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#include "db.hh"
#include "util.hh"
#include <memory>
/* Wrapper class to ensure proper destruction. */
class DestroyDbc
{
Dbc * dbc;
public:
DestroyDbc(Dbc * _dbc) : dbc(_dbc) { }
~DestroyDbc() { dbc->close(); /* close() frees dbc */ }
};
static void rethrow(DbException & e)
{
throw Error(e.what());
}
Transaction::Transaction()
: txn(0)
{
}
Transaction::Transaction(Database & db)
{
db.requireEnv();
try {
db.env->txn_begin(0, &txn, 0);
} catch (DbException e) { rethrow(e); }
}
Transaction::~Transaction()
{
if (txn) abort();
}
void Transaction::commit()
{
if (!txn) throw Error("commit called on null transaction");
debug(format("committing transaction %1%") % (void *) txn);
DbTxn * txn2 = txn;
txn = 0;
try {
txn2->commit(0);
} catch (DbException e) { rethrow(e); }
}
void Transaction::abort()
{
if (!txn) throw Error("abort called on null transaction");
debug(format("aborting transaction %1%") % (void *) txn);
DbTxn * txn2 = txn;
txn = 0;
try {
txn2->abort();
} catch (DbException e) { rethrow(e); }
}
void Database::requireEnv()
{
if (!env) throw Error("database environment not open");
}
Db * Database::getDb(TableId table)
{
map<TableId, Db *>::iterator i = tables.find(table);
if (i == tables.end())
throw Error("unknown table id");
return i->second;
}
Database::Database()
: env(0)
, nextId(1)
{
}
Database::~Database()
{
if (env) {
debug(format("closing database environment"));
try {
for (map<TableId, Db *>::iterator i = tables.begin();
i != tables.end(); i++)
{
debug(format("closing table %1%") % i->first);
Db * db = i->second;
db->close(0);
delete db;
}
env->txn_checkpoint(0, 0, 0);
env->close(0);
} catch (DbException e) { rethrow(e); }
delete env;
}
}
void Database::open(const string & path)
{
try {
if (env) throw Error(format("environment already open"));
env = new DbEnv(0);
env->set_lg_bsize(32 * 1024); /* default */
env->set_lg_max(256 * 1024); /* must be > 4 * lg_bsize */
env->set_lk_detect(DB_LOCK_DEFAULT);
env->open(path.c_str(),
DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_TXN |
DB_CREATE,
0666);
} catch (DbException e) { rethrow(e); }
}
TableId Database::openTable(const string & tableName)
{
requireEnv();
TableId table = nextId++;
try {
Db * db = new Db(env, 0);
try {
// !!! fixme when switching to BDB 4.1: use txn.
db->open(tableName.c_str(), 0, DB_HASH, DB_CREATE, 0666);
} catch (...) {
delete db;
throw;
}
tables[table] = db;
} catch (DbException e) { rethrow(e); }
return table;
}
bool Database::queryString(const Transaction & txn, TableId table,
const string & key, string & data)
{
try {
Db * db = getDb(table);
Dbt kt((void *) key.c_str(), key.length());
Dbt dt;
int err = db->get(txn.txn, &kt, &dt, 0);
if (err) return false;
if (!dt.get_data())
data = "";
else
data = string((char *) dt.get_data(), dt.get_size());
} catch (DbException e) { rethrow(e); }
return true;
}
bool Database::queryStrings(const Transaction & txn, TableId table,
const string & key, Strings & data)
{
string d;
if (!queryString(txn, table, key, d))
return false;
string::iterator it = d.begin();
while (it != d.end()) {
if (it + 4 > d.end())
throw Error(format("short db entry: `%1%'") % d);
unsigned int len;
len = (unsigned char) *it++;
len |= ((unsigned char) *it++) << 8;
len |= ((unsigned char) *it++) << 16;
len |= ((unsigned char) *it++) << 24;
if (it + len > d.end())
throw Error(format("short db entry: `%1%'") % d);
string s;
while (len--) s += *it++;
data.push_back(s);
}
return true;
}
void Database::setString(const Transaction & txn, TableId table,
const string & key, const string & data)
{
try {
Db * db = getDb(table);
Dbt kt((void *) key.c_str(), key.length());
Dbt dt((void *) data.c_str(), data.length());
db->put(txn.txn, &kt, &dt, 0);
} catch (DbException e) { rethrow(e); }
}
void Database::setStrings(const Transaction & txn, TableId table,
const string & key, const Strings & data)
{
string d;
for (Strings::const_iterator it = data.begin();
it != data.end(); it++)
{
string s = *it;
unsigned int len = s.size();
d += len & 0xff;
d += (len >> 8) & 0xff;
d += (len >> 16) & 0xff;
d += (len >> 24) & 0xff;
d += s;
}
setString(txn, table, key, d);
}
void Database::delPair(const Transaction & txn, TableId table,
const string & key)
{
try {
Db * db = getDb(table);
Dbt kt((void *) key.c_str(), key.length());
db->del(txn.txn, &kt, 0);
/* Non-existence of a pair with the given key is not an
error. */
} catch (DbException e) { rethrow(e); }
}
void Database::enumTable(const Transaction & txn, TableId table,
Strings & keys)
{
try {
Db * db = getDb(table);
Dbc * dbc;
db->cursor(txn.txn, &dbc, 0);
DestroyDbc destroyDbc(dbc);
Dbt kt, dt;
while (dbc->get(&kt, &dt, DB_NEXT) != DB_NOTFOUND)
keys.push_back(
string((char *) kt.get_data(), kt.get_size()));
} catch (DbException e) { rethrow(e); }
}
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