From 1c55f16a1648431301f044710644a674c018321d Mon Sep 17 00:00:00 2001
From: Matthew Bauer <mjbauer95@gmail.com>
Date: Fri, 12 Jun 2020 12:26:08 -0500
Subject: [PATCH] Add --flat to nix add-to-store

This can be used to add flat hashes to the nix store.
---
 src/nix/add-to-store.cc | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/nix/add-to-store.cc b/src/nix/add-to-store.cc
index f43f774c1..a5a77f17c 100644
--- a/src/nix/add-to-store.cc
+++ b/src/nix/add-to-store.cc
@@ -9,6 +9,7 @@ struct CmdAddToStore : MixDryRun, StoreCommand
 {
     Path path;
     std::optional<std::string> namePart;
+    FileIngestionMethod ingestionMethod = FileIngestionMethod::Recursive;
 
     CmdAddToStore()
     {
@@ -21,6 +22,13 @@ struct CmdAddToStore : MixDryRun, StoreCommand
             .labels = {"name"},
             .handler = {&namePart},
         });
+
+        addFlag({
+            .longName = "flat",
+            .shortName = 0,
+            .description = "use flat file ingestion",
+            .handler = {&ingestionMethod, FileIngestionMethod::Flat},
+        });
     }
 
     std::string description() override
@@ -45,10 +53,24 @@ struct CmdAddToStore : MixDryRun, StoreCommand
 
         auto narHash = hashString(htSHA256, *sink.s);
 
-        ValidPathInfo info(store->makeFixedOutputPath(FileIngestionMethod::Recursive, narHash, *namePart));
+        ValidPathInfo info(store->makeFixedOutputPath(ingestionMethod, narHash, *namePart));
         info.narHash = narHash;
         info.narSize = sink.s->size();
-        info.ca = makeFixedOutputCA(FileIngestionMethod::Recursive, info.narHash);
+
+        Hash hash;
+        switch (ingestionMethod) {
+        case FileIngestionMethod::Recursive: {
+            hash = info.narHash;
+            break;
+        }
+        case FileIngestionMethod::Flat: {
+            HashSink hsink(htSHA256);
+            readFile(path, hsink);
+            hash = hsink.finish().first;
+            break;
+        }
+        }
+        info.ca = makeFixedOutputCA(ingestionMethod, hash);
 
         if (!dryRun) {
             auto source = StringSource { *sink.s };