lix/src/libstore/db.hh
Eelco Dolstra f4d44a0026 * Allow certain operations to succeed even if we don't have write
permission to the Nix store or database.  E.g., `nix-env -qa' will
  work, but `nix-env -qas' won't (the latter needs DB access).  The
  option `--readonly-mode' forces this mode; otherwise, it's only
  activated when the database cannot be opened.
2004-10-25 14:38:23 +00:00

98 lines
1.6 KiB
C++

#ifndef __DB_H
#define __DB_H
#include <string>
#include <list>
#include <map>
#include <db_cxx.h>
#include "util.hh"
using namespace std;
class Database;
class Transaction
{
friend class Database;
private:
DbTxn * txn;
public:
Transaction();
Transaction(Database & _db);
~Transaction();
void abort();
void commit();
void moveTo(Transaction & t);
};
#define noTxn Transaction()
typedef unsigned int TableId; /* table handles */
class Database
{
friend class Transaction;
private:
DbEnv * env;
int fdLock;
int fdAccessors;
TableId nextId;
map<TableId, Db *> tables;
void requireEnv();
Db * getDb(TableId table);
public:
Database();
~Database();
void open(const string & path);
void close();
TableId openTable(const string & table);
bool queryString(const Transaction & txn, TableId table,
const string & key, string & data);
bool queryStrings(const Transaction & txn, TableId table,
const string & key, Strings & data);
void setString(const Transaction & txn, TableId table,
const string & key, const string & data);
void setStrings(const Transaction & txn, TableId table,
const string & key, const Strings & data,
bool deleteEmpty = true);
void delPair(const Transaction & txn, TableId table,
const string & key);
void enumTable(const Transaction & txn, TableId table,
Strings & keys);
};
class DbNoPermission : public Error
{
public:
DbNoPermission(const format & f) : Error(f) { };
};
#endif /* !__DB_H */