basic nonblocking input

Author: xloem

library_emterm.js

@@ -96,6 +96,25 @@ mergeInto(LibraryManager.library, {
         }
         return i;
       },
+      poll: function(stream) {
+        if (!stream.tty) {
+          throw new FS.ErrnoError({{{ cDefine('EBADF') }}});
+        }
+        var ret = 0;
+        if (Module.tty && Module.tty.poll_out) {
+          if (Module.tty.poll_out(stream.tty)) {
+            ret |= {{{ cDefine('POLLOUT') }}};
+          }
+        } else {
+          ret |= {{{ cDefine('POLLOUT') }}};
+        }
+        if (stream.tty.input.length) {
+          ret |= {{{ cDefine('POLLIN') }}};
+        } else if (Module.tty && Module.tty.poll_in && Module.tty.poll_in(stream.tty)) {
+          ret |= {{{ cDefine('POLLIN') }}};
+        }
+        return ret;
+      },
       ioctl: function(stream, op, argp) {
         if (!stream.tty) {
           throw new FS.ErrnoError({{{ cDefine('ENOTTY') }}});

shell_emterm.html

@@ -88,10 +88,12 @@
     <script type='text/javascript'>
       const term = new Terminal({convertEol: true, scrollback: 0});
       const fitAddon = new FitAddon.FitAddon();
+      var inputBuf = [];
       term.loadAddon(fitAddon);
       term.open(document.getElementById('output'));
       fitAddon.fit();
       window.addEventListener('resize', ()=>fitAddon.fit());
+      term.onData(data=> inputBuf = inputBuf.concat(intArrayFromString(data)));
       function write(text) {
         if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
         // These replacements are necessary if you render to raw HTML
@@ -109,7 +111,11 @@
             term.write(val);
           },
           get_char: function(tty) {
-            return undefined;
+            if (!inputBuf.length) return undefined;
+            return inputBuf.shift();
+          },
+          poll_in: function(tty) {
+            return inputBuf.length > 0;
           },
           get_winsize: function(tty, winsize) {
             winsize.ws_row = term.rows;