readline: keypress trigger for escape character

Fixes: #7379 PR-URL: #7382 Reviewed-By: jasnell - James M Snell <[email protected]> Reviewed-By: Roman Reiss <[email protected]>

Author: princejwesley

lib/internal/readline.js

@@ -376,11 +376,15 @@ function* emitKeys(stream){
 key.name=ch.toLowerCase();
 key.shift=/^[A-Z]$/.test(ch);
 key.meta=escaped;
+}elseif(escaped){
+// Escape sequence timeout
+key.name=ch.length ? undefined : 'escape';
+key.meta=true;
 }
 
 key.sequence=s;
 
-if(key.name!==undefined){
+if(s.length!==0&&(key.name!==undefined||escaped)){
 /* Named character or sequence */
 stream.emit('keypress',escaped ? undefined : s,key);
 }elseif(s.length===1){

lib/readline.js

@@ -926,6 +926,9 @@ exports.Interface = Interface;
 constKEYPRESS_DECODER=Symbol('keypress-decoder');
 constESCAPE_DECODER=Symbol('escape-decoder');
 
+// GNU readline library - keyseq-timeout is 500ms (default)
+constESCAPE_CODE_TIMEOUT=500;
+
 functionemitKeypressEvents(stream,iface){
 if(stream[KEYPRESS_DECODER])return;
 varStringDecoder=require('string_decoder').StringDecoder;// lazy load
@@ -934,17 +937,26 @@ function emitKeypressEvents(stream, iface){
 stream[ESCAPE_DECODER]=emitKeys(stream);
 stream[ESCAPE_DECODER].next();
 
+constescapeCodeTimeout=()=>stream[ESCAPE_DECODER].next('');
+lettimeoutId;
+
 functiononData(b){
 if(stream.listenerCount('keypress')>0){
 varr=stream[KEYPRESS_DECODER].write(b);
 if(r){
+clearTimeout(timeoutId);
+
 for(vari=0;i<r.length;i++){
 if(r[i]==='\t'&&typeofr[i+1]==='string'&&iface){
 iface.isCompletionEnabled=false;
 }
 
 try{
 stream[ESCAPE_DECODER].next(r[i]);
+// Escape letter at the tail position
+if(r[i]==='\x1b'&&i+1===r.length){
+timeoutId=setTimeout(escapeCodeTimeout,ESCAPE_CODE_TIMEOUT);
+}
 }catch(err){
 // if the generator throws (it could happen in the `keypress`
 // event), we need to restart it.

test/parallel/test-readline-keys.js

@@ -44,6 +44,49 @@ function addTest(sequences, expectedKeys){
 assert.deepStrictEqual(keys,expectedKeys);
 }
 
+// Simulate key interval test cases
+// Returns a function that takes `next` test case and returns a thunk
+// that can be called to run tests in sequence
+// e.g.
+// addKeyIntervalTest(..)
+// (addKeyIntervalTest(..)
+// (addKeyIntervalTest(..)(noop)))()
+// where noop is a terminal function(() =>{}).
+
+constaddKeyIntervalTest=(sequences,expectedKeys,interval=550,
+assertDelay=550)=>{
+return(next)=>()=>{
+
+if(!Array.isArray(sequences)){
+sequences=[sequences];
+}
+
+if(!Array.isArray(expectedKeys)){
+expectedKeys=[expectedKeys];
+}
+
+expectedKeys=expectedKeys.map(function(k){
+returnk ? extend({ctrl: false,meta: false,shift: false},k) : k;
+});
+
+constkeys=[];
+fi.on('keypress',(s,k)=>keys.push(k));
+
+constemitKeys=([head, ...tail])=>{
+if(head){
+fi.write(head);
+setTimeout(()=>emitKeys(tail),interval);
+}else{
+setTimeout(()=>{
+next();
+assert.deepStrictEqual(keys,expectedKeys);
+},assertDelay);
+}
+};
+emitKeys(sequences);
+};
+};
+
 // regular alphanumerics
 addTest('io.JS',[
 {name: 'i',sequence: 'i'},
@@ -149,3 +192,22 @@ addTest('\x1b[31ma\x1b[39ma', [
 {name: 'undefined',sequence: '\x1b[39m',code: '[39m'},
 {name: 'a',sequence: 'a'},
 ]);
+
+// Reduce array of addKeyIntervalTest(..) right to left
+// with () =>{} as initial function
+construnKeyIntervalTests=[
+// escape character
+addKeyIntervalTest('\x1b',[
+{name: 'escape',sequence: '\x1b',meta: true}
+]),
+// chain of escape characters
+addKeyIntervalTest('\x1b\x1b\x1b\x1b'.split(''),[
+{name: 'escape',sequence: '\x1b',meta: true},
+{name: 'escape',sequence: '\x1b',meta: true},
+{name: 'escape',sequence: '\x1b',meta: true},
+{name: 'escape',sequence: '\x1b',meta: true}
+])
+].reverse().reduce((acc,fn)=>fn(acc),()=>{});
+
+// run key interval tests one after another
+runKeyIntervalTests();