Make the Store API more type-safe

Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).

1 files changed, 10 insertions, 8 deletions

diff --git a/src/nix/sigs.cc b/src/nix/sigs.cc
index 23bc83ad0..5f07448e0 100644
--- a/src/nix/sigs.cc
+++ b/src/nix/sigs.cc
@@ -27,7 +27,7 @@ struct CmdCopySigs : StorePathsCommand
         return "copy path signatures from substituters (like binary caches)";
     }
 
-    void run(ref<Store> store, Paths storePaths) override
+    void run(ref<Store> store, StorePaths storePaths) override
     {
         if (substituterUris.empty())
             throw UsageError("you must specify at least one substituter using '-s'");
@@ -44,18 +44,20 @@ struct CmdCopySigs : StorePathsCommand
 
         //logger->setExpected(doneLabel, storePaths.size());
 
-        auto doPath = [&](const Path & storePath) {
+        auto doPath = [&](const Path & storePathS) {
             //Activity act(*logger, lvlInfo, format("getting signatures for '%s'") % storePath);
 
             checkInterrupt();
 
+            auto storePath = store->parseStorePath(storePathS);
+
             auto info = store->queryPathInfo(storePath);
 
             StringSet newSigs;
 
             for (auto & store2 : substituters) {
                 try {
-                    auto info2 = store2->queryPathInfo(storePath);
+                    auto info2 = store2->queryPathInfo(info->path);
 
                     /* Don't import signatures that don't match this
                        binary. */
@@ -80,11 +82,11 @@ struct CmdCopySigs : StorePathsCommand
         };
 
         for (auto & storePath : storePaths)
-            pool.enqueue(std::bind(doPath, storePath));
+            pool.enqueue(std::bind(doPath, store->printStorePath(storePath)));
 
         pool.process();
 
-        printInfo(format("imported %d signatures") % added);
+        printInfo("imported %d signatures", added);
     }
 };
 
@@ -109,7 +111,7 @@ struct CmdSignPaths : StorePathsCommand
         return "sign the specified paths";
     }
 
-    void run(ref<Store> store, Paths storePaths) override
+    void run(ref<Store> store, StorePaths storePaths) override
     {
         if (secretKeyFile.empty())
             throw UsageError("you must specify a secret key file using '-k'");
@@ -123,7 +125,7 @@ struct CmdSignPaths : StorePathsCommand
 
             auto info2(*info);
             info2.sigs.clear();
-            info2.sign(secretKey);
+            info2.sign(*store, secretKey);
             assert(!info2.sigs.empty());
 
             if (!info->sigs.count(*info2.sigs.begin())) {
@@ -132,7 +134,7 @@ struct CmdSignPaths : StorePathsCommand
             }
         }
 
-        printInfo(format("added %d signatures") % added);
+        printInfo("added %d signatures", added);
     }
 };