golang: Use pointer receiver where appropriate

- In order to avoid copying the whole structure functions should use pointer receiver when possible. - One exception is for enums, where it makes more sense to keep the copy receivers.

Author: Leonard Kramer

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/golang/GolangGenerator.java

@@ -553,9 +553,9 @@ private void generateEncodeDecodeOpen(
  final Boolean isMessage,
  final Boolean isExtensible)
  {
- generateEncodeHeader(encode, varName, typeName, isMessage);
+ generateEncodeHeader(encode, varName, typeName, isMessage, false);
  generateDecodeHeader(decode, varName, typeName, isMessage, isExtensible);
- generateRangeCheckHeader(rangeCheck, varName, typeName);
+ generateRangeCheckHeader(rangeCheck, varName, typeName, false);
  generateInitHeader(init, varName, typeName);
  }
 
@@ -809,7 +809,7 @@ private void generateEnumEncodeDecode(
  }
 
  // Encode
- generateEncodeHeader(sb, varName, enumName + "Enum", false);
+ generateEncodeHeader(sb, varName, enumName + "Enum", false, true);
  sb.append(String.format(
  "\tif err := _m.Write%1$s(_w, %2$s(%3$s)); err != nil {\n" +
  "\t\treturn err\n" +
@@ -835,7 +835,7 @@ private void generateEnumEncodeDecode(
  // struct to check which are legitimate
  imports.add("fmt");
  imports.add("reflect");
- generateRangeCheckHeader(sb, varName, enumName + "Enum");
+ generateRangeCheckHeader(sb, varName, enumName + "Enum", true);
 
  // For enums we can add new fields so if we're decoding a
  // newer version then the content is definitionally ok.
@@ -867,7 +867,7 @@ private void generateChoiceEncodeDecode(
  final char varName = Character.toLowerCase(choiceName.charAt(0));
 
  // Encode
- generateEncodeHeader(sb, varName, choiceName, false);
+ generateEncodeHeader(sb, varName, choiceName, false, false);
 
  sb.append(String.format(
  "\tvar wireval uint%1$d = 0\n" +
@@ -902,7 +902,8 @@ private void generateEncodeHeader(
  final StringBuilder sb,
  final char varName,
  final String typeName,
- final Boolean isMessage)
+ final Boolean isMessage,
+ final Boolean isEnum)
  {
  // Only messages get the rangeCheck flag
  String messageArgs = "";
@@ -912,11 +913,12 @@ private void generateEncodeHeader(
  }
 
  sb.append(String.format(
- "\nfunc (%1$s %2$s) Encode(_m *SbeGoMarshaller, _w io.Writer" +
+ "\nfunc (%1$s %3$s%2$s) Encode(_m *SbeGoMarshaller, _w io.Writer" +
  messageArgs +
  ") error {\n",
  varName,
- typeName));
+ typeName,
+ (isEnum ? "" : "*")));
  }
 
  private void generateDecodeHeader(
@@ -962,12 +964,14 @@ private void generateDecodeHeader(
  private void generateRangeCheckHeader(
  final StringBuilder sb,
  final char varName,
- final String typeName)
+ final String typeName,
+ final boolean isEnum)
  {
  sb.append(String.format(
- "\nfunc (%1$s %2$s) RangeCheck(actingVersion uint16, schemaVersion uint16) error {\n",
+ "\nfunc (%1$s %3$s%2$s) RangeCheck(actingVersion uint16, schemaVersion uint16) error {\n",
  varName,
- typeName));
+ typeName,
+ (isEnum ? "" : "*")));
  }
 
  private void generateInitHeader(
@@ -1363,10 +1367,10 @@ private void generateVarDataDescriptors(
 
  generateSinceActingDeprecated(sb, typeName, propertyName, token);
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sCharacterEncoding() string {\n" +
+ "\nfunc (%2$s) %3$sCharacterEncoding() string {\n" +
  "\treturn \"%4$s\"\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) %3$sHeaderLength() uint64 {\n" +
+ "\nfunc (%2$s) %3$sHeaderLength() uint64 {\n" +
  "\treturn %5$s\n" +
  "}\n",
  varName,
@@ -1399,7 +1403,7 @@ private void generateChoiceSet(final List<Token> tokens) throws IOException
 
  // EncodedLength
  sb.append(String.format(
- "\nfunc (%1$s %2$s) EncodedLength() int64 {\n" +
+ "\nfunc (%2$s) EncodedLength() int64 {\n" +
  "\treturn %3$s\n" +
  "}\n",
  varName,
@@ -1440,7 +1444,7 @@ private void generateEnum(final List<Token> tokens) throws IOException
 
  // EncodedLength
  sb.append(String.format(
- "\nfunc (%1$s %2$sEnum) EncodedLength() int64 {\n" +
+ "\nfunc (*%2$sEnum) EncodedLength() int64 {\n" +
  "\treturn %3$s\n" +
  "}\n",
  varName,
@@ -1827,7 +1831,7 @@ private void generateMinMaxNull(
 
  // MinValue
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sMinValue() %4$s {\n" +
+ "\nfunc (*%2$s) %3$sMinValue() %4$s {\n" +
  "\treturn %5$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -1838,7 +1842,7 @@ private void generateMinMaxNull(
 
  // MaxValue
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sMaxValue() %4$s {\n" +
+ "\nfunc (*%2$s) %3$sMaxValue() %4$s {\n" +
  "\treturn %5$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -1849,7 +1853,7 @@ private void generateMinMaxNull(
 
  // NullValue
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sNullValue() %4$s {\n" +
+ "\nfunc (*%2$s) %3$sNullValue() %4$s {\n" +
  "\treturn %5$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -1868,7 +1872,7 @@ private void generateCharacterEncoding(
  if (token.encoding().primitiveType() == CHAR && token.arrayLength() > 1)
  {
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sCharacterEncoding() string {\n" +
+ "\nfunc (%1$s *%2$s) %3$sCharacterEncoding() string {\n" +
  "\treturn \"%4$s\"\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -1885,7 +1889,7 @@ private void generateId(
  final Token token)
  {
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sId() uint16 {\n" +
+ "\nfunc (*%2$s) %3$sId() uint16 {\n" +
  "\treturn %4$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -1901,13 +1905,13 @@ private void generateSinceActingDeprecated(
  final Token token)
  {
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sSinceVersion() uint16 {\n" +
+ "\nfunc (*%2$s) %3$sSinceVersion() uint16 {\n" +
  "\treturn %4$s\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) %3$sInActingVersion(actingVersion uint16) bool {\n" +
+ "\nfunc (%1$s *%2$s) %3$sInActingVersion(actingVersion uint16) bool {\n" +
  "\treturn actingVersion >= %1$s.%3$sSinceVersion()\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) %3$sDeprecated() uint16 {\n" +
+ "\nfunc (*%2$s) %3$sDeprecated() uint16 {\n" +
  "\treturn %5$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -2014,7 +2018,7 @@ private void generateEncodedLength(
  final int size)
  {
  sb.append(String.format(
- "\nfunc (%1$s %2$s) EncodedLength() int64 {\n" +
+ "\nfunc (*%2$s) EncodedLength() int64 {\n" +
  "\treturn %3$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -2037,19 +2041,19 @@ private void generateMessageCode(
  generateEncodeDecode(sb, typeName, tokens, true, true);
 
  sb.append(String.format(
- "\nfunc (%1$s %2$s) SbeBlockLength() (blockLength %3$s) {\n" +
+ "\nfunc (*%2$s) SbeBlockLength() (blockLength %3$s) {\n" +
  "\treturn %4$s\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) SbeTemplateId() (templateId %5$s) {\n" +
+ "\nfunc (*%2$s) SbeTemplateId() (templateId %5$s) {\n" +
  "\treturn %6$s\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) SbeSchemaId() (schemaId %7$s) {\n" +
+ "\nfunc (*%2$s) SbeSchemaId() (schemaId %7$s) {\n" +
  "\treturn %8$s\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) SbeSchemaVersion() (schemaVersion %9$s) {\n" +
+ "\nfunc (*%2$s) SbeSchemaVersion() (schemaVersion %9$s) {\n" +
  "\treturn %10$s\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) SbeSemanticType() (semanticType []byte) {\n" +
+ "\nfunc (*%2$s) SbeSemanticType() (semanticType []byte) {\n" +
  "\treturn []byte(\"%11$s\")\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -2073,10 +2077,10 @@ private void generateExtensibilityMethods(
  final Token token)
  {
  sb.append(String.format(
- "\nfunc (%1$s %2$s) SbeBlockLength() (blockLength uint) {\n" +
+ "\nfunc (*%2$s) SbeBlockLength() (blockLength uint) {\n" +
  "\treturn %3$s\n" +
  "}\n" +
- "\nfunc (%1$s %2$s) SbeSchemaVersion() (schemaVersion %4$s) {\n" +
+ "\nfunc (*%2$s) SbeSchemaVersion() (schemaVersion %4$s) {\n" +
  "\treturn %5$s\n" +
  "}\n",
  Character.toLowerCase(typeName.charAt(0)),
@@ -2138,7 +2142,7 @@ private static void generateFieldMetaAttributeMethod(
  final String presence = encoding.presence() == null ? "" : encoding.presence().toString().toLowerCase();
 
  sb.append(String.format(
- "\nfunc (%1$s %2$s) %3$sMetaAttribute(meta int) string {\n" +
+ "\nfunc (*%2$s) %3$sMetaAttribute(meta int) string {\n" +
  "\tswitch meta {\n" +
  "\tcase 1:\n" +
  "\t\treturn \"%4$s\"\n" +