Move LockFile and related types to a separate file

src/libexpr/primops/flake.cc

@@ -1,4 +1,5 @@
 #include "flake.hh"
+#include "lockfile.hh"
 #include "primops.hh"
 #include "eval-inline.hh"
 #include "fetchGit.hh"
@@ -50,104 +51,6 @@ void writeRegistry(const FlakeRegistry & registry, const Path & path)
     writeFile(path, json.dump(4)); // The '4' is the number of spaces used in the indentation in the json file.
 }
 
-AbstractDep::AbstractDep(const nlohmann::json & json)
-    : ref(json["uri"])
-    , narHash(Hash((std::string) json["narHash"]))
-{
-    if (!ref.isImmutable())
-        throw Error("lockfile contains mutable flakeref '%s'", ref);
-}
-
-nlohmann::json AbstractDep::toJson() const
-{
-    nlohmann::json json;
-    json["uri"] = ref.to_string();
-    json["narHash"] = narHash.to_string(SRI);
-    return json;
-}
-
-Path AbstractDep::computeStorePath(Store & store) const
-{
-    return store.makeFixedOutputPath(true, narHash, "source");
-}
-
-FlakeDep::FlakeDep(const nlohmann::json & json)
-    : FlakeInputs(json)
-    , AbstractDep(json)
-    , id(json["id"])
-{
-}
-
-nlohmann::json FlakeDep::toJson() const
-{
-    auto json = FlakeInputs::toJson();
-    json.update(AbstractDep::toJson());
-    json["id"] = id;
-    return json;
-}
-
-FlakeInputs::FlakeInputs(const nlohmann::json & json)
-{
-    auto nonFlakeInputs = json["nonFlakeInputs"];
-    for (auto i = nonFlakeInputs.begin(); i != nonFlakeInputs.end(); ++i)
-        nonFlakeDeps.insert_or_assign(i.key(), NonFlakeDep(*i));
-
-    auto inputs = json["inputs"];
-    for (auto i = inputs.begin(); i != inputs.end(); ++i)
-        flakeDeps.insert_or_assign(i.key(), FlakeDep(*i));
-}
-
-nlohmann::json FlakeInputs::toJson() const
-{
-    nlohmann::json json;
-    {
-        auto j = nlohmann::json::object();
-        for (auto & i : nonFlakeDeps)
-            j[i.first] = i.second.toJson();
-        json["nonFlakeInputs"] = std::move(j);
-    }
-    {
-        auto j = nlohmann::json::object();
-        for (auto & i : flakeDeps)
-            j[i.first.to_string()] = i.second.toJson();
-        json["inputs"] = std::move(j);
-    }
-    return json;
-}
-
-nlohmann::json LockFile::toJson() const
-{
-    auto json = FlakeInputs::toJson();
-    json["version"] = 2;
-    return json;
-}
-
-LockFile readLockFile(const Path & path)
-{
-    if (pathExists(path)) {
-        auto json = nlohmann::json::parse(readFile(path));
-
-        auto version = json.value("version", 0);
-        if (version != 2)
-            throw Error("lock file '%s' has unsupported version %d", path, version);
-
-        return LockFile(json);
-    } else
-        return LockFile();
-}
-
-std::ostream & operator <<(std::ostream & stream, const LockFile & lockFile)
-{
-    stream << lockFile.toJson().dump(4); // '4' = indentation in json file
-    return stream;
-}
-
-void writeLockFile(const LockFile & lockFile, const Path & path)
-{
-    createDirs(dirOf(path));
-    writeFile(path, fmt("%s\n", lockFile));
-}
-
 Path getUserRegistryPath()
 {
     return getHome() + "/.config/nix/registry.json";
@@ -471,7 +374,7 @@ ResolvedFlake resolveFlake(EvalState & state, const FlakeRef & topRef, HandleLoc
     if (!recreateLockFile(handleLockFile)) {
         // If recreateLockFile, start with an empty lockfile
         // FIXME: symlink attack
-        oldLockFile = readLockFile(
+        oldLockFile = LockFile::read(
             state.store->toRealPath(flake.sourceInfo.storePath)
             + "/" + flake.sourceInfo.resolvedRef.subdir + "/flake.lock");
     }
@@ -483,7 +386,7 @@ ResolvedFlake resolveFlake(EvalState & state, const FlakeRef & topRef, HandleLoc
     if (!(lockFile == oldLockFile)) {
         if (allowedToWrite(handleLockFile)) {
             if (auto refData = std::get_if<FlakeRef::IsPath>(&topRef.data)) {
-                writeLockFile(lockFile, refData->path + (topRef.subdir == "" ? "" : "/" + topRef.subdir) + "/flake.lock");
+                lockFile.write(refData->path + (topRef.subdir == "" ? "" : "/" + topRef.subdir) + "/flake.lock");
 
                 // Hack: Make sure that flake.lock is visible to Git, so it ends up in the Nix store.
                 runProgram("git", true, { "-C", refData->path, "add",

src/libexpr/primops/flake.hh

@@ -2,15 +2,12 @@
 
 #include "types.hh"
 #include "flakeref.hh"
-
+#include "lockfile.hh"
-#include <variant>
-#include <nlohmann/json.hpp>
 
 namespace nix {
 
 struct Value;
 class EvalState;
-class Store;
 
 namespace flake {
 
@@ -40,86 +37,6 @@ enum HandleLockFile : unsigned int
     , UseNewLockFile // `RecreateLockFile` without writing to file
     };
 
-struct AbstractDep
-{
-    FlakeRef ref;
-    Hash narHash;
-
-    AbstractDep(const FlakeRef & flakeRef, const Hash & narHash)
-        : ref(flakeRef), narHash(narHash) {};
-
-    AbstractDep(const nlohmann::json & json);
-
-    nlohmann::json toJson() const;
-
-    Path computeStorePath(Store & store) const;
-};
-
-struct NonFlakeDep : AbstractDep
-{
-    using AbstractDep::AbstractDep;
-
-    bool operator ==(const NonFlakeDep & other) const
-    {
-        return ref == other.ref && narHash == other.narHash;
-    }
-};
-
-struct FlakeDep;
-
-struct FlakeInputs
-{
-    std::map<FlakeRef, FlakeDep> flakeDeps;
-    std::map<FlakeAlias, NonFlakeDep> nonFlakeDeps;
-
-    FlakeInputs() {};
-    FlakeInputs(const nlohmann::json & json);
-
-    nlohmann::json toJson() const;
-};
-
-struct FlakeDep : FlakeInputs, AbstractDep
-{
-    FlakeId id;
-
-    FlakeDep(const FlakeId & id, const FlakeRef & flakeRef, const Hash & narHash)
-        : AbstractDep(flakeRef, narHash), id(id) {};
-
-    FlakeDep(const nlohmann::json & json);
-
-    bool operator ==(const FlakeDep & other) const
-    {
-        return
-            id == other.id
-            && ref == other.ref
-            && narHash == other.narHash
-            && flakeDeps == other.flakeDeps
-            && nonFlakeDeps == other.nonFlakeDeps;
-    }
-
-    nlohmann::json toJson() const;
-};
-
-struct LockFile : FlakeInputs
-{
-    bool operator ==(const LockFile & other) const
-    {
-        return
-            flakeDeps == other.flakeDeps
-            && nonFlakeDeps == other.nonFlakeDeps;
-    }
-
-    LockFile() {}
-    LockFile(const nlohmann::json & json) : FlakeInputs(json) {}
-    LockFile(FlakeDep && dep)
-    {
-        flakeDeps = std::move(dep.flakeDeps);
-        nonFlakeDeps = std::move(dep.nonFlakeDeps);
-    }
-
-    nlohmann::json toJson() const;
-};
-
 struct SourceInfo
 {
     // Immutable flakeref that this source tree was obtained from.

src/libexpr/primops/lockfile.cc

@@ -0,0 +1,104 @@
+#include "lockfile.hh"
+#include "store-api.hh"
+
+namespace nix::flake {
+
+AbstractDep::AbstractDep(const nlohmann::json & json)
+    : ref(json["uri"])
+    , narHash(Hash((std::string) json["narHash"]))
+{
+    if (!ref.isImmutable())
+        throw Error("lockfile contains mutable flakeref '%s'", ref);
+}
+
+nlohmann::json AbstractDep::toJson() const
+{
+    nlohmann::json json;
+    json["uri"] = ref.to_string();
+    json["narHash"] = narHash.to_string(SRI);
+    return json;
+}
+
+Path AbstractDep::computeStorePath(Store & store) const
+{
+    return store.makeFixedOutputPath(true, narHash, "source");
+}
+
+FlakeDep::FlakeDep(const nlohmann::json & json)
+    : FlakeInputs(json)
+    , AbstractDep(json)
+    , id(json["id"])
+{
+}
+
+nlohmann::json FlakeDep::toJson() const
+{
+    auto json = FlakeInputs::toJson();
+    json.update(AbstractDep::toJson());
+    json["id"] = id;
+    return json;
+}
+
+FlakeInputs::FlakeInputs(const nlohmann::json & json)
+{
+    auto nonFlakeInputs = json["nonFlakeInputs"];
+    for (auto i = nonFlakeInputs.begin(); i != nonFlakeInputs.end(); ++i)
+        nonFlakeDeps.insert_or_assign(i.key(), NonFlakeDep(*i));
+
+    auto inputs = json["inputs"];
+    for (auto i = inputs.begin(); i != inputs.end(); ++i)
+        flakeDeps.insert_or_assign(i.key(), FlakeDep(*i));
+}
+
+nlohmann::json FlakeInputs::toJson() const
+{
+    nlohmann::json json;
+    {
+        auto j = nlohmann::json::object();
+        for (auto & i : nonFlakeDeps)
+            j[i.first] = i.second.toJson();
+        json["nonFlakeInputs"] = std::move(j);
+    }
+    {
+        auto j = nlohmann::json::object();
+        for (auto & i : flakeDeps)
+            j[i.first.to_string()] = i.second.toJson();
+        json["inputs"] = std::move(j);
+    }
+    return json;
+}
+
+nlohmann::json LockFile::toJson() const
+{
+    auto json = FlakeInputs::toJson();
+    json["version"] = 2;
+    return json;
+}
+
+LockFile LockFile::read(const Path & path)
+{
+    if (pathExists(path)) {
+        auto json = nlohmann::json::parse(readFile(path));
+
+        auto version = json.value("version", 0);
+        if (version != 2)
+            throw Error("lock file '%s' has unsupported version %d", path, version);
+
+        return LockFile(json);
+    } else
+        return LockFile();
+}
+
+std::ostream & operator <<(std::ostream & stream, const LockFile & lockFile)
+{
+    stream << lockFile.toJson().dump(4); // '4' = indentation in json file
+    return stream;
+}
+
+void LockFile::write(const Path & path) const
+{
+    createDirs(dirOf(path));
+    writeFile(path, fmt("%s\n", *this));
+}
+
+}

src/libexpr/primops/lockfile.hh

@@ -0,0 +1,110 @@
+#pragma once
+
+#include "flakeref.hh"
+
+#include <nlohmann/json.hpp>
+
+namespace nix {
+class Store;
+}
+
+namespace nix::flake {
+
+/* Common lock file information about a flake input, namely the
+   immutable ref and the NAR hash. */
+struct AbstractDep
+{
+    FlakeRef ref;
+    Hash narHash;
+
+    AbstractDep(const FlakeRef & flakeRef, const Hash & narHash)
+        : ref(flakeRef), narHash(narHash)
+    {
+        assert(ref.isImmutable());
+    };
+
+    AbstractDep(const nlohmann::json & json);
+
+    nlohmann::json toJson() const;
+
+    Path computeStorePath(Store & store) const;
+};
+
+/* Lock file information about a non-flake input. */
+struct NonFlakeDep : AbstractDep
+{
+    using AbstractDep::AbstractDep;
+
+    bool operator ==(const NonFlakeDep & other) const
+    {
+        return ref == other.ref && narHash == other.narHash;
+    }
+};
+
+struct FlakeDep;
+
+/* Lock file information about the dependencies of a flake. */
+struct FlakeInputs
+{
+    std::map<FlakeRef, FlakeDep> flakeDeps;
+    std::map<FlakeAlias, NonFlakeDep> nonFlakeDeps;
+
+    FlakeInputs() {};
+    FlakeInputs(const nlohmann::json & json);
+
+    nlohmann::json toJson() const;
+};
+
+/* Lock file information about a flake input. */
+struct FlakeDep : FlakeInputs, AbstractDep
+{
+    FlakeId id;
+
+    FlakeDep(const FlakeId & id, const FlakeRef & flakeRef, const Hash & narHash)
+        : AbstractDep(flakeRef, narHash), id(id) {};
+
+    FlakeDep(const nlohmann::json & json);
+
+    bool operator ==(const FlakeDep & other) const
+    {
+        return
+            id == other.id
+            && ref == other.ref
+            && narHash == other.narHash
+            && flakeDeps == other.flakeDeps
+            && nonFlakeDeps == other.nonFlakeDeps;
+    }
+
+    nlohmann::json toJson() const;
+};
+
+/* An entire lock file. Note that this cannot be a FlakeDep for the
+   top-level flake, because then the lock file would need to contain
+   the hash of the top-level flake, but committing the lock file
+   would invalidate that hash. */
+struct LockFile : FlakeInputs
+{
+    bool operator ==(const LockFile & other) const
+    {
+        return
+            flakeDeps == other.flakeDeps
+            && nonFlakeDeps == other.nonFlakeDeps;
+    }
+
+    LockFile() {}
+    LockFile(const nlohmann::json & json) : FlakeInputs(json) {}
+    LockFile(FlakeDep && dep)
+    {
+        flakeDeps = std::move(dep.flakeDeps);
+        nonFlakeDeps = std::move(dep.nonFlakeDeps);
+    }
+
+    nlohmann::json toJson() const;
+
+    static LockFile read(const Path & path);
+
+    void write(const Path & path) const;
+};
+
+}
+