WIP get settings info out of headers, out of libutil

src/libmain/config-upstream.cc

@@ -0,0 +1,40 @@
+namespace nix {
+
+#include "fs-sink.hh"
+#include "logging.hh"
+
+struct LoggerSettings : Config
+{
+    Setting<bool> showTrace{
+        this, false, "show-trace",
+        R"(
+          Whether Nix should print out a stack trace in case of Nix
+          expression evaluation errors.
+        )"};
+};
+
+static GlobalConfig::Register r1(&restoreSinkSettings);
+
+struct RestoreSinkSettings : Config
+{
+    Setting<bool> preallocateContents{this, false, "preallocate-contents",
+        "Whether to preallocate files when writing objects with known size."};
+};
+
+static GlobalConfig::Register rLoggerSettings(&loggerSettings);
+
+struct ArchiveSettings : Config
+{
+    Setting<bool> useCaseHack{this,
+        #if __APPLE__
+            true,
+        #else
+            false,
+        #endif
+        "use-case-hack",
+        "Whether to enable a Darwin-specific hack for dealing with file name collisions."};
+};
+
+static GlobalConfig::Register rArchiveSettings(&archiveSettings);
+
+}

src/libutil/config.cc → src/libmain/config.cc

@@ -452,26 +452,4 @@ void OptionalPathSetting::operator =(const std::optional<Path> & v)
     this->assign(v);
 }
 
-bool ExperimentalFeatureSettings::isEnabled(const ExperimentalFeature & feature) const
-{
-    auto & f = experimentalFeatures.get();
-    return std::find(f.begin(), f.end(), feature) != f.end();
-}
-
-void ExperimentalFeatureSettings::require(const ExperimentalFeature & feature) const
-{
-    if (!isEnabled(feature))
-        throw MissingExperimentalFeature(feature);
-}
-
-bool ExperimentalFeatureSettings::isEnabled(const std::optional<ExperimentalFeature> & feature) const
-{
-    return !feature || isEnabled(*feature);
-}
-
-void ExperimentalFeatureSettings::require(const std::optional<ExperimentalFeature> & feature) const
-{
-    if (feature) require(*feature);
-}
-
 }

src/libutil/config.hh → src/libmain/config.hh

@@ -257,9 +257,6 @@ public:
         , documentDefault(documentDefault)
     { }
 
-    operator const T &() const { return value; }
-    operator T &() { return value; }
-    const T & get() const { return value; }
     template<typename U>
     bool operator ==(const U & v2) const { return value == v2; }
     template<typename U>

src/libstore/derived-path.hh

@@ -3,7 +3,6 @@
 
 #include "path.hh"
 #include "outputs-spec.hh"
-#include "config.hh"
 #include "ref.hh"
 
 #include <variant>

src/libutil/archive.cc

@@ -6,29 +6,26 @@
 #include <strings.h> // for strcasecmp
 
 #include "archive.hh"
-#include "config-global.hh"
 #include "posix-source-accessor.hh"
 #include "source-path.hh"
 #include "file-system.hh"
 #include "signals.hh"
 
 namespace nix {
 
-struct ArchiveSettings : Config
-{
-    Setting<bool> useCaseHack{this,
-        #if __APPLE__
-            true,
-        #else
-            false,
-        #endif
-        "use-case-hack",
-        "Whether to enable a Darwin-specific hack for dealing with file name collisions."};
+const extern ArchiveSettings<JustValue> archiveSettingsDefaults = {
+    .useCaseHack = {
+        .value =
+#if __APPLE__
+            true
+#else
+            false
+#endif
+    },
 };
 
-static ArchiveSettings archiveSettings;
+ArchiveSettings<JustValue> archiveSettings = archiveSettingsDefaults;
 
-static GlobalConfig::Register rArchiveSettings(&archiveSettings);
 
 PathFilter defaultPathFilter = [](const Path &) { return true; };
 

src/libutil/archive.hh

@@ -2,12 +2,23 @@
 ///@file
 
 #include "types.hh"
+#include "config-abstract.hh"
 #include "serialise.hh"
 #include "fs-sink.hh"
 
 
 namespace nix {
 
+template<template<typename> class R>
+struct ArchiveSettings
+{
+    R<bool> useCaseHack;
+};
+
+const extern ArchiveSettings<JustValue> archiveSettingsDefaults;
+
+// FIXME: don't use a global variable.
+extern ArchiveSettings<JustValue> archiveSettings;
 
 /**
  * dumpPath creates a Nix archive of the specified path.

src/libutil/config-abstract.hh

@@ -0,0 +1,15 @@
+#pragma once
+///@type
+
+namespace nix {
+
+template<typename T>
+struct JustValue {
+    T value;
+
+    operator const T &() const { return value; }
+    operator T &() { return value; }
+    const T & get() const { return value; }
+};
+
+}

src/libutil/experimental-feature-settings.cc

@@ -0,0 +1,37 @@
+#include "experimental-feature-settings.hh"
+
+namespace nix {
+
+const extern ExperimentalFeatureSettings experimentalFeatureSettingsDefaults = {
+    {
+        .experimentalFeatures = {
+            .value = {}
+        },
+    }
+};
+
+ExperimentalFeatureSettings experimentalFeatureSettings = experimentalFeatureSettingsDefaults;
+
+bool ExperimentalFeatureSettings::isEnabled(const ExperimentalFeature & feature) const
+{
+    auto & f = experimentalFeatures.get();
+    return std::find(f.begin(), f.end(), feature) != f.end();
+}
+
+void ExperimentalFeatureSettings::require(const ExperimentalFeature & feature) const
+{
+    if (!isEnabled(feature))
+        throw MissingExperimentalFeature(feature);
+}
+
+bool ExperimentalFeatureSettings::isEnabled(const std::optional<ExperimentalFeature> & feature) const
+{
+    return !feature || isEnabled(*feature);
+}
+
+void ExperimentalFeatureSettings::require(const std::optional<ExperimentalFeature> & feature) const
+{
+    if (feature) require(*feature);
+}
+
+};

src/libutil/experimental-feature-settings.hh

@@ -0,0 +1,45 @@
+#pragma once
+///@file
+
+#include "experimental-features.hh"
+
+namespace nix {
+
+template<template<typename> class R>
+struct ExperimentalFeatureSettingsT
+{
+    R<std::set<ExperimentalFeature>> experimentalFeatures;
+};
+
+struct ExperimentalFeatureSettings : ExperimentalFeatureSettingsT<JustValue>
+{
+    /**
+     * Check whether the given experimental feature is enabled.
+     */
+    bool isEnabled(const ExperimentalFeature &) const;
+
+    /**
+     * Require an experimental feature be enabled, throwing an error if it is
+     * not.
+     */
+    void require(const ExperimentalFeature &) const;
+
+    /**
+     * `std::nullopt` pointer means no feature, which means there is nothing that could be
+     * disabled, and so the function returns true in that case.
+     */
+    bool isEnabled(const std::optional<ExperimentalFeature> &) const;
+
+    /**
+     * `std::nullopt` pointer means no feature, which means there is nothing that could be
+     * disabled, and so the function does nothing in that case.
+     */
+    void require(const std::optional<ExperimentalFeature> &) const;
+};
+
+const extern ExperimentalFeatureSettings experimentalFeatureSettingsDefaults;
+
+// FIXME: don't use a global variable.
+extern ExperimentalFeatureSettings experimentalFeatureSettings;
+
+}

src/libutil/experimental-features.hh

@@ -1,6 +1,7 @@
 #pragma once
 ///@file
 
+#include "config-abstract.hh"
 #include "error.hh"
 #include "json-utils.hh"
 #include "types.hh"

src/libutil/fs-sink.cc

@@ -1,7 +1,6 @@
 #include <fcntl.h>
 
 #include "error.hh"
-#include "config-global.hh"
 #include "fs-sink.hh"
 
 #if _WIN32
@@ -58,15 +57,7 @@ void copyRecursive(
 }
 
 
-struct RestoreSinkSettings : Config
-{
-    Setting<bool> preallocateContents{this, false, "preallocate-contents",
-        "Whether to preallocate files when writing objects with known size."};
-};
-
-static RestoreSinkSettings restoreSinkSettings;
-
-static GlobalConfig::Register r1(&restoreSinkSettings);
+RestoreSinkSettings<JustValue> restoreSinkSettings;
 
 
 void RestoreSink::createDirectory(const CanonPath & path)

src/libutil/fs-sink.hh

@@ -1,12 +1,20 @@
 #pragma once
 ///@file
 
+#include "config-abstract.hh"
 #include "serialise.hh"
 #include "source-accessor.hh"
 #include "file-system.hh"
 
 namespace nix {
 
+template<template<typename> class R>
+struct RestoreSinkSettings
+{
+    R<bool> preallocateContents;
+};
+
+
 /**
  * Actions on an open regular file in the process of creating it.
  *
@@ -22,6 +30,8 @@ struct CreateRegularFileSink : Sink
     virtual void preallocateContents(uint64_t size) { };
 };
 
+// FIXME: don't use a global variable.
+extern RestoreSinkSettings<JustValue> restoreSinkSettings;
 
 struct FileSystemObjectSink
 {

src/libutil/git.cc

@@ -6,7 +6,7 @@
 #include <strings.h> // for strcasecmp
 
 #include "signals.hh"
-#include "config.hh"
+#include "config-abstract.hh"
 #include "hash.hh"
 
 #include "git.hh"

src/libutil/git.hh

@@ -6,6 +6,7 @@
 #include <optional>
 
 #include "types.hh"
+#include "experimental-feature-settings.hh"
 #include "serialise.hh"
 #include "hash.hh"
 #include "source-path.hh"

src/libutil/hash.cc

@@ -5,7 +5,6 @@
 #include <openssl/md5.h>
 #include <openssl/sha.h>
 
-#include "args.hh"
 #include "hash.hh"
 #include "archive.hh"
 #include "split.hh"

src/libutil/logging.cc

@@ -3,7 +3,6 @@
 #include "environment-variables.hh"
 #include "terminal.hh"
 #include "util.hh"
-#include "config-global.hh"
 #include "source-path.hh"
 #include "position.hh"
 
@@ -14,9 +13,13 @@
 
 namespace nix {
 
-LoggerSettings loggerSettings;
+const extern LoggerSettings<JustValue> loggerSettingsDefaults = {
+    .showTrace = {
+        .value = false
+    },
+};
 
-static GlobalConfig::Register rLoggerSettings(&loggerSettings);
+LoggerSettings<JustValue> loggerSettings = loggerSettingsDefaults;
 
 static thread_local ActivityId curActivity = 0;
 

src/libutil/logging.hh

@@ -2,7 +2,7 @@
 ///@file
 
 #include "error.hh"
-#include "config.hh"
+#include "config-abstract.hh"
 
 #include <nlohmann/json_fwd.hpp>
 
@@ -39,17 +39,13 @@ typedef enum {
 
 typedef uint64_t ActivityId;
 
-struct LoggerSettings : Config
+template<template<typename> class R>
+struct LoggerSettings
 {
-    Setting<bool> showTrace{
-        this, false, "show-trace",
-        R"(
-          Whether Nix should print out a stack trace in case of Nix
-          expression evaluation errors.
-        )"};
+    R<bool> showTrace;
 };
 
-extern LoggerSettings loggerSettings;
+extern LoggerSettings<JustValue> loggerSettings;
 
 class Logger
 {