Refresh master with initial release/0.24 snapshot (#332)

* Initial port of release/0.24 source code

* Fix additional headers

* Fix a typo in launch.json

src/vs/editor/common/viewLayout/lineDecorations.ts

@@ -6,6 +6,7 @@
 
 import { InlineDecoration } from 'vs/editor/common/viewModel/viewModel';
 import { Constants } from 'vs/editor/common/core/uint';
+import * as strings from 'vs/base/common/strings';
 
 export class LineDecoration {
 	_lineDecorationBrand: void;
@@ -172,7 +173,7 @@ export class LineDecorationsNormalizer {
 	/**
 	 * Normalize line decorations. Overlapping decorations will generate multiple segments
 	 */
-	public static normalize(lineDecorations: LineDecoration[]): DecorationSegment[] {
+	public static normalize(lineContent: string, lineDecorations: LineDecoration[]): DecorationSegment[] {
 		if (lineDecorations.length === 0) {
 			return [];
 		}
@@ -184,16 +185,34 @@ export class LineDecorationsNormalizer {
 
 		for (let i = 0, len = lineDecorations.length; i < len; i++) {
 			let d = lineDecorations[i];
+			let startColumn = d.startColumn;
+			let endColumn = d.endColumn;
+			let className = d.className;
 
-			let currentStartOffset = d.startColumn - 1;
-			let currentEndOffset = d.endColumn - 2;
+			// If the position would end up in the middle of a high-low surrogate pair, we move it to before the pair
+			if (startColumn > 1) {
+				const charCodeBefore = lineContent.charCodeAt(startColumn - 2);
+				if (strings.isHighSurrogate(charCodeBefore)) {
+					startColumn--;
+				}
+			}
+
+			if (endColumn > 1) {
+				const charCodeBefore = lineContent.charCodeAt(endColumn - 2);
+				if (strings.isHighSurrogate(charCodeBefore)) {
+					endColumn--;
+				}
+			}
+
+			let currentStartOffset = startColumn - 1;
+			let currentEndOffset = endColumn - 2;
 
 			nextStartOffset = stack.consumeLowerThan(currentStartOffset, nextStartOffset, result);
 
 			if (stack.count === 0) {
 				nextStartOffset = currentStartOffset;
 			}
-			stack.insert(currentEndOffset, d.className);
+			stack.insert(currentEndOffset, className);
 		}
 
 		stack.consumeLowerThan(Constants.MAX_SAFE_SMALL_INTEGER, nextStartOffset, result);

src/vs/editor/common/viewLayout/viewLineRenderer.ts

@@ -531,7 +531,7 @@ function _applyRenderWhitespace(lineContent: string, len: number, tokens: LinePa
  */
 function _applyInlineDecorations(lineContent: string, len: number, tokens: LinePart[], _lineDecorations: LineDecoration[]): LinePart[] {
 	_lineDecorations.sort(LineDecoration.compare);
-	const lineDecorations = LineDecorationsNormalizer.normalize(_lineDecorations);
+	const lineDecorations = LineDecorationsNormalizer.normalize(lineContent, _lineDecorations);
 	const lineDecorationsLen = lineDecorations.length;
 
 	let lineDecorationIndex = 0;
@@ -636,10 +636,13 @@ function _renderLine(input: ResolvedRenderLineInput, sb: IStringBuilder): Render
 				}
 			}
 
-			if (!fontIsMonospace && !containsForeignElements) {
-				sb.appendASCIIString(' style="width:');
-				sb.appendASCIIString(String(spaceWidth * partContentCnt));
-				sb.appendASCIIString('px"');
+			if (!fontIsMonospace) {
+				const partIsOnlyWhitespace = (partType === 'vs-whitespace');
+				if (partIsOnlyWhitespace || !containsForeignElements) {
+					sb.appendASCIIString(' style="width:');
+					sb.appendASCIIString(String(spaceWidth * partContentCnt));
+					sb.appendASCIIString('px"');
+				}
 			}
 			sb.appendASCII(CharCode.GreaterThan);