NixOS · Apr 16, 2020 · Apr 16, 2020 · Apr 16, 2020 · Apr 16, 2020 · Apr 16, 2020
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
@@ -22,6 +22,8 @@
 
 #if HAVE_BOEHMGC
 
+#define GC_INCLUDE_NEW
+
 #include <gc/gc.h>
 #include <gc/gc_cpp.h>
 
@@ -56,6 +58,12 @@ static char * dupStringWithLen(const char * s, size_t size)
 }
 
 
+RootValue allocRootValue(Value * v)
+{
+    return std::allocate_shared<Value *>(traceable_allocator<Value *>(), v);
+}
+
+
 static void printValue(std::ostream & str, std::set<const Value *> & active, const Value & v)
 {
     checkInterrupt();

diff --git a/src/libexpr/json-to-value.cc b/src/libexpr/json-to-value.cc
@@ -4,7 +4,6 @@
 #include <nlohmann/json.hpp>
 
 using json = nlohmann::json;
-using std::unique_ptr;
 
 namespace nix {
 
@@ -13,69 +12,69 @@ namespace nix {
 class JSONSax : nlohmann::json_sax<json> {
     class JSONState {
     protected:
-        unique_ptr<JSONState> parent;
-        Value * v;
+        std::unique_ptr<JSONState> parent;
+        RootValue v;
     public:
-        virtual unique_ptr<JSONState> resolve(EvalState &)
+        virtual std::unique_ptr<JSONState> resolve(EvalState &)
         {
             throw std::logic_error("tried to close toplevel json parser state");
-        };
-        explicit JSONState(unique_ptr<JSONState>&& p) : parent(std::move(p)), v(nullptr) {};
-        explicit JSONState(Value* v) : v(v) {};
-        JSONState(JSONState& p) = delete;
-        Value& value(EvalState & state)
+        }
+        explicit JSONState(std::unique_ptr<JSONState> && p) : parent(std::move(p)) {}
+        explicit JSONState(Value * v) : v(allocRootValue(v)) {}
+        JSONState(JSONState & p) = delete;
+        Value & value(EvalState & state)
         {
-            if (v == nullptr)
-                v = state.allocValue();
-            return *v;
-        };
-        virtual ~JSONState() {};
-        virtual void add() {};
+            if (!v)
+                v = allocRootValue(state.allocValue());
+            return **v;
+        }
+        virtual ~JSONState() {}
+        virtual void add() {}
     };
 
     class JSONObjectState : public JSONState {
         using JSONState::JSONState;
-        ValueMap attrs = ValueMap();
-        virtual unique_ptr<JSONState> resolve(EvalState & state) override
+        ValueMap attrs;
+        std::unique_ptr<JSONState> resolve(EvalState & state) override
         {
-            Value& v = parent->value(state);
+            Value & v = parent->value(state);
             state.mkAttrs(v, attrs.size());
             for (auto & i : attrs)
                 v.attrs->push_back(Attr(i.first, i.second));
             return std::move(parent);
         }
-        virtual void add() override { v = nullptr; };
+        void add() override { v = nullptr; }
     public:
-        void key(string_t& name, EvalState & state)
+        void key(string_t & name, EvalState & state)
         {
-            attrs[state.symbols.create(name)] = &value(state);
+            attrs.insert_or_assign(state.symbols.create(name), &value(state));
         }
     };
 
     class JSONListState : public JSONState {
-        ValueVector values = ValueVector();
-        virtual unique_ptr<JSONState> resolve(EvalState & state) override
+        ValueVector values;
+        std::unique_ptr<JSONState> resolve(EvalState & state) override
         {
-            Value& v = parent->value(state);
+            Value & v = parent->value(state);
             state.mkList(v, values.size());
             for (size_t n = 0; n < values.size(); ++n) {
                 v.listElems()[n] = values[n];
             }
             return std::move(parent);
         }
-        virtual void add() override {
-            values.push_back(v);
+        void add() override {
+            values.push_back(*v);
             v = nullptr;
-        };
+        }
     public:
-        JSONListState(unique_ptr<JSONState>&& p, std::size_t reserve) : JSONState(std::move(p))
+        JSONListState(std::unique_ptr<JSONState> && p, std::size_t reserve) : JSONState(std::move(p))
         {
             values.reserve(reserve);
         }
     };
 
     EvalState & state;
-    unique_ptr<JSONState> rs;
+    std::unique_ptr<JSONState> rs;
 
     template<typename T, typename... Args> inline bool handle_value(T f, Args... args)
     {
@@ -107,12 +106,12 @@ class JSONSax : nlohmann::json_sax<json> {
         return handle_value(mkInt, val);
     }
 
-    bool number_float(number_float_t val, const string_t& s)
+    bool number_float(number_float_t val, const string_t & s)
     {
         return handle_value(mkFloat, val);
     }
 
-    bool string(string_t& val)
+    bool string(string_t & val)
     {
         return handle_value<void(Value&, const char*)>(mkString, val.c_str());
     }
@@ -123,7 +122,7 @@ class JSONSax : nlohmann::json_sax<json> {
         return true;
     }
 
-    bool key(string_t& name)
+    bool key(string_t & name)
     {
         dynamic_cast<JSONObjectState*>(rs.get())->key(name, state);
         return true;

diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
@@ -121,16 +121,16 @@ static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args
         }
         w.attrs->sort();
 
-        static Value * fun = nullptr;
+        static RootValue fun;
         if (!fun) {
-            fun = state.allocValue();
+            fun = allocRootValue(state.allocValue());
             state.eval(state.parseExprFromString(
                 #include "imported-drv-to-derivation.nix.gen.hh"
-                , "/"), *fun);
+                , "/"), **fun);
         }
 
-        state.forceFunction(*fun, pos);
-        mkApp(v, *fun, w);
+        state.forceFunction(**fun, pos);
+        mkApp(v, **fun, w);
         state.forceAttrs(v, pos);
     } else {
         state.forceAttrs(*args[0]);

diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh
@@ -253,12 +253,17 @@ void mkPath(Value & v, const char * s);
 
 
 #if HAVE_BOEHMGC
-typedef std::vector<Value *, gc_allocator<Value *> > ValueVector;
-typedef std::map<Symbol, Value *, std::less<Symbol>, gc_allocator<std::pair<const Symbol, Value *> > > ValueMap;
+typedef std::vector<Value *, traceable_allocator<Value *> > ValueVector;
+typedef std::map<Symbol, Value *, std::less<Symbol>, traceable_allocator<std::pair<const Symbol, Value *> > > ValueMap;
 #else
 typedef std::vector<Value *> ValueVector;
 typedef std::map<Symbol, Value *> ValueMap;
 #endif
 
 
+/* A value allocated in traceable memory. */
+typedef std::shared_ptr<Value *> RootValue;
+
+RootValue allocRootValue(Value * v);
+
 }
diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
@@ -3,6 +3,7 @@
 
 #include <atomic>
 #include <nlohmann/json.hpp>
+#include <iostream>
 
 namespace nix {
 
@@ -24,6 +25,11 @@ void Logger::warn(const std::string & msg)
     log(lvlWarn, ANSI_YELLOW "warning:" ANSI_NORMAL " " + msg);
 }
 
+void Logger::writeToStdout(std::string_view s)
+{
+    std::cout << s << "\n";
+}
+
 class SimpleLogger : public Logger
 {
 public:

diff --git a/src/libutil/logging.hh b/src/libutil/logging.hh
@@ -78,6 +78,16 @@ public:
     virtual void stopActivity(ActivityId act) { };
 
     virtual void result(ActivityId act, ResultType type, const Fields & fields) { };
+
+    virtual void writeToStdout(std::string_view s);
+
+    template<typename... Args>
+    inline void stdout(const std::string & fs, const Args & ... args)
+    {
+        boost::format f(fs);
+        formatHelper(f, args...);
+        writeToStdout(f.str());
+    }
 };
 
 ActivityId getCurActivity();

diff --git a/src/nix/add-to-store.cc b/src/nix/add-to-store.cc
@@ -50,7 +50,7 @@ struct CmdAddToStore : MixDryRun, StoreCommand
         if (!dryRun)
             store->addToStore(info, sink.s);
 
-        std::cout << fmt("%s\n", store->printStorePath(info.path));
+        logger->stdout("%s", store->printStorePath(info.path));
     }
 };
 

diff --git a/src/nix/command.hh b/src/nix/command.hh
@@ -41,7 +41,7 @@ private:
 
     std::shared_ptr<EvalState> evalState;
 
-    std::shared_ptr<Value> vSourceExpr;
+    RootValue vSourceExpr;
 };
 
 enum RealiseMode { Build, NoBuild, DryRun };

diff --git a/src/nix/eval.cc b/src/nix/eval.cc
@@ -55,16 +55,15 @@ struct CmdEval : MixJSON, InstallableCommand
         auto v = installable->toValue(*state).first;
         PathSet context;
 
-        stopProgressBar();
-
         if (raw) {
+            stopProgressBar();
             std::cout << state->coerceToString(noPos, *v, context);
         } else if (json) {
             JSONPlaceholder jsonOut(std::cout);
             printValueAsJSON(*state, true, *v, jsonOut, context);
         } else {
             state->forceValueDeep(*v);
-            std::cout << *v << "\n";
+            logger->stdout("%s", *v);
         }
     }
 };

diff --git a/src/nix/hash.cc b/src/nix/hash.cc
@@ -60,8 +60,7 @@ struct CmdHash : Command
 
             Hash h = hashSink->finish().first;
             if (truncate && h.hashSize > 20) h = compressHash(h, 20);
-            std::cout << format("%1%\n") %
-                h.to_string(base, base == SRI);
+            logger->stdout(h.to_string(base, base == SRI));
         }
     }
 };
@@ -95,7 +94,7 @@ struct CmdToBase : Command
     void run() override
     {
         for (auto s : args)
-            std::cout << fmt("%s\n", Hash(s, ht).to_string(base, base == SRI));
+            logger->stdout(Hash(s, ht).to_string(base, base == SRI));
     }
 };
 

diff --git a/src/nix/installables.cc b/src/nix/installables.cc
@@ -8,8 +8,6 @@
 #include "store-api.hh"
 #include "shared.hh"
 
-#include <gc/gc.h>
-
 #include <regex>
 
 namespace nix {
@@ -27,27 +25,24 @@ SourceExprCommand::SourceExprCommand()
 
 Value * SourceExprCommand::getSourceExpr(EvalState & state)
 {
-    if (vSourceExpr) return vSourceExpr.get();
+    if (vSourceExpr) return *vSourceExpr;
 
     auto sToplevel = state.symbols.create("_toplevel");
 
-    // Allocate the vSourceExpr Value as uncollectable. Boehm GC doesn't
-    // consider the member variable "alive" during execution causing it to be
-    // GC'ed in the middle of evaluation.
-    vSourceExpr = std::allocate_shared<Value>(traceable_allocator<Value>());
+    vSourceExpr = allocRootValue(state.allocValue());
 
     if (file != "")
-        state.evalFile(lookupFileArg(state, file), *vSourceExpr);
+        state.evalFile(lookupFileArg(state, file), **vSourceExpr);
 
     else {
 
         /* Construct the installation source from $NIX_PATH. */
 
         auto searchPath = state.getSearchPath();
 
-        state.mkAttrs(*vSourceExpr, 1024);
+        state.mkAttrs(**vSourceExpr, 1024);
 
-        mkBool(*state.allocAttr(*vSourceExpr, sToplevel), true);
+        mkBool(*state.allocAttr(**vSourceExpr, sToplevel), true);
 
         std::unordered_set<std::string> seen;
 
@@ -58,7 +53,7 @@ Value * SourceExprCommand::getSourceExpr(EvalState & state)
             mkPrimOpApp(*v1, state.getBuiltin("findFile"), state.getBuiltin("nixPath"));
             Value * v2 = state.allocValue();
             mkApp(*v2, *v1, mkString(*state.allocValue(), name));
-            mkApp(*state.allocAttr(*vSourceExpr, state.symbols.create(name)),
+            mkApp(*state.allocAttr(**vSourceExpr, state.symbols.create(name)),
                 state.getBuiltin("import"), *v2);
         };
 
@@ -72,10 +67,10 @@ Value * SourceExprCommand::getSourceExpr(EvalState & state)
             } else
                 addEntry(i.first);
 
-        vSourceExpr->attrs->sort();
+        (*vSourceExpr)->attrs->sort();
     }
 
-    return vSourceExpr.get();
+    return *vSourceExpr;
 }
 
 ref<EvalState> SourceExprCommand::getEvalState()

diff --git a/src/nix/ls.cc b/src/nix/ls.cc
@@ -34,16 +34,14 @@ struct MixLs : virtual Args, MixJSON
                         (st.isExecutable ? "-r-xr-xr-x" : "-r--r--r--") :
                     st.type == FSAccessor::Type::tSymlink ? "lrwxrwxrwx" :
                     "dr-xr-xr-x";
-                std::cout <<
-                    (format("%s %20d %s") % tp % st.fileSize % relPath);
+                auto line = fmt("%s %20d %s", tp, st.fileSize, relPath);
                 if (st.type == FSAccessor::Type::tSymlink)
-                    std::cout << " -> " << accessor->readLink(curPath)
-                    ;
-                std::cout << "\n";
+                    line += " -> " + accessor->readLink(curPath);
+                logger->stdout(line);
                 if (recursive && st.type == FSAccessor::Type::tDirectory)
                     doPath(st, curPath, relPath, false);
             } else {
-                std::cout << relPath << "\n";
+                logger->stdout(relPath);
                 if (recursive) {
                     auto st = accessor->stat(curPath);
                     if (st.type == FSAccessor::Type::tDirectory)

diff --git a/src/nix/progress-bar.cc b/src/nix/progress-bar.cc
@@ -7,6 +7,7 @@
 #include <atomic>
 #include <map>
 #include <thread>
+#include <iostream>
 
 namespace nix {
 
@@ -442,6 +443,18 @@ class ProgressBar : public Logger
 
         return res;
     }
+
+    void writeToStdout(std::string_view s) override
+    {
+        auto state(state_.lock());
+        if (state->active) {
+            std::cerr << "\r\e[K";
+            Logger::writeToStdout(s);
+            draw(*state);
+        } else {
+            Logger::writeToStdout(s);
+        }
+    }
 };
 
 void startProgressBar(bool printBuildLogs)