func doFinish(call rpc.ClientCall, numResults int) (C.SwiftByteArrayArray, error) {
// Have all the results be decoded into *vdl.Value.
resultPtrs := make([]interface{}, numResults)
for i := 0; i < numResults; i++ {
value := new(vdl.Value)
resultPtrs[i] = &value
}
if err := call.Finish(resultPtrs...); err != nil {
// Invocation error.
return EmptySwiftByteArrayArray(), err
}
// VOM-encode the results. Note in the future we'll want a pathway where we can get the original VOM results
// from finish so we don't end up wasting CPU & memory here.
// Prepare the byte array array that can be accessed from Swift via C.malloc
vomResultsMemory := C.malloc(C.size_t(numResults * int(C.sizeofSwiftByteArray)))
// Make that malloc'd memory available as a slice to Go.
vomResultsPtrsHdr := reflect.SliceHeader{
Data: uintptr(vomResultsMemory),
Len: numResults,
Cap: numResults,
}
vomResults := *(*[]C.SwiftByteArray)(unsafe.Pointer(&vomResultsPtrsHdr))
// Create the C Struct to return that encapsulates our byte array array
var cVomResults C.SwiftByteArrayArray
cVomResults.length = C._GoUint64(numResults)
cVomResults.data = (*C.SwiftByteArray)(vomResultsMemory)
// For each result, VOM encode into a byte array that we stick into the returned struct
for i, resultPtr := range resultPtrs {
// Remove the pointer from the result. Simply *resultPtr doesn't work
// as resultPtr is of type interface{}.
result := interface{}(sutil.DerefOrDie(resultPtr))
var vomResult []byte
var err error
if vomResult, err = vom.Encode(result); err != nil {
return EmptySwiftByteArrayArray(), err
}
cVomResultCopy := C.malloc(C.size_t(len(vomResult)))
C.memcpy(cVomResultCopy, unsafe.Pointer(&vomResult[0]), C.size_t(len(vomResult)))
var cVomResult C.SwiftByteArray
cVomResult.length = C._GoUint64(len(vomResult))
cVomResult.data = cVomResultCopy
vomResults[i] = cVomResult
}
return cVomResults, nil
}
func swiftBytesCopy(data []byte) C.SwiftByteArray {
var a C.SwiftByteArray
a.length = C._GoUint64(len(data))
a.data = C.malloc(C.size_t(len(data)))
if a.data == nil {
panic(fmt.Errorf("Unable to allocate %d bytes", a.length))
}
C.memmove(a.data, unsafe.Pointer(&data[0]), C.size_t(len(data)))
return a
}
//export swift_io_v_swift_impl_util_type_nativeBase64UrlDecode
func swift_io_v_swift_impl_util_type_nativeBase64UrlDecode(base64UrlEncoded *C.char) C.SwiftByteArray {
// Decode the base64 url encoded string to bytes in a way that prevents extra copies along the CGO boundary.
urlEncoded := C.GoString(base64UrlEncoded)
maxLength := base64.URLEncoding.DecodedLen(len(urlEncoded))
bytesBacking := C.malloc(C.size_t(maxLength))
if bytesBacking == nil {
vlog.Errorf("Unable allocate %v bytes", maxLength)
return EmptySwiftByteArray()
}
var bytes []byte = (*[1 << 30]byte)(unsafe.Pointer(bytesBacking))[:maxLength:maxLength]
n, err := base64.URLEncoding.Decode(bytes, []byte(urlEncoded))
if err != nil {
vlog.Errorf("Unable to base64 decode string: %v\n", err)
C.free(bytesBacking)
return EmptySwiftByteArray()
}
var swiftArray C.SwiftByteArray
swiftArray.length = C._GoUint64(n)
swiftArray.data = bytesBacking
return swiftArray
}