compiler/natives/src/internal/poll: Create no-op I/O poller implement…

…ation.

gopherjs test uses tempFile to create temporary files during execution
of examples. tempFile calls os.OpenFile to create a file. os.OpenFile
calls newFile, which in Go 1.9 tries to add the file to the runtime
poller.

Normally, on OSes like darwin, linux, etc., this tries to use a real
runtime poller from internal/poll package. We override that package
so that a no-op implementation (based on NaCL implementation) is used
instead.

Fixes:

	Error: runtime error: native function not implemented: internal/poll.runtime_pollServerInit

After this change, some basic tests pass:

	$ gopherjs test errors github.com/gopherjs/gopherjs/tests
	PASS
	ok  	errors	0.453s
	PASS
	ok  	github.com/gopherjs/gopherjs/tests	0.606s

build/build.go

@@ -93,13 +93,15 @@ func importWithSrcDir(path string, srcDir string, mode build.ImportMode, install
 
 	switch path {
 	case "os":
-		pkg.GoFiles = stripExecutable(pkg.GoFiles) // Need to strip executable implementation files, because some of them contain package scope variables that perform (indirectly) syscalls on init.
+		pkg.GoFiles = excludeExecutable(pkg.GoFiles) // Need to exclude executable implementation files, because some of them contain package scope variables that perform (indirectly) syscalls on init.
 	case "runtime":
 		pkg.GoFiles = []string{"error.go"}
 	case "runtime/internal/sys":
 		pkg.GoFiles = []string{fmt.Sprintf("zgoos_%s.go", buildContext.GOOS), "zversion.go"}
 	case "runtime/pprof":
 		pkg.GoFiles = nil
+	case "internal/poll":
+		pkg.GoFiles = exclude(pkg.GoFiles, "fd_poll_runtime.go")
 	case "crypto/rand":
 		pkg.GoFiles = []string{"rand.go", "util.go"}
 	case "crypto/x509":
@@ -131,9 +133,9 @@ func importWithSrcDir(path string, srcDir string, mode build.ImportMode, install
 	return &PackageData{Package: pkg, JSFiles: jsFiles}, nil
 }
 
-// stripExecutable strips all executable implementation .go files.
+// excludeExecutable excludes all executable implementation .go files.
 // They have "executable_" prefix.
-func stripExecutable(goFiles []string) []string {
+func excludeExecutable(goFiles []string) []string {
 	var s []string
 	for _, f := range goFiles {
 		if strings.HasPrefix(f, "executable_") {
@@ -144,6 +146,21 @@ func stripExecutable(goFiles []string) []string {
 	return s
 }
 
+// exclude returns files, excluding specified files.
+func exclude(files []string, exclude ...string) []string {
+	var s []string
+Outer:
+	for _, f := range files {
+		for _, e := range exclude {
+			if f == e {
+				continue Outer
+			}
+		}
+		s = append(s, f)
+	}
+	return s
+}
+
 // ImportDir is like Import but processes the Go package found in the named
 // directory.
 func ImportDir(dir string, mode build.ImportMode, installSuffix string, buildTags []string) (*PackageData, error) {

compiler/natives/src/internal/poll/fd_poll_js.go

@@ -0,0 +1,52 @@
+// +build js
+
+package poll
+
+import "time"
+
+// pollDesc is a no-op implementation of an I/O poller for GOARCH=js.
+type pollDesc struct {
+	closing bool
+}
+
+func (pd *pollDesc) init(fd *FD) error { return nil }
+
+func (pd *pollDesc) close() {}
+
+func (pd *pollDesc) evict() { pd.closing = true }
+
+func (pd *pollDesc) prepare(mode int, isFile bool) error {
+	if pd.closing {
+		return errClosing(isFile)
+	}
+	return nil
+}
+
+func (pd *pollDesc) prepareRead(isFile bool) error { return pd.prepare('r', isFile) }
+
+func (pd *pollDesc) prepareWrite(isFile bool) error { return pd.prepare('w', isFile) }
+
+func (pd *pollDesc) wait(mode int, isFile bool) error {
+	if pd.closing {
+		return errClosing(isFile)
+	}
+	return ErrTimeout
+}
+
+func (pd *pollDesc) waitRead(isFile bool) error { return pd.wait('r', isFile) }
+
+func (pd *pollDesc) waitWrite(isFile bool) error { return pd.wait('w', isFile) }
+
+func (*pollDesc) waitCanceled(mode int) {}
+
+func (*FD) SetDeadline(t time.Time) error { return nil }
+
+func (*FD) SetReadDeadline(t time.Time) error { return nil }
+
+func (*FD) SetWriteDeadline(t time.Time) error { return nil }
+
+// PollDescriptor returns the descriptor being used by the poller,
+// or ^uintptr(0) if there isn't one. This is only used for testing.
+func PollDescriptor() uintptr {
+	return ^uintptr(0)
+}