Factor out a `LogStore` interface

Continue progress on #5729.

Just as I hoped, this uncovered an issue: the daemon protocol is missing
a way to query build logs. This doesn't effect `unix://`, but does
effect `ssh://`. A FIXME is left for this, so we come back to it later.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/nix/store-copy-log.cc b/src/nix/store-copy-log.cc
index 079cd6b3e..22b3980c0 100644
--- a/src/nix/store-copy-log.cc
+++ b/src/nix/store-copy-log.cc
@@ -1,6 +1,7 @@
 #include "command.hh"
 #include "shared.hh"
 #include "store-api.hh"
+#include "log-store.hh"
 #include "sync.hh"
 #include "thread-pool.hh"
 
@@ -26,7 +27,10 @@ struct CmdCopyLog : virtual CopyCommand, virtual InstallablesCommand
 
     void run(ref<Store> srcStore) override
     {
+        auto & srcLogStore = LogStore::require(*srcStore);
+
         auto dstStore = getDstStore();
+        auto & dstLogStore = LogStore::require(*dstStore);
 
         StorePathSet drvPaths;
 
@@ -35,8 +39,8 @@ struct CmdCopyLog : virtual CopyCommand, virtual InstallablesCommand
                 drvPaths.insert(drvPath);
 
         for (auto & drvPath : drvPaths) {
-            if (auto log = srcStore->getBuildLog(drvPath))
-                dstStore->addBuildLog(drvPath, *log);
+            if (auto log = srcLogStore.getBuildLog(drvPath))
+                dstLogStore.addBuildLog(drvPath, *log);
             else
                 throw Error("build log for '%s' is not available", srcStore->printStorePath(drvPath));
         }