Support additional script search paths

These can currently be added/removed from C++ or through the Lua API.

Lua API.rst

@@ -1964,6 +1964,33 @@ and are only documented here for completeness:
 
   Wraps strerror() - returns a string describing a platform-specific error code
 
+* ``dfhack.internal.addScriptPath(path, search_before)``
+
+  Adds ``path`` to the list of paths searched for scripts (both in Lua and Ruby).
+  If ``search_before`` is passed and ``true``, the path will be searched before
+  the default paths (e.g. ``raw/scripts``, ``hack/scripts``); otherwise, it will
+  be searched after.
+
+  Returns ``true`` if successful or ``false`` otherwise (e.g. if the path does
+  not exist or has already been registered).
+
+* ``dfhack.internal.removeScriptPath(path)``
+
+  Removes ``path`` from the script search paths and returns ``true`` if successful.
+
+* ``dfhack.internal.getScriptPaths()``
+
+  Returns the list of script paths in the order they are searched, including defaults.
+  (This can change if a world is loaded.)
+
+* ``dfhack.internal.findScript(name)``
+
+  Searches script paths for the script ``name`` and returns the path of the first
+  file found, or ``nil`` on failure.
+
+  Note: This requires an extension to be specified (``.lua`` or ``.rb``) -
+  use ``dfhack.findScript()`` to include the ``.lua`` extension automatically.
+
 Core interpreter context
 ========================
 

library/Core.cpp

@@ -427,24 +427,65 @@ static bool try_autocomplete(color_ostream &con, const std::string &first, std::
     return false;
 }
 
-string findScript(string path, string name) {
-    if (df::global::world) {
-        //first try the save folder if it exists
-        string save = World::ReadWorldFolder();
-        if ( save != "" ) {
-            string file = path + "/data/save/" + save + "/raw/scripts/" + name;
-            if (fileExists(file)) {
-                return file;
-            }
+bool Core::addScriptPath(string path, bool search_before)
+{
+    lock_guard<mutex> lock(*script_path_mutex);
+    vector<string> &vec = script_paths[search_before ? 0 : 1];
+    if (std::find(vec.begin(), vec.end(), path) != vec.end())
+        return false;
+    if (!Filesystem::isdir(path))
+        return false;
+    vec.push_back(path);
+    return true;
+}
+
+bool Core::removeScriptPath(string path)
+{
+    lock_guard<mutex> lock(*script_path_mutex);
+    bool found = false;
+    for (int i = 0; i < 2; i++)
+    {
+        vector<string> &vec = script_paths[i];
+        while (1)
+        {
+            auto it = std::find(vec.begin(), vec.end(), path);
+            if (it == vec.end())
+                break;
+            vec.erase(it);
+            found = true;
         }
     }
-    string file = path + "/raw/scripts/" + name;
-    if (fileExists(file)) {
-        return file;
+    return found;
+}
+
+void Core::getScriptPaths(std::vector<std::string> *dest)
+{
+    lock_guard<mutex> lock(*script_path_mutex);
+    dest->clear();
+    string df_path = this->p->getPath();
+    for (auto it = script_paths[0].begin(); it != script_paths[0].end(); ++it)
+        dest->push_back(*it);
+    if (df::global::world) {
+        string save = World::ReadWorldFolder();
+        if (save.size())
+            dest->push_back(df_path + "/data/save/" + save + "/raw/scripts");
     }
-    file = path + "/hack/scripts/" + name;
-    if (fileExists(file)) {
-        return file;
+    dest->push_back(df_path + "/raw/scripts");
+    dest->push_back(df_path + "/hack/scripts");
+    for (auto it = script_paths[1].begin(); it != script_paths[1].end(); ++it)
+        dest->push_back(*it);
+}
+
+
+string Core::findScript(string name)
+{
+    vector<string> paths;
+    getScriptPaths(&paths);
+    for (auto it = paths.begin(); it != paths.end(); ++it)
+    {
+        string path = *it + "/" + name;
+        if (Filesystem::isfile(path))
+            return path;
     }
     return "";
 }
@@ -592,15 +633,14 @@ command_result Core::runCommand(color_ostream &con, const std::string &first_, v
                         return CR_OK;
                     }
                 }
-                string path = this->p->getPath();
-                string file = findScript(path, parts[0] + ".lua");
+                string file = findScript(parts[0] + ".lua");
                 if ( file != "" ) {
                     string help = getScriptHelp(file, "-- ");
                     con.print("%s: %s\n", parts[0].c_str(), help.c_str());
                     return CR_OK;
                 }
                 if (plug_mgr->ruby && plug_mgr->ruby->is_enabled() ) {
-                    file = findScript(path, parts[0] + ".rb");
+                    file = findScript(parts[0] + ".rb");
                     if ( file != "" ) {
                         string help = getScriptHelp(file, "# ");
                         con.print("%s: %s\n", parts[0].c_str(), help.c_str());
@@ -682,7 +722,7 @@ command_result Core::runCommand(color_ostream &con, const std::string &first_, v
 
                     if(!plug)
                     {
-                        std::string lua = findScript(this->p->getPath(), part + ".lua");
+                        std::string lua = findScript(part + ".lua");
                         if (lua.size())
                         {
                             res = enableLuaScript(con, part, enable);
@@ -873,11 +913,11 @@ command_result Core::runCommand(color_ostream &con, const std::string &first_, v
             {
                 con << " is part of plugin " << plug->getName() << "." << std::endl;
             }
-            else if (findScript(this->p->getPath(), parts[0] + ".lua").size())
+            else if (findScript(parts[0] + ".lua").size())
             {
                 con << " is a Lua script." << std::endl;
             }
-            else if (findScript(this->p->getPath(), parts[0] + ".rb").size())
+            else if (findScript(parts[0] + ".rb").size())
             {
                 con << " is a Ruby script." << std::endl;
             }
@@ -1100,11 +1140,10 @@ command_result Core::runCommand(color_ostream &con, const std::string &first_, v
             if(res == CR_NOT_IMPLEMENTED)
             {
                 string completed;
-                string path = this->p->getPath();
-                string filename = findScript(path, first + ".lua");
+                string filename = findScript(first + ".lua");
                 bool lua = filename != "";
                 if ( !lua ) {
-                    filename = findScript(path, first + ".rb");
+                    filename = findScript(first + ".rb");
                 }
                 if ( lua )
                     res = runLuaScript(con, first, parts);
@@ -1273,6 +1312,8 @@ Core::Core()
     server = NULL;
 
     color_ostream::log_errors_to_stderr = true;
+
+    script_path_mutex = new mutex();
 };
 
 void Core::fatal (std::string output, bool deactivate)

library/LuaApi.cpp

@@ -2637,6 +2637,47 @@ static int internal_getModifiers(lua_State *L)
     return 1;
 }
 
+static int internal_addScriptPath(lua_State *L)
+{
+    const char *path = luaL_checkstring(L, 1);
+    bool search_before = (lua_gettop(L) > 1 && lua_toboolean(L, 2));
+    lua_pushboolean(L, Core::getInstance().addScriptPath(path, search_before));
+    return 1;
+}
+
+static int internal_removeScriptPath(lua_State *L)
+{
+    const char *path = luaL_checkstring(L, 1);
+    lua_pushboolean(L, Core::getInstance().removeScriptPath(path));
+    return 1;
+}
+
+static int internal_getScriptPaths(lua_State *L)
+{
+    int i = 1;
+    lua_newtable(L);
+    std::vector<std::string> paths;
+    Core::getInstance().getScriptPaths(&paths);
+    for (auto it = paths.begin(); it != paths.end(); ++it)
+    {
+        lua_pushinteger(L, i++);
+        lua_pushstring(L, it->c_str());
+        lua_settable(L, -3);
+    }
+    return 1;
+}
+
+static int internal_findScript(lua_State *L)
+{
+    const char *name = luaL_checkstring(L, 1);
+    std::string path = Core::getInstance().findScript(name);
+    if (path.size())
+        lua_pushstring(L, path.c_str());
+    else
+        lua_pushnil(L);
+    return 1;
+}
+
 static const luaL_Reg dfhack_internal_funcs[] = {
     { "getAddress", internal_getAddress },
     { "setAddress", internal_setAddress },
@@ -2652,6 +2693,10 @@ static const luaL_Reg dfhack_internal_funcs[] = {
     { "getDir", filesystem_listdir },
     { "runCommand", internal_runCommand },
     { "getModifiers", internal_getModifiers },
+    { "addScriptPath", internal_addScriptPath },
+    { "removeScriptPath", internal_removeScriptPath },
+    { "getScriptPaths", internal_getScriptPaths },
+    { "findScript", internal_findScript },
     { NULL, NULL }
 };
 

library/PluginManager.cpp

@@ -1017,6 +1017,7 @@ void PluginManager::unregisterCommands( Plugin * p )
 
 Plugin *PluginManager::operator[] (std::string name)
 {
+    MUTEX_GUARD(plugin_mutex);
     if (all_plugins.find(name) == all_plugins.end())
     {
         if (Filesystem::isfile(getPluginPath(name)))

library/include/Core.h

@@ -159,6 +159,11 @@ namespace DFHack
         command_result runCommand(color_ostream &out, const std::string &command);
         bool loadScriptFile(color_ostream &out, std::string fname, bool silent = false);
 
+        bool addScriptPath(std::string path, bool search_before = false);
+        bool removeScriptPath(std::string path);
+        std::string findScript(std::string name);
+        void getScriptPaths(std::vector<std::string> *dest);
+
         bool ClearKeyBindings(std::string keyspec);
         bool AddKeyBinding(std::string keyspec, std::string cmdline);
         std::vector<std::string> ListKeyBindings(std::string keyspec);
@@ -231,6 +236,9 @@ namespace DFHack
         std::vector <Module *> allModules;
         DFHack::PluginManager * plug_mgr;
 
+        std::vector<std::string> script_paths[2];
+        tthread::mutex *script_path_mutex;
+
         // hotkey-related stuff
         struct KeyBinding {
             int modifiers;

library/lua/dfhack.lua

@@ -420,24 +420,7 @@ local scripts = internal.scripts
 local hack_path = dfhack.getHackPath()
 
 function dfhack.findScript(name)
-    local file
-    file = dfhack.getSavePath()
-    if file then
-        file = file .. '/raw/scripts/' .. name .. '.lua'
-        if dfhack.filesystem.exists(file) then
-            return file
-        end
-    end
-    local path = dfhack.getDFPath()
-    file = path..'/raw/scripts/' .. name .. '.lua'
-    if dfhack.filesystem.exists(file) then
-        return file
-    end
-    file = path..'/hack/scripts/'..name..'.lua'
-    if dfhack.filesystem.exists(file) then
-        return file
-    end
-    return nil
+    return dfhack.internal.findScript(name .. '.lua')
 end
 
 local valid_script_flags = {
@@ -477,7 +460,7 @@ function dfhack.script_environment(name, strict)
     if not scripts[path] or scripts[path]:needs_update() then
         local _, env = dfhack.run_script_with_env(nil, name, {
             module=true,
-            module_strict=strict and true or false  -- ensure that this key is present if 'strict' is nil
+            module_strict=(strict and true or false)  -- ensure that this key is present if 'strict' is nil
         })
         return env
     else