mongo_cursor.cpp

#include <iostream>
#include <client/dbclient.h>
#include "utils.h"
#include "common.h"

using namespace mongo;

extern void bson_to_lua(lua_State *L, const BSONObj &obj);

namespace {
inline DBClientCursor* userdata_to_cursor(lua_State* L, int index) {
    void *ud = luaL_checkudata(L, index, LUAMONGO_CURSOR);
    DBClientCursor *cursor = *((DBClientCursor **)ud);
    return cursor;
}
} // anonymous namespace

/*
 * cursor,err = db:query(ns, query)
 */
int cursor_create(lua_State *L, DBClientBase *connection, const char *ns,
                  const Query &query, int nToReturn, int nToSkip,
                  const BSONObj *fieldsToReturn, int queryOptions, int batchSize) {
    int resultcount = 1;

    try {
        std::auto_ptr<DBClientCursor> autocursor = connection->query(
            ns, query, nToReturn, nToSkip,
            fieldsToReturn, queryOptions, batchSize);

        if (!autocursor.get()) {
            lua_pushnil(L);
            lua_pushstring(L, LUAMONGO_ERR_CONNECTION_LOST);
            return 2;
        }

        DBClientCursor **cursor = (DBClientCursor **)lua_newuserdata(L, sizeof(DBClientCursor *));
        *cursor = autocursor.get();
        autocursor.release();

        luaL_getmetatable(L, LUAMONGO_CURSOR);
        lua_setmetatable(L, -2);
    } catch (std::exception &e) {
        lua_pushnil(L);
        lua_pushfstring(L, LUAMONGO_ERR_QUERY_FAILED, e.what());
        resultcount = 2;
    }

    return resultcount;
}

/*
 * res = cursor:next()
 */
static int cursor_next(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);

    if (cursor->more()) {
        bson_to_lua(L, cursor->next());
    } else {
        lua_pushnil(L);
    }

    return 1;
}

static int result_iterator(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, lua_upvalueindex(1));

    if (cursor->more()) {
        bson_to_lua(L, cursor->next());
    } else {
        lua_pushnil(L);
    }

    return 1;
}

/*
 * iter_func = cursor:results()
 */
static int cursor_results(lua_State *L) {
    lua_pushcclosure(L, result_iterator, 1);
    return 1;
}

/*
 * has_more = cursor:has_more(in_current_batch)
 *    pass true to call moreInCurrentBatch (mongo >=1.5)
 */
static int cursor_has_more(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);

    bool in_current_batch = lua_toboolean(L, 2);
    if (in_current_batch)
        lua_pushboolean(L, cursor->moreInCurrentBatch());
    else
        lua_pushboolean(L, cursor->more());

    return 1;
}

/*
 * it_count = cursor:itcount()
 */
static int cursor_itcount(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    lua_pushinteger(L, cursor->itcount());
    return 1;
}

/*
 * is_dead = cursor:is_dead()
 */
static int cursor_is_dead(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    lua_pushboolean(L, cursor->isDead());
    return 1;
}

/*
 * is_tailable = cursor:is_tailable()
 */
static int cursor_is_tailable(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    lua_pushboolean(L, cursor->tailable());
    return 1;
}

/*
 * has_result_flag = cursor:has_result_flag()
 */
static int cursor_has_result_flag(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    int flag = lua_tointeger(L, 2);
    lua_pushboolean(L, cursor->hasResultFlag(flag));
    return 1;
}

/*
 * id = cursor:get_id()
 */
static int cursor_get_id(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    lua_pushnumber(L, cursor->getCursorId());
    return 1;
}
/*
 * __gc
 */
static int cursor_gc(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    delete cursor;
    return 0;
}

/*
 * __tostring
 */
static int cursor_tostring(lua_State *L) {
    DBClientCursor *cursor = userdata_to_cursor(L, 1);
    lua_pushfstring(L, "%s: %p", LUAMONGO_CURSOR, cursor);
    return 1;
}

int mongo_cursor_register(lua_State *L) {
    static const luaL_Reg cursor_methods[] = {
        {"next", cursor_next},
        {"results", cursor_results},
        {"has_more", cursor_has_more},
        {"itcount", cursor_itcount},
        {"is_dead", cursor_is_dead},
        {"is_tailable", cursor_is_tailable},
        {"has_result_flag", cursor_has_result_flag},
        {"get_id", cursor_get_id},
        {NULL, NULL}
    };

    static const luaL_Reg cursor_class_methods[] = {
        {NULL, NULL}
    };

    luaL_newmetatable(L, LUAMONGO_CURSOR);
    //luaL_register(L, 0, cursor_methods);
    luaL_setfuncs(L, cursor_methods, 0);
    lua_pushvalue(L,-1);
    lua_setfield(L, -2, "__index");

    lua_pushcfunction(L, cursor_gc);
    lua_setfield(L, -2, "__gc");

    lua_pushcfunction(L, cursor_tostring);
    lua_setfield(L, -2, "__tostring");
    
    lua_pop(L,1);
    
    #if LUA_VERSION_NUM < 502
    luaL_register(L, LUAMONGO_CURSOR, cursor_class_methods);
    #else
    luaL_newlib(L, cursor_class_methods);
    #endif
    
    return 1;
}