Replace src/libutil/json.cc with nlohmann json generation

9 files changed, 57 insertions, 76 deletions

diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index a26770c79..12d0c32fb 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -9,7 +9,6 @@
 #include "remote-fs-accessor.hh"
 #include "nar-info-disk-cache.hh"
 #include "nar-accessor.hh"
-#include "json.hh"
 #include "thread-pool.hh"
 #include "callback.hh"
 
@@ -194,19 +193,12 @@ ref<const ValidPathInfo> BinaryCacheStore::addToStoreCommon(
     /* Optionally write a JSON file containing a listing of the
        contents of the NAR. */
     if (writeNARListing) {
-        std::ostringstream jsonOut;
-
-        {
-            JSONObject jsonRoot(jsonOut);
-            jsonRoot.attr("version", 1);
-
-            {
-                auto res = jsonRoot.placeholder("root");
-                listNar(res, ref<FSAccessor>(narAccessor), "", true);
-            }
-        }
+        nlohmann::json j = {
+            {"version", 1},
+            {"root", listNar(ref<FSAccessor>(narAccessor), "", true)},
+        };
 
-        upsertFile(std::string(info.path.hashPart()) + ".ls", jsonOut.str(), "application/json");
+        upsertFile(std::string(info.path.hashPart()) + ".ls", j.dump(), "application/json");
     }
 
     /* Optionally maintain an index of DWARF debug info files
diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index 00e375fe9..1938f4bcb 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -7,7 +7,6 @@
 #include "finally.hh"
 #include "util.hh"
 #include "archive.hh"
-#include "json.hh"
 #include "compression.hh"
 #include "worker-protocol.hh"
 #include "topo-sort.hh"
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 5cea3b590..c786e8613 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -8,7 +8,6 @@
 #include "finally.hh"
 #include "util.hh"
 #include "archive.hh"
-#include "json.hh"
 #include "compression.hh"
 #include "daemon.hh"
 #include "worker-protocol.hh"
@@ -56,6 +55,7 @@
 
 #include <pwd.h>
 #include <grp.h>
+#include <iostream>
 
 namespace nix {
 
diff --git a/src/libstore/nar-accessor.cc b/src/libstore/nar-accessor.cc
index 398147fc3..9a0003588 100644
--- a/src/libstore/nar-accessor.cc
+++ b/src/libstore/nar-accessor.cc
@@ -1,6 +1,5 @@
 #include "nar-accessor.hh"
 #include "archive.hh"
-#include "json.hh"
 
 #include <map>
 #include <stack>
@@ -243,42 +242,43 @@ ref<FSAccessor> makeLazyNarAccessor(const std::string & listing,
     return make_ref<NarAccessor>(listing, getNarBytes);
 }
 
-void listNar(JSONPlaceholder & res, ref<FSAccessor> accessor,
-    const Path & path, bool recurse)
+using nlohmann::json;
+json listNar(ref<FSAccessor> accessor, const Path & path, bool recurse)
 {
     auto st = accessor->stat(path);
 
-    auto obj = res.object();
+    json obj = json::object();
 
     switch (st.type) {
     case FSAccessor::Type::tRegular:
-        obj.attr("type", "regular");
-        obj.attr("size", st.fileSize);
+        obj["type"] = "regular";
+        obj["size"] = st.fileSize;
         if (st.isExecutable)
-            obj.attr("executable", true);
+            obj["executable"] = true;
         if (st.narOffset)
-            obj.attr("narOffset", st.narOffset);
+            obj["narOffset"] = st.narOffset;
         break;
     case FSAccessor::Type::tDirectory:
-        obj.attr("type", "directory");
+        obj["type"] = "directory";
         {
-            auto res2 = obj.object("entries");
+            obj["entries"] = json::object();
+            json &res2 = obj["entries"];
             for (auto & name : accessor->readDirectory(path)) {
                 if (recurse) {
-                    auto res3 = res2.placeholder(name);
-                    listNar(res3, accessor, path + "/" + name, true);
+                    res2[name] = listNar(accessor, path + "/" + name, true);
                 } else
-                    res2.object(name);
+                    res2[name] = json::object();
             }
         }
         break;
     case FSAccessor::Type::tSymlink:
-        obj.attr("type", "symlink");
-        obj.attr("target", accessor->readLink(path));
+        obj["type"] = "symlink";
+        obj["target"] = accessor->readLink(path);
         break;
     default:
         throw Error("path '%s' does not exist in NAR", path);
     }
+    return obj;
 }
 
 }
diff --git a/src/libstore/nar-accessor.hh b/src/libstore/nar-accessor.hh
index c2241a04c..7d998ae0b 100644
--- a/src/libstore/nar-accessor.hh
+++ b/src/libstore/nar-accessor.hh
@@ -2,6 +2,7 @@
 
 #include <functional>
 
+#include <nlohmann/json_fwd.hpp>
 #include "fs-accessor.hh"
 
 namespace nix {
@@ -24,11 +25,8 @@ ref<FSAccessor> makeLazyNarAccessor(
     const std::string & listing,
     GetNarBytes getNarBytes);
 
-class JSONPlaceholder;
-
 /* Write a JSON representation of the contents of a NAR (except file
    contents). */
-void listNar(JSONPlaceholder & res, ref<FSAccessor> accessor,
-    const Path & path, bool recurse);
+nlohmann::json listNar(ref<FSAccessor> accessor, const Path & path, bool recurse);
 
 }
diff --git a/src/libstore/parsed-derivations.cc b/src/libstore/parsed-derivations.cc
index f2288a04e..59a30db10 100644
--- a/src/libstore/parsed-derivations.cc
+++ b/src/libstore/parsed-derivations.cc
@@ -2,7 +2,6 @@
 
 #include <nlohmann/json.hpp>
 #include <regex>
-#include "json.hh"
 
 namespace nix {
 
@@ -144,16 +143,11 @@ std::optional<nlohmann::json> ParsedDerivation::prepareStructuredAttrs(Store & s
     auto e = json.find("exportReferencesGraph");
     if (e != json.end() && e->is_object()) {
         for (auto i = e->begin(); i != e->end(); ++i) {
-            std::ostringstream str;
-            {
-                JSONPlaceholder jsonRoot(str, true);
-                StorePathSet storePaths;
-                for (auto & p : *i)
-                    storePaths.insert(store.parseStorePath(p.get<std::string>()));
-                store.pathInfoToJSON(jsonRoot,
-                    store.exportReferences(storePaths, inputPaths), false, true);
-            }
-            json[i.key()] = nlohmann::json::parse(str.str()); // urgh
+            StorePathSet storePaths;
+            for (auto & p : *i)
+                storePaths.insert(store.parseStorePath(p.get<std::string>()));
+            json[i.key()] = store.pathInfoToJSON(
+                store.exportReferences(storePaths, inputPaths), false, true);
         }
     }
 
diff --git a/src/libstore/remote-fs-accessor.cc b/src/libstore/remote-fs-accessor.cc
index 0ce335646..fcfb527f5 100644
--- a/src/libstore/remote-fs-accessor.cc
+++ b/src/libstore/remote-fs-accessor.cc
@@ -1,6 +1,6 @@
+#include <nlohmann/json.hpp>
 #include "remote-fs-accessor.hh"
 #include "nar-accessor.hh"
-#include "json.hh"
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -38,10 +38,8 @@ ref<FSAccessor> RemoteFSAccessor::addToCache(std::string_view hashPart, std::str
 
     if (cacheDir != "") {
         try {
-            std::ostringstream str;
-            JSONPlaceholder jsonRoot(str);
-            listNar(jsonRoot, narAccessor, "", true);
-            writeFile(makeCacheFile(hashPart, "ls"), str.str());
+            nlohmann::json j = listNar(narAccessor, "", true);
+            writeFile(makeCacheFile(hashPart, "ls"), j.dump());
         } catch (...) {
             ignoreException();
         }
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 06a9758fc..8811ab578 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -6,14 +6,16 @@
 #include "util.hh"
 #include "nar-info-disk-cache.hh"
 #include "thread-pool.hh"
-#include "json.hh"
 #include "url.hh"
 #include "archive.hh"
 #include "callback.hh"
 #include "remote-store.hh"
 
+#include <nlohmann/json.hpp>
 #include <regex>
 
+using json = nlohmann::json;
+
 namespace nix {
 
 
@@ -838,56 +840,53 @@ StorePathSet Store::exportReferences(const StorePathSet & storePaths, const Stor
     return paths;
 }
 
-
-void Store::pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & storePaths,
+json Store::pathInfoToJSON(const StorePathSet & storePaths,
     bool includeImpureInfo, bool showClosureSize,
     Base hashBase,
     AllowInvalidFlag allowInvalid)
 {
-    auto jsonList = jsonOut.list();
+    json::array_t jsonList = json::array();
 
     for (auto & storePath : storePaths) {
-        auto jsonPath = jsonList.object();
+        auto& jsonPath = jsonList.emplace_back(json::object());
 
         try {
             auto info = queryPathInfo(storePath);
 
-            jsonPath.attr("path", printStorePath(info->path));
-            jsonPath
-                .attr("narHash", info->narHash.to_string(hashBase, true))
-                .attr("narSize", info->narSize);
+            jsonPath["path"] = printStorePath(info->path);
+            jsonPath["narHash"] = info->narHash.to_string(hashBase, true);
+            jsonPath["narSize"] = info->narSize;
 
             {
-                auto jsonRefs = jsonPath.list("references");
+                auto& jsonRefs = (jsonPath["references"] = json::array());
                 for (auto & ref : info->references)
-                    jsonRefs.elem(printStorePath(ref));
+                    jsonRefs.emplace_back(printStorePath(ref));
             }
 
             if (info->ca)
-                jsonPath.attr("ca", renderContentAddress(info->ca));
+                jsonPath["ca"] = renderContentAddress(info->ca);
 
             std::pair<uint64_t, uint64_t> closureSizes;
 
             if (showClosureSize) {
                 closureSizes = getClosureSize(info->path);
-                jsonPath.attr("closureSize", closureSizes.first);
+                jsonPath["closureSize"] = closureSizes.first;
             }
 
             if (includeImpureInfo) {
 
                 if (info->deriver)
-                    jsonPath.attr("deriver", printStorePath(*info->deriver));
+                    jsonPath["deriver"] = printStorePath(*info->deriver);
 
                 if (info->registrationTime)
-                    jsonPath.attr("registrationTime", info->registrationTime);
+                    jsonPath["registrationTime"] = info->registrationTime;
 
                 if (info->ultimate)
-                    jsonPath.attr("ultimate", info->ultimate);
+                    jsonPath["ultimate"] = info->ultimate;
 
                 if (!info->sigs.empty()) {
-                    auto jsonSigs = jsonPath.list("signatures");
                     for (auto & sig : info->sigs)
-                        jsonSigs.elem(sig);
+                        jsonPath["signatures"].push_back(sig);
                 }
 
                 auto narInfo = std::dynamic_pointer_cast<const NarInfo>(
@@ -895,21 +894,22 @@ void Store::pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & store
 
                 if (narInfo) {
                     if (!narInfo->url.empty())
-                        jsonPath.attr("url", narInfo->url);
+                        jsonPath["url"] = narInfo->url;
                     if (narInfo->fileHash)
-                        jsonPath.attr("downloadHash", narInfo->fileHash->to_string(hashBase, true));
+                        jsonPath["downloadHash"] = narInfo->fileHash->to_string(hashBase, true);
                     if (narInfo->fileSize)
-                        jsonPath.attr("downloadSize", narInfo->fileSize);
+                        jsonPath["downloadSize"] = narInfo->fileSize;
                     if (showClosureSize)
-                        jsonPath.attr("closureDownloadSize", closureSizes.second);
+                        jsonPath["closureDownloadSize"] = closureSizes.second;
                 }
             }
 
         } catch (InvalidPath &) {
-            jsonPath.attr("path", printStorePath(storePath));
-            jsonPath.attr("valid", false);
+            jsonPath["path"] = printStorePath(storePath);
+            jsonPath["valid"] = false;
         }
     }
+    return jsonList;
 }
 
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index c8a667c6d..151ec10d6 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -14,6 +14,7 @@
 #include "path-info.hh"
 #include "repair-flag.hh"
 
+#include <nlohmann/json_fwd.hpp>
 #include <atomic>
 #include <limits>
 #include <map>
@@ -68,7 +69,6 @@ struct Derivation;
 class FSAccessor;
 class NarInfoDiskCache;
 class Store;
-class JSONPlaceholder;
 
 
 enum CheckSigsFlag : bool { NoCheckSigs = false, CheckSigs = true };
@@ -512,7 +512,7 @@ public:
        variable elements such as the registration time are
        included. If ‘showClosureSize’ is true, the closure size of
        each path is included. */
-    void pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & storePaths,
+    nlohmann::json pathInfoToJSON(const StorePathSet & storePaths,
         bool includeImpureInfo, bool showClosureSize,
         Base hashBase = Base32,
         AllowInvalidFlag allowInvalid = DisallowInvalid);