Merge pull request aeron-io#685 from ian-p-cooke/streaming_rust

enhancements to Rust generator

Author: mjpt777

.gitignore

@@ -13,7 +13,7 @@
 # Build tools
 build-local.properties
 deps
-/bin
+*/bin
 build
 .gradle
 target
@@ -23,6 +23,7 @@ GPATH
 prop
 out
 .vs/
+.vscode
 
 # cmake
 

build.gradle

@@ -569,7 +569,8 @@ def cargo_exists() {
  try {
  def result = project.exec {
  executable = 'cargo'
- args = '-v'
+ args = [ '-V' ]
+ standardOutput = new ByteArrayOutputStream()
  }
  return result.exitValue == 0
  }

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/rust/RustCodecType.java

@@ -173,7 +173,7 @@ void appendWrapMethod(final Appendable appendable, final String structName)
  throws IOException
  {
  appendable.append("\n").append(INDENT).append(String.format(
- "fn wrap(%s: %s) -> %s {%n", scratchProperty(), RustGenerator.withLifetime(scratchType()),
+ "pub fn wrap(%s: %s) -> %s {%n", scratchProperty(), RustGenerator.withLifetime(scratchType()),
  RustGenerator.withLifetime(structName)));
  indent(appendable, 2, "%s { %s: %s }\n",
  structName, scratchProperty(), scratchProperty());

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/rust/RustGenerator.java

@@ -53,6 +53,8 @@ public RustGenerator(final Ir ir, final OutputManager outputManager)
 
  public void generate() throws IOException
  {
+ final int headerSize = totalByteSize(ir.headerStructure());
+
  generateSharedImports(outputManager);
  generateResultEnums(outputManager);
  generateDecoderScratchStruct(outputManager);
@@ -61,7 +63,7 @@ public void generate() throws IOException
  generateEnums(ir, outputManager);
  generateComposites(ir, outputManager);
  generateBitSets(ir, outputManager);
- final int headerSize = totalByteSize(ir.headerStructure());
+ generateMessageHeaderDecoder(outputManager, headerSize);
 
  for (final List<Token> tokens : ir.messages())
  {
@@ -285,6 +287,27 @@ private static void generateEntryPoint(
  }
  }
 
+ static void generateMessageHeaderDecoder(
+ final OutputManager outputManager,
+ final int headerSize) throws IOException
+ {
+ final String messageTypeName = "MessageHeader";
+ final RustCodecType codecType = RustCodecType.Decoder;
+ try (Writer writer = outputManager.createOutput(messageTypeName + format(" %s entry point", codecType.name())))
+ {
+ final String gerund = codecType.gerund();
+ writer.append(format("pub fn start_%s_%s<%s>(data: &%s%s [u8]) -> CodecResult<(&%s %s, %s)> {\n", gerund,
+ formatMethodName(messageTypeName), DATA_LIFETIME, DATA_LIFETIME,
+ codecType == RustCodecType.Encoder ? " mut" : "",
+ DATA_LIFETIME, messageTypeName,
+ withLifetime(codecType.scratchType())));
+ indent(writer, 1, format("let mut scratch = %s { data: data, pos: 0 };\n", codecType.scratchType()));
+ indent(writer, 1, format("let v = scratch.read_type::<%s>(%s)?;\n", messageTypeName, headerSize));
+ indent(writer, 1, "Ok((v, scratch))\n");
+ writer.append("}\n");
+ }
+ }
+
  static String withLifetime(final String typeName)
  {
  return format("%s<%s>", typeName, DATA_LIFETIME);
@@ -1163,7 +1186,7 @@ static void generateEncoderScratchStruct(final OutputManager outputManager) thro
  try (Writer writer = outputManager.createOutput("Scratch Encoder Data Wrapper - codec internal use only"))
  {
  writer.append("#[derive(Debug)]\n");
- writer.append(format("struct %s<%s> {\n", SCRATCH_ENCODER_TYPE, DATA_LIFETIME));
+ writer.append(format("pub struct %s<%s> {\n", SCRATCH_ENCODER_TYPE, DATA_LIFETIME));
  indent(writer, 1, "data: &%s mut [u8],\n", DATA_LIFETIME);
  indent(writer).append("pos: usize,\n");
  writer.append("}\n");
@@ -1291,7 +1314,7 @@ private static void generateDecoderScratchStruct(final OutputManager outputManag
  try (Writer writer = outputManager.createOutput("Scratch Decoder Data Wrapper - codec internal use only"))
  {
  writer.append("#[derive(Debug)]\n");
- writer.append(format("struct %s<%s> {\n", SCRATCH_DECODER_TYPE, DATA_LIFETIME));
+ writer.append(format("pub struct %s<%s> {\n", SCRATCH_DECODER_TYPE, DATA_LIFETIME));
  indent(writer, 1, "data: &%s [u8],\n", DATA_LIFETIME);
  indent(writer).append("pos: usize,\n");
  writer.append("}\n");
@@ -1798,6 +1821,18 @@ private void generateMessageHeaderDefault(
  indent(writer, 1, "pub message_header: MessageHeader\n");
  writer.append("}\n");
 
+ final String blockLength = Integer.toString(messageToken.encodedLength());
+ final String templateId = Integer.toString(messageToken.id());
+ final String schemaId = Integer.toString(ir.id());
+ final String version = Integer.toString(ir.version());
+
+ indent(writer, 0, "impl %s {\n", wrapperName);
+ indent(writer, 1, "pub const BLOCK_LENGTH : u16 = " + blockLength + ";\n");
+ indent(writer, 1, "pub const TEMPLATE_ID : u16 = " + templateId + ";\n");
+ indent(writer, 1, "pub const SCHEMA_ID : u16 = " + schemaId + ";\n");
+ indent(writer, 1, "pub const VERSION : u16 = " + version + ";\n");
+ indent(writer, 0, "}\n");
+
  indent(writer, 0, "impl Default for %s {\n", wrapperName);
  indent(writer, 1, "fn default() -> %s {\n", wrapperName);
  indent(writer, 2, "%s {\n", wrapperName);
@@ -1807,10 +1842,10 @@ private void generateMessageHeaderDefault(
  new HashMap<String, String>()
  {
  {
- put("block_length", Integer.toString(messageToken.encodedLength()));
- put("template_id", Integer.toString(messageToken.id()));
- put("schema_id", Integer.toString(ir.id()));
- put("version", Integer.toString(ir.version()));
+ put("block_length", blockLength);
+ put("template_id", templateId);
+ put("schema_id", schemaId);
+ put("version", version);
  }
  });
 

sbe-tool/src/test/java/uk/co/real_logic/sbe/generation/rust/RustGeneratorTest.java

@@ -237,7 +237,7 @@ private static boolean cargoExists()
  {
  try
  {
- final ProcessBuilder builder = new ProcessBuilder("cargo", "-v");
+ final ProcessBuilder builder = new ProcessBuilder("cargo", "-V");
  final Process process = builder.start();
  process.waitFor(5, TimeUnit.SECONDS);
  return process.exitValue() == 0;