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#pragma once
///@file
#include <functional>
#include <string>
#include "error.hh"
struct sqlite3;
struct sqlite3_stmt;
namespace nix {
enum class SQLiteOpenMode {
/**
* Open the database in read-write mode.
* If the database does not exist, it will be created.
*/
Normal,
/**
* Open the database in read-write mode.
* Fails with an error if the database does not exist.
*/
NoCreate,
/**
* Open the database in immutable mode.
* In addition to the database being read-only,
* no wal or journal files will be created by sqlite.
* Use this mode if the database is on a read-only filesystem.
* Fails with an error if the database does not exist.
*/
Immutable,
};
/**
* RAII wrapper to close a SQLite database automatically.
*/
struct SQLite
{
sqlite3 * db = 0;
SQLite() { }
SQLite(const Path & path, SQLiteOpenMode mode = SQLiteOpenMode::Normal);
SQLite(const SQLite & from) = delete;
SQLite& operator = (const SQLite & from) = delete;
SQLite& operator = (SQLite && from) { db = from.db; from.db = 0; return *this; }
~SQLite();
operator sqlite3 * () { return db; }
/**
* Disable synchronous mode, set truncate journal mode.
*/
void isCache();
void exec(const std::string & stmt);
uint64_t getLastInsertedRowId();
};
/**
* RAII wrapper to create and destroy SQLite prepared statements.
*/
struct SQLiteStmt
{
sqlite3 * db = 0;
sqlite3_stmt * stmt = 0;
std::string sql;
SQLiteStmt() { }
SQLiteStmt(sqlite3 * db, const std::string & sql) { create(db, sql); }
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:
~Use();
/**
* Bind the next parameter.
*/
Use & operator () (std::string_view value, bool notNull = true);
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);
std::optional<std::string> getStrNullable(int col);
int64_t getInt(int col);
bool isNull(int col);
};
Use use()
{
return Use(*this);
}
};
/**
* RAII helper that ensures transactions are aborted unless explicitly
* committed.
*/
struct SQLiteTxn
{
bool active = false;
sqlite3 * db;
SQLiteTxn(sqlite3 * db);
void commit();
~SQLiteTxn();
};
struct SQLiteError : Error
{
std::string path;
std::string errMsg;
int errNo, extendedErrNo, offset;
template<typename... Args>
[[noreturn]] static void throw_(sqlite3 * db, const std::string & fs, const Args & ... args) {
throw_(db, HintFmt(fs, args...));
}
SQLiteError(const char *path, const char *errMsg, int errNo, int extendedErrNo, int offset, HintFmt && hf);
protected:
template<typename... Args>
SQLiteError(const char *path, const char *errMsg, int errNo, int extendedErrNo, int offset, const std::string & fs, const Args & ... args)
: SQLiteError(path, errMsg, errNo, extendedErrNo, offset, HintFmt(fs, args...))
{ }
[[noreturn]] static void throw_(sqlite3 * db, HintFmt && hf);
};
MakeError(SQLiteBusy, SQLiteError);
void handleSQLiteBusy(const SQLiteBusy & e, time_t & nextWarning);
/**
* Convenience function for retrying a SQLite transaction when the
* database is busy.
*/
template<typename T, typename F>
T retrySQLite(F && fun)
{
time_t nextWarning = time(0) + 1;
while (true) {
try {
return fun();
} catch (SQLiteBusy & e) {
handleSQLiteBusy(e, nextWarning);
}
}
}
}
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