bson_reader.h

/*
* Copyright (C) 2019 YY Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); 
* you may not use this file except in compliance with the License. 
* You may obtain a copy of the License at
*
*	http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, 
* software distributed under the License is distributed on an "AS IS" BASIS, 
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
* See the License for the specific language governing permissions and 
* limitations under the License.
*/

#ifndef __X_BSON_READER_H
#define __X_BSON_READER_H

#include <map>
#include <vector>
#include <stdexcept>
#include <list>
#include <string.h>

#include "thirdparty/libbson/include/libbson-1.0/bson.h"

#include "util.h"
#include "xreader.h"

namespace x2struct {

typedef std::map<const char*, bson_iter_t, cmp_str> bson_objs_type;

struct BsonDoc;

struct BsonValue {
    bson_iter_t root;
    bson_objs_type objs;
    std::vector<bson_iter_t> vecs;
    bson_objs_type::iterator iter;
    BsonDoc* doc;
};

struct BsonDoc {
    std::string data;
    std::list<BsonValue> vals;
    BsonValue *Get(const bson_iter_t*iter, bool top=false) {
        BsonValue _tmp_val;
        vals.push_back(_tmp_val);
        BsonValue *val = &vals.back();
        memcpy(&val->root, iter, sizeof(val->root));

        bson_iter_t sub;
        if (top) {
            memcpy(&sub, &val->root, sizeof(sub));
            while (bson_iter_next(&sub)) {
                val->objs[bson_iter_key(&sub)] = sub;
            }
        } else if (bson_iter_recurse(&val->root, &sub)) {
            if (BSON_TYPE_ARRAY != bson_iter_type(&val->root)) {
                while (bson_iter_next(&sub)) {
                    val->objs[bson_iter_key(&sub)] = sub;
                }
            } else {
                while (bson_iter_next(&sub)) {
                    val->vecs.push_back(sub);
                }
            }
        }
        val->doc = this;
        return val;
    }
};

class BsonReader:public XReader<BsonReader> {
public:
    friend class XReader<BsonReader> ;
    using xdoc_type::convert;
    BsonReader(const uint8_t*data, size_t length, bool copy=true):xdoc_type(0, ""),_doc(new BsonDoc) {
        init(data, length, copy);
    }
    BsonReader(const std::string&data, bool copy=true):xdoc_type(0, ""),_doc(new BsonDoc) {
        init((const uint8_t*)data.data(), data.length(), copy);
    }
    ~BsonReader() {
        if (0 != _doc) {
            delete _doc;
        }
    }

    std::string json() const {
        if (0 == _data) {
            return "";
        }
        size_t length=BSON_UINT32_TO_LE(*(int32_t*)_data);
        bson_t b; // local is ok
        bson_init_static(&b, _data, length);

        size_t s;
        char *jstr = bson_as_json(&b, &s);
        if (jstr) {
            std::string j(jstr);
            bson_free(jstr);
            return j;
        } else {
            return "";
        }
    }
public:
    #define XTOSTRUCT_BSON_GETVAL(rtype, f)         \
        const BsonValue *v = get_val(key);          \
        if (NULL != v) {                            \
            val = (rtype) f(&v->root);              \
            return true;                            \
        } else return false
    bool convert(const char *key, std::string &val) {
        const BsonValue *v = get_val(key);
        if (NULL == v) {
            return false;
        }

        uint32_t length;
        const char* data = bson_iter_utf8(&v->root, &length);
        if (0 != data) {
            val = std::string(data, length);
        }
        return true;
    }
    bool convert(const char *key, bool &val) {
        XTOSTRUCT_BSON_GETVAL(bool, bson_iter_as_int64);
    }
    bool convert(const char *key, int16_t &val) {
        XTOSTRUCT_BSON_GETVAL(int16_t, bson_iter_as_int64);
    }
    bool convert(const char *key, uint16_t &val) {
        XTOSTRUCT_BSON_GETVAL(uint16_t, bson_iter_as_int64);
    }
    bool convert(const char *key, int32_t &val) {
        XTOSTRUCT_BSON_GETVAL(int32_t, bson_iter_as_int64);
    }
    bool convert(const char *key, uint32_t &val) {
        XTOSTRUCT_BSON_GETVAL(uint32_t, bson_iter_as_int64);
    }
    bool convert(const char *key, int64_t &val) {
        XTOSTRUCT_BSON_GETVAL(int64_t, bson_iter_as_int64);
    }
    bool convert(const char *key, uint64_t &val) {
        XTOSTRUCT_BSON_GETVAL(uint64_t, bson_iter_as_int64);
    }
    bool convert(const char *key, double &val) {
        XTOSTRUCT_BSON_GETVAL(double, bson_iter_double);
    }
    bool convert(const char *key, float &val) {
        XTOSTRUCT_BSON_GETVAL(float, bson_iter_double);
    }

    const std::string& type() {
        static std::string t("bson");
        return t;
    }
    bool has(const char*key) {
        bool ret = _val->objs.find(key)!=_val->objs.end();
        return ret;
    }
    size_t size(bool to_vec=true) {
        (void)to_vec;
        if (BSON_TYPE_ARRAY==bson_iter_type(&_val->root)) {
            return _val->vecs.size();
        } else {
            return 0;
        }
    }
    BsonReader operator[](const char *key) {
        bson_objs_type::iterator iter = _val->objs.find(key);
        if (iter != _val->objs.end()) {
            return BsonReader(_val->doc->Get(&iter->second), this, key);
        } else {
            throw std::runtime_error(std::string("Did not have ")+key);
        }
        return BsonReader(0, 0, "");
    }
    BsonReader operator[](size_t index) {
        if (index<_val->vecs.size()) {
            return BsonReader(_val->doc->Get(&_val->vecs[index]), this, index);
        } else {
            throw std::runtime_error("Out of index");
        }

        return BsonReader(0, 0, "");
    }
    BsonReader begin() {
        _val->iter = _val->objs.begin();
        if (_val->iter != _val->objs.end()) {
            return BsonReader(_val->doc->Get(&_val->iter->second), this, _val->iter->first);
        } else {
            return BsonReader(0, this, "");
        }
    }
    BsonReader next() {
        if (0==_parent || 0==_parent->_val) {
            throw std::runtime_error("parent null");
        } else {
            ++(_parent->_val->iter);
        }
        if (_parent->_val->iter != _parent->_val->objs.end()) {
            return BsonReader(_val->doc->Get(&_parent->_val->iter->second), _parent, _parent->_val->iter->first);
        } else {
            return BsonReader(0, _parent, "");
        }
    }
    operator bool() const {
        return 0!=_val;
    }

private:
    void init(const uint8_t*data, size_t length, bool copy){
        bson_t b; // local is ok
        length = (length>0)?length:BSON_UINT32_TO_LE(*(int32_t*)data);
        if (copy) {
            std::string tmp(std::string((const char*)data, length));
            _doc->data.swap(tmp);
            bson_init_static(&b, (const uint8_t*)_doc->data.data(), _doc->data.length());
            _data = (const uint8_t*)_doc->data.data();
        } else {
            bson_init_static(&b, data, length);
            _data = data;
        }

        bson_iter_t root;
        bson_iter_init(&root, &b);
        _val = _doc->Get(&root, true);
    }

    BsonReader():xdoc_type(0, ""),_data(0), _doc(0),_val(0) {
    }
    BsonReader(BsonValue* val, const BsonReader*parent, const char*key):xdoc_type(parent, key),_val(val) {
        _doc = 0;
        _data = 0;
    }
    BsonReader(BsonValue* val, const BsonReader*parent, size_t index):xdoc_type(parent, index),_val(val) {
        _doc = 0;
        _data = 0;
    }

    BsonReader* child(const char*key, BsonReader*tmp) {
        bson_objs_type::iterator iter;
        if (NULL!=_val && _val->objs.end()!=(iter=_val->objs.find(key))) {
            tmp->_key = key;
            tmp->_parent = this;
            tmp->_val = _val->doc->Get(&iter->second);
            tmp->_set_has = this->_set_has;
            return tmp;
        } else {
            return NULL;
        }
    }

    const BsonValue* get_val(const char *key) {
        if (NULL == key) {
            return _val;
        } else if (NULL != _val) {
            bson_objs_type::iterator iter = _val->objs.find(key);
            if (iter != _val->objs.end()) {
                return _val->doc->Get(&iter->second);
            } else {
                return NULL;
            }
        } else {
            return NULL;
        }
    }

    const uint8_t* _data;
    BsonDoc *_doc;
    mutable BsonValue *_val;
};

}

#endif