Merge remote-tracking branch 'laelath/provides-requires'

4 files changed, 90 insertions, 2 deletions

diff --git a/src/command_manager.cc b/src/command_manager.cc
index 5e8c8196..1fdfa34d 100644
--- a/src/command_manager.cc
+++ b/src/command_manager.cc
@@ -40,6 +40,36 @@ void CommandManager::register_command(String command_name,
                                  std::move(completer) };
 }
 
+bool CommandManager::module_defined(StringView module_name) const
+{
+    return m_modules.find(module_name) != m_modules.end();
+}
+
+void CommandManager::register_module(String module_name, String commands)
+{
+    auto module = m_modules.find(module_name);
+    if (module != m_modules.end() and module->value.loaded)
+        throw runtime_error{format("module already loaded: '{}'", module_name)};
+
+    m_modules[module_name] = { false, std::move(commands) };
+}
+
+void CommandManager::load_module(StringView module_name, Context& context)
+{
+    auto module = m_modules.find(module_name);
+    if (module == m_modules.end())
+        throw runtime_error{format("no such module: '{}'", module_name)};
+    if (module->value.loaded)
+        return;
+
+    module->value.loaded = true;
+    Context empty_context{Context::EmptyContextFlag{}};
+    execute(module->value.commands, empty_context);
+    module->value.commands.clear();
+
+    context.hooks().run_hook(Hook::ModuleLoad, module_name, context);
+}
+
 struct parse_error : runtime_error
 {
     parse_error(StringView error)
diff --git a/src/command_manager.hh b/src/command_manager.hh
index 0468a1fc..329c24f2 100644
--- a/src/command_manager.hh
+++ b/src/command_manager.hh
@@ -123,6 +123,12 @@ public:
 
     void clear_last_complete_command() { m_last_complete_command = String{}; }
 
+    bool module_defined(StringView module_name) const;
+
+    void register_module(String module_name, String commands);
+
+    void load_module(StringView module_name, Context& context);
+
 private:
     void execute_single_command(CommandParameters params,
                                 Context& context,
@@ -143,6 +149,14 @@ private:
     String m_last_complete_command;
     int m_command_depth = 0;
 
+    struct Module
+    {
+        bool loaded;
+        String commands;
+    };
+    using ModuleMap = HashMap<String, Module, MemoryDomain::Commands>;
+    ModuleMap m_modules;
+
     CommandMap::const_iterator find_command(const Context& context,
                                             StringView name) const;
 };
diff --git a/src/commands.cc b/src/commands.cc
index 559fe90b..51adb80c 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -2403,6 +2403,46 @@ const CommandDesc enter_user_mode_cmd = {
     }
 };
 
+const CommandDesc provide_module_cmd = {
+    "provide-module",
+    nullptr,
+    "provide-module [<switches>] <name> <cmds>: declares a module <name> provided by <cmds>",
+    ParameterDesc{
+        { { "override", { false, "allow overriding an existing module" } } },
+        ParameterDesc::Flags::None,
+        2, 2
+    },
+    CommandFlags::None,
+    CommandHelper{},
+    CommandCompleter{},
+    [](const ParametersParser& parser, Context& context, const ShellContext&)
+    {
+        const String& module_name = parser[0];
+        auto& cm = CommandManager::instance();
+
+        if (not all_of(module_name, is_identifier))
+            throw runtime_error(format("invalid module name: '{}'", module_name));
+
+        if (cm.module_defined(module_name) and not parser.get_switch("override"))
+            throw runtime_error(format("module '{}' already defined", module_name));
+        cm.register_module(module_name, parser[1]);
+    }
+};
+
+const CommandDesc require_module_cmd = {
+    "require-module",
+    nullptr,
+    "require-module <name>: ensures that <name> module has been loaded",
+    ParameterDesc{ {}, ParameterDesc::Flags::None, 1, 1 },
+    CommandFlags::None,
+    CommandHelper{},
+    CommandCompleter{},
+    [](const ParametersParser& parser, Context& context, const ShellContext&)
+    {
+        CommandManager::instance().load_module(parser[0], context);
+    }
+};
+
 }
 
 void register_commands()
@@ -2468,6 +2508,8 @@ void register_commands()
     register_command(fail_cmd);
     register_command(declare_user_mode_cmd);
     register_command(enter_user_mode_cmd);
+    register_command(provide_module_cmd);
+    register_command(require_module_cmd);
 }
 
 }
diff --git a/src/hook_manager.hh b/src/hook_manager.hh
index 909d24bc..f1e6667b 100644
--- a/src/hook_manager.hh
+++ b/src/hook_manager.hh
@@ -56,12 +56,13 @@ enum class Hook
     WinCreate,
     WinDisplay,
     WinResize,
-    WinSetOption
+    WinSetOption,
+    ModuleLoad
 };
 
 constexpr auto enum_desc(Meta::Type<Hook>)
 {
-    return make_array<EnumDesc<Hook>, 40>({
+    return make_array<EnumDesc<Hook>, 41>({
         {Hook::BufCreate, "BufCreate"},
         {Hook::BufNewFile, "BufNewFile"},
         {Hook::BufOpenFile, "BufOpenFile"},
@@ -102,6 +103,7 @@ constexpr auto enum_desc(Meta::Type<Hook>)
         {Hook::WinDisplay, "WinDisplay"},
         {Hook::WinResize, "WinResize"},
         {Hook::WinSetOption, "WinSetOption"},
+        {Hook::ModuleLoad, "ModuleLoad"}
     });
 }