From 4be3851d197c331a8789799b9bc54683f6fdd45b Mon Sep 17 00:00:00 2001 From: Denys Smirnov Date: Wed, 24 Oct 2018 20:09:00 +0000 Subject: [PATCH] syscall/js: add Wrapper interface to support external Value wrapper types The Callback and TypedArray are the only JavaScript types supported by the library, thus they are special-cased in a type switch of ValueOf. Instead, a Ref interface is defined to allow external wrapper types to be handled properly by ValueOf. Change-Id: I03240ba7ec46979336b88389a70b7bcac37fc715 GitHub-Last-Rev: c8cf08d8ccfaab2af98df9eec8bc7b60dbce2c64 GitHub-Pull-Request: golang/go#28181 Reviewed-on: https://go-review.googlesource.com/c/141644 Run-TryBot: Brad Fitzpatrick TryBot-Result: Gobot Gobot Reviewed-by: Richard Musiol Reviewed-by: Brad Fitzpatrick --- src/syscall/js/callback.go | 2 ++ src/syscall/js/js.go | 19 ++++++++++++++----- src/syscall/js/typedarray.go | 2 ++ 3 files changed, 18 insertions(+), 5 deletions(-) diff --git a/src/syscall/js/callback.go b/src/syscall/js/callback.go index 9d573074cb..2801e00b68 100644 --- a/src/syscall/js/callback.go +++ b/src/syscall/js/callback.go @@ -20,6 +20,8 @@ var ( nextCallbackID uint32 = 1 ) +var _ Wrapper = Callback{} // Callback must implement Wrapper + // Callback is a Go function that got wrapped for use as a JavaScript callback. type Callback struct { Value // the JavaScript function that queues the callback for execution diff --git a/src/syscall/js/js.go b/src/syscall/js/js.go index 9d826c3886..dc741e79a7 100644 --- a/src/syscall/js/js.go +++ b/src/syscall/js/js.go @@ -26,11 +26,22 @@ type ref uint64 // nanHead are the upper 32 bits of a ref which are set if the value is not encoded as an IEEE 754 number (see above). const nanHead = 0x7FF80000 +// Wrapper is implemented by types that are backed by a JavaScript value. +type Wrapper interface { + // JSValue returns a JavaScript value associated with an object. + JSValue() Value +} + // Value represents a JavaScript value. The zero value is the JavaScript value "undefined". type Value struct { ref ref } +// JSValue implements Wrapper interface. +func (v Value) JSValue() Value { + return v +} + func makeValue(v ref) Value { return Value{ref: v} } @@ -105,12 +116,10 @@ func Global() Value { // | map[string]interface{} | new object | func ValueOf(x interface{}) Value { switch x := x.(type) { - case Value: + case Value: // should precede Wrapper to avoid a loop return x - case TypedArray: - return x.Value - case Callback: - return x.Value + case Wrapper: + return x.JSValue() case nil: return valueNull case bool: diff --git a/src/syscall/js/typedarray.go b/src/syscall/js/typedarray.go index afa15488ec..aa56cf69f3 100644 --- a/src/syscall/js/typedarray.go +++ b/src/syscall/js/typedarray.go @@ -22,6 +22,8 @@ var ( float64Array = Global().Get("Float64Array") ) +var _ Wrapper = TypedArray{} // TypedArray must implement Wrapper + // TypedArray represents a JavaScript typed array. type TypedArray struct { Value -- 2.50.0