Use SetMetaData to initialize data writers in Recorder

Refactor the Recorder system to initialize IDataWriter outputs using
the new SetMetaData method instead of Initialize. FileDataWriter now
requires file paths on construction and accepts metadata via
SetMetaData. NetworkDataWriter implements a no-op SetMetaData to
satisfy the interface. This change improves separation of
responsibilities by decoupling metadata setup from generic Initialize
calls.

Author: ahmed-shariff

Runtime/Core/Recorder/Recorder.cs

@@ -77,15 +77,19 @@ private void StartRecordingInternal(string name, string extraMetadata = "", IDat
 
             if (outputs == null)
             {
-                IDataWriter fileDataWriter = new FileDataWriter();
+                var outputDir = Application.persistentDataPath;
+
+                FileDataWriter.GenerateFilePath(outputDir, name, out string filePath, out string metaFilePath);
+
+                IDataWriter fileDataWriter = new FileDataWriter(filePath, metaFilePath);
                 outputs = new IDataWriter[] { fileDataWriter };
             }
 
             Assert.IsFalse(outputs.Length == 0, "The outputs length is 0");
 
             foreach (IDataWriter output in outputs)
             {
-                output.Initialize(record);
+                output.SetMetaData(recordMetadata);
             }
 
             _dataDispatcher.Start(_context.CurrentRecord, outputs);

Runtime/Core/Recorder/Writer/FileDataWriter.cs

@@ -7,6 +7,7 @@
 using K4os.Compression.LZ4.Streams;
 using PLUME.Sample;
 using UnityEngine;
+using UnityEngine.Assertions;
 
 namespace PLUME.Core.Recorder.Writer
 {
@@ -15,39 +16,20 @@ namespace PLUME.Core.Recorder.Writer
     // TODO: use memory mapped files
     public class FileDataWriter : IDataWriter, IDisposable
     {
-        private Stream _stream;
-        private Stream _metaStream;
-        private CodedOutputStream _metaCodedOutputStream;
+        private readonly Stream _stream;
+        private readonly Stream _metaStream;
+        private readonly CodedOutputStream _metaCodedOutputStream;
 
+        private readonly RecordMetrics _metrics;
         private Sample.RecordMetadata _metadata;
-        private RecordMetrics _metrics;
-
-        private string filePath;
-        private string metaFilePath;
-
-        public FileDataWriter() { }
 
         /// <param name="filePath">The file path for the plm file.</param>
         /// <param name="metaFilePath">The file path for the meta file.</param>
         public FileDataWriter(string filePath, string metaFilePath)
         {
-            this.filePath = filePath;
-            this.metaFilePath = metaFilePath;
-        }
-
-        /// <inheritdoc />
-        public void Initialize(Record record)
-        {
-            if (string.IsNullOrWhiteSpace(filePath) ^ string.IsNullOrWhiteSpace(metaFilePath))
-            {
-                throw new InvalidOperationException($"Only one of filePath and metaFilePath are specifed. Either both need to be specified, or neither should be");
-            }
-            else if (string.IsNullOrWhiteSpace(filePath) && string.IsNullOrWhiteSpace(metaFilePath))
-            {
-                var outputDir = Application.persistentDataPath;
+            Assert.IsFalse(string.IsNullOrWhiteSpace(filePath), "filePath is null or empty");
+            Assert.IsFalse(string.IsNullOrWhiteSpace(metaFilePath), "metaFilePath is null or empty");
 
-                GenerateFilePath(outputDir, record.Metadata.Name, out filePath, out metaFilePath);
-            }
             Logger.Log($"Record will be saved to '{filePath}'.");
 
             PinnedMemory.MaxPooledSize = 0;
@@ -68,12 +50,15 @@ public void Initialize(Record record)
             _metaStream = File.Create(metaFilePath);
             _metaCodedOutputStream = new CodedOutputStream(_metaStream);
 
-            _metadata = record.Metadata.ToPayload();
             _metrics = new RecordMetrics
             {
                 IsSequential = true
             };
-            
+        }
+
+        public void SetMetaData(RecordMetadata metaData)
+        {
+            _metadata = metaData.ToPayload();
             UpdateMetaFile();
         }
 
@@ -123,6 +108,10 @@ public void WriteTimestampedData(DataChunksTimestamped dataChunks)
 
         private void UpdateMetaFile()
         {
+            if (_metadata == null)
+            {
+                return;
+            }
             _metaStream.SetLength(0);
             _metaStream.Position = 0;
             _metaCodedOutputStream.WriteLength(_metadata.CalculateSize());

Runtime/Core/Recorder/Writer/IDataWriter.cs

@@ -2,7 +2,7 @@ namespace PLUME.Core.Recorder.Writer
 {
     public interface IDataWriter
     {
-        public void Initialize(Record record);
+        public void SetMetaData(RecordMetadata metadata);
 
         public void WriteTimelessData(DataChunks dataChunks);
 

Runtime/Core/Recorder/Writer/NetworkDataWriter.cs

@@ -10,17 +10,9 @@ namespace PLUME.Core.Recorder.Writer
 {
     public class NetworkDataWriter : IDataWriter
     {
-        private Stream _stream;
-        private string ipAddress;
-        private int port;
+        private readonly Stream _stream;
 
         public NetworkDataWriter(string ipAddress="127.0.0.1", int port=8000)
-        {
-            this.ipAddress = ipAddress;
-            this.port = port;
-        }
-
-        public void Initialize(Record _)
         {
             // Create a tcp server
             var server = new TcpListener(IPAddress.Parse(ipAddress), port);
@@ -37,6 +29,9 @@ public void Initialize(Record _)
             _stream = LZ4Stream.Encode(stream, LZ4Level.L00_FAST);
         }
 
+        public void SetMetaData(RecordMetadata _)
+        {}
+
         public void WriteTimelessData(DataChunks dataChunks)
         {
         }