From 4e48298414efa69029246dd300a10c52c83db1a6 Mon Sep 17 00:00:00 2001
From: rmg-x <git@rmgx.io>
Date: Mon, 18 Nov 2024 17:20:33 -0600
Subject: [PATCH] LibWeb/Fetch: Implement `build_content_range(start, end,
 full_length)`

---
 .../LibWeb/Fetch/Infrastructure/HTTP/Headers.cpp    | 13 +++++++++++++
 .../LibWeb/Fetch/Infrastructure/HTTP/Headers.h      |  1 +
 2 files changed, 14 insertions(+)

diff --git a/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.cpp b/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.cpp
index a3632494e3b..8f2be78b19f 100644
--- a/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.cpp
+++ b/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.cpp
@@ -832,6 +832,19 @@ Variant<Vector<ByteBuffer>, ExtractHeaderParseFailure, Empty> extract_header_lis
     return values;
 }
 
+// https://fetch.spec.whatwg.org/#build-a-content-range
+ByteString build_content_range(u64 const& range_start, u64 const& range_end, u64 const& full_length)
+{
+    // 1. Let contentRange be `bytes `.
+    // 2. Append rangeStart, serialized and isomorphic encoded, to contentRange.
+    // 3. Append 0x2D (-) to contentRange.
+    // 4. Append rangeEnd, serialized and isomorphic encoded to contentRange.
+    // 5. Append 0x2F (/) to contentRange.
+    // 6. Append fullLength, serialized and isomorphic encoded to contentRange.
+    // 7. Return contentRange.
+    return ByteString::formatted("bytes {}-{}/{}", String::number(range_start), String::number(range_end), String::number(full_length));
+}
+
 // https://fetch.spec.whatwg.org/#simple-range-header-value
 Optional<RangeHeaderValue> parse_single_range_header_value(ReadonlyBytes const value, bool const allow_whitespace)
 {
diff --git a/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.h b/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.h
index d786005c318..f032aeb1fa2 100644
--- a/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.h
+++ b/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.h
@@ -93,6 +93,7 @@ struct ExtractHeaderParseFailure {
 [[nodiscard]] bool is_request_body_header_name(ReadonlyBytes);
 [[nodiscard]] Optional<Vector<ByteBuffer>> extract_header_values(Header const&);
 [[nodiscard]] Variant<Vector<ByteBuffer>, ExtractHeaderParseFailure, Empty> extract_header_list_values(ReadonlyBytes, HeaderList const&);
+[[nodiscard]] ByteString build_content_range(u64 const& range_start, u64 const& range_end, u64 const& full_length);
 [[nodiscard]] Optional<RangeHeaderValue> parse_single_range_header_value(ReadonlyBytes, bool);
 [[nodiscard]] ByteBuffer default_user_agent_value();