From df7cd9c319f42aaff3b3e79ef45a19ebda0cf719 Mon Sep 17 00:00:00 2001
From: Daniel Imms <daimms@microsoft.com>
Date: Wed, 23 Jan 2019 22:40:40 -0800
Subject: [PATCH] Get reflow smaller working for wide chars

---
 src/Buffer.test.ts       |  4 ++--
 src/Buffer.ts            |  9 ++++++++-
 src/BufferReflow.test.ts | 13 +++++++++++++
 src/BufferReflow.ts      | 17 +++++++++--------
 4 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/src/Buffer.test.ts b/src/Buffer.test.ts
index 8e1a2f60..82cdff6b 100644
--- a/src/Buffer.test.ts
+++ b/src/Buffer.test.ts
@@ -568,8 +568,8 @@ describe('Buffer', () => {
         buffer.resize(11, 10);
         assert.equal(buffer.ybase, 0);
         assert.equal(buffer.lines.length, 10);
-        assert.equal(buffer.lines.get(0).translateToString(true), '汉语汉语汉', '1');
-        assert.equal(buffer.lines.get(1).translateToString(true), '语汉语汉语', '2');
+        assert.equal(buffer.lines.get(0).translateToString(true), '汉语汉语汉');
+        assert.equal(buffer.lines.get(1).translateToString(true), '语汉语汉语');
         assert.equal(buffer.lines.get(2).translateToString(true), '汉语');
         buffer.resize(10, 10);
         assert.equal(buffer.lines.get(0).translateToString(true), '汉语汉语汉');
diff --git a/src/Buffer.ts b/src/Buffer.ts
index 30941324..5d3c1a52 100644
--- a/src/Buffer.ts
+++ b/src/Buffer.ts
@@ -429,7 +429,7 @@ export class Buffer implements IBuffer {
       let destCol = destLineLengths[destLineIndex]; // cellsNeeded % newCols;
       if (destCol === 0) {
         destLineIndex--;
-        destCol = newCols;
+        destCol = destLineLengths[destLineIndex];
       }
       let srcLineIndex = wrappedLines.length - linesToAdd - 1;
       let srcCol = lastLineLength;
@@ -449,6 +449,13 @@ export class Buffer implements IBuffer {
         }
       }
 
+      // Null out the end of the line ends if a wide character wrapped to the following line
+      for (let i = 0; i < wrappedLines.length; i++) {
+        if (destLineLengths[i] < newCols) {
+          wrappedLines[i].set(destLineLengths[i], FILL_CHAR_DATA);
+        }
+      }
+
       // Adjust viewport as needed
       let viewportAdjustments = linesToAdd - trimmedLines;
       while (viewportAdjustments-- > 0) {
diff --git a/src/BufferReflow.test.ts b/src/BufferReflow.test.ts
index a788fbc8..9c978dc0 100644
--- a/src/BufferReflow.test.ts
+++ b/src/BufferReflow.test.ts
@@ -5,6 +5,7 @@
 import { assert } from 'chai';
 import { BufferLine } from './BufferLine';
 import { reflowSmallerGetNewLineLengths } from './BufferReflow';
+import { NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE } from './Buffer';
 
 describe('BufferReflow', () => {
   describe('reflowSmallerGetNewLineLengths', () => {
@@ -76,5 +77,17 @@ describe('BufferReflow', () => {
       assert.deepEqual(reflowSmallerGetNewLineLengths([line1, line2], 6, 3), [3, 3, 3, 3], 'lines: a汉, 语b, a汉, 语b');
       assert.deepEqual(reflowSmallerGetNewLineLengths([line1, line2], 6, 2), [1, 2, 2, 2, 2, 2, 1], 'lines: a, 汉, 语, ba, 汉, 语, b');
     });
+    it('should work on lines ending in null space', () => {
+      const line = new BufferLine(5);
+      line.set(0, [null, '汉', 2, '汉'.charCodeAt(0)]);
+      line.set(1, [null, '', 0, undefined]);
+      line.set(2, [null, '语', 2, '语'.charCodeAt(0)]);
+      line.set(3, [null, '', 0, undefined]);
+      line.set(4, [null, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
+      assert.equal(line.translateToString(true), '汉语');
+      assert.equal(line.translateToString(false), '汉语 ');
+      assert.deepEqual(reflowSmallerGetNewLineLengths([line], 4, 3), [2, 2], 'line: 汉, 语');
+      assert.deepEqual(reflowSmallerGetNewLineLengths([line], 4, 2), [2, 2], 'line: 汉, 语');
+    });
   });
 });
diff --git a/src/BufferReflow.ts b/src/BufferReflow.ts
index f56d48c5..f99acd1c 100644
--- a/src/BufferReflow.ts
+++ b/src/BufferReflow.ts
@@ -80,21 +80,22 @@ export function reflowSmallerGetNewLineLengths(wrappedLines: BufferLine[], oldCo
 
   // Use srcCol and srcLine to find the new wrapping point, use that to get the cellsAvailable and
   // linesNeeded
-  let srcCol = -1;
+  let srcCol = 0;
   let srcLine = 0;
   let cellsAvailable = 0;
   while (cellsAvailable < cellsNeeded) {
-    srcCol += newCols;
-    if (srcCol >= oldCols) {
-      srcCol -= oldCols;
-      srcLine++;
-    }
-    if (srcLine >= wrappedLines.length) {
+    if (cellsNeeded - cellsAvailable < newCols) {
       // Add the final line and exit the loop
       newLineLengths.push(cellsNeeded - cellsAvailable);
       break;
     }
-    const endsWithWide = wrappedLines[srcLine].getWidth(srcCol) === 2;
+    srcCol += newCols;
+    const oldTrimmedLength = wrappedLines[srcLine].getTrimmedLength();
+    if (srcCol > oldTrimmedLength) {
+      srcCol -= oldTrimmedLength;
+      srcLine++;
+    }
+    const endsWithWide = wrappedLines[srcLine].getWidth(srcCol - 1) === 2;
     if (endsWithWide) {
       srcCol--;
     }