[PAN-2995] Make explicit that streamed accounts may be missing their address

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/core/AbstractWorldUpdater.java

@@ -234,6 +234,11 @@ public Address getAddress() {
       return address;
     }
 
+    @Override
+    public Hash getAddressHash() {
+      return Hash.hash(getAddress());
+    }
+
     @Override
     public long getNonce() {
       return nonce;

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/core/Account.java

@@ -12,146 +12,23 @@
  */
 package tech.pegasys.pantheon.ethereum.core;
 
-import tech.pegasys.pantheon.util.bytes.Bytes32;
-import tech.pegasys.pantheon.util.bytes.BytesValue;
-import tech.pegasys.pantheon.util.uint.UInt256;
-
-import java.util.NavigableMap;
-
 /**
  * A world state account.
  *
- * <p>An account has four properties associated with it:
- *
- * <ul>
- *   <li><b>Nonce:</b> the number of transactions sent (and committed) from the account.
- *   <li><b>Balance:</b> the amount of Wei (10^18 Ether) owned by the account.
- *   <li><b>Storage:</b> a key-value mapping between 256-bit integer values. Note that formally, a
- *       key always has an associated value in that mapping, with 0 being the default (and thus, in
- *       practice, only non-zero mappings are stored and setting a key to the value 0 is akin to
- *       "removing" that key).
- *   <li><b>Code:</b> arbitrary-length sequence of bytes that corresponds to EVM bytecode.
- *   <li><b>Version:</b> the version of the EVM bytecode.
- * </ul>
+ * <p>In addition to holding the account state, a full account provides access to the account
+ * address, which is not stored directly in the world state trie (account's are indexed by the hash
+ * of their address).
  */
-public interface Account {
+public interface Account extends AccountState {
 
   long DEFAULT_NONCE = 0L;
   Wei DEFAULT_BALANCE = Wei.ZERO;
   int DEFAULT_VERSION = 0;
 
-  /**
-   * The Keccak-256 hash of the account address.
-   *
-   * <p>Note that the world state does not store account addresses, only their hashes, and so this
-   * is how account are truly identified. So while accounts can be queried by their address (through
-   * first computing their hash), one cannot infer the address from an account simply from the world
-   * state.
-   *
-   * @return the Keccak-256 hash of the account address.
-   */
-  default Hash getAddressHash() {
-    return Hash.hash(getAddress());
-  }
-
   /**
    * The account address.
    *
    * @return the account address
    */
   Address getAddress();
-
-  /**
-   * The account nonce, that is the number of transactions sent from that account.
-   *
-   * @return the account nonce.
-   */
-  long getNonce();
-
-  /**
-   * The available balance of that account.
-   *
-   * @return the balance, in Wei, of the account.
-   */
-  Wei getBalance();
-
-  /**
-   * The EVM bytecode associated with this account.
-   *
-   * @return the account code (which can be empty).
-   */
-  BytesValue getCode();
-
-  /**
-   * The hash of the EVM bytecode associated with this account.
-   *
-   * @return the hash of the account code (which may be {@link Hash#EMPTY}).
-   */
-  Hash getCodeHash();
-
-  /**
-   * Whether the account has (non empty) EVM bytecode associated to it.
-   *
-   * <p>This is functionally equivalent to {@code !code().isEmpty()}, though could be implemented
-   * more efficiently.
-   *
-   * @return Whether the account has EVM bytecode associated to it.
-   */
-  default boolean hasCode() {
-    return !getCode().isEmpty();
-  }
-
-  /**
-   * The version of the EVM bytecode associated with this account.
-   *
-   * @return the version of the account code. Default is zero.
-   */
-  int getVersion();
-
-  /**
-   * Retrieves a value in the account storage given its key.
-   *
-   * @param key the key to retrieve in the account storage.
-   * @return the value associated to {@code key} in the account storage. Note that this is never
-   *     {@code null}, but 0 acts as a default value.
-   */
-  UInt256 getStorageValue(UInt256 key);
-
-  /**
-   * Retrieves the original value from before the current transaction in the account storage given
-   * its key.
-   *
-   * @param key the key to retrieve in the account storage.
-   * @return the original value associated to {@code key} in the account storage. Note that this is
-   *     never {@code null}, but 0 acts as a default value.
-   */
-  UInt256 getOriginalStorageValue(UInt256 key);
-
-  /**
-   * Whether the account is "empty".
-   *
-   * <p>An account is defined as empty if:
-   *
-   * <ul>
-   *   <li>its nonce is 0;
-   *   <li>its balance is 0;
-   *   <li>its associated code is empty (the zero-length byte sequence).
-   * </ul>
-   *
-   * @return {@code true} if the account is empty with regard to the definition above, {@code false}
-   *     otherwise.
-   */
-  default boolean isEmpty() {
-    return getNonce() == 0 && getBalance().isZero() && !hasCode();
-  }
-
-  /**
-   * Retrieve up to {@code limit} storage entries beginning from the first entry with hash equal to
-   * or greater than {@code startKeyHash}.
-   *
-   * @param startKeyHash the first key hash to return.
-   * @param limit the maximum number of entries to return.
-   * @return the requested storage entries as a map of key hash to entry.
-   */
-  NavigableMap<Bytes32, AccountStorageEntry> storageEntriesFrom(Bytes32 startKeyHash, int limit);
 }

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/core/AccountState.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright 2018 ConsenSys AG.
+ *
+ * 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 tech.pegasys.pantheon.ethereum.core;
+
+import tech.pegasys.pantheon.util.bytes.Bytes32;
+import tech.pegasys.pantheon.util.bytes.BytesValue;
+import tech.pegasys.pantheon.util.uint.UInt256;
+
+import java.util.NavigableMap;
+
+/**
+ * An account state.
+ *
+ * <p>An account has four properties associated with it:
+ *
+ * <ul>
+ *   <li><b>Nonce:</b> the number of transactions sent (and committed) from the account.
+ *   <li><b>Balance:</b> the amount of Wei (10^18 Ether) owned by the account.
+ *   <li><b>Storage:</b> a key-value mapping between 256-bit integer values. Note that formally, a
+ *       key always has an associated value in that mapping, with 0 being the default (and thus, in
+ *       practice, only non-zero mappings are stored and setting a key to the value 0 is akin to
+ *       "removing" that key).
+ *   <li><b>Code:</b> arbitrary-length sequence of bytes that corresponds to EVM bytecode.
+ *   <li><b>Version:</b> the version of the EVM bytecode.
+ * </ul>
+ */
+public interface AccountState {
+
+  /**
+   * The Keccak-256 hash of the account address.
+   *
+   * <p>Note that the world state does not store account addresses, only their hashes, and so this
+   * is how account are truly identified. So while accounts can be queried by their address (through
+   * first computing their hash), one cannot infer the address from an account simply from the world
+   * state.
+   *
+   * @return the Keccak-256 hash of the account address.
+   */
+  Hash getAddressHash();
+
+  /**
+   * The account nonce, that is the number of transactions sent from that account.
+   *
+   * @return the account nonce.
+   */
+  long getNonce();
+
+  /**
+   * The available balance of that account.
+   *
+   * @return the balance, in Wei, of the account.
+   */
+  Wei getBalance();
+
+  /**
+   * The EVM bytecode associated with this account.
+   *
+   * @return the account code (which can be empty).
+   */
+  BytesValue getCode();
+
+  /**
+   * The hash of the EVM bytecode associated with this account.
+   *
+   * @return the hash of the account code (which may be {@link Hash#EMPTY}).
+   */
+  Hash getCodeHash();
+
+  /**
+   * Whether the account has (non empty) EVM bytecode associated to it.
+   *
+   * <p>This is functionally equivalent to {@code !code().isEmpty()}, though could be implemented
+   * more efficiently.
+   *
+   * @return Whether the account has EVM bytecode associated to it.
+   */
+  default boolean hasCode() {
+    return !getCode().isEmpty();
+  }
+
+  /**
+   * The version of the EVM bytecode associated with this account.
+   *
+   * @return the version of the account code. Default is zero.
+   */
+  int getVersion();
+
+  /**
+   * Retrieves a value in the account storage given its key.
+   *
+   * @param key the key to retrieve in the account storage.
+   * @return the value associated to {@code key} in the account storage. Note that this is never
+   *     {@code null}, but 0 acts as a default value.
+   */
+  UInt256 getStorageValue(UInt256 key);
+
+  /**
+   * Retrieves the original value from before the current transaction in the account storage given
+   * its key.
+   *
+   * @param key the key to retrieve in the account storage.
+   * @return the original value associated to {@code key} in the account storage. Note that this is
+   *     never {@code null}, but 0 acts as a default value.
+   */
+  UInt256 getOriginalStorageValue(UInt256 key);
+
+  /**
+   * Whether the account is "empty".
+   *
+   * <p>An account is defined as empty if:
+   *
+   * <ul>
+   *   <li>its nonce is 0;
+   *   <li>its balance is 0;
+   *   <li>its associated code is empty (the zero-length byte sequence).
+   * </ul>
+   *
+   * @return {@code true} if the account is empty with regard to the definition above, {@code false}
+   *     otherwise.
+   */
+  default boolean isEmpty() {
+    return getNonce() == 0 && getBalance().isZero() && !hasCode();
+  }
+
+  /**
+   * Retrieve up to {@code limit} storage entries beginning from the first entry with hash equal to
+   * or greater than {@code startKeyHash}.
+   *
+   * @param startKeyHash the first key hash to return.
+   * @param limit the maximum number of entries to return.
+   * @return the requested storage entries as a map of key hash to entry.
+   */
+  NavigableMap<Bytes32, AccountStorageEntry> storageEntriesFrom(Bytes32 startKeyHash, int limit);
+}

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/core/WorldState.java

@@ -13,7 +13,11 @@
 package tech.pegasys.pantheon.ethereum.core;
 
 import tech.pegasys.pantheon.util.bytes.Bytes32;
+import tech.pegasys.pantheon.util.bytes.BytesValue;
+import tech.pegasys.pantheon.util.uint.UInt256;
 
+import java.util.NavigableMap;
+import java.util.Optional;
 import java.util.stream.Stream;
 
 /**
@@ -41,5 +45,65 @@ public interface WorldState extends WorldView {
    * @return a stream of all the accounts (in no particular order) contained in the world state
    *     represented by the root hash of this object at the time of the call.
    */
-  Stream<Account> streamAccounts(Bytes32 startKeyHash, int limit);
+  Stream<StreamableAccount> streamAccounts(Bytes32 startKeyHash, int limit);
+
+  class StreamableAccount implements AccountState {
+    private final Optional<Address> address;
+    private final AccountState accountState;
+
+    public StreamableAccount(final Optional<Address> address, final AccountState accountState) {
+      this.address = address;
+      this.accountState = accountState;
+    }
+
+    public Optional<Address> getAddress() {
+      return address;
+    }
+
+    @Override
+    public Hash getAddressHash() {
+      return accountState.getAddressHash();
+    }
+
+    @Override
+    public long getNonce() {
+      return accountState.getNonce();
+    }
+
+    @Override
+    public Wei getBalance() {
+      return accountState.getBalance();
+    }
+
+    @Override
+    public BytesValue getCode() {
+      return accountState.getCode();
+    }
+
+    @Override
+    public Hash getCodeHash() {
+      return accountState.getCodeHash();
+    }
+
+    @Override
+    public int getVersion() {
+      return accountState.getVersion();
+    }
+
+    @Override
+    public UInt256 getStorageValue(final UInt256 key) {
+      return accountState.getStorageValue(key);
+    }
+
+    @Override
+    public UInt256 getOriginalStorageValue(final UInt256 key) {
+      return accountState.getOriginalStorageValue(key);
+    }
+
+    @Override
+    public NavigableMap<Bytes32, AccountStorageEntry> storageEntriesFrom(
+        final Bytes32 startKeyHash, final int limit) {
+      return accountState.storageEntriesFrom(startKeyHash, limit);
+    }
+  }
 }