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#pragma once
#include <functional>
#include <string>
#include "types.hh"
class sqlite3;
class sqlite3_stmt;
namespace nix {
/* RAII wrapper to close a SQLite database automatically. */
struct SQLite
{
sqlite3 * db = 0;
SQLite() { }
SQLite(const Path & path, bool create = true);
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);
};
/* 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 () (const std::string & 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);
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();
};
MakeError(SQLiteError, Error);
MakeError(SQLiteBusy, SQLiteError);
[[noreturn]] void throwSQLiteError(sqlite3 * db, const FormatOrString & fs);
void handleSQLiteBusy(const SQLiteBusy & e);
/* Convenience function for retrying a SQLite transaction when the
database is busy. */
template<typename T>
T retrySQLite(std::function<T()> fun)
{
while (true) {
try {
return fun();
} catch (SQLiteBusy & e) {
handleSQLiteBusy(e);
}
}
}
}
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