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-rw-r--r--nix/libstore/sqlite.hh83
1 files changed, 83 insertions, 0 deletions
diff --git a/nix/libstore/sqlite.hh b/nix/libstore/sqlite.hh
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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;
+ SQLite() { db = 0; }
+ ~SQLite();
+ operator sqlite3 * () { return db; }
+};
+
+/* RAII wrapper to create and destroy SQLite prepared statements. */
+struct SQLiteStmt
+{
+ sqlite3 * db;
+ sqlite3_stmt * stmt;
+ unsigned int curArg;
+ SQLiteStmt() { stmt = 0; }
+ void create(sqlite3 * db, const std::string & s);
+ void reset();
+ ~SQLiteStmt();
+ operator sqlite3_stmt * () { return stmt; }
+ void bind(const std::string & value);
+ void bind(int value);
+ void bind64(long long value);
+ void bind();
+};
+
+/* Helper class to ensure that prepared statements are reset when
+ leaving the scope that uses them. Unfinished prepared statements
+ prevent transactions from being aborted, and can cause locks to be
+ kept when they should be released. */
+struct SQLiteStmtUse
+{
+ SQLiteStmt & stmt;
+ SQLiteStmtUse(SQLiteStmt & stmt);
+ ~SQLiteStmtUse();
+};
+
+/* 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 format & f);
+
+/* 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) {
+ }
+ }
+}
+
+}