Use bytes to represent memo text (#259)

The Java SDK assumes that all memo texts must be valid UTF 8 strings. However, that assumption is not valid. It turns out that any sequence of bytes is allowed to appear in the memo field (see stellar/go#2022 ).

Therefore, the correct representation for the memo field is a byte array.

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 As this project is pre 1.0, breaking changes may happen for minor version bumps. A breaking change will get clearly notified in this log.
 
+## 0.12.0
+
+* Represent memo text contents as bytes because a memo text may not be valid UTF-8 string (https://github.com/stellar/java-stellar-sdk/issues/257).
+* Validate name length when constructing org.stellar.sdk.ManageDataOperation instances.
+* Validate home domain length when constructing org.stellar.sdk.SetOptionsOperation instances.
+
 ## 0.11.0
 
 * Fix bug in `org.stellar.sdk.requests.OperationsRequestBuilder.operation(long operationId)`. The method submitted an HTTP request to Horizon with the following path, /operation/<id> , but the correct path is /operations/<id>

build.gradle

@@ -16,7 +16,7 @@ apply plugin: 'com.github.ben-manes.versions' // gradle dependencyUpdates -Drevi
 apply plugin: 'project-report' // gradle htmlDependencyReport
 
 sourceCompatibility = 1.6
-version = '0.11.0'
+version = '0.12.0'
 group = 'stellar'
 
 jar {

src/main/java/org/stellar/sdk/ManageDataOperation.java

@@ -1,10 +1,7 @@
 package org.stellar.sdk;
 
 import com.google.common.base.Objects;
-import org.stellar.sdk.xdr.DataValue;
-import org.stellar.sdk.xdr.ManageDataOp;
-import org.stellar.sdk.xdr.OperationType;
-import org.stellar.sdk.xdr.String64;
+import org.stellar.sdk.xdr.*;
 
 import java.util.Arrays;
 
@@ -21,6 +18,10 @@ public class ManageDataOperation extends Operation {
   private ManageDataOperation(String name, byte[] value) {
     this.name = checkNotNull(name, "name cannot be null");
     this.value = value;
+
+    if (new XdrString(this.name).getBytes().length > 64) {
+      throw new IllegalArgumentException("name cannot exceed 64 bytes");
+    }
   }
 
   /**
@@ -41,7 +42,7 @@ public byte[] getValue() {
   org.stellar.sdk.xdr.Operation.OperationBody toOperationBody() {
     ManageDataOp op = new ManageDataOp();
     String64 name = new String64();
-    name.setString64(this.name);
+    name.setString64(new XdrString(this.name));
     op.setDataName(name);
 
     if (value != null) {
@@ -68,7 +69,7 @@ public static class Builder {
      * @param op {@link ManageDataOp}
      */
     Builder(ManageDataOp op) {
-      name = op.getDataName().getString64();
+      name = op.getDataName().getString64().toString();
       if (op.getDataValue() != null) {
         value = op.getDataValue().getDataValue();
       } else {

src/main/java/org/stellar/sdk/Memo.java

@@ -30,6 +30,15 @@ public static MemoText text(String text) {
         return new MemoText(text);
     }
 
+    /**
+     * Creates new {@link MemoText} instance.
+     * @param text
+     */
+    public static MemoText text(byte[] text) {
+        return new MemoText(text);
+    }
+
+
     /**
      * Creates new {@link MemoId} instance.
      * @param id
@@ -78,7 +87,7 @@ public static Memo fromXdr(org.stellar.sdk.xdr.Memo memo) {
             case MEMO_ID:
                 return id(memo.getId().getUint64().longValue());
             case MEMO_TEXT:
-                return text(memo.getText());
+                return text(memo.getText().getBytes());
             case MEMO_HASH:
                 return hash(memo.getHash().getHash());
             case MEMO_RETURN:

src/main/java/org/stellar/sdk/MemoText.java

@@ -1,54 +1,63 @@
 package org.stellar.sdk;
 
-import com.google.common.base.Objects;
 import org.stellar.sdk.xdr.MemoType;
-
-import java.nio.charset.Charset;
+import org.stellar.sdk.xdr.XdrString;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
  * Represents MEMO_TEXT.
  */
 public class MemoText extends Memo {
-  private String text;
+  private XdrString text;
 
   public MemoText(String text) {
-    this.text = checkNotNull(text, "text cannot be null");
+    this(new XdrString(checkNotNull(text, "text cannot be null")));
+  }
+
+  public MemoText(byte[] text) {
+    this(new XdrString(checkNotNull(text, "text cannot be null")));
+  }
 
-    int length = text.getBytes((Charset.forName("UTF-8"))).length;
+  public MemoText(XdrString text) {
+    this.text = checkNotNull(text, "text cannot be null");
+    int length = this.text.getBytes().length;
     if (length > 28) {
       throw new MemoTooLongException("text must be <= 28 bytes. length=" + String.valueOf(length));
     }
   }
 
   public String getText() {
-    return text;
+    return this.text.toString();
+  }
+
+  public byte[] getBytes() {
+    return this.text.getBytes();
   }
 
   @Override
   org.stellar.sdk.xdr.Memo toXdr() {
     org.stellar.sdk.xdr.Memo memo = new org.stellar.sdk.xdr.Memo();
     memo.setDiscriminant(MemoType.MEMO_TEXT);
-    memo.setText(text);
+    memo.setText(this.text);
     return memo;
   }
 
   @Override
   public int hashCode() {
-    return Objects.hashCode(this.text);
+    return this.text.hashCode();
   }
 
   @Override
   public boolean equals(Object o) {
     if (this == o) return true;
     if (o == null || getClass() != o.getClass()) return false;
     MemoText memoText = (MemoText) o;
-    return Objects.equal(this.text, memoText.text);
+    return this.text.equals(memoText.text);
   }
 
     @Override
     public String toString() {
-        return text == null ? "" : text;
+        return text == null ? "" : this.getText();
     }
 }

src/main/java/org/stellar/sdk/SetOptionsOperation.java

@@ -36,6 +36,11 @@ private SetOptionsOperation(String inflationDestination, Integer clearFlags, Int
     this.homeDomain = homeDomain;
     this.signer = signer;
     this.signerWeight = signerWeight;
+
+    if (this.homeDomain != null && new XdrString(this.homeDomain).getBytes().length > 32) {
+      throw new IllegalArgumentException("home domain cannot exceed 32 bytes");
+    }
+
   }
 
   /**
@@ -148,7 +153,7 @@ org.stellar.sdk.xdr.Operation.OperationBody toOperationBody() {
     }
     if (homeDomain != null) {
       String32 homeDomain = new String32();
-      homeDomain.setString32(this.homeDomain);
+      homeDomain.setString32(new XdrString(this.homeDomain));
       op.setHomeDomain(homeDomain);
     }
     if (signer != null) {
@@ -206,7 +211,7 @@ public static class Builder {
         highThreshold = op.getHighThreshold().getUint32().intValue();
       }
       if (op.getHomeDomain() != null) {
-        homeDomain = op.getHomeDomain().getString32();
+        homeDomain = op.getHomeDomain().getString32().toString();
       }
       if (op.getSigner() != null) {
         signer = op.getSigner().getKey();

src/main/java/org/stellar/sdk/responses/TransactionDeserializer.java

@@ -9,7 +9,11 @@
 import com.google.gson.JsonParseException;
 
 import org.stellar.sdk.Memo;
+import org.stellar.sdk.xdr.TransactionEnvelope;
+import org.stellar.sdk.xdr.XdrDataInputStream;
 
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
 import java.lang.reflect.Type;
 
 public class TransactionDeserializer implements JsonDeserializer<TransactionResponse> {
@@ -31,12 +35,19 @@ public TransactionResponse deserialize(JsonElement json, Type typeOfT, JsonDeser
       // representation of a transaction. That's why we need to handle a special case
       // here.
       if (memoType.equals("text")) {
-        JsonElement memoField = json.getAsJsonObject().get("memo");
-        if (memoField != null) {
-          memo = Memo.text(memoField.getAsString());
-        } else {
-          memo = Memo.text("");
+        // we obtain the memo text from the xdr because the bytes may not be valid utf8
+        String envelopeXdr = json.getAsJsonObject().get("envelope_xdr").getAsString();
+        BaseEncoding base64Encoding = BaseEncoding.base64();
+        byte[] bytes = base64Encoding.decode(envelopeXdr);
+        TransactionEnvelope transactionEnvelope = null;
+        try {
+          transactionEnvelope = TransactionEnvelope.decode(new XdrDataInputStream(new ByteArrayInputStream(bytes)));
+        } catch (IOException e) {
+          // JsonDeserializer<TransactionResponse> cannot throw IOExceptions
+          // so we must throw it as a runtime exception
+          throw new RuntimeException(e);
         }
+        memo = Memo.text(transactionEnvelope.getTx().getMemo().getText().getBytes());
       } else {
         String memoValue = json.getAsJsonObject().get("memo").getAsString();
         BaseEncoding base64Encoding = BaseEncoding.base64();

src/main/java/org/stellar/sdk/xdr/Error.java

@@ -26,24 +26,24 @@ public ErrorCode getCode() {
   public void setCode(ErrorCode value) {
     this.code = value;
   }
-  private String msg;
-  public String getMsg() {
+  private XdrString msg;
+  public XdrString getMsg() {
     return this.msg;
   }
-  public void setMsg(String value) {
+  public void setMsg(XdrString value) {
     this.msg = value;
   }
   public static void encode(XdrDataOutputStream stream, Error encodedError) throws IOException{
     ErrorCode.encode(stream, encodedError.code);
-    stream.writeString(encodedError.msg);
+    encodedError.msg.encode(stream);
   }
   public void encode(XdrDataOutputStream stream) throws IOException {
     encode(stream, this);
   }
   public static Error decode(XdrDataInputStream stream) throws IOException {
     Error decodedError = new Error();
     decodedError.code = ErrorCode.decode(stream);
-    decodedError.msg = stream.readString();
+    decodedError.msg = XdrString.decode(stream, 100);
     return decodedError;
   }
   @Override

src/main/java/org/stellar/sdk/xdr/Hello.java

@@ -54,11 +54,11 @@ public Hash getNetworkID() {
   public void setNetworkID(Hash value) {
     this.networkID = value;
   }
-  private String versionStr;
-  public String getVersionStr() {
+  private XdrString versionStr;
+  public XdrString getVersionStr() {
     return this.versionStr;
   }
-  public void setVersionStr(String value) {
+  public void setVersionStr(XdrString value) {
     this.versionStr = value;
   }
   private Integer listeningPort;
@@ -94,7 +94,7 @@ public static void encode(XdrDataOutputStream stream, Hello encodedHello) throws
     Uint32.encode(stream, encodedHello.overlayVersion);
     Uint32.encode(stream, encodedHello.overlayMinVersion);
     Hash.encode(stream, encodedHello.networkID);
-    stream.writeString(encodedHello.versionStr);
+    encodedHello.versionStr.encode(stream);
     stream.writeInt(encodedHello.listeningPort);
     NodeID.encode(stream, encodedHello.peerID);
     AuthCert.encode(stream, encodedHello.cert);
@@ -109,7 +109,7 @@ public static Hello decode(XdrDataInputStream stream) throws IOException {
     decodedHello.overlayVersion = Uint32.decode(stream);
     decodedHello.overlayMinVersion = Uint32.decode(stream);
     decodedHello.networkID = Hash.decode(stream);
-    decodedHello.versionStr = stream.readString();
+    decodedHello.versionStr = XdrString.decode(stream, 100);
     decodedHello.listeningPort = stream.readInt();
     decodedHello.peerID = NodeID.decode(stream);
     decodedHello.cert = AuthCert.decode(stream);

src/main/java/org/stellar/sdk/xdr/Memo.java

@@ -34,11 +34,11 @@ public MemoType getDiscriminant() {
   public void setDiscriminant(MemoType value) {
     this.type = value;
   }
-  private String text;
-  public String getText() {
+  private XdrString text;
+  public XdrString getText() {
     return this.text;
   }
-  public void setText(String value) {
+  public void setText(XdrString value) {
     this.text = value;
   }
   private Uint64 id;
@@ -70,7 +70,7 @@ public static void encode(XdrDataOutputStream stream, Memo encodedMemo) throws I
   case MEMO_NONE:
   break;
   case MEMO_TEXT:
-  stream.writeString(encodedMemo.text);
+  encodedMemo.text.encode(stream);
   break;
   case MEMO_ID:
   Uint64.encode(stream, encodedMemo.id);
@@ -94,7 +94,7 @@ public static Memo decode(XdrDataInputStream stream) throws IOException {
   case MEMO_NONE:
   break;
   case MEMO_TEXT:
-  decodedMemo.text = stream.readString();
+  decodedMemo.text = XdrString.decode(stream, 28);
   break;
   case MEMO_ID:
   decodedMemo.id = Uint64.decode(stream);

src/main/java/org/stellar/sdk/xdr/String32.java

@@ -14,22 +14,22 @@
 
 //  ===========================================================================
 public class String32 implements XdrElement {
-  private String string32;
-  public String getString32() {
+  private XdrString string32;
+  public XdrString getString32() {
     return this.string32;
   }
-  public void setString32(String value) {
+  public void setString32(XdrString value) {
     this.string32 = value;
   }
   public static void encode(XdrDataOutputStream stream, String32  encodedString32) throws IOException {
-  stream.writeString(encodedString32.string32);
+  encodedString32.string32.encode(stream);
   }
   public void encode(XdrDataOutputStream stream) throws IOException {
     encode(stream, this);
   }
   public static String32 decode(XdrDataInputStream stream) throws IOException {
     String32 decodedString32 = new String32();
-  decodedString32.string32 = stream.readString();
+  decodedString32.string32 = XdrString.decode(stream, 32);
     return decodedString32;
   }
   @Override

src/main/java/org/stellar/sdk/xdr/String64.java

@@ -14,22 +14,22 @@
 
 //  ===========================================================================
 public class String64 implements XdrElement {
-  private String string64;
-  public String getString64() {
+  private XdrString string64;
+  public XdrString getString64() {
     return this.string64;
   }
-  public void setString64(String value) {
+  public void setString64(XdrString value) {
     this.string64 = value;
   }
   public static void encode(XdrDataOutputStream stream, String64  encodedString64) throws IOException {
-  stream.writeString(encodedString64.string64);
+  encodedString64.string64.encode(stream);
   }
   public void encode(XdrDataOutputStream stream) throws IOException {
     encode(stream, this);
   }
   public static String64 decode(XdrDataInputStream stream) throws IOException {
     String64 decodedString64 = new String64();
-  decodedString64.string64 = stream.readString();
+  decodedString64.string64 = XdrString.decode(stream, 64);
     return decodedString64;
   }
   @Override

src/main/java/org/stellar/sdk/xdr/XdrDataInputStream.java

@@ -21,13 +21,6 @@ public XdrDataInputStream(InputStream in) {
         mIn = (XdrInputStream) super.in;
     }
 
-    public String readString() throws IOException {
-        int l = readInt();
-        byte[] bytes = new byte[l];
-        read(bytes);
-        return new String(bytes, Charset.forName("UTF-8"));
-    }
-
     public int[] readIntArray() throws IOException {
         int l = readInt();
         return readIntArray(l);