Add 'minetest.write_json'

diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index abfb8f94ba0a9d8dc3a89e1ffbccc1599eb6de9c..135e2cfcd697756f28632d27ca16480adfef0318 100644 (file)
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -1530,7 +1530,16 @@ minetest.parse_json(string[, nullvalue]) -> something
 ^ nullvalue: returned in place of the JSON null; defaults to nil
 ^ On success returns a table, a string, a number, a boolean or nullvalue
 ^ On failure outputs an error message and returns nil
-^ Example: parse_json("[10, {\"a\":false}]") -> {[1] = 10, [2] = {a = false}}
+^ Example: parse_json("[10, {\"a\":false}]") -> {10, {a = false}}
+minetest.write_json(data[, styled]) -> string
+^ Convert a Lua table into a JSON string
+^ styled: Outputs in a human-readable format if this is set, defaults to false
+^ Un-serializable things like functions and userdata are saved as null.
+^ Warning: JSON is more strict than the Lua table format.
+    1. You can only use strings and positive integers of at least one as keys.
+    2. You can not mix string and integer keys.
+    This is due to the fact that Javascript has two distinct array and object values.
+^ Example: write_json({10, {a = false}}) -> "[10, {\"a\": false}]"
 minetest.serialize(table) -> string
 ^ Convert a table containing tables, strings, numbers, booleans and nils
   into string form readable by minetest.deserialize

diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index cf9f28d309c587adfffc1c238f81483d4b6e4876..8eb57ba41feddd30f8b25b39563d365b536f1371 100644 (file)
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -1081,3 +1081,52 @@ bool push_json_value(lua_State *L, const Json::Value &value, int nullindex)
        else
                return false;
 }
+
+// Converts Lua table --> JSON
+void get_json_value(lua_State *L, Json::Value &root, int index)
+{
+       int type = lua_type(L, index);
+       if (type == LUA_TBOOLEAN) {
+               root = (bool) lua_toboolean(L, index);
+       } else if (type == LUA_TNUMBER) {
+               root = lua_tonumber(L, index);
+       } else if (type == LUA_TSTRING) {
+               size_t len;
+               const char *str = lua_tolstring(L, index, &len);
+               root = std::string(str, len);
+       } else if (type == LUA_TTABLE) {
+               lua_pushnil(L);
+               while (lua_next(L, index)) {
+                       // Key is at -2 and value is at -1
+                       Json::Value value;
+                       get_json_value(L, value, lua_gettop(L));
+
+                       Json::ValueType roottype = root.type();
+                       int keytype = lua_type(L, -1);
+                       if (keytype == LUA_TNUMBER) {
+                               lua_Number key = lua_tonumber(L, -1);
+                               if (roottype != Json::nullValue && roottype != Json::arrayValue) {
+                                       throw LuaError(NULL, "Can't mix array and object values in JSON");
+                               } else if (key < 1) {
+                                       throw LuaError(NULL, "Can't use zero-based or negative indexes in JSON");
+                               } else if (floor(key) != key) {
+                                       throw LuaError(NULL, "Can't use indexes with a fractional part in JSON");
+                               }
+                               root[(Json::ArrayIndex) key - 1] = value;
+                       } else if (keytype == LUA_TSTRING) {
+                               if (roottype != Json::nullValue && roottype != Json::objectValue) {
+                                       throw LuaError(NULL, "Can't mix array and object values in JSON");
+                               }
+                               root[lua_tostring(L, -1)] = value;
+                       } else {
+                               throw LuaError(NULL, "Lua key to convert to JSON is not a string or number");
+                       }
+               }
+       } else if (type == LUA_TNIL) {
+               root = Json::nullValue;
+       } else {
+               throw LuaError(NULL, "Can only store booleans, numbers, strings, objects, arrays, and null in JSON");
+       }
+       lua_pop(L, 1); // Pop value
+}
+

diff --git a/src/script/common/c_content.h b/src/script/common/c_content.h
index 27019e29ee9a0549d0aa312fe7e6c39ac4a21d8a..3b85e5403f538521c64cdeaa4f092bb5b08bc0a1 100644 (file)
--- a/src/script/common/c_content.h
+++ b/src/script/common/c_content.h
@@ -150,6 +150,9 @@ void               luaentity_get             (lua_State *L,u16 id);
 bool               push_json_value           (lua_State *L,
                                               const Json::Value &value,
                                               int nullindex);
+void               get_json_value            (lua_State *L,
+                                              Json::Value &root,
+                                              int index);
 
 extern struct EnumString es_TileAnimationType[];
 

diff --git a/src/script/lua_api/l_util.cpp b/src/script/lua_api/l_util.cpp
index fe10e4f5716cdb75569f813c78d0ad44d07d4b72..9fa6fcb777a0c6996c45533e6de87390e7ef4023 100644 (file)
--- a/src/script/lua_api/l_util.cpp
+++ b/src/script/lua_api/l_util.cpp
@@ -179,6 +179,32 @@ int ModApiUtil::l_parse_json(lua_State *L)
        return 1;
 }
 
+// write_json(data[, styled]) -> string
+int ModApiUtil::l_write_json(lua_State *L)
+{
+       NO_MAP_LOCK_REQUIRED;
+
+       bool styled = false;
+       if (!lua_isnone(L, 2)) {
+               styled = lua_toboolean(L, 2);
+               lua_pop(L, 1);
+       }
+
+       Json::Value root;
+       get_json_value(L, root, 1);
+
+       std::string out;
+       if (styled) {
+               Json::StyledWriter writer;
+               out = writer.write(root);
+       } else {
+               Json::FastWriter writer;
+               out = writer.write(root);
+       }
+       lua_pushlstring(L, out.c_str(), out.size());
+       return 1;
+}
+
 // get_dig_params(groups, tool_capabilities[, time_from_last_punch])
 int ModApiUtil::l_get_dig_params(lua_State *L)
 {
@@ -249,6 +275,7 @@ void ModApiUtil::Initialize(lua_State *L, int top)
        API_FCT(setting_save);
 
        API_FCT(parse_json);
+       API_FCT(write_json);
 
        API_FCT(get_dig_params);
        API_FCT(get_hit_params);

diff --git a/src/script/lua_api/l_util.h b/src/script/lua_api/l_util.h
index d91c880cf9099da67839e61b7ecfff7c033e6c5f..13357587a73c97189c14afddd010f8f50a66911f 100644 (file)
--- a/src/script/lua_api/l_util.h
+++ b/src/script/lua_api/l_util.h
@@ -64,6 +64,9 @@ private:
        // parse_json(str[, nullvalue])
        static int l_parse_json(lua_State *L);
 
+       // write_json(data[, styled])
+       static int l_write_json(lua_State *L);
+
        // get_dig_params(groups, tool_capabilities[, time_from_last_punch])
        static int l_get_dig_params(lua_State *L);