Merge pull request #1822 from PerBothner/optimize-osc-parse

Optimize parsing of OSC_STRING to minimize string concatenation.
xtermjs · Dec 11, 2018 · a758f8c · a758f8c
2 parents 53f3b4e + bbbfc04
commit a758f8c
Showing 1 changed file with 15 additions and 9 deletions.
diff --git a/src/EscapeSequenceParser.ts b/src/EscapeSequenceParser.ts
@@ -67,7 +67,8 @@ const PRINTABLES = r(0x20, 0x7f);
 const EXECUTABLES = r(0x00, 0x18);
 EXECUTABLES.push(0x19);
 EXECUTABLES.push.apply(EXECUTABLES, r(0x1c, 0x20));
-const DEFAULT_TRANSITION = ParserAction.ERROR << 4 | ParserState.GROUND;
+// Pseudo-character placeholder for printable non-ascii characters.
+const NON_ASCII_PRINTABLE = 0xA0;
 
 /**
  * VT500 compatible transition table.
@@ -79,10 +80,10 @@ export const VT500_TRANSITION_TABLE = (function (): TransitionTable {
   const states: number[] = r(ParserState.GROUND, ParserState.DCS_PASSTHROUGH + 1);
   let state: any;
 
-  // table with default transition [any] --> DEFAULT_TRANSITION
+  // table with default transition
   for (state in states) {
     // NOTE: table lookup is capped at 0xa0 in parse to keep the table small
-    for (let code = 0; code < 160; ++code) {
+    for (let code = 0; code <= NON_ASCII_PRINTABLE; ++code) {
       table.add(code, state, ParserAction.ERROR, ParserState.GROUND);
     }
   }
@@ -184,6 +185,7 @@ export const VT500_TRANSITION_TABLE = (function (): TransitionTable {
   table.addMany(PRINTABLES, ParserState.DCS_PASSTHROUGH, ParserAction.DCS_PUT, ParserState.DCS_PASSTHROUGH);
   table.add(0x7f, ParserState.DCS_PASSTHROUGH, ParserAction.IGNORE, ParserState.DCS_PASSTHROUGH);
   table.addMany([0x1b, 0x9c], ParserState.DCS_PASSTHROUGH, ParserAction.DCS_UNHOOK, ParserState.GROUND);
+  table.add(NON_ASCII_PRINTABLE, ParserState.OSC_STRING, ParserAction.OSC_PUT, ParserState.OSC_STRING);
   return table;
 })();
 
@@ -391,7 +393,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
       }
 
       // normal transition & action lookup
-      transition = (code < 0xa0) ? (table[currentState << 8 | code]) : DEFAULT_TRANSITION;
+      transition = table[currentState << 8 | (code < 0xa0 ? code : NON_ASCII_PRINTABLE)];
       switch (transition >> 4) {
         case ParserAction.PRINT:
           print = (~print) ? print : i;
@@ -423,10 +425,6 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
               case ParserState.GROUND:
                 print = (~print) ? print : i;
                 break;
-              case ParserState.OSC_STRING:
-                osc += String.fromCharCode(code);
-                transition |= ParserState.OSC_STRING;
-                break;
               case ParserState.CSI_IGNORE:
                 transition |= ParserState.CSI_IGNORE;
                 break;
@@ -517,7 +515,15 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
           osc = '';
           break;
         case ParserAction.OSC_PUT:
-          osc += data.charAt(i);
+          for (let j = i + 1; ; j++) {
+            if (j >= l
+                || (code = data.charCodeAt(j)) < 0x20
+                || (code > 0x7f && code <= 0x9f)) {
+              osc += data.substring(i, j);
+              i = j - 1;
+              break;
+            }
+          }
           break;
         case ParserAction.OSC_END:
           if (osc && code !== 0x18 && code !== 0x1a) {