ArtifactBlob: Return file path

2 files changed, 22 insertions, 1 deletions

diff --git a/src/buildtool/common/artifact_blob.cpp b/src/buildtool/common/artifact_blob.cpp
index 8c48d34e..c46e54c6 100644
--- a/src/buildtool/common/artifact_blob.cpp
+++ b/src/buildtool/common/artifact_blob.cpp
@@ -15,7 +15,6 @@
 #include "src/buildtool/common/artifact_blob.hpp"
 
 #include <exception>
-#include <optional>
 
 #include "fmt/core.h"
 #include "src/buildtool/common/artifact_digest_factory.hpp"
@@ -202,6 +201,21 @@ auto ArtifactBlob::ReadIncrementally(std::size_t chunk_size) const& noexcept
     }
 }
 
+auto ArtifactBlob::GetFilePath() const& noexcept
+    -> std::optional<std::filesystem::path> {
+    using Result = std::optional<std::filesystem::path>;
+    static constexpr InPlaceVisitor kVisitor{
+        [](InMemory const&) -> Result { return std::nullopt; },
+        [](InFile const& value) -> Result { return value; },
+        [](InTempFile const& value) -> Result { return value->GetPath(); },
+    };
+    try {
+        return std::visit(kVisitor, content_);
+    } catch (...) {
+        return std::nullopt;
+    }
+}
+
 namespace std {
 auto hash<ArtifactBlob>::operator()(ArtifactBlob const& blob) const noexcept
     -> std::size_t {
diff --git a/src/buildtool/common/artifact_blob.hpp b/src/buildtool/common/artifact_blob.hpp
index 1e54f71b..1847e536 100644
--- a/src/buildtool/common/artifact_blob.hpp
+++ b/src/buildtool/common/artifact_blob.hpp
@@ -19,6 +19,7 @@
 #include <filesystem>
 #include <functional>
 #include <memory>
+#include <optional>
 #include <string>
 #include <utility>
 #include <variant>
@@ -111,6 +112,12 @@ class ArtifactBlob final {
     [[nodiscard]] auto ReadIncrementally(std::size_t chunk_size) const& noexcept
         -> expected<IncrementalReader, std::string>;
 
+    /// \brief Obtain the path to the file that is used as the content source.
+    /// If ArtifactBlob doesn't use a filesystem source or an internal error
+    /// occurs, std::nullopt is returned.
+    [[nodiscard]] auto GetFilePath() const& noexcept
+        -> std::optional<std::filesystem::path>;
+
     /// \brief Set executable permission.
     void SetExecutable(bool is_executable) noexcept {
         is_executable_ = is_executable;