Modify package.cpath (#1371)

* luaa.c: Remove useless stack operation

We get package.loaded and immediately throw away the result. That's
pointless, so remove this.

Signed-off-by: Uli Schlachter <psychon@znc.in>

* Refactor modification of package.path

Awesome adds various entries to package.path during startup. This commit
moves that into a helper function. No functional changes intended. The
only change I did to the code was changing a call to lua_type(L, 2) into
lua_type(L, -1);.

Signed-off-by: Uli Schlachter <psychon@znc.in>

* Modify package.cpath just like package.path

This adds, for example, paths specified via the --search argument also
to package.cpath.

Fixes: https://github.com/awesomeWM/awesome/issues/1248
Signed-off-by: Uli Schlachter <psychon@znc.in>

luaa.c

@@ -630,6 +630,54 @@ setup_awesome_signals(lua_State *L)
     lua_pop(L, 1);
 }
 
+/* Add things to the string on top of the stack */
+static void
+add_to_search_path(lua_State *L, string_array_t *searchpath, bool for_lua)
+{
+    if (LUA_TSTRING != lua_type(L, -1))
+    {
+        warn("package.path is not a string");
+        return;
+    }
+
+    foreach(entry, *searchpath)
+    {
+        int components;
+        size_t len = a_strlen(*entry);
+        lua_pushliteral(L, ";");
+        lua_pushlstring(L, *entry, len);
+        if (for_lua)
+            lua_pushliteral(L, "/?.lua");
+        else
+            lua_pushliteral(L, "/?.so");
+        lua_concat(L, 3);
+
+        if (for_lua)
+        {
+            lua_pushliteral(L, ";");
+            lua_pushlstring(L, *entry, len);
+            lua_pushliteral(L, "/?/init.lua");
+            lua_concat(L, 3);
+
+            components = 2;
+        } else {
+            components = 1;
+        }
+        lua_concat(L, components + 1); /* concatenate with string on top of the stack */
+    }
+
+    /* add Lua lib path (/usr/share/awesome/lib by default) */
+    if (for_lua)
+    {
+        lua_pushliteral(L, ";" AWESOME_LUA_LIB_PATH "/?.lua");
+        lua_pushliteral(L, ";" AWESOME_LUA_LIB_PATH "/?/init.lua");
+        lua_concat(L, 3); /* concatenate with thing on top of the stack when we were called */
+    } else {
+        lua_pushliteral(L, ";" AWESOME_LUA_LIB_PATH "/?.so");
+        lua_concat(L, 2); /* concatenate with thing on top of the stack when we were called */
+    }
+}
+
 /** Initialize the Lua VM
  * \param xdg An xdg handle to use to get XDG basedir.
  */
@@ -747,38 +795,14 @@ luaA_init(xdgHandle* xdg, string_array_t *searchpath)
         return;
     }
     lua_getfield(L, 1, "path");
-    if (LUA_TSTRING != lua_type(L, 2))
+    add_to_search_path(L, searchpath, true);
-    {
-        warn("package.path is not a string");
-        lua_pop(L, 1);
-        return;
-    }
-
-    foreach(entry, *searchpath)
-    {
-        size_t len = a_strlen(*entry);
-        lua_pushliteral(L, ";");
-        lua_pushlstring(L, *entry, len);
-        lua_pushliteral(L, "/?.lua");
-        lua_concat(L, 3);
-
-        lua_pushliteral(L, ";");
-        lua_pushlstring(L, *entry, len);
-        lua_pushliteral(L, "/?/init.lua");
-        lua_concat(L, 3);
-
-        lua_concat(L, 3); /* concatenate with package.path */
-    }
-
-    /* add Lua lib path (/usr/share/awesome/lib by default) */
-    lua_pushliteral(L, ";" AWESOME_LUA_LIB_PATH "/?.lua");
-    lua_pushliteral(L, ";" AWESOME_LUA_LIB_PATH "/?/init.lua");
-    lua_concat(L, 3); /* concatenate with package.path */
     lua_setfield(L, 1, "path"); /* package.path = "concatenated string" */
 
-    lua_getfield(L, 1, "loaded");
+    lua_getfield(L, 1, "cpath");
+    add_to_search_path(L, searchpath, false);
+    lua_setfield(L, 1, "cpath"); /* package.cpath = "concatenated string" */
 
-    lua_pop(L, 2); /* pop "package" and "package.loaded" */
+    lua_pop(L, 1); /* pop "package" */
 }
 
 static void