Fixes microsoft#72823: Do not compute char changes for huge chunks

alexdima · alexdima · commit b24844ce9d40 · 2019-10-08T13:57:27.000+02:00
diff --git a/src/vs/editor/common/diff/diffComputer.ts b/src/vs/editor/common/diff/diffComputer.ts
@@ -249,7 +249,8 @@ class LineChange implements ILineChange {
 			modifiedEndLineNumber = modifiedLineSequence.getEndLineNumber(diffChange.modifiedStart + diffChange.modifiedLength - 1);
 		}
 
-		if (shouldComputeCharChanges && diffChange.originalLength !== 0 && diffChange.modifiedLength !== 0 && continueProcessingPredicate()) {
+		if (shouldComputeCharChanges && diffChange.originalLength > 0 && diffChange.originalLength < 20 && diffChange.modifiedLength > 0 && diffChange.modifiedLength < 20 && continueProcessingPredicate()) {
+			// Compute character changes for diff chunks of at most 20 lines...
 			const originalCharSequence = originalLineSequence.createCharSequence(shouldIgnoreTrimWhitespace, diffChange.originalStart, diffChange.originalStart + diffChange.originalLength - 1);
 			const modifiedCharSequence = modifiedLineSequence.createCharSequence(shouldIgnoreTrimWhitespace, diffChange.modifiedStart, diffChange.modifiedStart + diffChange.modifiedLength - 1);
 

Original file line number	Diff line number	Diff line change
`@@ -249,7 +249,8 @@ class LineChange implements ILineChange {`
`249`	`249`	`modifiedEndLineNumber = modifiedLineSequence.getEndLineNumber(diffChange.modifiedStart + diffChange.modifiedLength - 1);`
`250`	`250`	`}`
`251`	`251`
`252`		`- if (shouldComputeCharChanges && diffChange.originalLength !== 0 && diffChange.modifiedLength !== 0 && continueProcessingPredicate()) {`
	`252`	`+ if (shouldComputeCharChanges && diffChange.originalLength > 0 && diffChange.originalLength < 20 && diffChange.modifiedLength > 0 && diffChange.modifiedLength < 20 && continueProcessingPredicate()) {`
	`253`	`+ // Compute character changes for diff chunks of at most 20 lines...`
`253`	`254`	`const originalCharSequence = originalLineSequence.createCharSequence(shouldIgnoreTrimWhitespace, diffChange.originalStart, diffChange.originalStart + diffChange.originalLength - 1);`
`254`	`255`	`const modifiedCharSequence = modifiedLineSequence.createCharSequence(shouldIgnoreTrimWhitespace, diffChange.modifiedStart, diffChange.modifiedStart + diffChange.modifiedLength - 1);`
`255`	`256`