Remove static initializers for RegisterLegacyCommand

This moves the "legacy"/"nix2" commands under a new `src/legacy/`
directory, instead of being scattered around in a bunch of different
directories.

A new `liblegacy` build target is defined, and the `nix` binary is
linked against it.

Then, `RegisterLegacyCommand` is replaced with `LegacyCommand::add`
calls in functions like `registerNixCollectGarbage()`. These
registration functions are called explicitly in `src/nix/main.cc`.

See: #359

Change-Id: Id450ffc3f793374907599cfcc121863b792aac1a

src/legacy/build-remote.cc

@@ -19,8 +19,9 @@
 #include "legacy.hh"
 #include "experimental-features.hh"
 #include "hash.hh"
+#include "build-remote.hh"
 
-using namespace nix;
+namespace nix {
 
 static void handleAlarm(int sig) {
 }
@@ -388,4 +389,8 @@ connected:
     }
 }
 
-static RegisterLegacyCommand r_build_remote("build-remote", main_build_remote);
+void registerBuildRemote() {
+    LegacyCommands::add("build-remote", main_build_remote);
+}
+
+}

src/legacy/build-remote.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerBuildRemote();
+
+}

src/legacy/meson.build

@@ -0,0 +1,35 @@
+legacy_include_directories = include_directories('.')
+
+legacy_sources = files(
+  # `build-remote` is not really legacy (it powers all remote builds), but it's
+  # not a `nix3` command.
+  'build-remote.cc',
+  'dotgraph.cc',
+  'graphml.cc',
+  'nix-build.cc',
+  'nix-channel.cc',
+  'nix-collect-garbage.cc',
+  'nix-copy-closure.cc',
+  'nix-env.cc',
+  'nix-env.hh',
+  'nix-instantiate.cc',
+  'nix-store.cc',
+  'user-env.cc',
+)
+
+legacy_headers = files(
+  'build-remote.hh',
+  'nix-build.hh',
+  'nix-channel.hh',
+  'nix-collect-garbage.hh',
+  'nix-copy-closure.hh',
+  'nix-instantiate.hh',
+  'nix-store.hh',
+)
+
+legacy_generated_headers = [
+  gen_header.process('buildenv.nix', preserve_path_from: meson.current_source_dir()),
+  gen_header.process('unpack-channel.nix', preserve_path_from: meson.current_source_dir()),
+]
+
+fs.copyfile('unpack-channel.nix')

src/legacy/nix-build.cc

@@ -24,12 +24,14 @@
 #include "attr-path.hh"
 #include "legacy.hh"
 #include "shlex.hh"
+#include "nix-build.hh"
+
+extern char * * environ __attribute__((weak)); // Man what even is this
+
+namespace nix {
 
-using namespace nix;
 using namespace std::string_literals;
 
-extern char * * environ __attribute__((weak));
-
 static void main_nix_build(int argc, char * * argv)
 {
     auto dryRun = false;
@@ -613,5 +615,9 @@ static void main_nix_build(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_build("nix-build", main_nix_build);
-static RegisterLegacyCommand r_nix_shell("nix-shell", main_nix_build);
+void registerNixBuildAndNixShell() {
+    LegacyCommands::add("nix-build", main_nix_build);
+    LegacyCommands::add("nix-shell", main_nix_build);
+}
+
+}

src/legacy/nix-build.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixBuildAndNixShell();
+
+}

src/legacy/nix-channel.cc

@@ -7,12 +7,13 @@
 #include "fetchers.hh"
 #include "eval-settings.hh" // for defexpr
 #include "users.hh"
+#include "nix-channel.hh"
 
 #include <fcntl.h>
 #include <regex>
 #include <pwd.h>
 
-using namespace nix;
+namespace nix {
 
 typedef std::map<std::string, std::string> Channels;
 
@@ -264,4 +265,8 @@ static int main_nix_channel(int argc, char ** argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_channel("nix-channel", main_nix_channel);
+void registerNixChannel() {
+    LegacyCommands::add("nix-channel", main_nix_channel);
+}
+
+}

src/legacy/nix-channel.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixChannel();
+
+}

src/legacy/nix-collect-garbage.cc

@@ -7,11 +7,12 @@
 #include "globals.hh"
 #include "legacy.hh"
 #include "signals.hh"
+#include "nix-collect-garbage.hh"
 
 #include <iostream>
 #include <cerrno>
 
-using namespace nix;
+namespace nix {
 
 std::string deleteOlderThan;
 bool dryRun = false;
@@ -110,4 +111,8 @@ static int main_nix_collect_garbage(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_collect_garbage("nix-collect-garbage", main_nix_collect_garbage);
+void registerNixCollectGarbage() {
+    LegacyCommands::add("nix-collect-garbage", main_nix_collect_garbage);
+}
+
+}

src/legacy/nix-collect-garbage.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixCollectGarbage();
+
+}

src/legacy/nix-copy-closure.cc

@@ -1,8 +1,9 @@
 #include "shared.hh"
 #include "store-api.hh"
 #include "legacy.hh"
+#include "nix-copy-closure.hh"
 
-using namespace nix;
+namespace nix {
 
 static int main_nix_copy_closure(int argc, char ** argv)
 {
@@ -60,4 +61,8 @@ static int main_nix_copy_closure(int argc, char ** argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_copy_closure("nix-copy-closure", main_nix_copy_closure);
+void registerNixCopyClosure() {
+    LegacyCommands::add("nix-copy-closure", main_nix_copy_closure);
+}
+
+}

src/legacy/nix-copy-closure.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixCopyClosure();
+
+}

src/legacy/nix-env.cc

@@ -17,6 +17,7 @@
 #include "xml-writer.hh"
 #include "legacy.hh"
 #include "eval-settings.hh" // for defexpr
+#include "nix-env.hh"
 
 #include <ctime>
 #include <algorithm>
@@ -28,9 +29,10 @@
 #include <unistd.h>
 #include <nlohmann/json.hpp>
 
-using namespace nix;
 using std::cout;
 
+namespace nix {
+
 
 typedef enum {
     srcNixExprDrvs,
@@ -1544,4 +1546,8 @@ static int main_nix_env(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_env("nix-env", main_nix_env);
+void registerNixEnv() {
+    LegacyCommands::add("nix-env", main_nix_env);
+}
+
+}

src/legacy/nix-env.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixEnv();
+
+}

src/legacy/nix-instantiate.cc

@@ -11,12 +11,13 @@
 #include "local-fs-store.hh"
 #include "common-eval-args.hh"
 #include "legacy.hh"
+#include "nix-instantiate.hh"
 
 #include <map>
 #include <iostream>
 
 
-using namespace nix;
+namespace nix {
 
 
 static Path gcRoot;
@@ -195,4 +196,8 @@ static int main_nix_instantiate(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_instantiate("nix-instantiate", main_nix_instantiate);
+void registerNixInstantiate() {
+    LegacyCommands::add("nix-instantiate", main_nix_instantiate);
+}
+
+}

src/legacy/nix-instantiate.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixInstantiate();
+
+}

src/legacy/nix-store.cc

@@ -15,6 +15,7 @@
 #include "graphml.hh"
 #include "legacy.hh"
 #include "path-with-outputs.hh"
+#include "nix-store.hh"
 
 #include <iostream>
 #include <algorithm>
@@ -24,10 +25,9 @@
 #include <fcntl.h>
 
 
-namespace nix_store {
+namespace nix {
 
 
-using namespace nix;
 using std::cin;
 using std::cout;
 
@@ -1176,6 +1176,8 @@ static int main_nix_store(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_store("nix-store", main_nix_store);
+void registerNixStore() {
+    LegacyCommands::add("nix-store", main_nix_store);
+}
 
 }

src/legacy/nix-store.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixStore();
+
+}

src/libcmd/legacy.cc

@@ -2,6 +2,6 @@
 
 namespace nix {
 
-RegisterLegacyCommand::Commands * RegisterLegacyCommand::commands = 0;
+LegacyCommands::Commands * LegacyCommands::commands = 0;
 
 }

src/libcmd/legacy.hh

@@ -9,12 +9,12 @@ namespace nix {
 
 typedef std::function<void(int, char * *)> MainFunction;
 
-struct RegisterLegacyCommand
+struct LegacyCommands
 {
     typedef std::map<std::string, MainFunction> Commands;
     static Commands * commands;
 
-    RegisterLegacyCommand(const std::string & name, MainFunction fun)
+    static void add(const std::string & name, MainFunction fun)
     {
         if (!commands) commands = new Commands;
         (*commands)[name] = fun;

src/meson.build

@@ -26,54 +26,9 @@ libasanoptions = declare_dependency(
   link_whole: asanoptions
 )
 
-build_remote_sources = files(
-  'build-remote/build-remote.cc',
-)
-nix_build_sources = files(
-  'nix-build/nix-build.cc',
-)
-nix_channel_sources = files(
-  'nix-channel/nix-channel.cc',
-)
-unpack_channel_gen = gen_header.process('nix-channel/unpack-channel.nix')
-nix_collect_garbage_sources = files(
-  'nix-collect-garbage/nix-collect-garbage.cc',
-)
-nix_copy_closure_sources = files(
-  'nix-copy-closure/nix-copy-closure.cc',
-)
-nix_env_buildenv_gen = gen_header.process('nix-env/buildenv.nix')
-nix_env_sources = files(
-  'nix-env/nix-env.cc',
-  'nix-env/user-env.cc',
-)
-nix_instantiate_sources = files(
-  'nix-instantiate/nix-instantiate.cc',
-)
-nix_store_sources = files(
-  'nix-store/dotgraph.cc',
-  'nix-store/graphml.cc',
-  'nix-store/nix-store.cc',
-)
-
-# Hurray for Meson list flattening!
-nix2_commands_sources = [
-  build_remote_sources,
-  nix_build_sources,
-  nix_channel_sources,
-  unpack_channel_gen,
-  nix_collect_garbage_sources,
-  nix_copy_closure_sources,
-  nix_env_buildenv_gen,
-  nix_env_sources,
-  nix_instantiate_sources,
-  nix_store_sources,
-]
+# Legacy commands.
+subdir('legacy')
 
 # Finally, the nix command itself, which all of the other commands are implmented in terms of
 # as a multicall binary.
 subdir('nix')
-
-# Just copies nix-channel/unpack-channel.nix to the build directory.
-# Done as a subdir to get Meson to respect the path hierarchy.
-subdir('nix-channel')

src/nix-channel/meson.build

@@ -1 +0,0 @@
-fs.copyfile('unpack-channel.nix')

src/nix/daemon-command.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixDaemon();
+
+}

src/nix/daemon.cc

@@ -14,6 +14,7 @@
 #include "signals.hh"
 #include "daemon.hh"
 #include "unix-domain-socket.hh"
+#include "daemon-command.hh"
 
 #include <algorithm>
 #include <climits>
@@ -36,7 +37,8 @@
 #include <sys/ucred.h>
 #endif
 
-using namespace nix;
+namespace nix {
+
 using namespace nix::daemon;
 
 /**
@@ -496,7 +498,9 @@ static int main_nix_daemon(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_daemon("nix-daemon", main_nix_daemon);
+void registerNixDaemon() {
+    LegacyCommands::add("nix-daemon", main_nix_daemon);
+}
 
 struct CmdDaemon : StoreCommand
 {
@@ -560,3 +564,5 @@ struct CmdDaemon : StoreCommand
 };
 
 static auto rCmdDaemon = registerCommand2<CmdDaemon>({"daemon"});
+
+}

src/nix/hash-command.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixHash();
+
+}

src/nix/hash.cc

@@ -5,8 +5,9 @@
 #include "shared.hh"
 #include "references.hh"
 #include "archive.hh"
+#include "hash-command.hh"
 
-using namespace nix;
+namespace nix {
 
 struct CmdHashBase : Command
 {
@@ -221,4 +222,8 @@ static int compatNixHash(int argc, char * * argv)
     return 0;
 }
 
-static RegisterLegacyCommand r_nix_hash("nix-hash", compatNixHash);
+void registerNixHash() {
+    LegacyCommands::add("nix-hash", compatNixHash);
+}
+
+}

src/nix/main.cc

@@ -15,6 +15,17 @@
 #include "markdown.hh"
 #include "experimental-features-json.hh"
 #include "deprecated-features-json.hh"
+#include "build-remote.hh"
+#include "daemon-command.hh"
+#include "hash-command.hh"
+#include "nix-build.hh"
+#include "nix-channel.hh"
+#include "nix-collect-garbage.hh"
+#include "nix-copy-closure.hh"
+#include "nix-env.hh"
+#include "nix-instantiate.hh"
+#include "nix-store.hh"
+#include "prefetch-command.hh"
 
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -30,6 +41,21 @@ void chrootHelper(int argc, char * * argv);
 
 namespace nix {
 
+void registerLegacyCommands()
+{
+    registerNixEnv();
+    registerNixBuildAndNixShell();
+    registerNixInstantiate();
+    registerNixCopyClosure();
+    registerNixCollectGarbage();
+    registerNixChannel();
+    registerNixStore();
+    registerBuildRemote();
+    registerNixDaemon();
+    registerNixPrefetchUrl();
+    registerNixHash();
+}
+
 static bool haveProxyEnvironmentVariables()
 {
     static const std::vector<std::string> proxyVariables = {
@@ -356,8 +382,10 @@ void mainWrapped(int argc, char * * argv)
     // Clean up the progress bar if shown using --log-format in a legacy command too.
     // Otherwise, this is a harmless no-op.
     Finally f([] { logger->pause(); });
+
     {
-        auto legacy = (*RegisterLegacyCommand::commands)[programName];
+        registerLegacyCommands();
+        auto legacy = (*LegacyCommands::commands)[programName];
         if (legacy) return legacy(argc, argv);
     }
 

src/nix/meson.build

@@ -71,11 +71,21 @@ nix_sources = files(
   'why-depends.cc',
 )
 
+nix_headers = files(
+  'daemon-command.hh',
+  'hash-command.hh',
+  'prefetch-command.hh',
+)
+
 nix = executable(
   'nix',
   nix_sources,
+  legacy_sources,
   nix_generated_headers,
-  nix2_commands_sources,
+  nix_headers,
+  legacy_headers,
+  legacy_generated_headers,
+  include_directories : legacy_include_directories,
   dependencies : [
     libasanoptions,
     liblixcmd,

src/nix/prefetch-command.hh

@@ -0,0 +1,8 @@
+#pragma once
+/// @file
+
+namespace nix {
+
+void registerNixPrefetchUrl();
+
+}

src/nix/prefetch.cc

@@ -9,10 +9,11 @@
 #include "eval-inline.hh" // IWYU pragma: keep
 #include "legacy.hh"
 #include "terminal.hh"
+#include "prefetch-command.hh"
 
 #include <nlohmann/json.hpp>
 
-using namespace nix;
+namespace nix {
 
 /* If ‘url’ starts with ‘mirror://’, then resolve it using the list of
    mirrors defined in Nixpkgs. */
@@ -248,7 +249,9 @@ static int main_nix_prefetch_url(int argc, char * * argv)
     }
 }
 
-static RegisterLegacyCommand r_nix_prefetch_url("nix-prefetch-url", main_nix_prefetch_url);
+void registerNixPrefetchUrl() {
+    LegacyCommands::add("nix-prefetch-url", main_nix_prefetch_url);
+}
 
 struct CmdStorePrefetchFile : StoreCommand, MixJSON
 {
@@ -328,3 +331,5 @@ struct CmdStorePrefetchFile : StoreCommand, MixJSON
 };
 
 static auto rCmdStorePrefetchFile = registerCommand2<CmdStorePrefetchFile>({"store", "prefetch-file"});
+
+}

src/nix/profile.cc

@@ -8,7 +8,7 @@
 #include "archive.hh"
 #include "builtins/buildenv.hh"
 #include "flake/flakeref.hh"
-#include "../nix-env/user-env.hh"
+#include "user-env.hh"
 #include "profiles.hh"
 #include "names.hh"
 

tests/functional/restricted.sh

@@ -11,8 +11,8 @@ nix-instantiate --restrict-eval ./simple.nix -I src1=simple.nix -I src2=config.n
 (! nix-instantiate --restrict-eval --eval -E 'builtins.readFile ./simple.nix')
 nix-instantiate --restrict-eval --eval -E 'builtins.readFile ./simple.nix' -I src=../..
 
-(! nix-instantiate --restrict-eval --eval -E 'builtins.readDir ../../src/nix-channel')
-nix-instantiate --restrict-eval --eval -E 'builtins.readDir ../../src/nix-channel' -I src=../../src
+(! nix-instantiate --restrict-eval --eval -E 'builtins.readDir ../../src/legacy')
+nix-instantiate --restrict-eval --eval -E 'builtins.readDir ../../src/legacy' -I src=../../src
 
 (! nix-instantiate --restrict-eval --eval -E 'let __nixPath = [ { prefix = "foo"; path = ./.; } ]; in <foo>')
 nix-instantiate --restrict-eval --eval -E 'let __nixPath = [ { prefix = "foo"; path = ./.; } ]; in <foo>' -I src=.

tests/unit/meson.build

@@ -255,7 +255,7 @@ test(
   env : default_test_env + {
     # No special meaning here, it's just a file laying around that is unlikely to go anywhere
     # any time soon.
-    '_NIX_TEST_UNIT_DATA': meson.project_source_root() / 'src/nix-env/buildenv.nix',
+    '_NIX_TEST_UNIT_DATA': meson.project_source_root() / 'src/legacy/buildenv.nix',
     # Use a temporary home directory for the unit tests.
     # Otherwise, /homeless-shelter is created in the single-user sandbox, and functional tests will fail.
     # TODO(alois31): handle TMPDIR properly (meson can't, and setting HOME in the test is too late)…