2 files changed, 90 insertions, 0 deletions
diff --git a/src/buildtool/execution_api/common/bytestream_utils.cpp b/src/buildtool/execution_api/common/bytestream_utils.cpp
index cd1f0d19..f1b53f05 100644
--- a/src/buildtool/execution_api/common/bytestream_utils.cpp
+++ b/src/buildtool/execution_api/common/bytestream_utils.cpp
@@ -102,3 +102,56 @@ auto ByteStreamUtils::ReadRequest::GetDigest() const noexcept
     -> bazel_re::Digest {
     return ToBazelDigest(hash_, size_);
 }
+
+ByteStreamUtils::WriteRequest::WriteRequest(
+    std::string instance_name,
+    std::string uuid,
+    bazel_re::Digest const& digest) noexcept
+    : instance_name_{std::move(instance_name)},
+      uuid_{std::move(uuid)},
+      hash_{digest.hash()},
+      size_{digest.size_bytes()} {}
+
+auto ByteStreamUtils::WriteRequest::ToString() && noexcept -> std::string {
+    return fmt::format("{}/{}/{}/{}/{}/{}",
+                       std::move(instance_name_),
+                       ByteStreamUtils::kUploads,
+                       std::move(uuid_),
+                       ByteStreamUtils::kBlobs,
+                       std::move(hash_),
+                       size_);
+}
+
+auto ByteStreamUtils::WriteRequest::FromString(
+    std::string const& request) noexcept -> std::optional<WriteRequest> {
+    static constexpr std::size_t kInstanceNameIndex = 0U;
+    static constexpr std::size_t kUploadsIndex = 1U;
+    static constexpr std::size_t kUUIDIndex = 2U;
+    static constexpr std::size_t kBlobsIndex = 3U;
+    static constexpr std::size_t kHashIndex = 4U;
+    static constexpr std::size_t kSizeIndex = 5U;
+    static constexpr std::size_t kWriteRequestPartsCount = 6U;
+
+    auto const parts = ::SplitRequest(request);
+    if (parts.size() != kWriteRequestPartsCount or
+        parts.at(kUploadsIndex).compare(ByteStreamUtils::kUploads) != 0 or
+        parts.at(kBlobsIndex).compare(ByteStreamUtils::kBlobs) != 0) {
+        return std::nullopt;
+    }
+
+    WriteRequest result;
+    result.instance_name_ = std::string(parts.at(kInstanceNameIndex));
+    result.uuid_ = std::string(parts.at(kUUIDIndex));
+    result.hash_ = std::string(parts.at(kHashIndex));
+    try {
+        result.size_ = std::stoi(std::string(parts.at(kSizeIndex)));
+    } catch (...) {
+        return std::nullopt;
+    }
+    return result;
+}
+
+auto ByteStreamUtils::WriteRequest::GetDigest() const noexcept
+    -> bazel_re::Digest {
+    return ToBazelDigest(hash_, size_);
+}
diff --git a/src/buildtool/execution_api/common/bytestream_utils.hpp b/src/buildtool/execution_api/common/bytestream_utils.hpp
index 9b46073f..672ae017 100644
--- a/src/buildtool/execution_api/common/bytestream_utils.hpp
+++ b/src/buildtool/execution_api/common/bytestream_utils.hpp
@@ -27,6 +27,7 @@ namespace bazel_re = build::bazel::remote::execution::v2;
 
 class ByteStreamUtils final {
     static constexpr auto* kBlobs = "blobs";
+    static constexpr auto* kUploads = "uploads";
 
   public:
     // Chunk size for uploads (default size used by BuildBarn)
@@ -61,6 +62,42 @@ class ByteStreamUtils final {
 
         ReadRequest() = default;
     };
+
+    /// \brief Create a write request for the bytestream service to be
+    /// transferred over the net. Handles serialization/deserialization on its
+    /// own. The pattern is:
+    /// "{instance_name}/{kUploads}/{uuid}/{kBlobs}/{digest.hash()}/{digest.size_bytes()}".
+    /// "instance_name_example/uploads/c4f03510-7d56-4490-8934-01bce1b1288e/blobs/62183d7a696acf7e69e218efc82c93135f8c85f895/4424712"
+    class WriteRequest final {
+      public:
+        explicit WriteRequest(std::string instance_name,
+                              std::string uuid,
+                              bazel_re::Digest const& digest) noexcept;
+
+        [[nodiscard]] auto ToString() && noexcept -> std::string;
+
+        [[nodiscard]] static auto FromString(
+            std::string const& request) noexcept -> std::optional<WriteRequest>;
+
+        [[nodiscard]] auto GetInstanceName() const noexcept
+            -> std::string const& {
+            return instance_name_;
+        }
+
+        [[nodiscard]] auto GetUUID() const noexcept -> std::string const& {
+            return uuid_;
+        }
+
+        [[nodiscard]] auto GetDigest() const noexcept -> bazel_re::Digest;
+
+      private:
+        std::string instance_name_;
+        std::string uuid_;
+        std::string hash_;
+        std::int64_t size_ = 0;
+
+        WriteRequest() = default;
+    };
 };
 
 #endif  // INCLUDED_SRC_BUILDTOOL_EXECUTION_API_COMMON_BYTESTREAM_UTILS_HPP