From eb0d8b4ca05f2bf4f6b9f82975db6e8549b07094 Mon Sep 17 00:00:00 2001 From: jaina heartles Date: Thu, 6 Jul 2023 00:13:28 -0700 Subject: [PATCH] create vtables --- src/sql/lib.zig | 785 +++++------------------------------------------- 1 file changed, 81 insertions(+), 704 deletions(-) diff --git a/src/sql/lib.zig b/src/sql/lib.zig index bb55dd3..3964125 100644 --- a/src/sql/lib.zig +++ b/src/sql/lib.zig @@ -1,726 +1,103 @@ const std = @import("std"); -const util = @import("util"); -const build_options = @import("build_options"); - -const postgres = if (build_options.enable_postgres) - @import("./engines/postgres.zig") -else - @import("./engines/null.zig"); - -const sqlite = if (build_options.enable_sqlite) - @import("./engines/sqlite.zig") -else - @import("./engines/null.zig"); -const common = @import("./engines/common.zig"); const Allocator = std.mem.Allocator; -const errors = @import("./errors.zig").library_errors; - -pub const AcquireError = OpenError || error{NoConnectionsLeft}; -pub const OpenError = errors.OpenError; -pub const QueryError = errors.QueryError; -pub const RowError = errors.RowError; -pub const QueryRowError = errors.QueryRowError; -pub const BeginError = errors.BeginError; -pub const CommitError = errors.CommitError; - -pub const DatabaseError = QueryError || RowError || QueryRowError || BeginError || CommitError; - -pub const QueryOptions = common.QueryOptions; - -pub const Engine = enum { - postgres, - sqlite, +pub const SqlValue = union(enum) { + int: i64, + uint: u64, + str: []const u8, + @"null": void, + float: f64, }; -/// Helper for building queries at runtime. All constituent parts of the -/// query should be defined at comptime, however the choice of whether -/// or not to include them can occur at runtime. -pub const QueryBuilder = struct { - array: std.ArrayList(u8), - where_clauses_appended: usize = 0, - set_statements_appended: usize = 0, - - pub fn init(alloc: std.mem.Allocator) QueryBuilder { - return QueryBuilder{ .array = std.ArrayList(u8).init(alloc) }; - } - - pub fn deinit(self: *const QueryBuilder) void { - self.array.deinit(); - } - - /// Add a chunk of sql to the query without processing - pub fn appendSlice(self: *QueryBuilder, comptime sql: []const u8) !void { - try self.array.appendSlice(sql); - } - - /// Add a where clause to the query. Clauses are assumed to be components - /// in an overall expression in Conjunctive Normal Form (AND of OR's). - /// https://en.wikipedia.org/wiki/Conjunctive_normal_form - /// All calls to andWhere must be contiguous, that is, they cannot be - /// interspersed with calls to appendSlice - pub fn andWhere(self: *QueryBuilder, comptime clause: []const u8) !void { - if (self.where_clauses_appended == 0) { - try self.array.appendSlice("\nWHERE "); - } else { - try self.array.appendSlice(" AND "); - } - - try self.array.appendSlice(clause); - self.where_clauses_appended += 1; - } - - pub fn set(self: *QueryBuilder, comptime col: []const u8, comptime val: []const u8) !void { - if (self.set_statements_appended == 0) { - try self.array.appendSlice("\nSET "); - } else { - try self.array.appendSlice(", "); - } - - try self.array.appendSlice(col ++ " = " ++ val); - self.set_statements_appended += 1; - } - - pub fn str(self: *const QueryBuilder) []const u8 { - return self.array.items; - } - - pub fn terminate(self: *QueryBuilder) ![:0]const u8 { - std.debug.assert(self.array.items.len != 0); - if (self.array.items[self.array.items.len - 1] != 0) try self.array.append(0); - - return std.meta.assumeSentinel(self.array.items, 0); - } +pub const QueryOptions = struct { + // If true, then it will not return an error on the SQLite backend + // if an argument passed does not map to a parameter in the query. + // Has no effect on the postgres backend. + ignore_unused_arguments: bool = false, }; -// TODO: make this suck less -pub const Config = union(Engine) { - postgres: struct { - pg_conn_str: [:0]const u8, - }, - sqlite: struct { - sqlite_file_path: [:0]const u8, - sqlite_is_uri: bool = false, - }, +pub const UnexpectedError = error{Unexpected}; +pub const ConstraintError = error{ + NotNullViolation, + ForeignKeyViolation, + UniqueViolation, + CheckViolation, + + /// Catchall for miscellaneous types of constraints + ConstraintViolation, }; -const RawResults = union(Engine) { - postgres: postgres.Results, - sqlite: sqlite.Results, +pub const OpenError = error{BadConnection} || UnexpectedError; - fn finish(self: RawResults) void { - switch (self) { - .postgres => |pg| pg.finish(), - .sqlite => |lite| lite.finish(), - } - } +pub const ExecError = error{ + Cancelled, + BadConnection, + InternalException, + DatabaseBusy, + PermissionDenied, + SqlException, - fn columnCount(self: RawResults) !u15 { - return try switch (self) { - .postgres => |pg| pg.columnCount(), - .sqlite => |lite| lite.columnCount(), - }; - } + /// Argument could not be marshalled for query + BindException, - fn columnIndex(self: RawResults, name: []const u8) error{ NotFound, Unexpected }!u15 { - return switch (self) { - .postgres => |pg| pg.columnIndex(name), - .sqlite => |lite| lite.columnIndex(name), - } catch |err| switch (err) { - error.OutOfRange => error.Unexpected, - error.NotFound => error.NotFound, - }; - } + /// An argument was not used by the query (not checked in all DB engines) + UnusedArgument, - fn row(self: *RawResults) RowError!?Row { - return switch (self.*) { - .postgres => |*pg| if (try pg.row()) |r| Row{ .postgres = r } else null, - .sqlite => |*lite| if (try lite.row()) |r| Row{ .sqlite = r } else null, - }; - } -}; + /// Memory error when marshalling argument for query + OutOfMemory, + AllocatorRequired, +} || ConstraintError || UnexpectedError; -const FieldRef = []const []const u8; -fn FieldPtr(comptime Ptr: type, comptime names: FieldRef) type { - if (names.len == 0) return Ptr; +pub const Db = struct { + const VTable = struct { + /// Closes the database connection + close: *const fn (ctx: *anyopaque) void, - const T = std.meta.Child(Ptr); - - const field = for (@typeInfo(T).Struct.fields) |f| { - if (std.mem.eql(u8, f.name, names[0])) break f; - } else @compileError("Unknown field " ++ names[0] ++ " in type " ++ @typeName(T)); - - return FieldPtr(*field.field_type, names[1..]); -} - -fn fieldPtr(ptr: anytype, comptime names: FieldRef) FieldPtr(@TypeOf(ptr), names) { - if (names.len == 0) return ptr; - - return fieldPtr(&@field(ptr.*, names[0]), names[1..]); -} - -fn getRecursiveFieldList(comptime T: type, comptime prefix: FieldRef, comptime options: anytype) []const FieldRef { - comptime { - if (std.meta.trait.is(.Union)(T) and prefix.len == 0 and options.embed_unions) { - @compileError("Cannot embed a union into nothing"); - } - - if (options.isScalar(T)) return &.{prefix}; - if (std.meta.trait.is(.Optional)(T)) return getRecursiveFieldList(std.meta.Child(T), prefix, options); - - const eff_prefix: FieldRef = if (std.meta.trait.is(.Union)(T) and options.embed_unions) - prefix[0 .. prefix.len - 1] - else - prefix; - - var fields: []const FieldRef = &.{}; - - for (std.meta.fields(T)) |f| { - const new_prefix = eff_prefix ++ &[_][]const u8{f.name}; - if (@hasDecl(T, "sql_serialize") and @hasDecl(T.sql_serialize, f.name) and @field(T.sql_serialize, f.name) == .json) { - fields = fields ++ &[_]FieldRef{new_prefix}; - } else { - const F = f.field_type; - fields = fields ++ getRecursiveFieldList(F, new_prefix, options); - } - } - - return fields; - } -} - -// Represents a set of results. -// row() must be called until it returns null, or the query may not complete -// Must be deallocated by a call to finish() -pub fn Results(comptime T: type) type { - // would normally make this a declaration of the struct, but it causes the compiler to crash - const fields = if (T == void) .{} else getRecursiveFieldList( - T, - &.{}, - util.serialize.default_options, - ); - return struct { - const Self = @This(); - - underlying: RawResults, - column_indices: [fields.len]u15, - - fn from(underlying: RawResults) QueryError!Self { - if (std.debug.runtime_safety and fields.len != underlying.columnCount() catch unreachable) { - std.log.err("Expected {} columns in result, got {}", .{ fields.len, underlying.columnCount() catch unreachable }); - return error.ColumnMismatch; - } - - return Self{ .underlying = underlying, .column_indices = blk: { - var indices: [fields.len]u15 = undefined; - inline for (fields) |f, i| { - if (comptime std.meta.trait.isTuple(T)) { - indices[i] = i; - } else { - const name = util.comptimeJoin(".", f); - indices[i] = - underlying.columnIndex(name) catch { - std.log.err("Could not find column index for field {s}", .{name}); - return error.ColumnMismatch; - }; - } - } - break :blk indices; - } }; - } - - pub fn finish(self: Self) void { - self.underlying.finish(); - } - - // Returns the next row of results, or null if there are no more rows. - // Caller owns all memory allocated. The entire object can be deallocated with a - // call to util.deepFree - pub fn row(self: *Self, alloc: ?Allocator) RowError!?T { - if (try self.underlying.row()) |row_val| { - var result: T = undefined; - var fields_allocated: usize = 0; - errdefer inline for (fields) |f, i| { - // Iteration bounds must be defined at comptime (inline for) but the number of fields we could - // successfully allocate is defined at runtime. So we iterate over the entire field array and - // conditionally deallocate fields in the loop. - const ptr = fieldPtr(&result, f); - if (i < fields_allocated) util.deepFree(alloc, ptr.*); - }; - - inline for (fields) |f, i| { - // TODO: Causes compiler segfault. why? - //const F = f.field_type; - //const F = @TypeOf(@field(result, f.name)); - const F = std.meta.Child(FieldPtr(*@TypeOf(result), f)); - const ptr = fieldPtr(&result, f); - const name = comptime util.comptimeJoin(".", f); - - const mode = comptime if (@hasDecl(T, "sql_serialize")) blk: { - if (@hasDecl(T.sql_serialize, name)) { - break :blk @field(T.sql_serialize, name); - } - break :blk .default; - } else .default; - switch (mode) { - .default => ptr.* = row_val.get(F, self.column_indices[i], alloc) catch |err| { - std.log.err("SQL: Error getting column {s} of type {}", .{ name, F }); - return err; - }, - .json => { - const str = row_val.get([]const u8, self.column_indices[i], alloc) catch |err| { - std.log.err("SQL: Error getting column {s} of type {}", .{ name, F }); - return err; - }; - const a = alloc orelse return error.AllocatorRequired; - defer a.free(str); - - var ts = std.json.TokenStream.init(str); - ptr.* = std.json.parse(F, &ts, .{ .allocator = a }) catch |err| { - std.log.err("SQL: Error parsing columns {s} of type {}: {}", .{ name, F, err }); - return error.ResultTypeMismatch; - }; - }, - else => @compileError("unknown mode"), - } - fields_allocated += 1; - } - - return result; - } else return null; - } - }; -} - -// Row is invalidated by the next call to result.row() -const Row = union(Engine) { - postgres: postgres.Row, - sqlite: sqlite.Row, - - // Returns a value of type T from the zero-indexed column given by idx. - // Not all types require an allocator to be present. If an allocator is needed but - // not required, it will return error.AllocatorRequired. - // The caller is responsible for deallocating T, if relevant. - fn get(self: Row, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T { - if (T == void) return; - return switch (self) { - .postgres => |pg| try pg.get(T, idx, alloc), - .sqlite => |lite| try lite.get(T, idx, alloc), - }; - } -}; - -pub const ConstraintMode = enum { - deferred, - immediate, -}; - -pub const ConnPool = struct { - const max_conns = 4; - const Conn = struct { - engine: union(Engine) { - postgres: postgres.Db, - sqlite: sqlite.Db, - }, - in_use: std.atomic.Atomic(bool) = std.atomic.Atomic(bool).init(false), - current_tx_level: u8 = 0, + /// Executes a SQL query. + /// All memory allocated with this allocator must be freed before this function returns. + exec: *const fn (ctx: *anyopaque, sql: []const u8, args: []const SqlValue, opt: QueryOptions, allocator: Allocator) ExecError!Results, }; - config: Config, - connections: [max_conns]Conn, - - pub fn init(cfg: Config) OpenError!ConnPool { - var self = ConnPool{ - .config = cfg, - .connections = undefined, - }; - var count: usize = 0; - errdefer for (self.connections[0..count]) |*c| closeConn(c); - for (self.connections) |*c| { - c.* = try self.createConn(); - count += 1; - } - - return self; - } - - pub fn deinit(self: *ConnPool) void { - for (self.connections) |*c| closeConn(c); - } - - pub fn acquire(self: *ConnPool) AcquireError!Db { - for (self.connections) |*c| { - if (tryAcquire(c)) return Db{ .conn = c }; - } - return error.NoConnectionsLeft; - } - - fn tryAcquire(conn: *Conn) bool { - const acquired = !conn.in_use.swap(true, .AcqRel); - if (acquired) { - if (conn.current_tx_level != 0) @panic("Transaction still open on unused db connection"); - return true; - } - - return false; - } - - fn createConn(self: *ConnPool) OpenError!Conn { - return switch (self.config) { - .postgres => |postgres_cfg| Conn{ - .engine = .{ - .postgres = try postgres.Db.open(postgres_cfg.pg_conn_str), - }, - }, - .sqlite => |lite_cfg| Conn{ - .engine = .{ - .sqlite = if (lite_cfg.sqlite_is_uri) - try sqlite.Db.openUri(lite_cfg.sqlite_file_path) - else - try sqlite.Db.open(lite_cfg.sqlite_file_path), - }, - }, - }; - } - - fn closeConn(conn: *Conn) void { - if (conn.in_use.loadUnchecked()) @panic("DB Conn still open"); - switch (conn.engine) { - .postgres => |pg| pg.close(), - .sqlite => |lite| lite.close(), - } - } + vtable: VTable, }; -pub const Db = Tx(0); +pub const ColumnCountError = error{OutOfRange}; +pub const ColumnIndexError = error{ NotFound, OutOfRange }; +pub const ColumnIndex = u32; -/// When tx_level == 0, the DB is operating in "implied transaction" mode where -/// every command is its own transaction -/// When tx_level >= 1, the DB has an explicit transaction open -/// When tx_level >= 2, the DB has (tx_level - 1) levels of transaction savepoints open -/// (like nested transactions) -fn Tx(comptime tx_level: u8) type { - return struct { - const Self = @This(); - const savepoint_name = if (tx_level == 0) - @compileError("Transaction not started") - else - std.fmt.comptimePrint("save_{}", .{tx_level}); - const next_savepoint_name = Tx(tx_level + 1).savepoint_name; +pub const RowError = error{ + Cancelled, + BadConnection, + InternalException, + DatabaseBusy, + PermissionDenied, + SqlException, +} || ConstraintError || UnexpectedError; - conn: *ConnPool.Conn, - - /// The type of SQL engine being used. Use of this function should be discouraged - pub fn sqlEngine(self: Self) Engine { - return self.conn.engine; - } - - /// Return the connection to the pool - pub fn releaseConnection(self: Self) void { - if (tx_level != 0) @compileError("close must be called on root db"); - if (self.conn.current_tx_level != 0) { - std.log.warn("Database released while transaction in progress!", .{}); - self.rollbackUnchecked() catch {}; // TODO: Burn database connection - } - - if (!self.conn.in_use.swap(false, .AcqRel)) @panic("Double close on db conection"); - } - - // ********* Transaction management functions ********** - - /// Start an explicit transaction - pub fn begin(self: Self) !Tx(1) { - if (tx_level != 0) @compileError("Transaction already started"); - if (self.conn.current_tx_level != 0) return error.BadTransactionState; - - try self.exec("BEGIN", {}, null); - - self.conn.current_tx_level = 1; - - return Tx(1){ .conn = self.conn }; - } - - /// Create a savepoint (nested transaction) - pub fn savepoint(self: Self) !Tx(tx_level + 1) { - if (tx_level == 0) @compileError("Cannot place a savepoint on an implicit transaction"); - if (self.conn.current_tx_level != tx_level) return error.BadTransactionState; - - try self.exec("SAVEPOINT " ++ next_savepoint_name, {}, null); - - self.conn.current_tx_level = tx_level + 1; - - return Tx(tx_level + 1){ .conn = self.conn }; - } - - /// Commit the entire transaction - pub fn commit(self: Self) !void { - if (tx_level == 0) @compileError("Transaction not started"); - if (tx_level >= 2) @compileError("Cannot commit a savepoint"); - if (self.conn.current_tx_level == 0) return error.BadTransactionState; - - try self.exec("COMMIT", {}, null); - - self.conn.current_tx_level = 0; - } - - /// Release the current savepoint and all savepoints created from it. - pub fn release(self: Self) !void { - if (tx_level == 0) @compileError("Transaction not started"); - if (tx_level == 1) @compileError("Cannot release a transaction"); - if (self.conn.current_tx_level < tx_level) return error.BadTransactionState; - - try self.exec("RELEASE SAVEPOINT " ++ savepoint_name, {}, null); - - self.conn.current_tx_level = tx_level - 1; - } - - /// Rolls back the entire transaction - pub fn rollbackTx(self: Self) !void { - if (tx_level == 0) @compileError("Transaction not started"); - if (tx_level >= 2) @compileError("Cannot rollback a transaction using a savepoint"); - if (self.conn.current_tx_level == 0) return error.BadTransactionState; - - try self.rollbackUnchecked(); - - self.conn.current_tx_level = 0; - } - - /// Attempts to roll back to a savepoint - pub fn rollbackSavepoint(self: Self) !void { - if (tx_level == 0) @compileError("Transaction not started"); - if (tx_level == 1) @compileError("Cannot rollback a savepoint on the entire transaction"); - if (self.conn.current_tx_level < tx_level) return error.BadTransactionState; - - try self.exec("ROLLBACK TO " ++ savepoint_name, {}, null); - - self.conn.current_tx_level = tx_level - 1; - } - - /// Perform whichever rollback is appropriate for the situation - pub fn rollback(self: Self) void { - (if (tx_level < 2) self.rollbackTx() else self.rollbackSavepoint()) catch |err| { - std.log.err("Failed to rollback transaction: {}", .{err}); - std.log.err("{any}", .{@errorReturnTrace()}); - @panic("TODO: more gracefully handle rollback failures"); - }; - } - - pub const BeginOrSavepoint = Tx(tx_level + 1); - pub const beginOrSavepoint = if (tx_level == 0) begin else savepoint; - pub const commitOrRelease = if (tx_level < 2) commit else release; - - // Allows relaxing *some* constraints for the lifetime of the transaction. - // You should generally not do this, but it's useful when bootstrapping - // the initial admin community and cluster operator user. - pub fn setConstraintMode(self: Self, mode: ConstraintMode) !void { - if (tx_level == 0) @compileError("Transaction not started"); - if (tx_level >= 2) @compileError("Cannot set constraint mode on a savepoint"); - switch (self.sqlEngine()) { - .sqlite => try self.exec( - switch (mode) { - .immediate => "PRAGMA defer_foreign_keys = FALSE", - .deferred => "PRAGMA defer_foreign_keys = TRUE", - }, - {}, - null, - ), - .postgres => try self.exec( - switch (mode) { - .immediate => "SET CONSTRAINTS ALL IMMEDIATE", - .deferred => "SET CONSTRAINTS ALL DEFERRED", - }, - {}, - null, - ), - } - } - - // ********** Query Helpers ************ - - /// Runs a command without returning results - pub fn exec( - self: Self, - sql: [:0]const u8, - args: anytype, - alloc: ?std.mem.Allocator, - ) !void { - try self.execInternal(sql, args, .{ .allocator = alloc }, true); - } - - pub fn execWithOptions( - self: Self, - sql: [:0]const u8, - args: anytype, - options: QueryOptions, - ) !void { - try self.execInternal(sql, args, options, true); - } - - pub fn queryWithOptions( - self: Self, - comptime RowType: type, - sql: [:0]const u8, - args: anytype, - options: QueryOptions, - ) QueryError!Results(RowType) { - return Results(RowType).from(try self.runSql(sql, args, options, true)); - } - - pub fn query( - self: Self, - comptime RowType: type, - sql: [:0]const u8, - args: anytype, - alloc: ?Allocator, - ) QueryError!Results(RowType) { - return self.queryWithOptions(RowType, sql, args, .{ .allocator = alloc }); - } - - /// Runs a query to completion and returns a row of results, unless the query - /// returned a different number of rows. - pub fn queryRow( - self: Self, - comptime RowType: type, - q: [:0]const u8, - args: anytype, - alloc: ?Allocator, - ) QueryRowError!RowType { - var results = try self.query(RowType, q, args, alloc); - defer results.finish(); - - const row = (try results.row(alloc)) orelse return error.NoRows; - errdefer util.deepFree(alloc, row); - - // execute query to completion - var more_rows = false; - while (try results.row(alloc)) |r| { - util.deepFree(alloc, r); - more_rows = true; - } - if (more_rows) return error.TooManyRows; - - return row; - } - - pub fn queryRows( - self: Self, - comptime RowType: type, - q: [:0]const u8, - args: anytype, - max_items: ?usize, - alloc: std.mem.Allocator, - ) QueryRowError![]RowType { - return try self.queryRowsWithOptions(RowType, q, args, max_items, .{ .allocator = alloc }); - } - - // Runs a query to completion and returns the results as a slice - pub fn queryRowsWithOptions( - self: Self, - comptime RowType: type, - q: [:0]const u8, - args: anytype, - max_items: ?usize, - options: QueryOptions, - ) QueryRowError![]RowType { - var results = try self.queryWithOptions(RowType, q, args, options); - defer results.finish(); - - const alloc = options.allocator orelse return error.AllocatorRequired; - - var result_array = std.ArrayList(RowType).init(alloc); - errdefer result_array.deinit(); - if (max_items) |max| try result_array.ensureTotalCapacity(max); - - errdefer for (result_array.items) |r| util.deepFree(alloc, r); - - var too_many: bool = false; - while (try results.row(alloc)) |row| { - errdefer util.deepFree(alloc, row); - if (max_items) |max| { - if (result_array.items.len >= max) { - util.deepFree(alloc, row); - too_many = true; - continue; - } - } - - try result_array.append(row); - } - - if (too_many) return error.TooManyRows; - - return result_array.toOwnedSlice(); - } - - // Inserts a single value into a table - pub fn insert( - self: Self, - comptime table: []const u8, - value: anytype, - alloc: ?std.mem.Allocator, - ) !void { - const ValueType = comptime @TypeOf(value); - - const fields = std.meta.fields(ValueType); - comptime var types: [fields.len]type = undefined; - comptime var table_spec: []const u8 = table ++ "("; - comptime var value_spec: []const u8 = "("; - inline for (fields) |field, i| { - // This causes a compiler crash. Why? - //const F = field.field_type; - const F = @TypeOf(@field(value, field.name)); - // causes issues if F is @TypeOf(null), use dummy type - types[i] = if (F == @TypeOf(null)) ?i64 else F; - table_spec = comptime (table_spec ++ field.name ++ ","); - value_spec = comptime value_spec ++ std.fmt.comptimePrint("${},", .{i + 1}); - } - table_spec = comptime table_spec[0 .. table_spec.len - 1] ++ ")"; - value_spec = comptime value_spec[0 .. value_spec.len - 1] ++ ")"; - const q = comptime std.fmt.comptimePrint( - "INSERT INTO {s} VALUES {s}", - .{ table_spec, value_spec }, - ); - - var args_tuple: std.meta.Tuple(&types) = undefined; - inline for (fields) |field, i| { - args_tuple[i] = @field(value, field.name); - } - try self.exec(q, args_tuple, alloc); - } - - // internal helpers - - fn runSql( - self: Self, - sql: [:0]const u8, - args: anytype, - opt: QueryOptions, - comptime check_tx: bool, - ) !RawResults { - if (check_tx and self.conn.current_tx_level != tx_level) return error.BadTransactionState; - - return switch (self.conn.engine) { - .postgres => |pg| RawResults{ .postgres = try pg.exec(sql, args, opt) }, - .sqlite => |lite| RawResults{ .sqlite = try lite.exec(sql, args, opt) }, - }; - } - - fn execInternal( - self: Self, - sql: [:0]const u8, - args: anytype, - options: QueryOptions, - comptime check_tx: bool, - ) !void { - var results = try self.runSql(sql, args, options, check_tx); - defer results.finish(); - - while (try results.row()) |_| {} - } - - fn rollbackUnchecked(self: Self) !void { - try self.execInternal("ROLLBACK", {}, .{}, false); - self.conn.current_tx_level = 0; - } +pub const Results = struct { + const VTable = struct { + columnCount: *const fn (ctx: *anyopaque) ColumnCountError!ColumnIndex, + columnIndex: *const fn (ctx: *anyopaque) ColumnIndexError!ColumnIndex, + row: *const fn (ctx: *anyopaque) RowError!?Row, + finish: *const fn (ctx: *anyopaque) void, }; -} + + vtable: VTable, +}; + +pub const GetError = error{ + TypeMismatch, + InvalidIndex, +} || UnexpectedError; + +pub const Row = struct { + const VTable = struct { + isNull: *const fn (ctx: *anyopaque, idx: ColumnIndex) GetError!bool, + getStr: *const fn (ctx: *anyopaque, idx: ColumnIndex) GetError![]const u8, + getInt: *const fn (ctx: *anyopaque, idx: ColumnIndex) GetError!i64, + getUint: *const fn (ctx: *anyopaque, idx: ColumnIndex) GetError!u64, + getFloat: *const fn (ctx: *anyopaque, idx: ColumnIndex) GetError!f64, + }; + + vtable: VTable, +};