Add a name to the stores

So that it can be printed by `nix describe-stores`

src/libstore/build.cc

@@ -2872,11 +2872,16 @@ void DerivationGoal::writeStructuredAttrs()
     chownToBuilder(tmpDir + "/.attrs.sh");
 }
 
+struct RestrictedStoreConfig : LocalFSStoreConfig
+{
+    using LocalFSStoreConfig::LocalFSStoreConfig;
+    const std::string name() { return "Restricted Store"; }
+};
 
 /* A wrapper around LocalStore that only allows building/querying of
    paths that are in the input closures of the build or were added via
    recursive Nix calls. */
-struct RestrictedStore : public LocalFSStore
+struct RestrictedStore : public LocalFSStore, public virtual RestrictedStoreConfig
 {
     ref<LocalStore> next;
 

src/libstore/dummy-store.cc

@@ -4,6 +4,8 @@ namespace nix {
 
 struct DummyStoreConfig : virtual StoreConfig {
     using StoreConfig::StoreConfig;
+
+    const std::string name() override { return "Dummy Store"; }
 };
 
 struct DummyStore : public Store, public virtual DummyStoreConfig

src/libstore/http-binary-cache-store.cc

@@ -10,6 +10,8 @@ MakeError(UploadToHTTP, Error);
 struct HttpBinaryCacheStoreConfig : virtual BinaryCacheStoreConfig
 {
     using BinaryCacheStoreConfig::BinaryCacheStoreConfig;
+
+    const std::string name() override { return "Http Binary Cache Store"; }
 };
 
 class HttpBinaryCacheStore : public BinaryCacheStore, public HttpBinaryCacheStoreConfig

src/libstore/legacy-ssh-store.cc

@@ -17,6 +17,8 @@ struct LegacySSHStoreConfig : virtual StoreConfig
     const Setting<bool> compress{this, false, "compress", "whether to compress the connection"};
     const Setting<Path> remoteProgram{this, "nix-store", "remote-program", "path to the nix-store executable on the remote system"};
     const Setting<std::string> remoteStore{this, "", "remote-store", "URI of the store on the remote system"};
+
+    const std::string name() override { return "Legacy SSH Store"; }
 };
 
 struct LegacySSHStore : public Store, public virtual LegacySSHStoreConfig

src/libstore/local-binary-cache-store.cc

@@ -7,6 +7,8 @@ namespace nix {
 struct LocalBinaryCacheStoreConfig : virtual BinaryCacheStoreConfig
 {
     using BinaryCacheStoreConfig::BinaryCacheStoreConfig;
+
+    const std::string name() override { return "Local Binary Cache Store"; }
 };
 
 class LocalBinaryCacheStore : public BinaryCacheStore, public virtual LocalBinaryCacheStoreConfig

src/libstore/local-store.hh

@@ -37,6 +37,8 @@ struct LocalStoreConfig : virtual LocalFSStoreConfig
     Setting<bool> requireSigs{(StoreConfig*) this,
         settings.requireSigs,
         "require-sigs", "whether store paths should have a trusted signature on import"};
+
+    const std::string name() override { return "Local Store"; }
 };
 
 

src/libstore/remote-store.hh

@@ -158,6 +158,8 @@ struct UDSRemoteStoreConfig : virtual LocalFSStoreConfig, virtual RemoteStoreCon
         : UDSRemoteStoreConfig(Store::Params({}))
     {
     }
+
+    const std::string name() override { return "Local Daemon Store"; }
 };
 
 class UDSRemoteStore : public LocalFSStore, public RemoteStore, public virtual UDSRemoteStoreConfig

src/libstore/s3-binary-cache-store.cc

@@ -186,6 +186,8 @@ struct S3BinaryCacheStoreConfig : virtual BinaryCacheStoreConfig
         this, false, "multipart-upload", "whether to use multi-part uploads"};
     const Setting<uint64_t> bufferSize{
         this, 5 * 1024 * 1024, "buffer-size", "size (in bytes) of each part in multi-part uploads"};
+
+    const std::string name() override { return "S3 Binary Cache Store"; }
 };
 
 struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore, virtual S3BinaryCacheStoreConfig

src/libstore/ssh-store.cc

@@ -16,6 +16,8 @@ struct SSHStoreConfig : virtual RemoteStoreConfig
     const Setting<bool> compress{(StoreConfig*) this, false, "compress", "whether to compress the connection"};
     const Setting<Path> remoteProgram{(StoreConfig*) this, "nix-daemon", "remote-program", "path to the nix-daemon executable on the remote system"};
     const Setting<std::string> remoteStore{(StoreConfig*) this, "", "remote-store", "URI of the store on the remote system"};
+
+    const std::string name() override { return "SSH Store"; }
 };
 
 class SSHStore : public virtual RemoteStore, public virtual SSHStoreConfig

src/libstore/store-api.hh

@@ -194,6 +194,7 @@ struct StoreConfig : public Config
      */
     StoreConfig() { assert(false); }
 
+    virtual const std::string name() = 0;
 
     const PathSetting storeDir_{this, false, settings.nixStore,
         "store", "path to the Nix store"};

src/nix/describe-stores.cc

@@ -18,13 +18,14 @@ struct CmdDescribeStores : Command, MixJSON
 
     void run() override
     {
-
+        auto res = nlohmann::json::object();
-        if (json) {
-            auto res = nlohmann::json::array();
         for (auto & implem : *Implementations::registered) {
             auto storeConfig = implem.getConfig();
-                std::cout << storeConfig->toJSON().dump() << std::endl;
+            auto storeName = storeConfig->name();
+            res[storeName] = storeConfig->toJSON();
         }
+        if (json) {
+            std::cout << res;
         } else {
             throw Error("Only json is available for describe-stores");
         }