misc/wasm: add stub for fs.read on browsers

Using fmt.Scanln in a browser environment caused a panic, since there
was no stub for fs.read. This commit adds a stub that returns ENOSYS.

Fixes #27773.

Change-Id: I79b019039e4bc90da51d71a4edddf3bd7809ff45
Reviewed-on: https://go-review.googlesource.com/c/150617
Run-TryBot: Richard Musiol <neelance@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/misc/wasm/wasm_exec.js b/misc/wasm/wasm_exec.js
index 83704a054f012ae5b711b38d8cc1d237c905c8f9..743eaf70b2ced60142d4145f85019517dbeec516 100644 (file)
--- a/misc/wasm/wasm_exec.js
+++ b/misc/wasm/wasm_exec.js
@@ -61,6 +61,11 @@
                                err.code = "ENOSYS";
                                callback(err);
                        },
+                       read(fd, buffer, offset, length, position, callback) {
+                               const err = new Error("not implemented");
+                               err.code = "ENOSYS";
+                               callback(err);
+                       },
                        fsync(fd, callback) {
                                callback(null);
                        },