diff options
Diffstat (limited to 'src/syscall/js/js.go')
| -rw-r--r-- | src/syscall/js/js.go | 105 |
1 files changed, 96 insertions, 9 deletions
diff --git a/src/syscall/js/js.go b/src/syscall/js/js.go index f7e32eb366d..74c02cdbe64 100644 --- a/src/syscall/js/js.go +++ b/src/syscall/js/js.go @@ -210,7 +210,13 @@ func ValueOf(x any) Value { } } +// stringVal copies string x to Javascript and returns a ref. +// +// (noescape): This is safe because no references are maintained to the +// Go string x after the syscall returns. +// //go:wasmimport gojs syscall/js.stringVal +//go:noescape func stringVal(x string) ref // Type represents the JavaScript type of a Value. @@ -294,7 +300,13 @@ func (v Value) Get(p string) Value { return r } +// valueGet returns a ref to JavaScript property p of ref v. +// +// (noescape): This is safe because no references are maintained to the +// Go string p after the syscall returns. +// //go:wasmimport gojs syscall/js.valueGet +//go:noescape func valueGet(v ref, p string) ref // Set sets the JavaScript property p of value v to ValueOf(x). @@ -309,7 +321,13 @@ func (v Value) Set(p string, x any) { runtime.KeepAlive(xv) } +// valueSet sets property p of ref v to ref x. +// +// (noescape): This is safe because no references are maintained to the +// Go string p after the syscall returns. +// //go:wasmimport gojs syscall/js.valueSet +//go:noescape func valueSet(v ref, p string, x ref) // Delete deletes the JavaScript property p of value v. @@ -322,7 +340,13 @@ func (v Value) Delete(p string) { runtime.KeepAlive(v) } +// valueDelete deletes the JavaScript property p of ref v. +// +// (noescape): This is safe because no references are maintained to the +// Go string p after the syscall returns. +// //go:wasmimport gojs syscall/js.valueDelete +//go:noescape func valueDelete(v ref, p string) // Index returns JavaScript index i of value v. @@ -354,15 +378,36 @@ func (v Value) SetIndex(i int, x any) { //go:wasmimport gojs syscall/js.valueSetIndex func valueSetIndex(v ref, i int, x ref) -func makeArgs(args []any) ([]Value, []ref) { - argVals := make([]Value, len(args)) - argRefs := make([]ref, len(args)) +// makeArgSlices makes two slices to hold JavaScript arg data. +// It can be paired with storeArgs to make-and-store JavaScript arg slices. +// However, the two functions are separated to ensure makeArgSlices is inlined +// which will prevent the slices from being heap allocated for small (<=16) +// numbers of args. +func makeArgSlices(size int) (argVals []Value, argRefs []ref) { + // value chosen for being power of two, and enough to handle all web APIs + // in particular, note that WebGL2's texImage2D takes up to 10 arguments + const maxStackArgs = 16 + if size <= maxStackArgs { + // as long as makeArgs is inlined, these will be stack-allocated + argVals = make([]Value, size, maxStackArgs) + argRefs = make([]ref, size, maxStackArgs) + } else { + // allocates on the heap, but exceeding maxStackArgs should be rare + argVals = make([]Value, size) + argRefs = make([]ref, size) + } + return +} + +// storeArgs maps input args onto respective Value and ref slices. +// It can be paired with makeArgSlices to make-and-store JavaScript arg slices. +func storeArgs(args []any, argValsDst []Value, argRefsDst []ref) { + // would go in makeArgs if the combined func was simple enough to inline for i, arg := range args { v := ValueOf(arg) - argVals[i] = v - argRefs[i] = v.ref + argValsDst[i] = v + argRefsDst[i] = v.ref } - return argVals, argRefs } // Length returns the JavaScript property "length" of v. @@ -383,7 +428,8 @@ func valueLength(v ref) int // It panics if v has no method m. // The arguments get mapped to JavaScript values according to the ValueOf function. func (v Value) Call(m string, args ...any) Value { - argVals, argRefs := makeArgs(args) + argVals, argRefs := makeArgSlices(len(args)) + storeArgs(args, argVals, argRefs) res, ok := valueCall(v.ref, m, argRefs) runtime.KeepAlive(v) runtime.KeepAlive(argVals) @@ -399,15 +445,24 @@ func (v Value) Call(m string, args ...any) Value { return makeValue(res) } +// valueCall does a JavaScript call to the method name m of ref v with the given arguments. +// +// (noescape): This is safe because no references are maintained to the +// Go string m after the syscall returns. Additionally, the args slice +// is only used temporarily to collect the JavaScript objects for +// the JavaScript method invocation. +// //go:wasmimport gojs syscall/js.valueCall //go:nosplit +//go:noescape func valueCall(v ref, m string, args []ref) (ref, bool) // Invoke does a JavaScript call of the value v with the given arguments. // It panics if v is not a JavaScript function. // The arguments get mapped to JavaScript values according to the ValueOf function. func (v Value) Invoke(args ...any) Value { - argVals, argRefs := makeArgs(args) + argVals, argRefs := makeArgSlices(len(args)) + storeArgs(args, argVals, argRefs) res, ok := valueInvoke(v.ref, argRefs) runtime.KeepAlive(v) runtime.KeepAlive(argVals) @@ -420,14 +475,22 @@ func (v Value) Invoke(args ...any) Value { return makeValue(res) } +// valueInvoke does a JavaScript call to value v with the given arguments. +// +// (noescape): This is safe because the args slice is only used temporarily +// to collect the JavaScript objects for the JavaScript method +// invocation. +// //go:wasmimport gojs syscall/js.valueInvoke +//go:noescape func valueInvoke(v ref, args []ref) (ref, bool) // New uses JavaScript's "new" operator with value v as constructor and the given arguments. // It panics if v is not a JavaScript function. // The arguments get mapped to JavaScript values according to the ValueOf function. func (v Value) New(args ...any) Value { - argVals, argRefs := makeArgs(args) + argVals, argRefs := makeArgSlices(len(args)) + storeArgs(args, argVals, argRefs) res, ok := valueNew(v.ref, argRefs) runtime.KeepAlive(v) runtime.KeepAlive(argVals) @@ -440,7 +503,13 @@ func (v Value) New(args ...any) Value { return makeValue(res) } +// valueNew uses JavaScript's "new" operator with value v as a constructor and the given arguments. +// +// (noescape): This is safe because the args slice is only used temporarily +// to collect the JavaScript objects for the constructor execution. +// //go:wasmimport gojs syscall/js.valueNew +//go:noescape func valueNew(v ref, args []ref) (ref, bool) func (v Value) isNumber() bool { @@ -543,7 +612,13 @@ func jsString(v Value) string { //go:wasmimport gojs syscall/js.valuePrepareString func valuePrepareString(v ref) (ref, int) +// valueLoadString loads string data located at ref v into byte slice b. +// +// (noescape): This is safe because the byte slice is only used as a destination +// for storing the string data and references to it are not maintained. +// //go:wasmimport gojs syscall/js.valueLoadString +//go:noescape func valueLoadString(v ref, b []byte) // InstanceOf reports whether v is an instance of type t according to JavaScript's instanceof operator. @@ -581,7 +656,13 @@ func CopyBytesToGo(dst []byte, src Value) int { return n } +// copyBytesToGo copies bytes from src to dst. +// +// (noescape): This is safe because the dst byte slice is only used as a dst +// copy buffer and no references to it are maintained. +// //go:wasmimport gojs syscall/js.copyBytesToGo +//go:noescape func copyBytesToGo(dst []byte, src ref) (int, bool) // CopyBytesToJS copies bytes from src to dst. @@ -596,5 +677,11 @@ func CopyBytesToJS(dst Value, src []byte) int { return n } +// copyBytesToJs copies bytes from src to dst. +// +// (noescape): This is safe because the src byte slice is only used as a src +// copy buffer and no references to it are maintained. +// //go:wasmimport gojs syscall/js.copyBytesToJS +//go:noescape func copyBytesToJS(dst ref, src []byte) (int, bool) |