forked from lix-project/lix
163 lines
3.5 KiB
C++
163 lines
3.5 KiB
C++
#pragma once
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///@file
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#include <functional>
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#include <string>
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#include "error.hh"
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struct sqlite3;
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struct sqlite3_stmt;
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namespace nix {
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/**
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* RAII wrapper to close a SQLite database automatically.
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*/
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struct SQLite
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{
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sqlite3 * db = 0;
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SQLite() { }
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SQLite(const Path & path, bool create = true);
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SQLite(const SQLite & from) = delete;
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SQLite& operator = (const SQLite & from) = delete;
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SQLite& operator = (SQLite && from) { db = from.db; from.db = 0; return *this; }
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~SQLite();
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operator sqlite3 * () { return db; }
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/**
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* Disable synchronous mode, set truncate journal mode.
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*/
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void isCache();
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void exec(const std::string & stmt);
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uint64_t getLastInsertedRowId();
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};
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/**
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* RAII wrapper to create and destroy SQLite prepared statements.
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*/
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struct SQLiteStmt
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{
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sqlite3 * db = 0;
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sqlite3_stmt * stmt = 0;
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std::string sql;
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SQLiteStmt() { }
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SQLiteStmt(sqlite3 * db, const std::string & sql) { create(db, sql); }
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void create(sqlite3 * db, const std::string & s);
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~SQLiteStmt();
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operator sqlite3_stmt * () { return stmt; }
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/**
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* Helper for binding / executing statements.
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*/
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class Use
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{
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friend struct SQLiteStmt;
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private:
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SQLiteStmt & stmt;
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unsigned int curArg = 1;
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Use(SQLiteStmt & stmt);
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public:
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~Use();
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/**
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* Bind the next parameter.
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*/
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Use & operator () (std::string_view value, bool notNull = true);
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Use & operator () (const unsigned char * data, size_t len, bool notNull = true);
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Use & operator () (int64_t value, bool notNull = true);
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Use & bind(); // null
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int step();
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/**
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* Execute a statement that does not return rows.
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*/
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void exec();
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/**
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* For statements that return 0 or more rows. Returns true iff
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* a row is available.
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*/
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bool next();
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std::string getStr(int col);
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int64_t getInt(int col);
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bool isNull(int col);
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};
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Use use()
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{
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return Use(*this);
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}
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};
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/**
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* RAII helper that ensures transactions are aborted unless explicitly
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* committed.
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*/
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struct SQLiteTxn
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{
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bool active = false;
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sqlite3 * db;
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SQLiteTxn(sqlite3 * db);
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void commit();
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~SQLiteTxn();
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};
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struct SQLiteError : Error
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{
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std::string path;
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std::string errMsg;
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int errNo, extendedErrNo, offset;
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template<typename... Args>
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[[noreturn]] static void throw_(sqlite3 * db, const std::string & fs, const Args & ... args) {
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throw_(db, hintfmt(fs, args...));
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}
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SQLiteError(const char *path, const char *errMsg, int errNo, int extendedErrNo, int offset, hintformat && hf);
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protected:
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template<typename... Args>
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SQLiteError(const char *path, const char *errMsg, int errNo, int extendedErrNo, int offset, const std::string & fs, const Args & ... args)
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: SQLiteError(path, errNo, extendedErrNo, offset, hintfmt(fs, args...))
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{ }
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[[noreturn]] static void throw_(sqlite3 * db, hintformat && hf);
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};
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MakeError(SQLiteBusy, SQLiteError);
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void handleSQLiteBusy(const SQLiteBusy & e, time_t & nextWarning);
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/**
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* Convenience function for retrying a SQLite transaction when the
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* database is busy.
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*/
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template<typename T, typename F>
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T retrySQLite(F && fun)
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{
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time_t nextWarning = time(0) + 1;
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while (true) {
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try {
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return fun();
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} catch (SQLiteBusy & e) {
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handleSQLiteBusy(e, nextWarning);
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}
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}
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}
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}
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