lix/src/libstore/sqlite.hh

119 lines
2.6 KiB
C++
Raw Normal View History

2016-03-30 11:27:25 +00:00
#pragma once
#include <functional>
#include <string>
2020-05-11 21:52:15 +00:00
#include "error.hh"
2016-03-30 11:27:25 +00:00
2020-03-24 13:26:13 +00:00
struct sqlite3;
struct sqlite3_stmt;
2016-03-30 11:27:25 +00:00
namespace nix {
/* RAII wrapper to close a SQLite database automatically. */
struct SQLite
{
2016-08-09 12:27:30 +00:00
sqlite3 * db = 0;
SQLite() { }
2020-03-24 13:26:13 +00:00
SQLite(const Path & path, bool create = true);
2016-08-09 12:27:30 +00:00
SQLite(const SQLite & from) = delete;
SQLite& operator = (const SQLite & from) = delete;
SQLite& operator = (SQLite && from) { db = from.db; from.db = 0; return *this; }
2016-03-30 11:27:25 +00:00
~SQLite();
operator sqlite3 * () { return db; }
2016-08-09 12:27:30 +00:00
2020-03-24 13:26:13 +00:00
/* Disable synchronous mode, set truncate journal mode. */
void isCache();
2016-08-09 12:27:30 +00:00
void exec(const std::string & stmt);
2016-03-30 11:27:25 +00:00
};
/* RAII wrapper to create and destroy SQLite prepared statements. */
struct SQLiteStmt
{
sqlite3 * db = 0;
sqlite3_stmt * stmt = 0;
2017-02-28 12:59:11 +00:00
std::string sql;
SQLiteStmt() { }
2017-02-28 12:59:11 +00:00
SQLiteStmt(sqlite3 * db, const std::string & sql) { create(db, sql); }
2016-03-30 11:27:25 +00:00
void create(sqlite3 * db, const std::string & s);
~SQLiteStmt();
operator sqlite3_stmt * () { return stmt; }
/* Helper for binding / executing statements. */
class Use
{
friend struct SQLiteStmt;
private:
SQLiteStmt & stmt;
unsigned int curArg = 1;
Use(SQLiteStmt & stmt);
public:
2016-04-05 13:29:56 +00:00
~Use();
/* Bind the next parameter. */
Use & operator () (const std::string & value, bool notNull = true);
2020-03-24 13:26:13 +00:00
Use & operator () (const unsigned char * data, size_t len, bool notNull = true);
Use & operator () (int64_t value, bool notNull = true);
Use & bind(); // null
int step();
/* Execute a statement that does not return rows. */
void exec();
/* For statements that return 0 or more rows. Returns true iff
a row is available. */
bool next();
std::string getStr(int col);
int64_t getInt(int col);
bool isNull(int col);
};
Use use()
{
return Use(*this);
}
2016-03-30 11:27:25 +00:00
};
/* RAII helper that ensures transactions are aborted unless explicitly
committed. */
struct SQLiteTxn
{
bool active = false;
sqlite3 * db;
SQLiteTxn(sqlite3 * db);
void commit();
~SQLiteTxn();
};
MakeError(SQLiteError, Error);
MakeError(SQLiteBusy, SQLiteError);
[[noreturn]] void throwSQLiteError(sqlite3 * db, const FormatOrString & fs);
2016-03-30 11:27:25 +00:00
2020-04-29 03:06:08 +00:00
void handleSQLiteBusy(SQLiteBusy & e);
2017-02-28 12:59:11 +00:00
2016-03-30 11:27:25 +00:00
/* Convenience function for retrying a SQLite transaction when the
database is busy. */
template<typename T, typename F>
T retrySQLite(F && fun)
2016-03-30 11:27:25 +00:00
{
while (true) {
try {
return fun();
} catch (SQLiteBusy & e) {
2017-02-28 12:59:11 +00:00
handleSQLiteBusy(e);
2016-03-30 11:27:25 +00:00
}
}
}
}