# HG changeset patch
# User jbe
# Date 1407691105 -7200
# Node ID 433fa98329ecc71ed1ec9005202eeb8ea147e94e
# Parent  00fee67a0c2734cb878459ee7f0bd7fae990cbef
Bugfix in json.export(...); Better argument checking for json.export(...)

diff -r 00fee67a0c27 -r 433fa98329ec libraries/json/json.c
--- a/libraries/json/json.c	Sun Aug 10 19:06:18 2014 +0200
+++ b/libraries/json/json.c	Sun Aug 10 19:18:25 2014 +0200
@@ -1037,16 +1037,27 @@
   json_container_t *container = NULL; // pointer to current C struct for container information
   // stack shall contain two function arguments:
   lua_settop(L, 2);
-  // use default indentation if indentation argument is (boolean) true:
-  if (
-    lua_isboolean(L, json_export_indentstring_idx) &&
-    lua_toboolean(L, json_export_indentstring_idx)
-  ) {
-    lua_pushliteral(L, "  ");
-    lua_replace(L, json_export_indentstring_idx);
+  // check if pretty printing (with indentation) is desired:
+  if (lua_toboolean(L, json_export_indentstring_idx)) {
+    // if yes,
+    // set pretty variable to 1:
+    pretty = 1;
+    // check if second argument is a boolean (true):
+    if (lua_isboolean(L, json_export_indentstring_idx)) {
+      // if yes,
+      // use default indentation if indentation argument is boolean true:
+      lua_pushliteral(L, "  ");
+      lua_replace(L, json_export_indentstring_idx);
+    } else {
+      // if no,
+      // require second argument to be a string:
+      luaL_checktype(L, json_export_indentstring_idx, LUA_TSTRING);
+    }
+  } else {
+    // if no,
+    // set pretty variable to 0:
+    pretty = 0;
   }
-  // set pretty variable to 1 if pretty printing (with indentation) is desired:
-  pretty = lua_toboolean(L, json_export_indentstring_idx);
   // push objectmt onto stack position 3:
   json_regfetch(L, objectmt);
   // push arraymt onto stack position 4:
@@ -1118,12 +1129,9 @@
       break;
     // value to encode is of type table (this includes JSON objects and JSON arrays):
     case LUA_TTABLE:
-      // use value as container:
-      lua_pushvalue(L, json_export_value_idx);
-      lua_replace(L, json_export_luacontainer_idx);
       // use table's metatable to try to determine type of table:
       tabletype = JSON_TABLETYPE_UNKNOWN;
-      if (lua_getmetatable(L, json_export_luacontainer_idx)) {
+      if (lua_getmetatable(L, json_export_value_idx)) {
         if (lua_rawequal(L, -1, json_export_objectmt_idx)) {
           tabletype = JSON_TABLETYPE_OBJECT;
         } else {
@@ -1137,10 +1145,10 @@
         lua_pop(L, 1);
       }
       // replace table with its shadow table if existent, and reset stack:
-      lua_pushvalue(L, json_export_luacontainer_idx);
+      lua_pushvalue(L, json_export_value_idx);
       lua_rawget(L, json_export_shadowtbl_idx);
       if (lua_isnil(L, -1)) lua_pop(L, 1);
-      else lua_replace(L, json_export_luacontainer_idx);
+      else lua_replace(L, json_export_value_idx);
       // check if type of table is still undetermined
       // and optionally calculate number of string keys (keycount)
       // or set keycount to zero:
@@ -1148,7 +1156,7 @@
       if (tabletype == JSON_TABLETYPE_UNKNOWN) {
         // if type of table is undetermined,
         // iterate over all keys:
-        for (lua_pushnil(L); lua_next(L, json_export_luacontainer_idx); lua_pop(L, 1)) {
+        for (lua_pushnil(L); lua_next(L, json_export_value_idx); lua_pop(L, 1)) {
           switch (lua_type(L, -2)) {
           case LUA_TSTRING:
             // for string keys,
@@ -1183,6 +1191,9 @@
         lua_pushvalue(L, json_export_ccontainer_idx);
         lua_rawseti(L, json_export_stackswap_idx, ++stackswapidx);
       }
+      // use value as current container:
+      lua_pushvalue(L, json_export_value_idx);
+      lua_replace(L, json_export_luacontainer_idx);
       // distinguish between JSON objects and JSON arrays:
       switch (tabletype) {
       // JSON object: