acceptableAuditTransaction(audit_log_hash, tx_map.get( new ChainHash( input.getSrcTxId() ) ) ))
+          {
+            prev =  new ChainHash( input.getSrcTxId() );
+            acceptable_sources++;
+          }
+        }
+        // Only continue if there is exactly one obvious choice
+        if (acceptable_sources == 1) curr = prev;
+        else curr = null;
+
+      }
+      else
+      {
+        curr = null;
+      }
+
+    }
+
+
+    if (chain_len > 0) return chain.build();
+    return null;
+  }
+
+  private static boolean acceptableAuditTransaction(AddressSpecHash audit_log_hash, Transaction tx)
+  {
+    if (tx == null) return false;
+    TransactionInner inner = TransactionUtil.getInner(tx);
+
+    // Must have exactly one output to log address
+    int log_outputs = 0;
+    for(TransactionOutput out : inner.getOutputsList())
+    {
+      if (audit_log_hash.equals(out.getRecipientSpecHash())) log_outputs++;
+    }
+    if (log_outputs != 1) return false;
+
+
+    // Must be signed by log address
+    int log_sig = 0;
+    for(AddressSpec claim : inner.getClaimsList())
+    {
+      AddressSpecHash addr = AddressUtil.getHashForSpec(claim);
+      if (addr.equals(audit_log_hash)) log_sig++;
+    }
+
+    if (log_sig != 1) return false;
+
+    return true;
+
+  }
+
 
 }

client/src/SnowBlossomClient.java

@@ -340,6 +340,19 @@ else if (command.equals("audit_log_record"))
         System.out.println(AuditLog.recordLog(client, msg));
 
       }
+      else if (command.equals("audit_log_report"))
+      {
+        if (args.length != 3)
+        {
+          System.out.println("Syntax: audit_log_report <address>");
+          System.exit(-1);
+        }
+
+        AddressSpecHash audit_log_hash = AddressUtil.getHashForAddress(client.getParams().getAddressPrefix(), args[2]);
+
+        AuditLogReport report = AuditLog.getAuditReport(client, audit_log_hash);
+        System.out.println(report);
+      }
       else
       {
         logger.log(Level.SEVERE, String.format("Unknown command %s.", command));
@@ -360,6 +373,7 @@ else if (command.equals("audit_log_record"))
         System.out.println("  rpcserver - run a local rpc server for client commands");
         System.out.println("  audit_log_init <msg> - initialize a new audit log chain");
         System.out.println("  audit_log_record <msg> - record next audit log in chain");
+        System.out.println("  audit_log_report <address> - get a report of audit log on address");
 
         System.exit(-1);
       }

protolib/util.proto

@@ -51,3 +51,18 @@ message TransactionFactoryResult {
   int64 fee = 3;
   int32 signatures_added = 4;
 }
+
+message AuditLogReport {
+  repeated AuditLogChain chains = 1;
+}
+
+message AuditLogChain {
+  repeated AuditLogItem items = 1;
+}
+
+message AuditLogItem {
+  bytes tx_hash = 1;
+  int32 confirmed_height = 2;
+  bytes log_msg = 3;
+}
+