tvl-depot/src/libstore/db.hh
Eelco Dolstra 9e975458b4 * Get rid of the substitutes database table (NIX-47). Instead, if we
need any info on substitutable paths, we just call the substituters
  (such as download-using-manifests.pl) directly.  This means that
  it's no longer necessary for nix-pull to register substitutes or for
  nix-channel to clear them, which makes those operations much faster
  (NIX-95).  Also, we don't have to worry about keeping nix-pull
  manifests (in /nix/var/nix/manifests) and the database in sync with
  each other.

  The downside is that there is some overhead in calling an external
  program to get the substitutes info.  For instance, "nix-env -qas"
  takes a bit longer.

  Abolishing the substitutes table also makes the logic in
  local-store.cc simpler, as we don't need to store info for invalid
  paths.  On the downside, you cannot do things like "nix-store -qR"
  on a substitutable but invalid path (but nobody did that anyway).

* Never catch interrupts (the Interrupted exception).
2007-08-12 00:29:28 +00:00

107 lines
1.8 KiB
C++

#ifndef __DB_H
#define __DB_H
#include "types.hh"
#include <map>
/* Defined externally. */
class DbTxn;
class DbEnv;
class Db;
namespace nix {
class Database;
class Transaction
{
friend class Database;
private:
DbTxn * txn;
public:
Transaction();
Transaction(Database & _db);
~Transaction();
void begin(Database & db);
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;
TableId nextId;
std::map<TableId, Db *> tables;
void requireEnv();
Db * getDb(TableId table);
void open2(const string & path, bool removeOldEnv);
public:
Database();
~Database();
void open(const string & path);
void close();
TableId openTable(const string & table, bool sorted = false);
void closeTable(TableId table);
void deleteTable(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, const string & keyPrefix = "");
void clearTable(const Transaction & txn, TableId table);
};
class DbNoPermission : public Error
{
public:
DbNoPermission(const format & f) : Error(f) { };
};
}
#endif /* !__DB_H */