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* Automatically abort transactions if they go out of scope without

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committing.
This commit is contained in:
Eelco Dolstra 2010-02-18 14:40:07 +00:00
parent e0305bb7a8
commit cfb09e0fad
1 changed files with 37 additions and 6 deletions
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41
src/libstore/local-store.cc
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@ -65,6 +65,37 @@ SQLiteStmt::~SQLiteStmt()
} }
struct SQLiteTxn
{
bool active;
sqlite3 * db;
SQLiteTxn(sqlite3 * db) : active(false) {
this->db = db;
if (sqlite3_exec(db, "begin;", 0, 0, 0) != SQLITE_OK)
throw SQLiteError(db, "starting transaction");
active = true;
}
void commit()
{
if (sqlite3_exec(db, "commit;", 0, 0, 0) != SQLITE_OK)
throw SQLiteError(db, "committing transaction");
active = false;
}
~SQLiteTxn()
{
try {
if (active && sqlite3_exec(db, "rollback;", 0, 0, 0) != SQLITE_OK)
throw SQLiteError(db, "aborting transaction");
} catch (...) {
ignoreException();
}
}
};
void checkStoreNotSymlink() void checkStoreNotSymlink()
{ {
if (getEnv("NIX_IGNORE_SYMLINK_STORE") == "1") return; if (getEnv("NIX_IGNORE_SYMLINK_STORE") == "1") return;
@ -130,7 +161,8 @@ LocalStore::LocalStore()
throw SQLiteError(db, "setting timeout"); throw SQLiteError(db, "setting timeout");
/* Check the current database schema and if necessary do an /* Check the current database schema and if necessary do an
upgrade. */ upgrade. !!! Race condition: several processes could start
the upgrade at the same time. */
int curSchema = getSchema(); int curSchema = getSchema();
if (curSchema > nixSchemaVersion) if (curSchema > nixSchemaVersion)
throw Error(format("current Nix store schema is version %1%, but I only support %2%") throw Error(format("current Nix store schema is version %1%, but I only support %2%")
@ -1264,8 +1296,7 @@ void LocalStore::upgradeStore6()
PathSet validPaths = queryValidPaths(); PathSet validPaths = queryValidPaths();
if (sqlite3_exec(db, "begin;", 0, 0, 0) != SQLITE_OK) SQLiteTxn txn(db);
throw SQLiteError(db, "running `begin' command");
std::map<Path, sqlite3_int64> pathToId; std::map<Path, sqlite3_int64> pathToId;
@ -1319,8 +1350,8 @@ void LocalStore::upgradeStore6()
std::cerr << "\n"; std::cerr << "\n";
if (sqlite3_exec(db, "commit;", 0, 0, 0) != SQLITE_OK) txn.commit();
throw SQLiteError(db, "running `commit' command");
writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str()); writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str());
lockFile(globalLock, ltRead, true); lockFile(globalLock, ltRead, true);