fix repeat preceding character sequence (REP)

src/InputHandler.api.ts

@@ -241,6 +241,56 @@ describe('InputHandler Integration Tests', function(): void {
         });
       });
     });
+
+    it('REP: Repeat preceding character, ECMA48 - CSI Ps b', async function(): Promise<any> {
+      // default to 1
+      await page.evaluate(`
+        window.term.resize(10, 10);
+        window.term.write('#\x1b[b');
+        window.term.writeln('');
+        window.term.write('#\x1b[0b');
+        window.term.writeln('');
+        window.term.write('#\x1b[1b');
+        window.term.writeln('');
+        window.term.write('#\x1b[5b');
+      `);
+      assert.deepEqual(await getLinesAsArray(4), ['##', '##', '##', '######']);
+      assert.deepEqual(await getCursor(), {col: 6, row: 3});
+      // should not repeat on fullwidth chars
+      await page.evaluate(`
+        window.term.reset();
+        window.term.write('￥\x1b[10b');
+      `);
+      assert.deepEqual(await getLinesAsArray(1), ['￥']);
+      // should repeat only base char of combining
+      await page.evaluate(`
+        window.term.reset();
+        window.term.write('e\u0301\x1b[5b');
+      `);
+      assert.deepEqual(await getLinesAsArray(1), ['e\u0301eeeee']);
+      // should wrap correctly
+      await page.evaluate(`
+        window.term.reset();
+        window.term.write('#\x1b[15b');
+      `);
+      assert.deepEqual(await getLinesAsArray(2), ['##########', '######']);
+      await page.evaluate(`
+        window.term.reset();
+        window.term.write('\x1b[?7l');  // disable wrap around
+        window.term.write('#\x1b[15b');
+      `);
+      assert.deepEqual(await getLinesAsArray(2), ['##########', '']);
+      // any successful sequence should reset REP
+      await page.evaluate(`
+        window.term.reset();
+        window.term.write('\x1b[?7h');  // re-enable wrap around
+        window.term.write('#\\n\x1b[3b');
+        window.term.write('#\\r\x1b[3b');
+        window.term.writeln('');
+        window.term.write('abcdefg\x1b[3D\x1b[10b#\x1b[3b');
+      `);
+      assert.deepEqual(await getLinesAsArray(3), ['#', ' #', 'abcd####']);
+    });
   });
 });
 
@@ -274,3 +324,11 @@ async function simulatePaste(text: string): Promise<string> {
   `);
   return await page.evaluate(`window.result_${id}`);
 }
+
+async function getCursor(): Promise<{col: number, row: number}> {
+  return page.evaluate(`
+  (function() {
+    return {col: term.buffer.cursorX, row: term.buffer.cursorY};
+  })();
+  `);
+}

src/InputHandler.ts

@@ -453,6 +453,20 @@ export class InputHandler extends Disposable implements IInputHandler {
         }
       }
     }
+    // store last char in Parser.precedingCodepoint for REP to work correctly
+    // This needs to check whether:
+    //  - fullwidth + surrogates: reset
+    //  - combining: only base char gets carried on (bug in xterm?)
+    if (end) {
+      bufferRow.loadCell(buffer.x - 1, this._workCell);
+      if (this._workCell.getWidth() === 2 || this._workCell.getCode() > 0xFFFF) {
+        this._parser.precedingCodepoint = 0;
+      } else if (this._workCell.isCombined()) {
+        this._parser.precedingCodepoint = this._workCell.getChars().charCodeAt(0);
+      } else {
+        this._parser.precedingCodepoint = this._workCell.content;
+      }
+    }
     this._terminal.updateRange(buffer.y);
   }
 
@@ -1004,17 +1018,37 @@ export class InputHandler extends Disposable implements IInputHandler {
 
   /**
    * CSI Ps b  Repeat the preceding graphic character Ps times (REP).
+   * From ECMA 48 (@see http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf)
+   *    Notation: (Pn)
+   *    Representation: CSI Pn 06/02
+   *    Parameter default value: Pn = 1
+   *    REP is used to indicate that the preceding character in the data stream,
+   *    if it is a graphic character (represented by one or more bit combinations) including SPACE,
+   *    is to be repeated n times, where n equals the value of Pn.
+   *    If the character preceding REP is a control function or part of a control function,
+   *    the effect of REP is not defined by this Standard.
+   *
+   * Since we propagate the terminal as xterm-256color we have to follow xterm's behavior:
+   *    - fullwidth + surrogate chars are ignored
+   *    - for combining chars only the base char gets repeated
+   *    - text attrs are applied normally
+   *    - wrap around is respected
+   *    - any valid sequence resets the carried forward char
+   *
+   * Note: To get reset on a valid sequence working correctly without much runtime penalty,
+   * the preceding codepoint is stored on the parser in `this.print` and reset during `parser.parse`.
    */
   public repeatPrecedingCharacter(params: number[]): void {
-    // make buffer local for faster access
-    const buffer = this._terminal.buffer;
-    const line = buffer.lines.get(buffer.ybase + buffer.y);
-    line.loadCell(buffer.x - 1, this._workCell);
-    line.replaceCells(buffer.x,
-      buffer.x + (params[0] || 1),
-      (this._workCell.content !== undefined) ? this._workCell : buffer.getNullCell(DEFAULT_ATTR_DATA)
-    );
-    // FIXME: no updateRange here?
+    if (!this._parser.precedingCodepoint) {
+      return;
+    }
+    // call print to insert the chars and handle correct wrapping
+    const length = params[0] || 1;
+    const data = new Uint32Array(length);
+    for (let i = 0; i < length; ++i) {
+      data[i] = this._parser.precedingCodepoint;
+    }
+    this.print(data, 0, data.length);
   }
 
   /**

src/Terminal.integration.ts

@@ -107,7 +107,7 @@ if (os.platform() !== 'win32') {
     // for (let i = 0; i < files.length; ++i) console.debug(i, files[i]);
     // only successful tests for now
     const skip = [
-      10, 16, 17, 19, 32, 33, 34, 35, 36, 39,
+      10, 16, 17, 19, 32, 34, 35, 36, 39,
       40, 42, 43, 44, 45, 46, 47, 48, 49, 50,
       51, 52, 54, 55, 56, 57, 58, 59, 60, 61,
       63, 68

src/core/parser/EscapeSequenceParser.ts

@@ -231,6 +231,7 @@ class DcsDummy implements IDcsHandler {
 export class EscapeSequenceParser extends Disposable implements IEscapeSequenceParser {
   public initialState: number;
   public currentState: number;
+  public precedingCodepoint: number;
 
   // buffers over several parse calls
   protected _osc: string;
@@ -264,6 +265,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
     this._osc = '';
     this._params = [0];
     this._collect = '';
+    this.precedingCodepoint = 0;
 
     // set default fallback handlers and handler lookup containers
     this._printHandlerFb = (data, start, end): void => { };
@@ -394,6 +396,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
     this._params = [0];
     this._collect = '';
     this._activeDcsHandler = null;
+    this.precedingCodepoint = 0;
   }
 
   /**
@@ -453,6 +456,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
           }
           break;
         case ParserAction.EXECUTE:
+          this.precedingCodepoint = 0;
           callback = this._executeHandlers[code];
           if (callback) callback();
           else this._executeHandlerFb(code);
@@ -474,6 +478,10 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
           // inject values: currently not implemented
           break;
         case ParserAction.CSI_DISPATCH:
+          // dont reset preceding codepoint for REP itself
+          if (code !== 98) { // 'b'
+            this.precedingCodepoint = 0;
+          }
           // Trigger CSI Handler
           const handlers = this._csiHandlers[code];
           let j = handlers ? handlers.length - 1 : -1;
@@ -499,6 +507,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
           collect += String.fromCharCode(code);
           break;
         case ParserAction.ESC_DISPATCH:
+          this.precedingCodepoint = 0;
           callback = this._escHandlers[collect + String.fromCharCode(code)];
           if (callback) callback(collect, code);
           else this._escHandlerFb(collect, code);
@@ -509,6 +518,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
           collect = '';
           break;
         case ParserAction.DCS_HOOK:
+          this.precedingCodepoint = 0;
           dcsHandler = this._dcsHandlers[collect + String.fromCharCode(code)];
           if (!dcsHandler) dcsHandler = this._dcsHandlerFb;
           dcsHandler.hook(collect, params, code);
@@ -550,6 +560,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
           }
           break;
         case ParserAction.OSC_END:
+          this.precedingCodepoint = 0;
           if (osc && code !== 0x18 && code !== 0x1a) {
             // NOTE: OSC subparsing is not part of the original parser
             // we do basic identifier parsing here to offer a jump table for OSC as well

src/core/parser/Types.ts

@@ -102,6 +102,12 @@ export interface IDcsHandler {
 * EscapeSequenceParser interface.
 */
 export interface IEscapeSequenceParser extends IDisposable {
+  /**
+   * Preceding codepoint to get REP working correctly.
+   * This must be set by the print handler as last action.
+   * It gets reset by the parser for any valid sequence beside REP itself.
+   */
+  precedingCodepoint: number;
   /**
    * Reset the parser to its initial state (handlers are kept).
    */