Move Command and MultiCommand to libutil

(cherry picked from commit f70434b1fb)

src/libutil/args.cc

@@ -200,4 +200,73 @@ void printTable(std::ostream & out, const Table2 & table)
     }
 }
 
+void Command::printHelp(const string & programName, std::ostream & out)
+{
+    Args::printHelp(programName, out);
+
+    auto exs = examples();
+    if (!exs.empty()) {
+        out << "\n";
+        out << "Examples:\n";
+        for (auto & ex : exs)
+            out << "\n"
+                << "  " << ex.description << "\n" // FIXME: wrap
+                << "  $ " << ex.command << "\n";
+    }
+}
+
+MultiCommand::MultiCommand(const std::vector<ref<Command>> & _commands)
+{
+    for (auto & command : _commands)
+        commands.emplace(command->name(), command);
+
+    expectedArgs.push_back(ExpectedArg{"command", 1, true, [=](std::vector<std::string> ss) {
+        assert(!command);
+        auto i = commands.find(ss[0]);
+        if (i == commands.end())
+            throw UsageError("'%s' is not a recognised command", ss[0]);
+        command = i->second;
+    }});
+}
+
+void MultiCommand::printHelp(const string & programName, std::ostream & out)
+{
+    if (command) {
+        command->printHelp(programName + " " + command->name(), out);
+        return;
+    }
+
+    out << "Usage: " << programName << " <COMMAND> <FLAGS>... <ARGS>...\n";
+
+    out << "\n";
+    out << "Common flags:\n";
+    printFlags(out);
+
+    out << "\n";
+    out << "Available commands:\n";
+
+    Table2 table;
+    for (auto & command : commands) {
+        auto descr = command.second->description();
+        if (!descr.empty())
+            table.push_back(std::make_pair(command.second->name(), descr));
+    }
+    printTable(out, table);
+}
+
+bool MultiCommand::processFlag(Strings::iterator & pos, Strings::iterator end)
+{
+    if (Args::processFlag(pos, end)) return true;
+    if (command && command->processFlag(pos, end)) return true;
+    return false;
+}
+
+bool MultiCommand::processArgs(const Strings & args, bool finish)
+{
+    if (command)
+        return command->processArgs(args, finish);
+    else
+        return Args::processArgs(args, finish);
+}
+
 }

src/libutil/args.hh

@@ -188,6 +188,48 @@ public:
     friend class MultiCommand;
 };
 
+/* A command is an argument parser that can be executed by calling its
+   run() method. */
+struct Command : virtual Args
+{
+    virtual ~Command() { }
+    virtual std::string name() = 0;
+    virtual void prepare() { };
+    virtual void run() = 0;
+
+    struct Example
+    {
+        std::string description;
+        std::string command;
+    };
+
+    typedef std::list<Example> Examples;
+
+    virtual Examples examples() { return Examples(); }
+
+    void printHelp(const string & programName, std::ostream & out) override;
+};
+
+typedef std::map<std::string, ref<Command>> Commands;
+
+/* An argument parser that supports multiple subcommands,
+   i.e. ‘<command> <subcommand>’. */
+class MultiCommand : virtual Args
+{
+public:
+    Commands commands;
+
+    std::shared_ptr<Command> command;
+
+    MultiCommand(const std::vector<ref<Command>> & commands);
+
+    void printHelp(const string & programName, std::ostream & out) override;
+
+    bool processFlag(Strings::iterator & pos, Strings::iterator end) override;
+
+    bool processArgs(const Strings & args, bool finish) override;
+};
+
 Strings argvToStrings(int argc, char * * argv);
 
 /* Helper function for rendering argument labels. */

src/nix/command.cc

@@ -7,80 +7,6 @@ namespace nix {
 
 std::vector<ref<Command>> * RegisterCommand::commands = 0;
 
-void Command::printHelp(const string & programName, std::ostream & out)
-{
-    Args::printHelp(programName, out);
-
-    auto exs = examples();
-    if (!exs.empty()) {
-        out << "\n";
-        out << "Examples:\n";
-        for (auto & ex : exs)
-            out << "\n"
-                << "  " << ex.description << "\n" // FIXME: wrap
-                << "  $ " << ex.command << "\n";
-    }
-}
-
-MultiCommand::MultiCommand(const std::vector<ref<Command>> & _commands)
-{
-    for (auto & command : _commands)
-        commands.emplace(command->name(), command);
-
-    expectedArgs.push_back(ExpectedArg{"command", 1, true, [=](std::vector<std::string> ss) {
-        assert(!command);
-        auto i = commands.find(ss[0]);
-        if (i == commands.end())
-            throw UsageError("'%s' is not a recognised command", ss[0]);
-        command = i->second;
-    }});
-}
-
-void MultiCommand::printHelp(const string & programName, std::ostream & out)
-{
-    if (command) {
-        command->printHelp(programName + " " + command->name(), out);
-        return;
-    }
-
-    out << "Usage: " << programName << " <COMMAND> <FLAGS>... <ARGS>...\n";
-
-    out << "\n";
-    out << "Common flags:\n";
-    printFlags(out);
-
-    out << "\n";
-    out << "Available commands:\n";
-
-    Table2 table;
-    for (auto & command : commands) {
-        auto descr = command.second->description();
-        if (!descr.empty())
-            table.push_back(std::make_pair(command.second->name(), descr));
-    }
-    printTable(out, table);
-
-#if 0
-    out << "\n";
-    out << "For full documentation, run 'man " << programName << "' or 'man " << programName << "-<COMMAND>'.\n";
-#endif
-}
-
-bool MultiCommand::processFlag(Strings::iterator & pos, Strings::iterator end)
-{
-    if (Args::processFlag(pos, end)) return true;
-    if (command && command->processFlag(pos, end)) return true;
-    return false;
-}
-
-bool MultiCommand::processArgs(const Strings & args, bool finish)
-{
-    if (command)
-        return command->processArgs(args, finish);
-    else
-        return Args::processArgs(args, finish);
-}
-
 StoreCommand::StoreCommand()
 {
 }

src/nix/command.hh

@@ -11,29 +11,6 @@ struct Value;
 class Bindings;
 class EvalState;
 struct Pos;
-
-/* A command is an argument parser that can be executed by calling its
-   run() method. */
-struct Command : virtual Args
-{
-    virtual ~Command() { }
-    virtual std::string name() = 0;
-    virtual void prepare() { };
-    virtual void run() = 0;
-
-    struct Example
-    {
-        std::string description;
-        std::string command;
-    };
-
-    typedef std::list<Example> Examples;
-
-    virtual Examples examples() { return Examples(); }
-
-    void printHelp(const string & programName, std::ostream & out) override;
-};
-
 class Store;
 
 /* A command that requires a Nix store. */
@@ -171,26 +148,6 @@ struct StorePathCommand : public InstallablesCommand
     void run(ref<Store> store) override;
 };
 
-typedef std::map<std::string, ref<Command>> Commands;
-
-/* An argument parser that supports multiple subcommands,
-   i.e. ‘<command> <subcommand>’. */
-class MultiCommand : virtual Args
-{
-public:
-    Commands commands;
-
-    std::shared_ptr<Command> command;
-
-    MultiCommand(const std::vector<ref<Command>> & commands);
-
-    void printHelp(const string & programName, std::ostream & out) override;
-
-    bool processFlag(Strings::iterator & pos, Strings::iterator end) override;
-
-    bool processArgs(const Strings & args, bool finish) override;
-};
-
 /* A helper class for registering commands globally. */
 struct RegisterCommand
 {

src/nix/main.cc

@@ -107,6 +107,11 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
     void printHelp(const string & programName, std::ostream & out)
     {
         MultiCommand::printHelp(programName, out);
+
+#if 0
+        out << "\nFor full documentation, run 'man " << programName << "' or 'man " << programName << "-<COMMAND>'.\n";
+#endif
+
         std::cout << "\nNote: this program is EXPERIMENTAL and subject to change.\n";
     }