Add pkg-dns-simple-server and fix bug in reader.skip. (#2205)

Co-authored-by: Kasper Lund <[email protected]>

external/CMakeLists.txt

@@ -26,6 +26,7 @@ set(TOIT_REPOS
     https://github.com/nilwes/LIS3DH
     https://github.com/toitlang/jaguar
     https://github.com/toitlang/pkg-ar
+    https://github.com/toitlang/pkg-dns-simple-server
     https://github.com/toitlang/pkg-font-tiny
     https://github.com/toitlang/pkg-host
     https://github.com/toitlang/pkg-http

lib/io/reader.toit

@@ -158,6 +158,9 @@ abstract class Reader implements old-reader.Reader:
     buffered := buffered_
     if not buffered:
       if not more_: throw UNEXPECTED-END-OF-READER
+      // The call to $more_ may have changed $buffered_ if
+      // it was null. Read the field again.
+      buffered = buffered_
 
     while n > 0:
       if buffered.size == 0:

lib/net/modules/dns.toit

@@ -639,6 +639,18 @@ class SrvResource extends StringResource:
   constructor name/string type/int ttl/int flush/bool value/string .priority .weight .port:
     super name type ttl flush value
 
+/**
+Decodes a name from a DNS (RFC 1035) packet.
+The block is invoked with the index of the next data in the packet.
+
+Deprecated. Use $(decode-name reader packet) instead.
+*/
+decode-name packet/ByteArray position/int [position-block] -> string:
+  reader := io.Reader packet[position..]
+  result := decode-name reader packet
+  position-block.call (position + reader.processed)
+  return result
+
 /**
 Decodes a name from a DNS (RFC 1035) packet.
 

tests/io-reader3-test.toit

@@ -0,0 +1,11 @@
+// Copyright (C) 2024 Toitware ApS.
+// Use of this source code is governed by a Zero-Clause BSD license that can
+// be found in the tests/LICENSE file.
+
+import expect show *
+import io
+
+main:
+  reader := io.Reader #[1, 2, 3, 4]
+  reader.skip 2
+  expect-equals #[3, 4] (reader.read-bytes 2)