UNIX Domain Socket support (helidon-io#10894)

* add support for UNIX domain sockets to webserver and webclient
* use SocketChannel in server listener (required for the above)
* add support for socket channels when accepting connections to webserver
* bind-address was left in configuration from older versions of Helidon, and it now has a new meaning - fix all usages
* fix Optional.of() to ofNullable() for local certificate and principal.

Author: tomas-langer

common/buffers/src/main/java/io/helidon/common/buffers/BufferData.java

@@ -214,6 +214,14 @@ static BufferData create(String stringValue) {
      */
     int readFrom(InputStream in);
 
+    /**
+     * Read bytes from the provided buffer.
+     *
+     * @param buf byte buffer with data
+     * @return number of bytes read, -1 if the buffer is finished
+     */
+    int readFrom(ByteBuffer buf);
+
     /**
      * Read a single byte from this buffer.
      * @return next byte

common/buffers/src/main/java/io/helidon/common/buffers/CompositeArrayBufferData.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -58,6 +58,16 @@ public int readFrom(InputStream in) {
         throw new IllegalStateException("The composite buffer is fully written, cannot write additional bytes");
     }
 
+    @Override
+    public int readFrom(ByteBuffer buf) {
+        for (BufferData datum : data) {
+            if (datum.capacity() > 0) {
+                return datum.readFrom(buf);
+            }
+        }
+        throw new IllegalStateException("The composite buffer is fully written, cannot write additional bytes");
+    }
+
     @Override
     public int read() {
         for (BufferData datum : data) {

common/buffers/src/main/java/io/helidon/common/buffers/CompositeListBufferData.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -76,6 +76,16 @@ public int readFrom(InputStream in) {
         throw new IllegalStateException("The composite buffer is fully written, cannot write additional bytes");
     }
 
+    @Override
+    public int readFrom(ByteBuffer buf) {
+        for (BufferData datum : data) {
+            if (datum.capacity() > 0) {
+                return datum.readFrom(buf);
+            }
+        }
+        throw new IllegalStateException("The composite buffer is fully written, cannot write additional bytes");
+    }
+
     @Override
     public int read() {
         for (BufferData datum : data) {

common/buffers/src/main/java/io/helidon/common/buffers/DataReader.java

@@ -168,10 +168,10 @@ public boolean startsWithNewLine() {
         ensureAvailable();
         byte[] bytes = head.bytes;
         int pos = head.position;
-        if (bytes[pos] == Bytes.CR_BYTE && ((pos + 1 < bytes.length) ? bytes[pos + 1] : head.next().peek()) == Bytes.LF_BYTE) {
-            return true;
+        if (pos + 1 < bytes.length) {
+            return bytes[pos] == Bytes.CR_BYTE && bytes[pos + 1] == Bytes.LF_BYTE;
         }
-        return false;
+        return bytes[pos] == Bytes.CR_BYTE && head.next().peek() == Bytes.LF_BYTE;
     }
 
     /**

common/buffers/src/main/java/io/helidon/common/buffers/FixedBufferData.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -91,6 +91,15 @@ public int readFrom(InputStream in) {
         return read;
     }
 
+    @Override
+    public int readFrom(ByteBuffer buf) {
+        int toRead = length - writePosition;
+        int read = Math.min(toRead, buf.remaining());
+        buf.get(bytes, writePosition, read);
+        writePosition += read;
+        return read;
+    }
+
     @Override
     public int read() {
         if (readPosition >= writePosition) {
@@ -129,7 +138,7 @@ public FixedBufferData write(int value) {
 
     @Override
     public int writeTo(ByteBuffer writeBuffer, int length) {
-        int toWrite = Math.min(writeBuffer.limit() - writeBuffer.position(), this.length - readPosition);
+        int toWrite = Math.min(writeBuffer.limit() - writeBuffer.position(), writePosition - readPosition);
         toWrite = Math.min(toWrite, length);
         if (toWrite == 0) {
             return 0;

common/buffers/src/main/java/io/helidon/common/buffers/GrowingBufferData.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -83,6 +83,14 @@ public int readFrom(InputStream in) {
         }
     }
 
+    @Override
+    public int readFrom(ByteBuffer buf) {
+        int read = Math.min(buf.remaining(), bytes.length - writePosition);
+        buf.get(bytes, writePosition, read);
+        writePosition += read;
+        return read;
+    }
+
     @Override
     public int read() {
         if (readPosition >= writePosition) {
@@ -120,8 +128,9 @@ public GrowingBufferData write(int value) {
         return this;
     }
 
+    @Override
     public int writeTo(ByteBuffer writeBuffer, int limit) {
-        int toWrite = Math.min(writeBuffer.capacity(), length - readPosition);
+        int toWrite = Math.min(writeBuffer.limit() - writeBuffer.position(), writePosition - readPosition);
         toWrite = Math.min(toWrite, limit);
         if (toWrite == 0) {
             return 0;

common/buffers/src/main/java/io/helidon/common/buffers/ReadOnlyArrayData.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -58,6 +58,11 @@ public int readFrom(InputStream in) {
         throw new UnsupportedOperationException();
     }
 
+    @Override
+    public int readFrom(ByteBuffer buf) {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public int read() {
         if (position >= length) {

common/socket/src/main/java/io/helidon/common/socket/HelidonSocket.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,7 +48,9 @@ public interface HelidonSocket extends SocketContext, Supplier<byte[]> {
      *
      * @param buffer buffer to read to
      * @return number of bytes read
+     * @deprecated this method is not used in Helidon, and will be removed
      */
+    @Deprecated(forRemoval = true, since = "4.4.0")
     int read(BufferData buffer);
 
     /**