Extend Value into the Object type (#74)

* basic return of an Object from value

* implement object set property

* get the global object and get object instance from template

* Object Get methods and locking in the API for this PR

* fix C++ failing issues

* basic tests for the Object methods

* value tests and iso fix

* update changelog

* address comments from review

Author: rogchap

CHANGELOG.md

@@ -11,12 +11,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Create Object Templates with primitive values, including other Object Templates
 - Configure Object Template as the global object of any new Context
 - Function Templates with callbacks to Go
+- Value to Object type, including Get/Set/Has/Delete methods
+- Get Global Object from the Context
+- Convert a Object Template to an instance of an Object
 
 ### Changed
 - NewContext() API has been improved to handle optional global object, as well as optional Isolate
 - Package error messages are now prefixed with `v8go` rather than the struct name
 - Deprecated `iso.Close()` in favor of `iso.Dispose()` to keep consistancy with the C++ API
 - Upgraded V8 to 8.8.278.14
+- Licence BSD 3-Clause (same as V8 and Go)
 
 ## [v0.4.0] - 2021-01-14
 

context.go

@@ -106,6 +106,20 @@ func (c *Context) RunScript(source string, origin string) (*Value, error) {
 	return getValue(c, rtn), getError(rtn)
 }
 
+// Global returns the global proxy object.
+// Global proxy object is a thin wrapper whose prototype points to actual
+// context's global object with the properties like Object, etc. This is
+// done that way for security reasons.
+// Please note that changes to global proxy object prototype most probably
+// would break the VM — V8 expects only global object as a prototype of
+// global proxy object.
+func (c *Context) Global() *Object {
+	valPtr := C.ContextGlobal(c.ptr)
+	v := &Value{valPtr, c}
+	runtime.SetFinalizer(v, (*Value).finalizer)
+	return &Object{v}
+}
+
 // Close will dispose the context and free the memory.
 func (c *Context) Close() {
 	c.finalizer()

json.go

@@ -26,8 +26,8 @@ func JSONParse(ctx *Context, str string) (*Value, error) {
 }
 
 // JSONStringify tries to stringify the JSON-serializable object value and returns it as string.
-func JSONStringify(ctx *Context, val *Value) (string, error) {
-	if val == nil {
+func JSONStringify(ctx *Context, val Valuer) (string, error) {
+	if val == nil || val.value() == nil {
 		return "", errors.New("v8go: Value is required")
 	}
 	// If a nil context is passed we'll use the context/isolate that created the value.
@@ -36,7 +36,7 @@ func JSONStringify(ctx *Context, val *Value) (string, error) {
 		ctxPtr = ctx.ptr
 	}
 
-	str := C.JSONStringify(ctxPtr, val.ptr)
+	str := C.JSONStringify(ctxPtr, val.value().ptr)
 	defer C.free(unsafe.Pointer(str))
 	return C.GoString(str), nil
 }

json_test.go

@@ -27,7 +27,15 @@ func TestJSONParse(t *testing.T) {
 	if _, ok := err.(*v8go.JSError); !ok {
 		t.Errorf("expected error to be of type JSError, got: %T", err)
 	}
+}
+
+func TestJSONStringify(t *testing.T) {
+	t.Parallel()
 
+	ctx, _ := v8go.NewContext()
+	if _, err := v8go.JSONStringify(ctx, nil); err == nil {
+		t.Error("expected error but got <nil>")
+	}
 }
 
 func ExampleJSONParse() {

object.go

@@ -0,0 +1,103 @@
+// Copyright 2021 Roger Chapman and the v8go contributors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package v8go
+
+// #include <stdlib.h>
+// #include "v8go.h"
+import "C"
+import (
+	"errors"
+	"fmt"
+	"math/big"
+	"unsafe"
+)
+
+// Object is a JavaScript object (ECMA-262, 4.3.3)
+type Object struct {
+	*Value
+}
+
+// Set will set a property on the Object to a given value.
+// Supports all value types, eg: Object, Array, Date, Set, Map etc
+// If the value passed is a Go supported primitive (string, int32, uint32, int64, uint64, float64, big.Int)
+// then a *Value will be created and set as the value property.
+func (o *Object) Set(key string, val interface{}) error {
+	if len(key) == 0 {
+		return errors.New("v8go: You must provide a valid property key")
+	}
+	return set(o, key, 0, val)
+}
+
+// Set will set a given index on the Object to a given value.
+// Supports all value types, eg: Object, Array, Date, Set, Map etc
+// If the value passed is a Go supported primitive (string, int32, uint32, int64, uint64, float64, big.Int)
+// then a *Value will be created and set as the value property.
+func (o *Object) SetIdx(idx uint32, val interface{}) error {
+	return set(o, "", idx, val)
+}
+
+func set(o *Object, key string, idx uint32, val interface{}) error {
+	var value *Value
+	switch v := val.(type) {
+	case string, int32, uint32, int64, uint64, float64, bool, *big.Int:
+		// ignoring error as code cannot reach the error state as we are already
+		// validating the new value types in this case statement
+		value, _ = NewValue(o.ctx.iso, v)
+	case Valuer:
+		value = v.value()
+	default:
+		return fmt.Errorf("v8go: unsupported object property type `%T`", v)
+	}
+
+	if len(key) > 0 {
+		ckey := C.CString(key)
+		defer C.free(unsafe.Pointer(ckey))
+		C.ObjectSet(o.ptr, ckey, value.ptr)
+		return nil
+	}
+
+	C.ObjectSetIdx(o.ptr, C.uint32_t(idx), value.ptr)
+	return nil
+}
+
+// Get tries to get a Value for a given Object property key.
+func (o *Object) Get(key string) (*Value, error) {
+	ckey := C.CString(key)
+	defer C.free(unsafe.Pointer(ckey))
+
+	rtn := C.ObjectGet(o.ptr, ckey)
+	return getValue(o.ctx, rtn), getError(rtn)
+}
+
+// GetIdx tries to get a Value at a give Object index.
+func (o *Object) GetIdx(idx uint32) (*Value, error) {
+	rtn := C.ObjectGetIdx(o.ptr, C.uint32_t(idx))
+	return getValue(o.ctx, rtn), getError(rtn)
+}
+
+// Has calls the abstract operation HasProperty(O, P) described in ECMA-262, 7.3.10.
+// Returns true, if the object has the property, either own or on the prototype chain.
+func (o *Object) Has(key string) bool {
+	ckey := C.CString(key)
+	defer C.free(unsafe.Pointer(ckey))
+	return C.ObjectHas(o.ptr, ckey) != 0
+}
+
+// HasIdx returns true if the object has a value at the given index.
+func (o *Object) HasIdx(idx uint32) bool {
+	return C.ObjectHasIdx(o.ptr, C.uint32_t(idx)) != 0
+}
+
+// Delete returns true if successful in deleting a named property on the object.
+func (o *Object) Delete(key string) bool {
+	ckey := C.CString(key)
+	defer C.free(unsafe.Pointer(ckey))
+	return C.ObjectDelete(o.ptr, ckey) != 0
+}
+
+// DeleteIdx returns true if successful in deleting a value at a given index of the object.
+func (o *Object) DeleteIdx(idx uint32) bool {
+	return C.ObjectDeleteIdx(o.ptr, C.uint32_t(idx)) != 0
+}

object_template.go

@@ -49,6 +49,16 @@ func NewObjectTemplate(iso *Isolate) (*ObjectTemplate, error) {
 	return &ObjectTemplate{tmpl}, nil
 }
 
+// NewInstance creates a new Object based on the template.
+func (o *ObjectTemplate) NewInstance(ctx *Context) (*Object, error) {
+	if ctx == nil {
+		return nil, errors.New("v8go: Context cannot be <nil>")
+	}
+
+	valPtr := C.ObjectTemplateNewInstance(o.ptr, ctx.ptr)
+	return &Object{&Value{valPtr, ctx}}, nil
+}
+
 func (o *ObjectTemplate) apply(opts *contextOptions) {
 	opts.gTmpl = o
 }

object_template_test.go

@@ -117,3 +117,20 @@ func TestGlobalObjectTemplate(t *testing.T) {
 		})
 	}
 }
+
+func TestObjectTemplateNewInstance(t *testing.T) {
+	t.Parallel()
+	iso, _ := v8go.NewIsolate()
+	tmpl, _ := v8go.NewObjectTemplate(iso)
+	if _, err := tmpl.NewInstance(nil); err == nil {
+		t.Error("expected error but got <nil>")
+	}
+
+	tmpl.Set("foo", "bar")
+	ctx, _ := v8go.NewContext(iso)
+	obj, _ := tmpl.NewInstance(ctx)
+	if foo, _ := obj.Get("foo"); foo.String() != "bar" {
+		t.Errorf("unexpected value for object property: %v", foo)
+	}
+
+}

object_test.go

@@ -0,0 +1,116 @@
+// Copyright 2021 Roger Chapman and the v8go contributors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package v8go_test
+
+import (
+	"fmt"
+	"testing"
+
+	"rogchap.com/v8go"
+)
+
+func TestObjectSet(t *testing.T) {
+	t.Parallel()
+
+	ctx, _ := v8go.NewContext()
+	val, _ := ctx.RunScript("const foo = {}; foo", "")
+	obj, _ := val.AsObject()
+	obj.Set("bar", "baz")
+	baz, _ := ctx.RunScript("foo.bar", "")
+	if baz.String() != "baz" {
+		t.Errorf("unexpected value: %q", baz)
+	}
+	if err := obj.Set("", nil); err == nil {
+		t.Error("expected error but got <nil>")
+	}
+	if err := obj.Set("a", 0); err == nil {
+		t.Error("expected error but got <nil>")
+	}
+	obj.SetIdx(10, "ten")
+	if ten, _ := ctx.RunScript("foo[10]", ""); ten.String() != "ten" {
+		t.Errorf("unexpected value: %q", ten)
+	}
+}
+
+func TestObjectGet(t *testing.T) {
+	t.Parallel()
+
+	ctx, _ := v8go.NewContext()
+	val, _ := ctx.RunScript("const foo = { bar: 'baz'}; foo", "")
+	obj, _ := val.AsObject()
+	if bar, _ := obj.Get("bar"); bar.String() != "baz" {
+		t.Errorf("unexpected value: %q", bar)
+	}
+	if baz, _ := obj.Get("baz"); !baz.IsUndefined() {
+		t.Errorf("unexpected value: %q", baz)
+	}
+	ctx.RunScript("foo[5] = 5", "")
+	if five, _ := obj.GetIdx(5); five.Integer() != 5 {
+		t.Errorf("unexpected value: %q", five)
+	}
+	if u, _ := obj.GetIdx(55); !u.IsUndefined() {
+		t.Errorf("unexpected value: %q", u)
+	}
+}
+
+func TestObjectHas(t *testing.T) {
+	t.Parallel()
+
+	ctx, _ := v8go.NewContext()
+	val, _ := ctx.RunScript("const foo = {a: 1, '2': 2}; foo", "")
+	obj, _ := val.AsObject()
+	if !obj.Has("a") {
+		t.Error("expected true, got false")
+	}
+	if obj.Has("c") {
+		t.Error("expected false, got true")
+	}
+	if !obj.HasIdx(2) {
+		t.Error("expected true, got false")
+	}
+	if obj.HasIdx(1) {
+		t.Error("expected false, got true")
+	}
+}
+
+func TestObjectDelete(t *testing.T) {
+	t.Parallel()
+
+	ctx, _ := v8go.NewContext()
+	val, _ := ctx.RunScript("const foo = { bar: 'baz', '2': 2}; foo", "")
+	obj, _ := val.AsObject()
+	if !obj.Has("bar") {
+		t.Error("expected property to exist")
+	}
+	if !obj.Delete("bar") {
+		t.Error("expected delete to return true, got false")
+	}
+	if obj.Has("bar") {
+		t.Error("expected property to be deleted")
+	}
+	if !obj.DeleteIdx(2) {
+		t.Error("expected delete to return true, got false")
+	}
+
+}
+
+func ExampleObject_global() {
+	iso, _ := v8go.NewIsolate()
+	ctx, _ := v8go.NewContext(iso)
+	global := ctx.Global()
+
+	console, _ := v8go.NewObjectTemplate(iso)
+	logfn, _ := v8go.NewFunctionTemplate(iso, func(info *v8go.FunctionCallbackInfo) *v8go.Value {
+		fmt.Println(info.Args()[0])
+		return nil
+	})
+	console.Set("log", logfn)
+	consoleObj, _ := console.NewInstance(ctx)
+
+	global.Set("console", consoleObj)
+	ctx.RunScript("console.log('foo')", "")
+	// Output:
+	// foo
+}