# HG changeset patch
# User jbe
# Date 1406677077 -7200
# Node ID 641619d3fcb150ca812ec25fdcf97c571e99c03a
# Parent  a4ce17051eff38e7e71cbea248d8ecf3a25d11a5
Fixed problem with unbalanced stack in json.import(...) function

diff -r a4ce17051eff -r 641619d3fcb1 libraries/json/json.c
--- a/libraries/json/json.c	Tue Jul 29 22:02:01 2014 +0200
+++ b/libraries/json/json.c	Wed Jul 30 01:37:57 2014 +0200
@@ -162,6 +162,8 @@
     lua_pushvalue(L, -2);
     lua_pushvalue(L, -2);
     lua_rawset(L, json_import_shadowtbl_idx);
+    // add nil as key (needed to keep stack balance) and as magic to detect arrays:
+    lua_pushnil(L);
     // increment level:
     level++;
     // expect array value (or end of array) and continue with loop:
@@ -179,6 +181,8 @@
     // if end of JSON array is not expected here, then return an error:
     if (mode != JSON_STATE_ARRAY_VALUE && mode != JSON_STATE_ARRAY_SEPARATOR)
       goto json_import_syntax_error;
+    // pop nil key/magic:
+    lua_pop(L, 1);
     // continue with common code for end of JSON object and JSON array:
   // common code for end of JSON object or JSON array:
   json_import_close:
@@ -189,23 +193,17 @@
     // check if nested:
     if (--level) {
       // if nested, then check if outer(!) structure is an array or object:
-      lua_getmetatable(L, c == '}' ? -4 : -3);  // TODO: this approach doesn't work, because objects have an extra key on stack!
-      if (lua_rawequal(L, -1, json_import_arraymt_idx)) {
+      if (lua_isnil(L, -2)) {
         // select array value processing:
-        fprintf(stderr, "DEBUG: Process array\n");
         mode = JSON_STATE_ARRAY_VALUE;
       } else {
         // select object value processing:
-        fprintf(stderr, "DEBUG: Process object\n");
         mode = JSON_STATE_OBJECT_VALUE;
       }
-      // pop metatable from stack (that was needed for type distinction):
-      lua_pop(L, 1);
       // store value in outer structure:
       goto json_import_process_value;
     }
     // if not nested, then expect end of JSON document and continue with loop:
-    fprintf(stderr, "DEBUG: Process document\n");
     mode = JSON_STATE_END;
     goto json_import_loop;
   // key terminator:
@@ -354,7 +352,7 @@
   // an array value has been read:
   case JSON_STATE_ARRAY_VALUE:
     // store value in outer shadow table:
-    lua_rawseti(L, -2, lua_rawlen(L, -2) + 1);
+    lua_rawseti(L, -3, lua_rawlen(L, -3) + 1);
     // expect value terminator (or end of object) and continue with loop:
     mode = JSON_STATE_ARRAY_SEPARATOR;
     goto json_import_loop;