tiny.sql.LifecycleWorkspace

1/// Owns one database and the storage that database runs on, created by a tool2/// at startup to open its database through it. The workspace holds the file3/// workspace and, once opened, the database itself, and hands callers a pointer4/// to that database. Because callers hold that pointer, the workspace has to5/// stay at one address from the open until the opened database is released, so6/// callers place it on the heap. The workspace takes its storage either from7/// the caller with `init` or from an allocator with `allocate`, and gives it8/// back with the matching `deinit` or `deallocate`. The workspace opens one9/// database at a time, reports `WorkspaceBusy` for a second open while the10/// first is live, and refuses teardown by assertion while a database is still11/// open.12pub const Workspace = struct {13    pub const Limits = file_mod.Database.Workspace.Limits;14    pub const Capacity = file_mod.Database.Workspace.Capacity;15    pub const Storage = file_mod.Database.Workspace.Storage;16    pub const InitError = file_mod.Database.Workspace.InitError;17    pub const AllocateError = file_mod.Database.Workspace.AllocateError;18    pub const AcquireError = file_mod.Database.Workspace.AcquireError;1920    file_workspace: file_mod.Database.Workspace,21    database: file_mod.Database = undefined,22    database_live: bool = false,2324    pub fn init(25        storage: Storage,26        limits: Limits,27    ) InitError!Workspace {28        return .{29            .file_workspace = try file_mod.Database.Workspace.init(storage, limits),30        };31    }3233    pub fn allocate(allocator: Allocator, limits: Limits) AllocateError!Workspace {34        return .{35            .file_workspace = try file_mod.Database.Workspace.allocate(allocator, limits),36        };37    }3839    pub fn activate(self: *Workspace) void {40        std.debug.assert(!self.database_live);41        self.file_workspace.activate();42    }4344    pub fn deinit(self: *Workspace) Storage {45        std.debug.assert(!self.database_live);46        const storage = self.file_workspace.deinit();47        self.* = undefined;48        return storage;49    }5051    pub fn deallocate(self: *Workspace, allocator: Allocator) void {52        std.debug.assert(!self.database_live);53        self.file_workspace.deallocate(allocator);54        self.* = undefined;55    }5657    pub fn retainedBytes(self: *const Workspace) usize {58        return self.file_workspace.retainedBytes();59    }6061    fn acquireWritable(62        self: *Workspace,63        allocator: Allocator,64        dir: std.Io.Dir,65        options: file_mod.OpenOptions,66    ) file_mod.Error!*file_mod.Database {67        if (self.database_live) return error.WorkspaceBusy;68        const writable = try file_mod.Database.open(69            allocator,70            &self.file_workspace,71            dir,72            options,73        );74        self.database = writable;75        self.database_live = true;76        return &self.database;77    }7879    fn acquireReadOnly(80        self: *Workspace,81        allocator: Allocator,82        dir: std.Io.Dir,83        options: file_mod.ReadOpenOptions,84    ) file_mod.Error!*file_mod.Database {85        if (self.database_live) return error.WorkspaceBusy;86        self.database = try file_mod.Database.openReadOnly(87            allocator,88            &self.file_workspace,89            dir,90            options,91        );92        self.database_live = true;93        return &self.database;94    }9596    fn releaseDatabase(self: *Workspace, database: *file_mod.Database) void {97        std.debug.assert(self.database_live);98        std.debug.assert(database == &self.database);99        database.deinit();100        self.database_live = false;101    }102103    fn ownerOf(writable: *file_mod.Database) *Workspace {104        const owner: *Workspace = @alignCast(@fieldParentPtr(105            "file_workspace",106            writable.workspace,107        ));108        std.debug.assert(owner.database_live);109        std.debug.assert(writable == &owner.database);110        return owner;111    }112};

1pub const LifecycleWorkspace = lifecycle.Workspace;