tiny.sql.LazyHistory

1pub const LazyHistory = struct {2    allocator: Allocator,3    io: std.Io,4    dir: std.Io.Dir,5    path: []u8,6    state: State,7    retired: ?history_mod.refs.Snapshot = null,8    read_only: bool = false,910    const State = union(enum) {11        deferred: history_mod.refs.Snapshot,12        open: history_mod.History,13    };1415    pub fn full(self: *LazyHistory) Error!*history_mod.History {16        switch (self.state) {17            .open => {},18            .deferred => |snapshot| {19                std.debug.assert(self.retired == null);20                const opened = try history_mod.History.open(self.allocator, self.dir, .{21                    .io = self.io,22                    .path = self.path,23                    .recovery = .reject,24                    .create = !self.read_only,25                    .read_only = self.read_only,26                });27                self.retired = snapshot;28                self.state = .{ .open = opened };29            },30        }31        return &self.state.open;32    }3334    pub fn replayed(self: *const LazyHistory) bool {35        return self.state == .open;36    }3738    pub fn checkoutBranch(self: *const LazyHistory, name: []const u8) Error!branch.Checkout {39        return switch (self.state) {40            .open => |*history| try history.checkoutBranch(name),41            .deferred => |*snapshot| checkout: {42                const entry = snapshot.find(name) orelse return error.RefNotFound;43                break :checkout branch.Checkout.init(44                    .{ .name = entry.name, .target = entry.head },45                    entry.root,46                );47            },48        };49    }5051    pub fn deinit(self: *LazyHistory) void {52        switch (self.state) {53            .open => |*history| history.deinit(),54            .deferred => |*snapshot| snapshot.deinit(),55        }56        if (self.retired) |*snapshot| snapshot.deinit();57        self.dir.close(self.io);58        self.allocator.free(self.path);59        self.* = undefined;60    }61};

1pub const LazyHistory = lifecycle.LazyHistory;