From 6092852640096c777f700cf669666504b10e2a58 Mon Sep 17 00:00:00 2001
From: Justin Frank <justinpfrank@protonmail.com>
Date: Tue, 12 Mar 2019 10:34:30 -0700
Subject: [PATCH] Added 'provide-module' and 'require-module' commands

---
 src/command_manager.cc | 27 +++++++++++++++++++++++++++
 src/command_manager.hh | 14 ++++++++++++++
 src/commands.cc        | 12 +++++++++++-
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/src/command_manager.cc b/src/command_manager.cc
index 5e8c8196..91c41bd3 100644
--- a/src/command_manager.cc
+++ b/src/command_manager.cc
@@ -40,6 +40,33 @@ 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;
+    execute(module->value.commands, context);
+    module->value.commands.clear();
+}
+
 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 3c50accb..264ad46c 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -2417,8 +2417,17 @@ const CommandDesc provide_module_cmd = {
     CommandFlags::None,
     CommandHelper{},
     CommandCompleter{},
-    [](const ParametersParser& parse, Context& context, const ShellContext&)
+    [](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]);
     }
 };
 
@@ -2432,6 +2441,7 @@ const CommandDesc require_module_cmd = {
     CommandCompleter{},
     [](const ParametersParser& parser, Context& context, const ShellContext&)
     {
+        CommandManager::instance().load_module(parser[0], context);
     }
 };