saving work

build.zig

@@ -118,7 +118,9 @@ pub fn build(b: *std.build.Builder) !void {
     const unittest_sql = b.addTest("src/sql/lib.zig");
     unittest_sql_cmd.dependOn(&unittest_sql.step);
     unittest_sql.addPackage(unittest_pkgs.util);
-    //unittest_sql.linkLibC();
+    unittest_sql.addSystemIncludePath("/nix/store/c2vkxzbqb3z5220bsgdw1s0kasg61lry-sqlite-3.41.2-dev/include/"); // TODO: why
+    unittest_sql.linkSystemLibrary("sqlite3");
+    unittest_sql.linkLibC();
 
     const unittest_template_cmd = b.step("unit:template", "Run tests for template package");
     const unittest_template = b.addTest("src/template/lib.zig");

default.nix

@@ -0,0 +1,10 @@
+{ }:
+
+let pkgs = import <nixpkgs> { };
+
+in pkgs.stdenv.mkDerivation {
+  name = "fediglam";
+  src = ./.;
+
+  buildInputs = with pkgs; [ zig postgresql sqlite ];
+}

src/api/methods/auth.zig

@@ -17,6 +17,8 @@ pub fn register(
     alloc: std.mem.Allocator,
     ctx: ApiContext,
     svcs: anytype,
+    username: []const u8,
+    password: []const u8,
     opt: RegistrationOptions,
 ) !Uuid {
     const tx = try svcs.beginTx();
@@ -44,8 +46,8 @@ pub fn register(
         alloc,
         tx,
         .{
-            .username = opt.username,
+            .username = username,
-            .password = opt.password,
+            .password = password,
             .community_id = ctx.community.id,
             .invite_id = if (maybe_invite) |inv| @as(?Uuid, inv.id) else null,
             .email = opt.email,
@@ -356,9 +358,9 @@ test "register" {
                 allocator,
                 .{ .community = community },
                 &svc,
+                test_args.username,
+                test_args.password,
                 .{
-                    .username = test_args.username,
-                    .password = test_args.password,
                     .invite_code = if (test_args.use_invite) test_invite_code else null,
                 },
                 // shortcut out of memory errors to test allocation

src/api/types.zig

@@ -15,8 +15,6 @@ fn QueryResult(comptime R: type, comptime A: type) type {
 
 pub const auth = struct {
     pub const RegistrationOptions = struct {
-        username: []const u8,
-        password: []const u8,
         invite_code: ?[]const u8 = null,
         email: ?[]const u8 = null,
     };

src/main/controllers/api/users.zig

@@ -14,12 +14,10 @@ pub const create = struct {
 
     pub fn handler(req: anytype, res: anytype, srv: anytype) !void {
         const options = .{
-            .username = req.body.username,
-            .password = req.body.password,
             .invite_code = req.body.invite_code,
             .email = req.body.email,
         };
-        const user = srv.register(options) catch |err| switch (err) {
+        const user = srv.register(req.body.username, req.body.password, options) catch |err| switch (err) {
             error.UsernameTaken => return res.err(.unprocessable_entity, "Username Unavailable", {}),
             else => return err,
         };

src/sql/engines/sqlite.zig

@@ -1,14 +1,270 @@
+const sql = @import("../lib.zig");
 const std = @import("std");
-const util = @import("util");
-const common = @import("./common.zig");
 const c = @cImport({
     @cInclude("sqlite3.h");
 });
 
-const Uuid = util.Uuid;
+const QueryOptions = sql.QueryOptions;
-const DateTime = util.DateTime;
+const ExecError = sql.ExecError;
+const SqlValue = sql.SqlValue;
+const Results = sql.Results;
+
 const Allocator = std.mem.Allocator;
 
+pub const Engine = struct {
+    conn: *c.sqlite3,
+
+    pub fn open(path: [:0]const u8) !Engine {
+        return openInternal(path, false);
+    }
+
+    pub fn openUri(path: [:0]const u8) !Engine {
+        return openInternal(path, true);
+    }
+
+    fn openInternal(path: [:0]const u8, is_uri: bool) !Engine {
+        const flags = c.SQLITE_OPEN_READWRITE | c.SQLITE_OPEN_CREATE | c.SQLITE_OPEN_EXRESCODE | if (is_uri) c.SQLITE_OPEN_URI else 0;
+
+        var conn: ?*c.sqlite3 = null;
+        switch (c.sqlite3_open_v2(@ptrCast([*c]const u8, path), &conn, flags, null)) {
+            c.SQLITE_OK => {},
+            else => |code| {
+                if (conn == null) {
+                    // this path should only be hit if out of memory, but log it anyways
+                    std.log.err(
+                        "Unable to open SQLite DB \"{s}\". Error: {?s} ({})",
+                        .{ path, c.sqlite3_errstr(code), code },
+                    );
+                    return error.BadConnection;
+                }
+
+                const ext_code = c.sqlite3_extended_errcode(conn);
+                std.log.err(
+                    \\Unable to open SQLite DB "{s}". Error: {?s} ({})
+                    \\Details: {?s}
+                ,
+                    .{ path, c.sqlite3_errstr(ext_code), ext_code, c.sqlite3_errmsg(conn) },
+                );
+
+                return error.Unexpected;
+            },
+        }
+
+        return Engine{
+            .conn = conn.?,
+        };
+    }
+
+    pub fn db(self: *Engine) sql.Db {
+        return .{
+            .ptr = self,
+            .vtable = &.{
+                .exec = Engine.exec,
+            },
+        };
+    }
+
+    pub fn close(self: *Engine) void {
+        switch (c.sqlite3_close(self.conn)) {
+            c.SQLITE_OK => {},
+
+            c.SQLITE_BUSY => {
+                std.log.err("SQLite DB could not be closed as it is busy.\n{s}", .{c.sqlite3_errmsg(self.conn)});
+            },
+
+            else => |err| {
+                std.log.err("Could not close SQLite DB", .{});
+                handleUnexpectedError(self.conn, err, null) catch {};
+            },
+        }
+    }
+
+    fn exec(
+        ctx: *anyopaque,
+        cmd: []const u8,
+        args: []const SqlValue,
+        opts: QueryOptions,
+        _: Allocator,
+    ) ExecError!Results {
+        const self = @ptrCast(*Engine, @alignCast(@alignOf(Engine), ctx));
+
+        var stmt: ?*c.sqlite3_stmt = undefined;
+        switch (c.sqlite3_prepare_v2(self.conn, cmd.ptr, @intCast(c_int, cmd.len), &stmt, null)) {
+            c.SQLITE_OK => {},
+            else => |err| return handleUnexpectedError(self.conn, err, sql),
+        }
+        errdefer switch (c.sqlite3_finalize(stmt)) {
+            c.SQLITE_OK => {},
+            else => |err| {
+                handleUnexpectedError(self.conn, err, sql) catch {};
+            },
+        };
+
+        if (args.len != 0) {
+            for (args) |arg, i| {
+                const buf_size = 21; // ceil(log10(2^64)) + 1
+                var name_buf: [buf_size]u8 = undefined;
+                const name = std.fmt.bufPrintZ(&name_buf, "{}", .{i}) catch unreachable;
+
+                const db_idx = c.sqlite3_bind_parameter_index(stmt.?, name.ptr);
+                if (db_idx != 0)
+                    try self.bindArgument(stmt.?, @intCast(u15, db_idx), arg)
+                else if (!opts.ignore_unused_arguments)
+                    return error.UnusedArgument;
+            }
+        }
+
+        @panic("unimplemented");
+    }
+
+    fn bindArgument(self: *Engine, stmt: *c.sqlite3_stmt, idx: u15, val: SqlValue) !void {
+        return switch (val) {
+            .int => |v| self.bindInt(stmt, idx, i64, v),
+            .uint => |v| self.bindInt(stmt, idx, u64, v),
+            .str => |str| {
+                const len = std.math.cast(c_int, str.len) orelse {
+                    std.log.err("SQLite: string len {} too large", .{str.len});
+                    return error.BindException;
+                };
+
+                switch (c.sqlite3_bind_text(stmt, idx, str.ptr, len, c.SQLITE_TRANSIENT)) {
+                    c.SQLITE_OK => {},
+                    else => |result| {
+                        std.log.err("SQLite: Unable to bind string to index {}", .{idx});
+                        std.log.debug("SQLite: {s}", .{str});
+                        return handleUnexpectedError(self.conn, result, null);
+                    },
+                }
+            },
+            .float => |v| {
+                switch (c.sqlite3_bind_double(stmt, idx, v)) {
+                    c.SQLITE_OK => {},
+                    else => |result| {
+                        std.log.err("SQLite: Unable to bind float to index {}", .{idx});
+                        std.log.debug("SQLite: {}", .{v});
+                        return handleUnexpectedError(self.conn, result, null);
+                    },
+                }
+            },
+            .@"null" => {
+                switch (c.sqlite3_bind_null(stmt, idx)) {
+                    c.SQLITE_OK => {},
+                    else => |result| {
+                        std.log.err("SQLite: Unable to bind NULL to index {}", .{idx});
+                        return handleUnexpectedError(self.conn, result, null);
+                    },
+                }
+            },
+        };
+    }
+
+    fn bindInt(self: *Engine, stmt: *c.sqlite3_stmt, idx: u15, comptime T: type, val: T) !void {
+        const v = std.math.cast(i64, val) orelse {
+            std.log.err("SQLite: integer {} does not fit within i64", .{val});
+            return error.BindException;
+        };
+        switch (c.sqlite3_bind_int64(stmt, idx, v)) {
+            c.SQLITE_OK => {},
+            else => |result| {
+                std.log.err("SQLite: Unable to bind int to index {}", .{idx});
+                std.log.debug("SQLite: {}", .{v});
+                return handleUnexpectedError(self.conn, result, null);
+            },
+        }
+    }
+};
+
+const SqliteResults = struct {
+    stmt: *c.sqlite3_stmt,
+    conn: *c.sqlite3,
+    allocator: std.mem.Allocator,
+
+    fn results(self: *SqliteResults) Results {
+        return .{
+            .ptr = self,
+            .vtable = &.{},
+        };
+    }
+
+    fn finish(ctx: *anyopaque) void {
+        const self = @ptrCast(*SqliteResults, @alignCast(@alignOf(SqliteResults), ctx));
+
+        _ = c.sqlite3_finalize(self.stmt);
+        self.allocator.destroy(self);
+    }
+
+    fn row(ctx: *anyopaque) sql.RowError!?sql.Row {
+        const self = @ptrCast(*SqliteResults, @alignCast(@alignOf(SqliteResults), ctx));
+
+        switch (c.sqlite3_step(self.stmt)) {
+            c.SQLITE_ROW => {},
+
+            c.SQLITE_DONE => return null,
+
+            c.SQLITE_CONSTRAINT_UNIQUE => return error.UniqueViolation,
+            c.SQLITE_CONSTRAINT_CHECK => return error.CheckViolation,
+            c.SQLITE_CONSTRAINT_NOTNULL => return error.NotNullViolation,
+            c.SQLITE_CONSTRAINT_FOREIGNKEY => return error.ForeignKeyViolation,
+            c.SQLITE_CONSTRAINT => return error.ConstraintViolation,
+
+            else => |err| return handleUnexpectedError(self.db, err, self.getGeneratingSql()),
+        }
+
+        return sql.Row{
+            .ptr = self,
+            .vtable = &.{},
+        };
+    }
+
+    fn columnCount(ctx: *anyopaque) sql.ColumnCountError!sql.ColumnIndex {
+        const self = @ptrCast(*SqliteResults, @alignCast(@alignOf(SqliteResults), ctx));
+
+        return @intCast(sql.ColumnIndex, c.sqlite3_column_count(self.stmt));
+    }
+
+    fn columnIndex(ctx: *anyopaque, name: []const u8) sql.ColumnIndexError!sql.ColumnIndex {
+        const self = @ptrCast(*SqliteResults, @alignCast(@alignOf(SqliteResults), ctx));
+
+        var i: u15 = 0;
+        const count = try self.columnCount();
+        while (i < count) : (i += 1) {
+            const column = try self.columnName(i);
+            if (std.mem.eql(u8, name, column)) return i;
+        }
+
+        return error.NotFound;
+    }
+
+    fn isNull(ctx: *anyopaque, idx: sql.ColumnIndex) sql.GetError!bool {
+        const self = @ptrCast(*SqliteResults, @alignCast(@alignOf(SqliteResults), ctx));
+
+        return c.sqlite3_column_type(self.stmt, idx) == c.SQLITE_NULL;
+    }
+
+    fn getStr(ctx: *anyopaque, idx: sql.ColumnIndex) sql.GetError![]const u8 {
+        const self = @ptrCast(*SqliteResults, @alignCast(@alignOf(SqliteResults), ctx));
+
+        if (c.sqlite3_column_text(self.stmt, idx)) |ptr| {
+            const size = @intCast(usize, c.sqlite3_column_bytes(self.stmt, idx));
+            const str = std.mem.sliceTo(ptr[0..size], 0);
+
+            return str;
+        } else {
+            std.log.err("SQLite column {}: TEXT value requested but null pointer returned (out of memory?)", .{idx});
+            return error.Unexpected;
+        }
+    }
+
+    fn getFloat(ctx: *anyopaque, idx: sql.ColumnIndex) sql.getError!f64 {}
+
+    fn columnName(self: Results, idx: u15) ![]const u8 {
+        return if (c.sqlite3_column_name(self.stmt, idx)) |ptr|
+            ptr[0..std.mem.len(ptr)]
+        else
+            unreachable;
+    }
+};
+
 fn getCharPos(text: []const u8, offset: c_int) struct { row: usize, col: usize } {
     var row: usize = 0;
     var col: usize = 0;
@@ -33,352 +289,14 @@ fn handleUnexpectedError(db: *c.sqlite3, code: c_int, sql_text: ?[]const u8) err
 
     std.log.debug("Additional details:", .{});
     std.log.debug("{?s}", .{c.sqlite3_errmsg(db)});
-    if (sql_text) |sql| {
+    if (sql_text) |text| {
         const byte_offset = c.sqlite3_error_offset(db);
         if (byte_offset >= 0) {
-            const pos = getCharPos(sql, byte_offset);
+            const pos = getCharPos(text, byte_offset);
-            std.log.debug("Failed at char ({}:{}) of SQL:\n{s}", .{ pos.row, pos.col, sql });
+            std.log.debug("Failed at char ({}:{}) of SQL:\n{s}", .{ pos.row, pos.col, text });
         }
     }
     std.log.debug("{?}", .{@errorReturnTrace()});
 
     return error.Unexpected;
 }
-
-pub const Db = struct {
-    db: *c.sqlite3,
-
-    pub fn open(path: [:0]const u8) common.OpenError!Db {
-        return openInternal(path, false);
-    }
-
-    pub fn openUri(path: [:0]const u8) common.OpenError!Db {
-        return openInternal(path, true);
-    }
-
-    fn openInternal(path: [:0]const u8, is_uri: bool) common.OpenError!Db {
-        const flags = c.SQLITE_OPEN_READWRITE | c.SQLITE_OPEN_CREATE | c.SQLITE_OPEN_EXRESCODE | if (is_uri) c.SQLITE_OPEN_URI else 0;
-
-        var db: ?*c.sqlite3 = null;
-        switch (c.sqlite3_open_v2(@ptrCast([*c]const u8, path), &db, flags, null)) {
-            c.SQLITE_OK => {},
-            else => |code| {
-                if (db == null) {
-                    // this path should only be hit if out of memory, but log it anyways
-                    std.log.err(
-                        "Unable to open SQLite DB \"{s}\". Error: {?s} ({})",
-                        .{ path, c.sqlite3_errstr(code), code },
-                    );
-                    return error.BadConnection;
-                }
-
-                const ext_code = c.sqlite3_extended_errcode(db);
-                std.log.err(
-                    \\Unable to open SQLite DB "{s}". Error: {?s} ({})
-                    \\Details: {?s}
-                ,
-                    .{ path, c.sqlite3_errstr(ext_code), ext_code, c.sqlite3_errmsg(db) },
-                );
-
-                return error.Unexpected;
-            },
-        }
-
-        return Db{
-            .db = db.?,
-        };
-    }
-
-    pub fn close(self: Db) void {
-        switch (c.sqlite3_close(self.db)) {
-            c.SQLITE_OK => {},
-
-            c.SQLITE_BUSY => {
-                std.log.err("SQLite DB could not be closed as it is busy.\n{s}", .{c.sqlite3_errmsg(self.db)});
-            },
-
-            else => |err| {
-                std.log.err("Could not close SQLite DB", .{});
-                handleUnexpectedError(self.db, err, null) catch {};
-            },
-        }
-    }
-
-    pub fn exec(self: Db, sql: []const u8, args: anytype, opts: common.QueryOptions) common.ExecError!Results {
-        var stmt: ?*c.sqlite3_stmt = undefined;
-        switch (c.sqlite3_prepare_v2(self.db, sql.ptr, @intCast(c_int, sql.len), &stmt, null)) {
-            c.SQLITE_OK => {},
-            else => |err| return handleUnexpectedError(self.db, err, sql),
-        }
-        errdefer switch (c.sqlite3_finalize(stmt)) {
-            c.SQLITE_OK => {},
-            else => |err| {
-                handleUnexpectedError(self.db, err, sql) catch {};
-            },
-        };
-
-        if (@TypeOf(args) != void) {
-            // TODO: Fix for stage1 compiler
-            //inline for (args) |arg, i| {
-            inline for (std.meta.fields(@TypeOf(args))) |field, i| {
-                const arg = @field(args, field.name);
-                // SQLite treats $NNN args as having the name NNN, not index NNN.
-                // As such, if you reference $2 and not $1 in your query (such as
-                // when dynamically constructing queries), it could assign $2 the
-                // index 1. So we can't assume the index according to the 1-indexed
-                // arg array is equivalent to the param to bind it to.
-                // We can, however, look up the exact index to bind to.
-                // If the argument is not used in the query, then it will have an "index"
-                // of 0, and we must not bind the argument.
-                const name = std.fmt.comptimePrint("${}", .{i + 1});
-                const db_idx = c.sqlite3_bind_parameter_index(stmt.?, name);
-                if (db_idx != 0)
-                    try self.bindArgument(stmt.?, @intCast(u15, db_idx), arg)
-                else if (!opts.ignore_unused_arguments)
-                    return error.UnusedArgument;
-            }
-        }
-
-        return Results{ .stmt = stmt.?, .db = self.db };
-    }
-
-    fn bindArgument(self: Db, stmt: *c.sqlite3_stmt, idx: u15, val: anytype) !void {
-        if (comptime std.meta.trait.isZigString(@TypeOf(val))) {
-            return self.bindString(stmt, idx, val);
-        }
-
-        const T = @TypeOf(val);
-
-        switch (@typeInfo(T)) {
-            .Union => {
-                const arr = if (@hasDecl(T, "toCharArray"))
-                    val.toCharArray()
-                else if (@hasDecl(T, "toCharArrayZ"))
-                    val.toCharArrayZ()
-                else {
-                    inline for (std.meta.fields(T)) |field| {
-                        const Tag = std.meta.Tag(T);
-                        const tag = @field(Tag, field.name);
-
-                        if (val == tag) return try self.bindArgument(stmt, idx, @field(val, field.name));
-                    }
-                    unreachable;
-                };
-
-                const len = std.mem.len(&arr);
-                return self.bindString(stmt, idx, arr[0..len]);
-            },
-
-            .Struct => {
-                const arr = if (@hasDecl(T, "toCharArray"))
-                    val.toCharArray()
-                else if (@hasDecl(T, "toCharArrayZ"))
-                    val.toCharArrayZ()
-                else
-                    @compileError("SQLite: Could not serialize " ++ @typeName(T) ++ " into staticly sized string");
-
-                const len = std.mem.len(&arr);
-                return self.bindString(stmt, idx, arr[0..len]);
-            },
-            .Enum => |info| {
-                const name = if (info.is_exhaustive)
-                    @tagName(val)
-                else
-                    @compileError("SQLite: Could not serialize non-exhaustive enum " ++ @typeName(T) ++ " into string");
-                return self.bindString(stmt, idx, name);
-            },
-            .Optional => {
-                return if (val) |v| self.bindArgument(stmt, idx, v) else self.bindNull(stmt, idx);
-            },
-            .Null => return self.bindNull(stmt, idx),
-            .Int => return self.bindInt(stmt, idx, std.math.cast(i64, val) orelse unreachable),
-            .Float => return self.bindFloat(stmt, idx, val),
-            .Bool => return self.bindInt(stmt, idx, if (val) 1 else 0),
-            else => @compileError("Unable to serialize type " ++ @typeName(T)),
-        }
-    }
-
-    fn bindString(self: Db, stmt: *c.sqlite3_stmt, idx: u15, str: []const u8) !void {
-        const len = std.math.cast(c_int, str.len) orelse {
-            std.log.err("SQLite: string len {} too large", .{str.len});
-            return error.BindException;
-        };
-
-        switch (c.sqlite3_bind_text(stmt, idx, str.ptr, len, c.SQLITE_TRANSIENT)) {
-            c.SQLITE_OK => {},
-            else => |result| {
-                std.log.err("SQLite: Unable to bind string to index {}", .{idx});
-                std.log.debug("SQLite: {s}", .{str});
-                return handleUnexpectedError(self.db, result, null);
-            },
-        }
-    }
-
-    fn bindNull(self: Db, stmt: *c.sqlite3_stmt, idx: u15) !void {
-        switch (c.sqlite3_bind_null(stmt, idx)) {
-            c.SQLITE_OK => {},
-            else => |result| {
-                std.log.err("SQLite: Unable to bind NULL to index {}", .{idx});
-                return handleUnexpectedError(self.db, result, null);
-            },
-        }
-    }
-
-    fn bindInt(self: Db, stmt: *c.sqlite3_stmt, idx: u15, val: i64) !void {
-        switch (c.sqlite3_bind_int64(stmt, idx, val)) {
-            c.SQLITE_OK => {},
-            else => |result| {
-                std.log.err("SQLite: Unable to bind int to index {}", .{idx});
-                std.log.debug("SQLite: {}", .{val});
-                return handleUnexpectedError(self.db, result, null);
-            },
-        }
-    }
-
-    fn bindFloat(self: Db, stmt: *c.sqlite3_stmt, idx: u15, val: f64) !void {
-        switch (c.sqlite3_bind_double(stmt, idx, val)) {
-            c.SQLITE_OK => {},
-            else => |result| {
-                std.log.err("SQLite: Unable to bind float to index {}", .{idx});
-                std.log.debug("SQLite: {}", .{val});
-                return handleUnexpectedError(self.db, result, null);
-            },
-        }
-    }
-};
-
-pub const Results = struct {
-    stmt: *c.sqlite3_stmt,
-    db: *c.sqlite3,
-
-    pub fn finish(self: Results) void {
-        _ = c.sqlite3_finalize(self.stmt);
-    }
-
-    pub fn row(self: Results) common.RowError!?Row {
-        return switch (c.sqlite3_step(self.stmt)) {
-            c.SQLITE_ROW => Row{ .stmt = self.stmt, .db = self.db },
-            c.SQLITE_DONE => null,
-
-            c.SQLITE_CONSTRAINT_UNIQUE => return error.UniqueViolation,
-            c.SQLITE_CONSTRAINT_CHECK => return error.CheckViolation,
-            c.SQLITE_CONSTRAINT_NOTNULL => return error.NotNullViolation,
-            c.SQLITE_CONSTRAINT_FOREIGNKEY => return error.ForeignKeyViolation,
-            c.SQLITE_CONSTRAINT => return error.ConstraintViolation,
-
-            else => |err| handleUnexpectedError(self.db, err, self.getGeneratingSql()),
-        };
-    }
-
-    fn getGeneratingSql(self: Results) ?[]const u8 {
-        const ptr = c.sqlite3_sql(self.stmt) orelse return null;
-        return ptr[0..std.mem.len(ptr)];
-    }
-
-    pub fn columnCount(self: Results) common.ColumnCountError!u15 {
-        return @intCast(u15, c.sqlite3_column_count(self.stmt));
-    }
-
-    fn columnName(self: Results, idx: u15) ![]const u8 {
-        return if (c.sqlite3_column_name(self.stmt, idx)) |ptr|
-            ptr[0..std.mem.len(ptr)]
-        else
-            unreachable;
-    }
-
-    pub fn columnIndex(self: Results, name: []const u8) common.ColumnIndexError!u15 {
-        var i: u15 = 0;
-        const count = try self.columnCount();
-        while (i < count) : (i += 1) {
-            const column = try self.columnName(i);
-            if (std.mem.eql(u8, name, column)) return i;
-        }
-
-        return error.NotFound;
-    }
-};
-
-pub const Row = struct {
-    stmt: *c.sqlite3_stmt,
-    db: *c.sqlite3,
-
-    pub fn get(self: Row, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T {
-        return getColumn(self.stmt, T, idx, alloc);
-    }
-};
-
-fn getColumn(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T {
-    const Eff = if (comptime std.meta.trait.is(.Optional)(T)) std.meta.Child(T) else T;
-    return switch (c.sqlite3_column_type(stmt, idx)) {
-        c.SQLITE_INTEGER => try getColumnInt(stmt, Eff, idx),
-        c.SQLITE_FLOAT => try getColumnFloat(stmt, Eff, idx),
-        c.SQLITE_TEXT => try getColumnText(stmt, Eff, idx, alloc),
-        c.SQLITE_NULL => {
-            if (T == DateTime) {
-                std.log.warn("SQLite: Treating NULL as DateTime epoch", .{});
-                return std.mem.zeroes(DateTime);
-            }
-
-            if (@typeInfo(T) != .Optional) {
-                std.log.err("SQLite column {}: Expected value of type {}, got (null)", .{ idx, T });
-                return error.ResultTypeMismatch;
-            }
-
-            return null;
-        },
-        c.SQLITE_BLOB => {
-            std.log.err("SQLite column {}: SQLite value had unsupported storage class BLOB", .{idx});
-            return error.ResultTypeMismatch;
-        },
-        else => |class| {
-            std.log.err("SQLite column {}: SQLite value had unknown storage class {}", .{ idx, class });
-            return error.ResultTypeMismatch;
-        },
-    };
-}
-
-fn getColumnInt(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15) common.GetError!T {
-    const val: i64 = c.sqlite3_column_int64(stmt, idx);
-
-    switch (T) {
-        DateTime => return DateTime{ .seconds_since_epoch = val },
-        else => switch (@typeInfo(T)) {
-            .Int => if (std.math.cast(T, val)) |v| return v else {
-                std.log.err("SQLite column {}: Expected value of type {}, got {} (outside of range)", .{ idx, T, val });
-                return error.ResultTypeMismatch;
-            },
-            .Bool => if (val == 0) return false else return true,
-            else => {
-                std.log.err("SQLite column {}: Storage class INT cannot be parsed into type {}", .{ idx, T });
-                return error.ResultTypeMismatch;
-            },
-        },
-    }
-}
-
-fn getColumnFloat(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15) common.GetError!T {
-    const val: f64 = c.sqlite3_column_double(stmt, idx);
-    switch (T) {
-        // Only support floats that fit in range for now
-        f16, f32, f64 => return @floatCast(T, val),
-        DateTime => return DateTime{
-            .seconds_since_epoch = std.math.lossyCast(i64, val * @intToFloat(f64, std.time.epoch.secs_per_day)),
-        },
-        else => {
-            std.log.err("SQLite column {}: Storage class FLOAT cannot be parsed into type {}", .{ idx, T });
-            return error.ResultTypeMismatch;
-        },
-    }
-}
-
-fn getColumnText(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T {
-    if (c.sqlite3_column_text(stmt, idx)) |ptr| {
-        const size = @intCast(usize, c.sqlite3_column_bytes(stmt, idx));
-        const str = std.mem.sliceTo(ptr[0..size], 0);
-
-        return common.parseValueNotNull(alloc, T, str);
-    } else {
-        std.log.err("SQLite column {}: TEXT value stored but engine returned null pointer (out of memory?)", .{idx});
-        return error.ResultTypeMismatch;
-    }
-}

src/sql/lib.zig

@@ -1,726 +1,110 @@
 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 SqlValue = union(enum) {
-
+    int: i64,
-pub const AcquireError = OpenError || error{NoConnectionsLeft};
+    uint: u64,
-pub const OpenError = errors.OpenError;
+    str: []const u8,
-pub const QueryError = errors.QueryError;
+    @"null": void,
-pub const RowError = errors.RowError;
+    float: f64,
-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,
 };
 
-/// Helper for building queries at runtime. All constituent parts of the
+pub const QueryOptions = struct {
-/// query should be defined at comptime, however the choice of whether
+    // If true, then it will not return an error on the SQLite backend
-/// or not to include them can occur at runtime.
+    // if an argument passed does not map to a parameter in the query.
-pub const QueryBuilder = struct {
+    // Has no effect on the postgres backend.
-    array: std.ArrayList(u8),
+    ignore_unused_arguments: bool = false,
-    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);
-    }
 };
 
-// TODO: make this suck less
+pub const UnexpectedError = error{Unexpected};
-pub const Config = union(Engine) {
+pub const ConstraintError = error{
-    postgres: struct {
+    NotNullViolation,
-        pg_conn_str: [:0]const u8,
+    ForeignKeyViolation,
-    },
+    UniqueViolation,
-    sqlite: struct {
+    CheckViolation,
-        sqlite_file_path: [:0]const u8,
+
-        sqlite_is_uri: bool = false,
+    /// Catchall for miscellaneous types of constraints
-    },
+    ConstraintViolation,
 };
 
-const RawResults = union(Engine) {
+pub const ExecError = error{
-    postgres: postgres.Results,
+    Cancelled,
-    sqlite: sqlite.Results,
+    BadConnection,
+    InternalException,
+    DatabaseBusy,
+    PermissionDenied,
+    SqlException,
 
-    fn finish(self: RawResults) void {
+    /// Argument could not be marshalled for query
-        switch (self) {
+    BindException,
-            .postgres => |pg| pg.finish(),
-            .sqlite => |lite| lite.finish(),
-        }
-    }
 
-    fn columnCount(self: RawResults) !u15 {
+    /// An argument was not used by the query (not checked in all DB engines)
-        return try switch (self) {
+    UnusedArgument,
-            .postgres => |pg| pg.columnCount(),
-            .sqlite => |lite| lite.columnCount(),
-        };
-    }
 
-    fn columnIndex(self: RawResults, name: []const u8) error{ NotFound, Unexpected }!u15 {
+    /// Memory error when marshalling argument for query
-        return switch (self) {
+    OutOfMemory,
-            .postgres => |pg| pg.columnIndex(name),
+    AllocatorRequired,
-            .sqlite => |lite| lite.columnIndex(name),
+} || ConstraintError || UnexpectedError;
-        } catch |err| switch (err) {
-            error.OutOfRange => error.Unexpected,
-            error.NotFound => error.NotFound,
-        };
-    }
 
-    fn row(self: *RawResults) RowError!?Row {
+pub const Db = struct {
-        return switch (self.*) {
+    pub const VTable = struct {
-            .postgres => |*pg| if (try pg.row()) |r| Row{ .postgres = r } else null,
+        /// Executes a SQL query.
-            .sqlite => |*lite| if (try lite.row()) |r| Row{ .sqlite = r } else null,
+        exec: *const fn (ctx: *anyopaque, sql: []const u8, args: []const SqlValue, opt: QueryOptions, allocator: Allocator) ExecError!Results,
-        };
-    }
-};
-
-const FieldRef = []const []const u8;
-fn FieldPtr(comptime Ptr: type, comptime names: FieldRef) type {
-    if (names.len == 0) return Ptr;
-
-    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,
     };
 
-    config: Config,
+    vtable: *const VTable,
-    connections: [max_conns]Conn,
+    ptr: *anyopaque,
-
-    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(),
-        }
-    }
 };
 
-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
+pub const RowError = error{
-/// every command is its own transaction
+    Cancelled,
-/// When tx_level >= 1, the DB has an explicit transaction open
+    BadConnection,
-/// When tx_level >= 2, the DB has (tx_level - 1) levels of transaction savepoints open
+    InternalException,
-/// (like nested transactions)
+    DatabaseBusy,
-fn Tx(comptime tx_level: u8) type {
+    PermissionDenied,
-    return struct {
+    SqlException,
-        const Self = @This();
+} || ConstraintError || UnexpectedError;
-        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;
 
-        conn: *ConnPool.Conn,
+pub const Results = struct {
-
+    pub const VTable = struct {
-        /// The type of SQL engine being used. Use of this function should be discouraged
+        columnCount: *const fn (ctx: *anyopaque) ColumnCountError!ColumnIndex,
-        pub fn sqlEngine(self: Self) Engine {
+        columnIndex: *const fn (ctx: *anyopaque) ColumnIndexError!ColumnIndex,
-            return self.conn.engine;
+        row: *const fn (ctx: *anyopaque) RowError!?Row,
-        }
+        finish: *const fn (ctx: *anyopaque) void,
-
-        /// 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;
-        }
     };
+
+    vtable: *const VTable,
+    ptr: *anyopaque,
+};
+
+pub const GetError = error{
+    TypeMismatch,
+    InvalidIndex,
+} || UnexpectedError;
+
+pub const Row = struct {
+    pub 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: *const VTable,
+    ptr: *anyopaque,
+};
+
+test "test" {
+    const backend = @import("./engines/sqlite.zig");
+    var engine = try backend.Engine.open(":memory:");
+    defer engine.close();
+
+    const db = engine.db();
+
+    _ = try db.vtable.exec(db.ptr, "CREATE TABLE foo(bar INT PRIMARY KEY);", &.{}, .{}, std.testing.allocator);
 }

src/sql/sqlite.bak.zig

@@ -0,0 +1,384 @@
+const std = @import("std");
+const util = @import("util");
+const common = @import("./common.zig");
+const c = @cImport({
+    @cInclude("sqlite3.h");
+});
+
+const Uuid = util.Uuid;
+const DateTime = util.DateTime;
+const Allocator = std.mem.Allocator;
+
+fn getCharPos(text: []const u8, offset: c_int) struct { row: usize, col: usize } {
+    var row: usize = 0;
+    var col: usize = 0;
+    var i: usize = 0;
+
+    if (offset > text.len) return .{ .row = 0, .col = 0 };
+
+    while (i != offset) : (i += 1) {
+        if (text[i] == '\n') {
+            row += 1;
+            col = 0;
+        } else {
+            col += 1;
+        }
+    }
+
+    return .{ .row = row, .col = col };
+}
+
+fn handleUnexpectedError(db: *c.sqlite3, code: c_int, sql_text: ?[]const u8) error{Unexpected} {
+    std.log.err("Unexpected error in SQLite engine: {s} ({})", .{ c.sqlite3_errstr(code), code });
+
+    std.log.debug("Additional details:", .{});
+    std.log.debug("{?s}", .{c.sqlite3_errmsg(db)});
+    if (sql_text) |sql| {
+        const byte_offset = c.sqlite3_error_offset(db);
+        if (byte_offset >= 0) {
+            const pos = getCharPos(sql, byte_offset);
+            std.log.debug("Failed at char ({}:{}) of SQL:\n{s}", .{ pos.row, pos.col, sql });
+        }
+    }
+    std.log.debug("{?}", .{@errorReturnTrace()});
+
+    return error.Unexpected;
+}
+
+pub const Db = struct {
+    db: *c.sqlite3,
+
+    pub fn open(path: [:0]const u8) common.OpenError!Db {
+        return openInternal(path, false);
+    }
+
+    pub fn openUri(path: [:0]const u8) common.OpenError!Db {
+        return openInternal(path, true);
+    }
+
+    fn openInternal(path: [:0]const u8, is_uri: bool) common.OpenError!Db {
+        const flags = c.SQLITE_OPEN_READWRITE | c.SQLITE_OPEN_CREATE | c.SQLITE_OPEN_EXRESCODE | if (is_uri) c.SQLITE_OPEN_URI else 0;
+
+        var db: ?*c.sqlite3 = null;
+        switch (c.sqlite3_open_v2(@ptrCast([*c]const u8, path), &db, flags, null)) {
+            c.SQLITE_OK => {},
+            else => |code| {
+                if (db == null) {
+                    // this path should only be hit if out of memory, but log it anyways
+                    std.log.err(
+                        "Unable to open SQLite DB \"{s}\". Error: {?s} ({})",
+                        .{ path, c.sqlite3_errstr(code), code },
+                    );
+                    return error.BadConnection;
+                }
+
+                const ext_code = c.sqlite3_extended_errcode(db);
+                std.log.err(
+                    \\Unable to open SQLite DB "{s}". Error: {?s} ({})
+                    \\Details: {?s}
+                ,
+                    .{ path, c.sqlite3_errstr(ext_code), ext_code, c.sqlite3_errmsg(db) },
+                );
+
+                return error.Unexpected;
+            },
+        }
+
+        return Db{
+            .db = db.?,
+        };
+    }
+
+    pub fn close(self: Db) void {
+        switch (c.sqlite3_close(self.db)) {
+            c.SQLITE_OK => {},
+
+            c.SQLITE_BUSY => {
+                std.log.err("SQLite DB could not be closed as it is busy.\n{s}", .{c.sqlite3_errmsg(self.db)});
+            },
+
+            else => |err| {
+                std.log.err("Could not close SQLite DB", .{});
+                handleUnexpectedError(self.db, err, null) catch {};
+            },
+        }
+    }
+
+    pub fn exec(self: Db, sql: []const u8, args: anytype, opts: common.QueryOptions) common.ExecError!Results {
+        var stmt: ?*c.sqlite3_stmt = undefined;
+        switch (c.sqlite3_prepare_v2(self.db, sql.ptr, @intCast(c_int, sql.len), &stmt, null)) {
+            c.SQLITE_OK => {},
+            else => |err| return handleUnexpectedError(self.db, err, sql),
+        }
+        errdefer switch (c.sqlite3_finalize(stmt)) {
+            c.SQLITE_OK => {},
+            else => |err| {
+                handleUnexpectedError(self.db, err, sql) catch {};
+            },
+        };
+
+        if (@TypeOf(args) != void) {
+            // TODO: Fix for stage1 compiler
+            //inline for (args) |arg, i| {
+            inline for (std.meta.fields(@TypeOf(args))) |field, i| {
+                const arg = @field(args, field.name);
+                // SQLite treats $NNN args as having the name NNN, not index NNN.
+                // As such, if you reference $2 and not $1 in your query (such as
+                // when dynamically constructing queries), it could assign $2 the
+                // index 1. So we can't assume the index according to the 1-indexed
+                // arg array is equivalent to the param to bind it to.
+                // We can, however, look up the exact index to bind to.
+                // If the argument is not used in the query, then it will have an "index"
+                // of 0, and we must not bind the argument.
+                const name = std.fmt.comptimePrint("${}", .{i + 1});
+                const db_idx = c.sqlite3_bind_parameter_index(stmt.?, name);
+                if (db_idx != 0)
+                    try self.bindArgument(stmt.?, @intCast(u15, db_idx), arg)
+                else if (!opts.ignore_unused_arguments)
+                    return error.UnusedArgument;
+            }
+        }
+
+        return Results{ .stmt = stmt.?, .db = self.db };
+    }
+
+    fn bindArgument(self: Db, stmt: *c.sqlite3_stmt, idx: u15, val: anytype) !void {
+        if (comptime std.meta.trait.isZigString(@TypeOf(val))) {
+            return self.bindString(stmt, idx, val);
+        }
+
+        const T = @TypeOf(val);
+
+        switch (@typeInfo(T)) {
+            .Union => {
+                const arr = if (@hasDecl(T, "toCharArray"))
+                    val.toCharArray()
+                else if (@hasDecl(T, "toCharArrayZ"))
+                    val.toCharArrayZ()
+                else {
+                    inline for (std.meta.fields(T)) |field| {
+                        const Tag = std.meta.Tag(T);
+                        const tag = @field(Tag, field.name);
+
+                        if (val == tag) return try self.bindArgument(stmt, idx, @field(val, field.name));
+                    }
+                    unreachable;
+                };
+
+                const len = std.mem.len(&arr);
+                return self.bindString(stmt, idx, arr[0..len]);
+            },
+
+            .Struct => {
+                const arr = if (@hasDecl(T, "toCharArray"))
+                    val.toCharArray()
+                else if (@hasDecl(T, "toCharArrayZ"))
+                    val.toCharArrayZ()
+                else
+                    @compileError("SQLite: Could not serialize " ++ @typeName(T) ++ " into staticly sized string");
+
+                const len = std.mem.len(&arr);
+                return self.bindString(stmt, idx, arr[0..len]);
+            },
+            .Enum => |info| {
+                const name = if (info.is_exhaustive)
+                    @tagName(val)
+                else
+                    @compileError("SQLite: Could not serialize non-exhaustive enum " ++ @typeName(T) ++ " into string");
+                return self.bindString(stmt, idx, name);
+            },
+            .Optional => {
+                return if (val) |v| self.bindArgument(stmt, idx, v) else self.bindNull(stmt, idx);
+            },
+            .Null => return self.bindNull(stmt, idx),
+            .Int => return self.bindInt(stmt, idx, std.math.cast(i64, val) orelse unreachable),
+            .Float => return self.bindFloat(stmt, idx, val),
+            .Bool => return self.bindInt(stmt, idx, if (val) 1 else 0),
+            else => @compileError("Unable to serialize type " ++ @typeName(T)),
+        }
+    }
+
+    fn bindString(self: Db, stmt: *c.sqlite3_stmt, idx: u15, str: []const u8) !void {
+        const len = std.math.cast(c_int, str.len) orelse {
+            std.log.err("SQLite: string len {} too large", .{str.len});
+            return error.BindException;
+        };
+
+        switch (c.sqlite3_bind_text(stmt, idx, str.ptr, len, c.SQLITE_TRANSIENT)) {
+            c.SQLITE_OK => {},
+            else => |result| {
+                std.log.err("SQLite: Unable to bind string to index {}", .{idx});
+                std.log.debug("SQLite: {s}", .{str});
+                return handleUnexpectedError(self.db, result, null);
+            },
+        }
+    }
+
+    fn bindNull(self: Db, stmt: *c.sqlite3_stmt, idx: u15) !void {
+        switch (c.sqlite3_bind_null(stmt, idx)) {
+            c.SQLITE_OK => {},
+            else => |result| {
+                std.log.err("SQLite: Unable to bind NULL to index {}", .{idx});
+                return handleUnexpectedError(self.db, result, null);
+            },
+        }
+    }
+
+    fn bindInt(self: Db, stmt: *c.sqlite3_stmt, idx: u15, val: i64) !void {
+        switch (c.sqlite3_bind_int64(stmt, idx, val)) {
+            c.SQLITE_OK => {},
+            else => |result| {
+                std.log.err("SQLite: Unable to bind int to index {}", .{idx});
+                std.log.debug("SQLite: {}", .{val});
+                return handleUnexpectedError(self.db, result, null);
+            },
+        }
+    }
+
+    fn bindFloat(self: Db, stmt: *c.sqlite3_stmt, idx: u15, val: f64) !void {
+        switch (c.sqlite3_bind_double(stmt, idx, val)) {
+            c.SQLITE_OK => {},
+            else => |result| {
+                std.log.err("SQLite: Unable to bind float to index {}", .{idx});
+                std.log.debug("SQLite: {}", .{val});
+                return handleUnexpectedError(self.db, result, null);
+            },
+        }
+    }
+};
+
+pub const Results = struct {
+    stmt: *c.sqlite3_stmt,
+    db: *c.sqlite3,
+
+    pub fn finish(self: Results) void {
+        _ = c.sqlite3_finalize(self.stmt);
+    }
+
+    pub fn row(self: Results) common.RowError!?Row {
+        return switch (c.sqlite3_step(self.stmt)) {
+            c.SQLITE_ROW => Row{ .stmt = self.stmt, .db = self.db },
+            c.SQLITE_DONE => null,
+
+            c.SQLITE_CONSTRAINT_UNIQUE => return error.UniqueViolation,
+            c.SQLITE_CONSTRAINT_CHECK => return error.CheckViolation,
+            c.SQLITE_CONSTRAINT_NOTNULL => return error.NotNullViolation,
+            c.SQLITE_CONSTRAINT_FOREIGNKEY => return error.ForeignKeyViolation,
+            c.SQLITE_CONSTRAINT => return error.ConstraintViolation,
+
+            else => |err| handleUnexpectedError(self.db, err, self.getGeneratingSql()),
+        };
+    }
+
+    fn getGeneratingSql(self: Results) ?[]const u8 {
+        const ptr = c.sqlite3_sql(self.stmt) orelse return null;
+        return ptr[0..std.mem.len(ptr)];
+    }
+
+    pub fn columnCount(self: Results) common.ColumnCountError!u15 {
+        return @intCast(u15, c.sqlite3_column_count(self.stmt));
+    }
+
+    fn columnName(self: Results, idx: u15) ![]const u8 {
+        return if (c.sqlite3_column_name(self.stmt, idx)) |ptr|
+            ptr[0..std.mem.len(ptr)]
+        else
+            unreachable;
+    }
+
+    pub fn columnIndex(self: Results, name: []const u8) common.ColumnIndexError!u15 {
+        var i: u15 = 0;
+        const count = try self.columnCount();
+        while (i < count) : (i += 1) {
+            const column = try self.columnName(i);
+            if (std.mem.eql(u8, name, column)) return i;
+        }
+
+        return error.NotFound;
+    }
+};
+
+pub const Row = struct {
+    stmt: *c.sqlite3_stmt,
+    db: *c.sqlite3,
+
+    pub fn get(self: Row, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T {
+        return getColumn(self.stmt, T, idx, alloc);
+    }
+};
+
+fn getColumn(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T {
+    const Eff = if (comptime std.meta.trait.is(.Optional)(T)) std.meta.Child(T) else T;
+    return switch (c.sqlite3_column_type(stmt, idx)) {
+        c.SQLITE_INTEGER => try getColumnInt(stmt, Eff, idx),
+        c.SQLITE_FLOAT => try getColumnFloat(stmt, Eff, idx),
+        c.SQLITE_TEXT => try getColumnText(stmt, Eff, idx, alloc),
+        c.SQLITE_NULL => {
+            if (T == DateTime) {
+                std.log.warn("SQLite: Treating NULL as DateTime epoch", .{});
+                return std.mem.zeroes(DateTime);
+            }
+
+            if (@typeInfo(T) != .Optional) {
+                std.log.err("SQLite column {}: Expected value of type {}, got (null)", .{ idx, T });
+                return error.ResultTypeMismatch;
+            }
+
+            return null;
+        },
+        c.SQLITE_BLOB => {
+            std.log.err("SQLite column {}: SQLite value had unsupported storage class BLOB", .{idx});
+            return error.ResultTypeMismatch;
+        },
+        else => |class| {
+            std.log.err("SQLite column {}: SQLite value had unknown storage class {}", .{ idx, class });
+            return error.ResultTypeMismatch;
+        },
+    };
+}
+
+fn getColumnInt(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15) common.GetError!T {
+    const val: i64 = c.sqlite3_column_int64(stmt, idx);
+
+    switch (T) {
+        DateTime => return DateTime{ .seconds_since_epoch = val },
+        else => switch (@typeInfo(T)) {
+            .Int => if (std.math.cast(T, val)) |v| return v else {
+                std.log.err("SQLite column {}: Expected value of type {}, got {} (outside of range)", .{ idx, T, val });
+                return error.ResultTypeMismatch;
+            },
+            .Bool => if (val == 0) return false else return true,
+            else => {
+                std.log.err("SQLite column {}: Storage class INT cannot be parsed into type {}", .{ idx, T });
+                return error.ResultTypeMismatch;
+            },
+        },
+    }
+}
+
+fn getColumnFloat(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15) common.GetError!T {
+    const val: f64 = c.sqlite3_column_double(stmt, idx);
+    switch (T) {
+        // Only support floats that fit in range for now
+        f16, f32, f64 => return @floatCast(T, val),
+        DateTime => return DateTime{
+            .seconds_since_epoch = std.math.lossyCast(i64, val * @intToFloat(f64, std.time.epoch.secs_per_day)),
+        },
+        else => {
+            std.log.err("SQLite column {}: Storage class FLOAT cannot be parsed into type {}", .{ idx, T });
+            return error.ResultTypeMismatch;
+        },
+    }
+}
+
+fn getColumnText(stmt: *c.sqlite3_stmt, comptime T: type, idx: u15, alloc: ?Allocator) common.GetError!T {
+    if (c.sqlite3_column_text(stmt, idx)) |ptr| {
+        const size = @intCast(usize, c.sqlite3_column_bytes(stmt, idx));
+        const str = std.mem.sliceTo(ptr[0..size], 0);
+
+        return common.parseValueNotNull(alloc, T, str);
+    } else {
+        std.log.err("SQLite column {}: TEXT value stored but engine returned null pointer (out of memory?)", .{idx});
+        return error.ResultTypeMismatch;
+    }
+}