Ability to return typed arrays

Author: karlseguin

build.zig.zon

@@ -13,8 +13,8 @@
             .hash = "tigerbeetle_io-0.0.0-ViLgxpyRBAB5BMfIcj3KMXfbJzwARs9uSl8aRy2OXULd",
         },
         .v8 = .{
-            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/f0c7eaaffe39f2f1a224fbe97e550daca0ca1801.tar.gz",
-            .hash = "v8-0.0.0-xddH62T4IADchAHFgo4nx79w1VedNDhIVErtSNgup-Tk",
+            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/fc764e7d29bc1514924e8df09255a057e03d453a.tar.gz",
+            .hash = "v8-0.0.0-xddH6zUZIQBJf109L94sC-mWH1NJXWCnOJGJttKtfasI",
         },
         //.v8 = .{ .path = "../zig-v8-fork" },
         //.tigerbeetle_io = .{ .path = "../tigerbeetle-io" },

src/runtime/js.zig

@@ -1012,6 +1012,22 @@ pub fn Env(comptime State: type, comptime WebApis: type) type {
             }
         };
 
+        // If a function returns a []i32, should that map to a plain-old
+        // JavaScript array, or a Int32Array? It's ambiguous. By default, we'll
+        // map arrays/slices to the JavaScript arrays. If you want a TypedArray
+        // wrap it in this.
+        // Also, this type has nothing to do with the Env. But we place it here
+        // for consistency. Want a callback? Env.Callback. Want a JsObject?
+        // Env.JsObject. Want a TypedArray? Env.TypedArray.
+        pub fn TypedArray(comptime T: type) type {
+            return struct {
+                // See Callback._CALLBACK_ID_KLUDGE
+                const _TYPED_ARRAY_ID_KLUDGE = true;
+
+                values: []const T,
+            };
+        }
+
         pub const Inspector = struct {
             isolate: v8.Isolate,
             inner: *v8.Inspector,
@@ -2632,6 +2648,53 @@ fn simpleZigValueToJs(isolate: v8.Isolate, value: anytype, comptime fail: bool)
             }
             return v8.initNull(isolate).toValue();
         },
+        .@"struct" => {
+            const T = @TypeOf(value);
+            if (@hasDecl(T, "_TYPED_ARRAY_ID_KLUDGE")) {
+                const values = value.values;
+                const value_type = @typeInfo(@TypeOf(values)).pointer.child;
+                const len = values.len;
+                const bits = switch (@typeInfo(value_type)) {
+                    .int => |n| n.bits,
+                    .float => |f| f.bits,
+                    else => @compileError("Invalid TypeArray type: " ++ @typeName(value_type)),
+                };
+
+                const buffer_len = len * bits / 8;
+                const backing_store = v8.BackingStore.init(isolate, buffer_len);
+                const data: [*]u8 = @alignCast(@ptrCast(backing_store.getData()));
+                @memcpy(data[0..buffer_len], @as([]const u8, @ptrCast(values))[0..buffer_len]);
+                const array_buffer = v8.ArrayBuffer.initWithBackingStore(isolate, &backing_store.toSharedPtr());
+
+                switch (@typeInfo(value_type)) {
+                    .int => |n| switch (n.signedness) {
+                        .unsigned => switch (n.bits) {
+                            8 => return v8.Uint8Array.init(array_buffer, 0, len).toValue(),
+                            16 => return v8.Uint16Array.init(array_buffer, 0, len).toValue(),
+                            32 => return v8.Uint32Array.init(array_buffer, 0, len).toValue(),
+                            64 => return v8.BigUint64Array.init(array_buffer, 0, len).toValue(),
+                            else => {},
+                        },
+                        .signed => switch (n.bits) {
+                            8 => return v8.Int8Array.init(array_buffer, 0, len).toValue(),
+                            16 => return v8.Int16Array.init(array_buffer, 0, len).toValue(),
+                            32 => return v8.Int32Array.init(array_buffer, 0, len).toValue(),
+                            64 => return v8.BigInt64Array.init(array_buffer, 0, len).toValue(),
+                            else => {},
+                        },
+                    },
+                    .float => |f| switch (f.bits) {
+                        32 => return v8.Float32Array.init(array_buffer, 0, len).toValue(),
+                        64 => return v8.Float64Array.init(array_buffer, 0, len).toValue(),
+                        else => {},
+                    },
+                    else => {},
+                }
+                // We normally don't fail in this function unless fail == true
+                // but this can never be valid.
+                @compileError("Invalid TypeArray type: " ++ @typeName(value_type));
+            }
+        },
         .@"union" => return simpleZigValueToJs(isolate, std.meta.activeTag(value), fail),
         else => {},
     }

src/runtime/test_primitive_types.zig

@@ -17,6 +17,10 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 // TODO: use functions instead of "fake" struct once we handle function API generation
+
+const Runner = testing.Runner(void, void, .{Primitives});
+const Env = Runner.Env;
+
 const Primitives = struct {
     pub fn constructor() Primitives {
         return .{};
@@ -114,6 +118,46 @@ const Primitives = struct {
         }
     }
 
+    pub fn _returnUint8(_: *const Primitives) Env.TypedArray(u8) {
+        return .{ .values = &.{ 10, 20, 250 } };
+    }
+
+    pub fn _returnInt8(_: *const Primitives) Env.TypedArray(i8) {
+        return .{ .values = &.{ 10, -20, -120 } };
+    }
+
+    pub fn _returnUint16(_: *const Primitives) Env.TypedArray(u16) {
+        return .{ .values = &.{ 10, 200, 2050 } };
+    }
+
+    pub fn _returnInt16(_: *const Primitives) Env.TypedArray(i16) {
+        return .{ .values = &.{ 10, -420, 0 } };
+    }
+
+    pub fn _returnUint32(_: *const Primitives) Env.TypedArray(u32) {
+        return .{ .values = &.{ 10, 2444343, 43432432 } };
+    }
+
+    pub fn _returnInt32(_: *const Primitives) Env.TypedArray(i32) {
+        return .{ .values = &.{ 10, -20, -495929123 } };
+    }
+
+    pub fn _returnUint64(_: *const Primitives) Env.TypedArray(u64) {
+        return .{ .values = &.{ 10, 495812375924, 0 } };
+    }
+
+    pub fn _returnInt64(_: *const Primitives) Env.TypedArray(i64) {
+        return .{ .values = &.{ 10, -49283838122, -2 } };
+    }
+
+    pub fn _returnFloat32(_: *const Primitives) Env.TypedArray(f32) {
+        return .{ .values = &.{ 1.1, -200.035, 0.0003 } };
+    }
+
+    pub fn _returnFloat64(_: *const Primitives) Env.TypedArray(f64) {
+        return .{ .values = &.{ 8881.22284, -4928.3838122, -0.00004 } };
+    }
+
     pub fn _int16(_: *const Primitives, arr: []i16) void {
         for (arr) |*a| {
             a.* -= @intCast(arr.len);
@@ -153,7 +197,7 @@ const Primitives = struct {
 
 const testing = @import("testing.zig");
 test "JS: primitive types" {
-    var runner = try testing.Runner(void, void, .{Primitives}).init({}, {});
+    var runner = try Runner.init({}, {});
     defer runner.deinit();
 
     // constructor
@@ -280,5 +324,16 @@ test "JS: primitive types" {
         .{ "try { p.int64(arr_u64) } catch(e) { e instanceof TypeError; }", "true" },
         .{ "try { p.intu64(arr_i64) } catch(e) { e instanceof TypeError; }", "true" },
         .{ "try { p.intu64(arr_u32) } catch(e) { e instanceof TypeError; }", "true" },
+
+        .{ "p.returnUint8()", "10,20,250" },
+        .{ "p.returnInt8()", "10,-20,-120" },
+        .{ "p.returnUint16()", "10,200,2050" },
+        .{ "p.returnInt16()", "10,-420,0" },
+        .{ "p.returnUint32()", "10,2444343,43432432" },
+        .{ "p.returnInt32()", "10,-20,-495929123" },
+        .{ "p.returnUint64()", "10,495812375924,0" },
+        .{ "p.returnInt64()", "10,-49283838122,-2" },
+        .{ "p.returnFloat32()", "1.100000023841858,-200.03500366210938,0.0003000000142492354" },
+        .{ "p.returnFloat64()", "8881.22284,-4928.3838122,-0.00004" },
     }, .{});
 }

src/runtime/testing.zig

@@ -26,15 +26,16 @@ pub const allocator = std.testing.allocator;
 // browser.Env or the browser.SessionState
 pub fn Runner(comptime State: type, comptime Global: type, comptime types: anytype) type {
     const AdjustedTypes = if (Global == void) generate.Tuple(.{ types, DefaultGlobal }) else types;
-    const Env = js.Env(State, struct {
-        pub const Interfaces = AdjustedTypes;
-    });
 
     return struct {
         env: *Env,
         scope: *Env.Scope,
         executor: Env.Executor,
 
+        pub const Env = js.Env(State, struct {
+            pub const Interfaces = AdjustedTypes;
+        });
+
         const Self = @This();
 
         pub fn init(state: State, global: Global) !*Self {