github.com/igggame/nebulas-go@v2.1.0+incompatible/nf/nvm/v8/samples/memory_storage.cc (about)

     1  // Copyright (C) 2017 go-nebulas authors
     2  //
     3  // This file is part of the go-nebulas library.
     4  //
     5  // the go-nebulas library is free software: you can redistribute it and/or
     6  // modify it under the terms of the GNU General Public License as published by
     7  // the Free Software Foundation, either version 3 of the License, or
     8  // (at your option) any later version.
     9  //
    10  // the go-nebulas library is distributed in the hope that it will be useful,
    11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13  // GNU General Public License for more details.
    14  //
    15  // You should have received a copy of the GNU General Public License
    16  // along with the go-nebulas library.  If not, see
    17  // <http://www.gnu.org/licenses/>.
    18  //
    19  #include "memory_storage.h"
    20  
    21  #include <atomic>
    22  #include <mutex>
    23  #include <string>
    24  #include <unordered_map>
    25  
    26  #include <stdio.h>
    27  #include <stdlib.h>
    28  #include <string.h>
    29  
    30  using namespace std;
    31  
    32  static std::mutex mapMutex;
    33  static unordered_map<string, string> memoryMap;
    34  static atomic<uintptr_t> handlerCounter(1234);
    35  
    36  string genKey(void *handler, const char *key) {
    37    uintptr_t prefix = (uintptr_t)handler;
    38    string sKey = to_string(prefix);
    39    sKey.append("-");
    40    sKey.append(key);
    41    return sKey;
    42  }
    43  
    44  void *CreateStorageHandler() { return (void *)handlerCounter.fetch_add(1); }
    45  
    46  void DeleteStorageHandler(void *handler) {}
    47  
    48  char *StorageGet(void *handler, const char *key, size_t *cnt) {
    49    char *ret = NULL;
    50    string sKey = genKey(handler, key);
    51  
    52    mapMutex.lock();
    53    auto it = memoryMap.find(sKey);
    54    if (it != memoryMap.end()) {
    55      string &value = it->second;
    56      ret = (char *)calloc(value.length() + 1, sizeof(char));
    57      strncpy(ret, value.c_str(), value.length());
    58    }
    59    mapMutex.unlock();
    60  
    61    *cnt = 0;
    62  
    63    return ret;
    64  }
    65  
    66  int StoragePut(void *handler, const char *key, const char *value, size_t *cnt) {
    67    string sKey = genKey(handler, key);
    68  
    69    mapMutex.lock();
    70    memoryMap[sKey] = string(value);
    71    mapMutex.unlock();
    72  
    73    *cnt = strlen(key) + strlen(value);
    74    return 0;
    75  }
    76  
    77  int StorageDel(void *handler, const char *key, size_t *cnt) {
    78    string sKey = genKey(handler, key);
    79  
    80    mapMutex.lock();
    81    memoryMap.erase(sKey);
    82    mapMutex.unlock();
    83  
    84    *cnt = 0;
    85  
    86    return 0;
    87  }