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* Started using Berkeley DB environments. This is necessary for

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transaction support (but we don't actually use transactions yet).
This commit is contained in:
Eelco Dolstra 2003-07-31 13:47:13 +00:00
parent 758bd4673a
commit 4a013962bd
12 changed files with 256 additions and 107 deletions
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170
src/db.cc
View file

@ -3,66 +3,142 @@
#include <memory>
#include <db_cxx.h>
/* Wrapper classes that ensures that the database is closed upon
object destruction. */
class Db2 : public Db
/* Wrapper class to ensure proper destruction. */
class DestroyDb
{
Db * db;
public:
Db2(DbEnv *env, u_int32_t flags) : Db(env, flags) { }
~Db2() { close(0); }
DestroyDb(Db * _db) : db(_db) { }
~DestroyDb() { db->close(0); delete db; }
};
class DbcClose
class DestroyDbc
{
Dbc * cursor;
Dbc * dbc;
public:
DbcClose(Dbc * c) : cursor(c) { }
~DbcClose() { cursor->close(); }
DestroyDbc(Dbc * _dbc) : dbc(_dbc) { }
~DestroyDbc() { dbc->close(); /* close() frees dbc */ }
};
static auto_ptr<Db2> openDB(const string & filename, const string & dbname,
bool readonly)
{
auto_ptr<Db2> db(new Db2(0, 0));
db->open(filename.c_str(), dbname.c_str(),
DB_HASH, readonly ? DB_RDONLY : DB_CREATE, 0666);
return db;
}
static void rethrow(DbException & e)
{
throw Error(e.what());
}
void createDB(const string & filename, const string & dbname)
Transaction::Transaction()
: txn(0)
{
}
Transaction::Transaction(Database & db)
{
db.requireEnv();
db.env->txn_begin(0, &txn, 0);
}
Transaction::~Transaction()
{
if (txn) {
txn->abort();
txn = 0;
}
}
void Transaction::commit()
{
if (!txn) throw Error("commit called on null transaction");
txn->commit(0);
txn = 0;
}
void Database::requireEnv()
{
if (!env) throw Error("database environment not open");
}
Db * Database::openDB(const Transaction & txn,
const string & table, bool create)
{
requireEnv();
Db * db = new Db(env, 0);
try {
// !!! fixme when switching to BDB 4.1: use txn.
db->open(table.c_str(), 0,
DB_HASH, create ? DB_CREATE : 0, 0666);
} catch (...) {
delete db;
throw;
}
return db;
}
Database::Database()
: env(0)
{
}
Database::~Database()
{
if (env) {
env->close(0);
delete env;
}
}
void Database::open(const string & path)
{
try {
openDB(filename, dbname, false);
if (env) throw Error(format("environment already open"));
env = new DbEnv(0);
debug("foo" + path);
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); }
}
bool queryDB(const string & filename, const string & dbname,
void Database::createTable(const string & table)
{
try {
Db * db = openDB(noTxn, table, true);
DestroyDb destroyDb(db);
} catch (DbException e) { rethrow(e); }
}
bool Database::queryString(const Transaction & txn, const string & table,
const string & key, string & data)
{
try {
int err;
auto_ptr<Db2> db = openDB(filename, dbname, true);
Db * db = openDB(txn, table, false);
DestroyDb destroyDb(db);
Dbt kt((void *) key.c_str(), key.length());
Dbt dt;
err = db->get(0, &kt, &dt, 0);
int err = db->get(txn.txn, &kt, &dt, 0);
if (err) return false;
if (!dt.get_data())
@ -76,12 +152,12 @@ bool queryDB(const string & filename, const string & dbname,
}
bool queryListDB(const string & filename, const string & dbname,
bool Database::queryStrings(const Transaction & txn, const string & table,
const string & key, Strings & data)
{
string d;
if (!queryDB(filename, dbname, key, d))
if (!queryString(txn, table, key, d))
return false;
string::iterator it = d.begin();
@ -110,19 +186,21 @@ bool queryListDB(const string & filename, const string & dbname,
}
void setDB(const string & filename, const string & dbname,
void Database::setString(const Transaction & txn, const string & table,
const string & key, const string & data)
{
try {
auto_ptr<Db2> db = openDB(filename, dbname, false);
Db * db = openDB(txn, table, false);
DestroyDb destroyDb(db);
Dbt kt((void *) key.c_str(), key.length());
Dbt dt((void *) data.c_str(), data.length());
db->put(0, &kt, &dt, 0);
db->put(txn.txn, &kt, &dt, 0);
} catch (DbException e) { rethrow(e); }
}
void setListDB(const string & filename, const string & dbname,
void Database::setStrings(const Transaction & txn, const string & table,
const string & key, const Strings & data)
{
string d;
@ -141,34 +219,36 @@ void setListDB(const string & filename, const string & dbname,
d += s;
}
setDB(filename, dbname, key, d);
setString(txn, table, key, d);
}
void delDB(const string & filename, const string & dbname,
void Database::delPair(const Transaction & txn, const string & table,
const string & key)
{
try {
auto_ptr<Db2> db = openDB(filename, dbname, false);
Db * db = openDB(txn, table, false);
DestroyDb destroyDb(db);
Dbt kt((void *) key.c_str(), key.length());
db->del(0, &kt, 0);
db->del(txn.txn, &kt, 0);
} catch (DbException e) { rethrow(e); }
}
void enumDB(const string & filename, const string & dbname,
void Database::enumTable(const Transaction & txn, const string & table,
Strings & keys)
{
try {
auto_ptr<Db2> db = openDB(filename, dbname, true);
Db * db = openDB(txn, table, false);
DestroyDb destroyDb(db);
Dbc * cursor;
db->cursor(0, &cursor, 0);
DbcClose cursorCloser(cursor);
Dbc * dbc;
db->cursor(0, &dbc, 0);
DestroyDbc destroyDbc(dbc);
Dbt kt, dt;
while (cursor->get(&kt, &dt, DB_NEXT) != DB_NOTFOUND)
while (dbc->get(&kt, &dt, DB_NEXT) != DB_NOTFOUND)
keys.push_back(
string((char *) kt.get_data(), kt.get_size()));