[Add] CoW foundation and scriptable rm command.

Putting down the nessassary steps for the Copy-on-Write described in the
previous commit. Implemented the first script based write command, 'rm'

client/src/terminal.cpp

@@ -1,5 +1,4 @@
 #include <cstdio>
-#include <sstream>
 #include <SDL3/SDL.h>
 #include <GL/glew.h>
 #include <SDL3/SDL_events.h>

common/src/command_processor.cpp

@@ -1,4 +1,5 @@
 #include "command_processor.h"
+#include <sstream>
 #include "vfs.h"
 #include "lua_processor.h"
 
@@ -22,7 +23,16 @@ std::string CommandProcessor::process_command(const std::string& command) {
   cmd = (end == std::string::npos) ? "" : cmd.substr(0, end+1);
 
   /* === Generic script executer. === */
-  std::string command_name = cmd.substr(0, cmd.find(" "));
+  /* Parse the command and it's arguments. */
+  std::stringstream ss(cmd);
+  std::string command_name;
+  ss >> command_name;
+
+  std::vector<std::string> args;
+  std::string arg;
+  while(ss >> arg) {
+    args.push_back(arg);
+  }
 
   /* Search for script in the /bin directory. */
   std::string script_filename = command_name + ".lua";
@@ -32,8 +42,7 @@ std::string CommandProcessor::process_command(const std::string& command) {
   }
   if(root->children.count("bin") && root->children["bin"]->children.count(script_filename)) {
     vfs_node* script_node = root->children["bin"]->children[script_filename];
-    /* TODO: Pass arguments to the Lua script. */
-    return _lua->execute(script_node->content, _current_dir);
+    return _lua->execute(script_node->content, _current_dir, args);
   }
 
 

common/src/lua_processor.cpp

@@ -8,15 +8,45 @@ LuaProcessor::LuaProcessor(void) {
   _lua.new_usertype<vfs_node>("vfs_node",
                               "name",       &vfs_node::name,
                               "type",       &vfs_node::type,
-                              "children",   &vfs_node::children);
+                              "children",   &vfs_node::children,
+                              "read_only",  &vfs_node::read_only);
+
+  /* Create the 'vfs' table for our API. */
+  sol::table vfs_api = _lua.create_table("vfs");
+  vfs_api.set_function("rm", [](std::string path, vfs_node* current_dir) {
+    /* for now, we'll just support deleting from the current directory. */
+    if(current_dir->children.count(path)) {
+      vfs_node* target_node = current_dir->children[path];
+      if(target_node->read_only || current_dir->read_only) {
+        return std::string("rm: Permission denied. File or directory is read-only.");
+      }
+      if(target_node->type == DIR_NODE) {
+        return std::string("rm: cannot remove '" + path + "': Is a directory.");
+      }
+
+      current_dir->children.erase(path);
+      delete target_node; /* Clean up memry. */
+      return std::string(""); /* Success. */
+    }
+    return std::string("rm: cannot remove '" + path + "': No such file or directory.");
+  });
 }
 
 LuaProcessor::~LuaProcessor(void) {}
 
-std::string LuaProcessor::execute(const std::string& script, vfs_node* current_dir) {
+std::string LuaProcessor::execute(const std::string& script, vfs_node* current_dir,
+                                  const std::vector<std::string>& args) {
   try {
-    /* Pass the pointer for the current directory into the Lua env. */
+    /* Pass C++ objects/points into the Lua env. */
     _lua["current_dir"] = current_dir;
+
+    /* Create and populate the 'arg' table for the script. */
+    sol::table arg_table = _lua.create_table();;;;
+    for(size_t i = 0; i < args.size(); ++i) {
+      arg_table[i+1] = args[i]; /* Lua array are 1-indexed. Not that Skuzzy would know. */
+    }
+    _lua["arg"] = arg_table;
+
     sol::object result = _lua.script(script);
     if(result.is<std::string>()) {
       return result.as<std::string>();

common/src/lua_processor.h

@@ -1,18 +1,18 @@
 #pragma once
 
 #include <sol/sol.hpp>
+#include <vector>
+#include <vfs.h>
 #include <string>
 
-/* Don't want the full header. */
-struct vfs_node;
-
 class LuaProcessor {
 public:
   LuaProcessor(void);
   ~LuaProcessor(void);
 
   /* Executes a string of lua code and returns result as a string. */
-  std::string execute(const std::string& script, vfs_node* current_dir);
+  std::string execute(const std::string& script, vfs_node* current_dir,
+                      const std::vector<std::string>& args);
 private:
   sol::state _lua;
 };

common/src/vfs.h

@@ -16,6 +16,7 @@ enum vfs_node_type {
 struct vfs_node {
   std::string name;
   vfs_node_type type;
+  bool read_only;
 
   /* Files. */
   std::string content;

common/src/vfs_manager.cpp

@@ -7,6 +7,7 @@ vfs_node* new_node(std::string name, vfs_node_type type, vfs_node* parent) {
   node->name      = name;
   node->type      = type;
   node->parent    = parent;
+  node->read_only = false; /* Writable by default. */
   return node;
 }
 
@@ -16,6 +17,9 @@ VFSManager::VFSManager(void) {
   vfs_node* bin = new_node("bin", DIR_NODE, _vfs_root);
   _vfs_root->children["bin"] = bin;
 
+  _vfs_root->read_only  = true;
+  bin->read_only        = true;
+
   /* TODO:
    * Load all scripts from assets/scripts/bin into the bind node.
    * We'll create ls.lua manually for now.
@@ -37,6 +41,14 @@ VFSManager::VFSManager(void) {
                              )lua";
 
   bin->children["ls.lua"] = ls_script;
+
+  vfs_node* rm_script = new_node("rm.lua", FILE_NODE, bin);
+  rm_script->content = R"lua(-- /bin/rm.lua - Removes a file.
+                             local file_to_remove = arg[1]
+                             if not file_to_remove then return "rm: missing operand" end
+                             return vfs.rm(file_to_remove, current_dir)
+                             )lua";
+  bin->children["rm.lua"] = rm_script;
 }
 
 VFSManager::~VFSManager(void) {