Merge branch 'main' into sb/zen-helpsb/zen-help

- Combine HelpCommand (this branch) with HistoryCommand (main) in zen CLI dispatcher
- Keep filter-aware TuiPickOne rewrite; adopt main's ASCII arrow glyphs in doc comment

1 files changed, 55 insertions, 0 deletions

diff --git a/thirdparty/tourist/trace/src/preamble.cpp b/thirdparty/tourist/trace/src/preamble.cpp
new file mode 100644
index 000000000..7b54dbc8e
--- /dev/null
+++ b/thirdparty/tourist/trace/src/preamble.cpp
@@ -0,0 +1,55 @@
+#include <foundation/types.h>
+
+#include <trace/detail/exceptions.h>
+#include <trace/detail/preamble.h>
+#include <trace/detail/protocol.h>
+#include <trace/detail/transport.h>
+
+//------------------------------------------------------------------------------
+Preamble::Preamble(DataSource& source, Allocator& allocator)
+: _stream(source, allocator)
+{
+}
+
+//------------------------------------------------------------------------------
+Transport Preamble::get_transport()
+{
+    if (!_parsed)
+        parse_header();
+
+    return Transport(std::move(_stream));
+}
+
+//------------------------------------------------------------------------------
+Protocol Preamble::get_protocol()
+{
+    if (!_parsed)
+        parse_header();
+
+    return Protocol(_protocol_version);
+}
+
+//------------------------------------------------------------------------------
+void Preamble::parse_header()
+{
+    // magic
+    uint32 magic = _stream.read<uint32>();
+    if (magic != 'TRC2')
+        throw Exception::StreamError("Unexpected magic value", 0, magic);
+
+    // meta
+    uint32 meta_size = _stream.read<uint16>();
+    _stream.read(meta_size);
+
+    // transport
+    _transport_version = _stream.read<uint8>();
+    if (_transport_version != 4)
+        throw Exception::StreamError("Unexpected transport version", 0, _transport_version);
+
+    // protocol
+    _protocol_version = _stream.read<uint8>();
+    if (_protocol_version != 6 && _protocol_version != 7)
+        throw Exception::StreamError("Unexpected protocol version", 0, _protocol_version);
+
+    _parsed = true;
+}