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| author | John Ericson <John.Ericson@Obsidian.Systems> | 2020-08-07 17:05:14 +0000 |
|---|---|---|
| committer | John Ericson <John.Ericson@Obsidian.Systems> | 2020-08-07 17:05:14 +0000 |
| commit | 47644e49ca252441fcc3ae57f5a01e7fc579ba8c (patch) | |
| tree | 17cefdcf99d35144295696799d2af55fa6ed8c66 /src/libstore/worker-protocol.hh | |
| parent | 8b175f58d1a25dd904fb0ffdf5b2b9501983dba0 (diff) | |
Specialize `std::optional<StorePath>` so this is backwards compatible
While I am cautious to break parametricity, I think it's OK in this
cases---we're not about to try to do some crazy polymorphic protocol
anytime soon.
Diffstat (limited to 'src/libstore/worker-protocol.hh')
| -rw-r--r-- | src/libstore/worker-protocol.hh | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh index c50995d7c..b3576fbeb 100644 --- a/src/libstore/worker-protocol.hh +++ b/src/libstore/worker-protocol.hh @@ -90,6 +90,13 @@ std::optional<T> read(const Store & store, Source & from, Phantom<std::optional< template<typename T> void write(const Store & store, Sink & out, const std::optional<T> & optVal); +/* Specialization which uses and empty string for the empty case, taking + advantage of the fact StorePaths always serialize to a non-empty string. + This is done primarily for backwards compatability, so that StorePath <= + std::optional<StorePath>, where <= is the compatability partial order. + */ +template<> +void write(const Store & store, Sink & out, const std::optional<StorePath> & optVal); template<typename T> std::map<std::string, T> read(const Store & store, Source & from, Phantom<std::map<std::string, T>> _) |