# HG changeset patch
# User jbe
# Date 1452044390 -3600
# Node ID 04172238d79baa1b7160991213e6684665e6ccf6
# Parent  ad437022be901b5627b4dfb23cc98f6cdb87d3be
Do not require "engine" field to be set for mondelefant.connect{...}; Fixed bugs in mondelefant.connect{...} that could have crashed Lua; Shortened Lua registry key for mondelefant library

diff -r ad437022be90 -r 04172238d79b libraries/mondelefant/mondelefant_native.c
--- a/libraries/mondelefant/mondelefant_native.c	Mon Jan 04 00:48:47 2016 +0100
+++ b/libraries/mondelefant/mondelefant_native.c	Wed Jan 06 02:39:50 2016 +0100
@@ -9,7 +9,7 @@
 // NOTE: Comments with format "// <number>" denote the Lua stack position
 
 // prefix for all Lua registry entries of this library:
-#define MONDELEFANT_REGKEY "e449ba8d9a53d353_mondelefant_"
+#define MONDELEFANT_REGKEY "mondelefant_"
 
 // registry key of module "mondelefant_native":
 #define MONDELEFANT_MODULE_REGKEY (MONDELEFANT_REGKEY "module")
@@ -194,76 +194,63 @@
 // "connect" function of library, which establishes a database connection
 // and returns a database connection handle:
 static int mondelefant_connect(lua_State *L) {
-  luaL_Buffer buf;  // Lua string buffer to create 'conninfo' (see below)
   const char *conninfo;  // string for PQconnectdb function
   PGconn *pgconn;  // PGconn object as returned by PQconnectdb function
   mondelefant_conn_t *conn;  // C-structure for userdata
-  // expect a table as first argument:
-  luaL_checktype(L, 1, LUA_TTABLE);
-  // if engine is anything but "postgresql", then raise error:
-  lua_settop(L, 1);
-  lua_getfield(L, 1, "engine");  // 2
-  if (!lua_toboolean(L, 2)) {
-    return luaL_argerror(L, 1, "no database engine selected");
-  }
-  lua_pushliteral(L, "postgresql");  // 3
-  if (!lua_rawequal(L, 2, 3)) {
-    return luaL_argerror(L, 1,
-      "only database engine 'postgresql' is supported"
-    );
-  }
-  // copy conninfo string for PQconnectdb function from argument table to
-  // stack position 2:
-  lua_settop(L, 1);
-  lua_getfield(L, 1, "conninfo");  // 2
-  // if no conninfo string was found, then assemble one from the named
-  // options except "engine" option:
-  if (!lua_toboolean(L, 2)) {
+  // check if string is given as first argument:
+  if (lua_type(L, 1) != LUA_TSTRING) {
+    // expect a table as first argument if no string is given:
+    luaL_checktype(L, 1, LUA_TTABLE);
+    // copy conninfo string for PQconnectdb function from argument table to
+    // stack position 2:
     lua_settop(L, 1);
-    lua_pushnil(L);  // slot for key at stack position 2
-    lua_pushnil(L);  // slot for value at stack position 3
-    luaL_buffinit(L, &buf);
-    {
+    lua_getfield(L, 1, "conninfo");  // 2
+    // check if conninfo is set:
+    if (!lua_isnil(L, 2)) {
+      // if yes, use that value but check its type:
+      luaL_argcheck(L, lua_type(L, 2) == LUA_TSTRING, 2, "\"conninfo\" value is not a string");
+    } else {
+      // otherwise assemble conninfo string from the named options:
+      luaL_Buffer buf;
       int need_seperator = 0;
+      const char *value;
+      size_t value_len;
+      size_t value_pos = 0;
+      lua_settop(L, 1);
+      lua_pushnil(L);  // slot for key at stack position 2
+      lua_pushnil(L);  // slot for value at stack position 3
+      luaL_buffinit(L, &buf);
       while (lua_pushvalue(L, 2), lua_next(L, 1)) {
+        luaL_argcheck(L, lua_isstring(L, -2), 1, "key in table is not a string");
+        luaL_argcheck(L, lua_isstring(L, -1), 1, "value in table is not a string");
+        value = lua_tolstring(L, -1, &value_len);
         lua_replace(L, 3);
+        lua_pop(L, 1);
         lua_replace(L, 2);
+        if (need_seperator) luaL_addchar(&buf, ' ');
         // NOTE: numbers will be converted to strings automatically here,
         // but perhaps this will change in future versions of lua
-        luaL_argcheck(L,
-          lua_isstring(L, 2) && lua_isstring(L, 3), 1, "key is not a string"
-        );
         lua_pushvalue(L, 2);
-        lua_pushliteral(L, "engine");
-        if (!lua_rawequal(L, -2, -1)) {
-          const char *value;
-          size_t value_len;
-          size_t value_pos = 0;
-          lua_pop(L, 1);
-          if (need_seperator) luaL_addchar(&buf, ' ');
-          luaL_addvalue(&buf);
-          luaL_addchar(&buf, '=');
-          luaL_addchar(&buf, '\'');
-          value = lua_tolstring(L, 3, &value_len);
-          do {
-            char c;
-            c = value[value_pos++];
-            if (c == '\'') luaL_addchar(&buf, '\\');
-            luaL_addchar(&buf, c);
-          } while (value_pos < value_len);
-          luaL_addchar(&buf, '\'');
-          need_seperator = 1;
-        } else {
-          lua_pop(L, 1);
-        }
+        luaL_addvalue(&buf);
+        luaL_addchar(&buf, '=');
+        luaL_addchar(&buf, '\'');
+        do {
+          char c;
+          c = value[value_pos++];
+          if (c == '\'') luaL_addchar(&buf, '\\');
+          luaL_addchar(&buf, c);
+        } while (value_pos < value_len);
+        luaL_addchar(&buf, '\'');
+        need_seperator = 1;
       }
+      luaL_pushresult(&buf);
     }
-    luaL_pushresult(&buf);
-    lua_replace(L, 2);
-    lua_settop(L, 2);
+    // ensure that string is on stack position 1 which is the top of stack:
+    lua_replace(L, 1);
+    lua_settop(L, 1);
   }
-  // use conninfo string on stack position 2:
-  conninfo = lua_tostring(L, 2);
+  // use conninfo string on stack position 1:
+  conninfo = lua_tostring(L, 1);
   // call PQconnectdb function of libpq:
   pgconn = PQconnectdb(conninfo);
   // throw or return errors, if neccessary:
@@ -273,18 +260,18 @@
     );
   }
   if (PQstatus(pgconn) != CONNECTION_OK) {
-    lua_pushnil(L);  // 3
-    mondelefant_push_first_line(L, PQerrorMessage(pgconn));  // 4
-    lua_newtable(L);  // 5
+    lua_pushnil(L);  // 2
+    mondelefant_push_first_line(L, PQerrorMessage(pgconn));  // 3
+    lua_newtable(L);  // 4
     lua_getfield(L,
       LUA_REGISTRYINDEX,
       MONDELEFANT_ERROROBJECT_MT_REGKEY
     );
-    lua_setmetatable(L, 5);
+    lua_setmetatable(L, 4);
     lua_pushliteral(L, MONDELEFANT_ERRCODE_CONNECTION);
-    lua_setfield(L, 5, "code");
-    lua_pushvalue(L, 4);
-    lua_setfield(L, 5, "message");
+    lua_setfield(L, 4, "code");
+    lua_pushvalue(L, 3);
+    lua_setfield(L, 4, "message");
     PQfinish(pgconn);
     return 3;
   }