Add start of 'nix profile' command

src/nix/command.cc

@@ -123,4 +123,9 @@ void MixProfile::updateProfile(const Buildables & buildables)
     updateProfile(*result);
 }
 
+MixDefaultProfile::MixDefaultProfile()
+{
+    profile = getDefaultProfile();
+}
+
 }

src/nix/command.hh

@@ -188,4 +188,9 @@ struct MixProfile : virtual Args, virtual StoreCommand
     void updateProfile(const Buildables & buildables);
 };
 
+struct MixDefaultProfile : MixProfile
+{
+    MixDefaultProfile();
+};
+
 }

src/nix/flake.cc

@@ -653,6 +653,7 @@ struct CmdFlake : virtual MultiCommand, virtual Command
     {
         if (!command)
             throw UsageError("'nix flake' requires a sub-command.");
+        command->prepare();
         command->run();
     }
 

src/nix/installables.cc

@@ -294,7 +294,7 @@ Value * InstallableFlake::getFlakeOutputs(EvalState & state, const flake::Resolv
     return (*aOutputs)->value;
 }
 
-std::vector<flake::EvalCache::Derivation> InstallableFlake::toDerivations()
+std::tuple<std::string, FlakeRef, flake::EvalCache::Derivation> InstallableFlake::toDerivation()
 {
     auto state = cmd.getEvalState();
 
@@ -312,7 +312,7 @@ std::vector<flake::EvalCache::Derivation> InstallableFlake::toDerivations()
         auto drv = evalCache.getDerivation(fingerprint, attrPath);
         if (drv) {
             if (state->store->isValidPath(drv->drvPath))
-                return {*drv};
+                return {attrPath, resFlake.flake.sourceInfo.resolvedRef, *drv};
         }
 
         if (!vOutputs)
@@ -334,7 +334,7 @@ std::vector<flake::EvalCache::Derivation> InstallableFlake::toDerivations()
 
             evalCache.addDerivation(fingerprint, attrPath, drv);
 
-            return {drv};
+            return {attrPath, resFlake.flake.sourceInfo.resolvedRef, drv};
         } catch (AttrPathNotFound & e) {
         }
     }
@@ -343,6 +343,11 @@ std::vector<flake::EvalCache::Derivation> InstallableFlake::toDerivations()
         flakeRef, concatStringsSep(", ", quoteStrings(attrPaths)));
 }
 
+std::vector<flake::EvalCache::Derivation> InstallableFlake::toDerivations()
+{
+    return {std::get<2>(toDerivation())};
+}
+
 Value * InstallableFlake::toValue(EvalState & state)
 {
     auto resFlake = resolveFlake(state, flakeRef, cmd.getLockFileMode());

src/nix/installables.hh

@@ -8,6 +8,7 @@
 namespace nix {
 
 struct Value;
+struct DrvInfo;
 class EvalState;
 class SourceExprCommand;
 
@@ -89,6 +90,8 @@ struct InstallableFlake : InstallableValue
 
     Value * getFlakeOutputs(EvalState & state, const flake::ResolvedFlake & resFlake);
 
+    std::tuple<std::string, FlakeRef, flake::EvalCache::Derivation> toDerivation();
+
     std::vector<flake::EvalCache::Derivation> toDerivations() override;
 
     Value * toValue(EvalState & state) override;

src/nix/profile.cc

@@ -0,0 +1,234 @@
+#include "command.hh"
+#include "common-args.hh"
+#include "shared.hh"
+#include "store-api.hh"
+#include "derivations.hh"
+#include "archive.hh"
+#include "builtins/buildenv.hh"
+#include "flake/flakeref.hh"
+
+#include <nlohmann/json.hpp>
+
+using namespace nix;
+
+struct ProfileElementSource
+{
+    FlakeRef originalRef;
+    FlakeRef resolvedRef;
+    std::string attrPath;
+    // FIXME: output names
+};
+
+struct ProfileElement
+{
+    PathSet storePaths;
+    std::optional<ProfileElementSource> source;
+    bool active = true;
+    // FIXME: priority
+};
+
+struct ProfileManifest
+{
+    std::vector<ProfileElement> elements;
+
+    ProfileManifest(const Path & profile)
+    {
+        auto manifestPath = profile + "/manifest.json";
+
+        if (pathExists(manifestPath)) {
+            auto json = nlohmann::json::parse(readFile(manifestPath));
+
+            auto version = json.value("version", 0);
+            if (version != 1)
+                throw Error("profile manifest '%s' has unsupported version %d", manifestPath, version);
+
+            for (auto & e : json["elements"]) {
+                ProfileElement element;
+                for (auto & p : e["storePaths"])
+                    element.storePaths.insert((std::string) p);
+                element.active = e["active"];
+                if (e.value("uri", "") != "") {
+                    element.source = ProfileElementSource{
+                        FlakeRef(e["originalUri"]),
+                        FlakeRef(e["uri"]),
+                        e["attrPath"]
+                    };
+                }
+                elements.emplace_back(std::move(element));
+            }
+        }
+    }
+
+    std::string toJSON() const
+    {
+        auto array = nlohmann::json::array();
+        for (auto & element : elements) {
+            auto paths = nlohmann::json::array();
+            for (auto & path : element.storePaths)
+                paths.push_back(path);
+            nlohmann::json obj;
+            obj["storePaths"] = paths;
+            obj["active"] = element.active;
+            if (element.source) {
+                obj["originalUri"] = element.source->originalRef.to_string();
+                obj["uri"] = element.source->resolvedRef.to_string();
+                obj["attrPath"] = element.source->attrPath;
+            }
+            array.push_back(obj);
+        }
+        nlohmann::json json;
+        json["version"] = 1;
+        json["elements"] = array;
+        return json.dump();
+    }
+
+    Path build(ref<Store> store)
+    {
+        auto tempDir = createTempDir();
+
+        ValidPathInfo info;
+
+        Packages pkgs;
+        for (auto & element : elements) {
+            for (auto & path : element.storePaths) {
+                if (element.active)
+                    pkgs.emplace_back(path, true, 5);
+                info.references.insert(path);
+            }
+        }
+
+        buildProfile(tempDir, std::move(pkgs));
+
+        writeFile(tempDir + "/manifest.json", toJSON());
+
+        /* Add the symlink tree to the store. */
+        StringSink sink;
+        dumpPath(tempDir, sink);
+
+        info.narHash = hashString(htSHA256, *sink.s);
+        info.narSize = sink.s->size();
+        info.path = store->makeFixedOutputPath(true, info.narHash, "profile", info.references);
+        info.ca = makeFixedOutputCA(true, info.narHash);
+
+        store->addToStore(info, sink.s);
+
+        return info.path;
+    }
+};
+
+struct CmdProfileInstall : InstallablesCommand, MixDefaultProfile
+{
+    std::string description() override
+    {
+        return "install a package into a profile";
+    }
+
+    Examples examples() override
+    {
+        return {
+            Example{
+                "To install a package from Nixpkgs:",
+                "nix profile install nixpkgs#hello"
+            },
+            Example{
+                "To install a package from a specific branch of Nixpkgs:",
+                "nix profile install nixpkgs/release-19.09#hello"
+            },
+            Example{
+                "To install a package from a specific revision of Nixpkgs:",
+                "nix profile install nixpkgs/1028bb33859f8dfad7f98e1c8d185f3d1aaa7340#hello"
+            },
+        };
+    }
+
+    void run(ref<Store> store) override
+    {
+        ProfileManifest manifest(*profile);
+
+        PathSet pathsToBuild;
+
+        for (auto & installable : installables) {
+            if (auto installable2 = std::dynamic_pointer_cast<InstallableFlake>(installable)) {
+                auto [attrPath, resolvedRef, drv] = installable2->toDerivation();
+
+                ProfileElement element;
+                element.storePaths = {drv.outPath}; // FIXME
+                element.source = ProfileElementSource{
+                    installable2->flakeRef,
+                    resolvedRef,
+                    attrPath,
+                };
+
+                pathsToBuild.insert(makeDrvPathWithOutputs(drv.drvPath, {"out"})); // FIXME
+
+                manifest.elements.emplace_back(std::move(element));
+            } else
+                throw Error("'nix profile install' does not support argument '%s'", installable->what());
+        }
+
+        store->buildPaths(pathsToBuild);
+
+        updateProfile(manifest.build(store));
+    }
+};
+
+struct CmdProfileInfo : virtual StoreCommand, MixDefaultProfile
+{
+    std::string description() override
+    {
+        return "info";
+    }
+
+    Examples examples() override
+    {
+        return {
+            Example{
+                "To show what packages are installed in the default profile:",
+                "nix profile info"
+            },
+        };
+    }
+
+    void run(ref<Store> store) override
+    {
+        ProfileManifest manifest(*profile);
+
+        for (auto & element : manifest.elements) {
+            std::cout << fmt("%s %s\n",
+                element.source ? element.source->originalRef.to_string() + "#" + element.source->attrPath : "-",
+                element.source ? element.source->resolvedRef.to_string() + "#" + element.source->attrPath : "-",
+                concatStringsSep(" ", element.storePaths));
+        }
+    }
+};
+
+struct CmdProfile : virtual MultiCommand, virtual Command
+{
+    CmdProfile()
+        : MultiCommand({
+              {"install", []() { return make_ref<CmdProfileInstall>(); }},
+              {"info", []() { return make_ref<CmdProfileInfo>(); }},
+          })
+    { }
+
+    std::string description() override
+    {
+        return "manage Nix profiles";
+    }
+
+    void run() override
+    {
+        if (!command)
+            throw UsageError("'nix profile' requires a sub-command.");
+        command->prepare();
+        command->run();
+    }
+
+    void printHelp(const string & programName, std::ostream & out) override
+    {
+        MultiCommand::printHelp(programName, out);
+    }
+};
+
+static auto r1 = registerCommand<CmdProfile>("profile");
+