perf(diffview): only compute syntax highlight for printed lines

Andrey Nering created 6 months ago

Change summary

internal/exp/diffview/diffview.go | 347 +++++++++++++++++---------------
1 file changed, 182 insertions(+), 165 deletions(-)

Detailed changes

internal/exp/diffview/diffview.go

@@ -362,23 +362,29 @@ func (dv *DiffView) renderUnified() string {
 
 	fullContentStyle := lipgloss.NewStyle().MaxWidth(dv.fullCodeWidth)
 	printedLines := -dv.yOffset
-
-	write := func(s string) {
-		if printedLines >= 0 {
-			b.WriteString(s)
-		}
+	shouldWrite := func() bool { return printedLines >= 0 }
+
+	getContent := func(in string, ls LineStyle) (content string, leadingEllipsis bool) {
+		content = strings.TrimSuffix(in, "\n")
+		content = dv.hightlightCode(content, ls.Code.GetBackground())
+		content = ansi.GraphemeWidth.Cut(content, dv.xOffset, len(content))
+		content = ansi.Truncate(content, dv.codeWidth, "…")
+		leadingEllipsis = dv.xOffset > 0 && strings.TrimSpace(content) != ""
+		return
 	}
 
 outer:
 	for i, h := range dv.unified.Hunks {
-		ls := dv.style.DividerLine
-		if dv.lineNumbers {
-			write(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
-			write(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+		if shouldWrite() {
+			ls := dv.style.DividerLine
+			if dv.lineNumbers {
+				b.WriteString(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
+				b.WriteString(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+			}
+			content := ansi.Truncate(dv.hunkLineFor(h), dv.fullCodeWidth, "…")
+			b.WriteString(ls.Code.Width(dv.fullCodeWidth).Render(content))
+			b.WriteString("\n")
 		}
-		content := ansi.Truncate(dv.hunkLineFor(h), dv.fullCodeWidth, "…")
-		write(ls.Code.Width(dv.fullCodeWidth).Render(content))
-		write("\n")
 		printedLines++
 
 		beforeLine := h.FromLine
@@ -390,80 +396,82 @@ outer:
 			isLastHunk := i+1 == len(dv.unified.Hunks)
 			isLastLine := j+1 == len(h.Lines)
 			if hasReachedHeight && (!isLastHunk || !isLastLine) {
-				ls := dv.lineStyleForType(l.Kind)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
-					write(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.lineStyleForType(l.Kind)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
+						b.WriteString(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+					}
+					b.WriteString(fullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth).Render("  …"),
+					))
+					b.WriteRune('\n')
 				}
-				write(fullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth).Render("  …"),
-				))
-				write("\n")
 				break outer
 			}
 
-			getContent := func(ls LineStyle) string {
-				content := strings.TrimSuffix(l.Content, "\n")
-				content = dv.hightlightCode(content, ls.Code.GetBackground())
-				content = ansi.GraphemeWidth.Cut(content, dv.xOffset, len(content))
-				content = ansi.Truncate(content, dv.codeWidth, "…")
-				return content
-			}
-
-			leadingEllipsis := dv.xOffset > 0 && strings.TrimSpace(content) != ""
-
 			switch l.Kind {
 			case udiff.Equal:
-				ls := dv.style.EqualLine
-				content := getContent(ls)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
-					write(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.EqualLine
+					content, leadingEllipsis := getContent(l.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
+						b.WriteString(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+					}
+					b.WriteString(fullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth).Render(ternary(leadingEllipsis, " …", "  ") + content),
+					))
 				}
-				write(fullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth).Render(ternary(leadingEllipsis, " …", "  ") + content),
-				))
 				beforeLine++
 				afterLine++
 			case udiff.Insert:
-				ls := dv.style.InsertLine
-				content := getContent(ls)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
-					write(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.InsertLine
+					content, leadingEllipsis := getContent(l.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
+						b.WriteString(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+					}
+					b.WriteString(fullContentStyle.Render(
+						ls.Symbol.Render(ternary(leadingEllipsis, "+…", "+ ")) +
+							ls.Code.Width(dv.codeWidth).Render(content),
+					))
 				}
-				write(fullContentStyle.Render(
-					ls.Symbol.Render(ternary(leadingEllipsis, "+…", "+ ")) +
-						ls.Code.Width(dv.codeWidth).Render(content),
-				))
 				afterLine++
 			case udiff.Delete:
-				ls := dv.style.DeleteLine
-				content := getContent(ls)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
-					write(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.DeleteLine
+					content, leadingEllipsis := getContent(l.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
+						b.WriteString(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+					}
+					b.WriteString(fullContentStyle.Render(
+						ls.Symbol.Render(ternary(leadingEllipsis, "-…", "- ")) +
+							ls.Code.Width(dv.codeWidth).Render(content),
+					))
 				}
-				write(fullContentStyle.Render(
-					ls.Symbol.Render(ternary(leadingEllipsis, "-…", "- ")) +
-						ls.Code.Width(dv.codeWidth).Render(content),
-				))
 				beforeLine++
 			}
-			write("\n")
+			if shouldWrite() {
+				b.WriteRune('\n')
+			}
 
 			printedLines++
 		}
 	}
 
 	for printedLines < dv.height {
-		ls := dv.style.MissingLine
-		if dv.lineNumbers {
-			write(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
-			write(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+		if shouldWrite() {
+			ls := dv.style.MissingLine
+			if dv.lineNumbers {
+				b.WriteString(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
+				b.WriteString(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+			}
+			b.WriteString(ls.Code.Width(dv.fullCodeWidth).Render("  "))
+			b.WriteRune('\n')
 		}
-		write(ls.Code.Width(dv.fullCodeWidth).Render("  "))
-		write("\n")
 		printedLines++
 	}
 
@@ -477,26 +485,32 @@ func (dv *DiffView) renderSplit() string {
 	beforeFullContentStyle := lipgloss.NewStyle().MaxWidth(dv.fullCodeWidth)
 	afterFullContentStyle := lipgloss.NewStyle().MaxWidth(dv.fullCodeWidth + btoi(dv.extraColOnAfter))
 	printedLines := -dv.yOffset
-
-	write := func(s string) {
-		if printedLines >= 0 {
-			b.WriteString(s)
-		}
+	shouldWrite := func() bool { return printedLines >= 0 }
+
+	getContent := func(in string, ls LineStyle) (content string, leadingEllipsis bool) {
+		content = strings.TrimSuffix(in, "\n")
+		content = dv.hightlightCode(content, ls.Code.GetBackground())
+		content = ansi.GraphemeWidth.Cut(content, dv.xOffset, len(content))
+		content = ansi.Truncate(content, dv.codeWidth, "…")
+		leadingEllipsis = dv.xOffset > 0 && strings.TrimSpace(content) != ""
+		return
 	}
 
 outer:
 	for i, h := range dv.splitHunks {
-		ls := dv.style.DividerLine
-		if dv.lineNumbers {
-			write(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
-		}
-		content := ansi.Truncate(dv.hunkLineFor(dv.unified.Hunks[i]), dv.fullCodeWidth, "…")
-		write(ls.Code.Width(dv.fullCodeWidth).Render(content))
-		if dv.lineNumbers {
-			write(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+		if shouldWrite() {
+			ls := dv.style.DividerLine
+			if dv.lineNumbers {
+				b.WriteString(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
+			}
+			content := ansi.Truncate(dv.hunkLineFor(dv.unified.Hunks[i]), dv.fullCodeWidth, "…")
+			b.WriteString(ls.Code.Width(dv.fullCodeWidth).Render(content))
+			if dv.lineNumbers {
+				b.WriteString(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+			}
+			b.WriteString(ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render(" "))
+			b.WriteRune('\n')
 		}
-		write(ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render(" "))
-		write("\n")
 		printedLines++
 
 		beforeLine := h.fromLine
@@ -508,126 +522,129 @@ outer:
 			isLastHunk := i+1 == len(dv.unified.Hunks)
 			isLastLine := j+1 == len(h.lines)
 			if hasReachedHeight && (!isLastHunk || !isLastLine) {
-				ls := dv.style.MissingLine
-				if l.before != nil {
-					ls = dv.lineStyleForType(l.before.Kind)
-				}
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.MissingLine
+					if l.before != nil {
+						ls = dv.lineStyleForType(l.before.Kind)
+					}
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad("…", dv.beforeNumDigits)))
+					}
+					b.WriteString(beforeFullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth).Render("  …"),
+					))
+					ls = dv.style.MissingLine
+					if l.after != nil {
+						ls = dv.lineStyleForType(l.after.Kind)
+					}
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
+					}
+					b.WriteString(afterFullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth).Render("  …"),
+					))
+					b.WriteRune('\n')
 				}
-				write(beforeFullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth).Render("  …"),
-				))
-				ls = dv.style.MissingLine
-				if l.after != nil {
-					ls = dv.lineStyleForType(l.after.Kind)
-				}
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad("…", dv.afterNumDigits)))
-				}
-				write(afterFullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth).Render("  …"),
-				))
-				write("\n")
 				break outer
 			}
 
-			getContent := func(content string, ls LineStyle) string {
-				content = strings.TrimSuffix(content, "\n")
-				content = dv.hightlightCode(content, ls.Code.GetBackground())
-				content = ansi.GraphemeWidth.Cut(content, dv.xOffset, len(content))
-				content = ansi.Truncate(content, dv.codeWidth, "…")
-				return content
-			}
-			getLeadingEllipsis := func(content string) bool {
-				return dv.xOffset > 0 && strings.TrimSpace(content) != ""
-			}
-
 			switch {
 			case l.before == nil:
-				ls := dv.style.MissingLine
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.MissingLine
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
+					}
+					b.WriteString(beforeFullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth).Render("  "),
+					))
 				}
-				write(beforeFullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth).Render("  "),
-				))
 			case l.before.Kind == udiff.Equal:
-				ls := dv.style.EqualLine
-				content := getContent(l.before.Content, ls)
-				leadingEllipsis := getLeadingEllipsis(content)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.EqualLine
+					content, leadingEllipsis := getContent(l.before.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
+					}
+					b.WriteString(beforeFullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth).Render(ternary(leadingEllipsis, " …", "  ") + content),
+					))
 				}
-				write(beforeFullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth).Render(ternary(leadingEllipsis, " …", "  ") + content),
-				))
 				beforeLine++
 			case l.before.Kind == udiff.Delete:
-				ls := dv.style.DeleteLine
-				content := getContent(l.before.Content, ls)
-				leadingEllipsis := getLeadingEllipsis(content)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.DeleteLine
+					content, leadingEllipsis := getContent(l.before.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(beforeLine, dv.beforeNumDigits)))
+					}
+					b.WriteString(beforeFullContentStyle.Render(
+						ls.Symbol.Render(ternary(leadingEllipsis, "-…", "- ")) +
+							ls.Code.Width(dv.codeWidth).Render(content),
+					))
 				}
-				write(beforeFullContentStyle.Render(
-					ls.Symbol.Render(ternary(leadingEllipsis, "-…", "- ")) +
-						ls.Code.Width(dv.codeWidth).Render(content),
-				))
 				beforeLine++
 			}
 
 			switch {
 			case l.after == nil:
-				ls := dv.style.MissingLine
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.MissingLine
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+					}
+					b.WriteString(afterFullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render("  "),
+					))
 				}
-				write(afterFullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render("  "),
-				))
 			case l.after.Kind == udiff.Equal:
-				ls := dv.style.EqualLine
-				content := getContent(l.after.Content, ls)
-				leadingEllipsis := getLeadingEllipsis(content)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.EqualLine
+					content, leadingEllipsis := getContent(l.after.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+					}
+					b.WriteString(afterFullContentStyle.Render(
+						ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render(ternary(leadingEllipsis, " …", "  ") + content),
+					))
 				}
-				write(afterFullContentStyle.Render(
-					ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render(ternary(leadingEllipsis, " …", "  ") + content),
-				))
 				afterLine++
 			case l.after.Kind == udiff.Insert:
-				ls := dv.style.InsertLine
-				content := getContent(l.after.Content, ls)
-				leadingEllipsis := getLeadingEllipsis(content)
-				if dv.lineNumbers {
-					write(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+				if shouldWrite() {
+					ls := dv.style.InsertLine
+					content, leadingEllipsis := getContent(l.after.Content, ls)
+					if dv.lineNumbers {
+						b.WriteString(ls.LineNumber.Render(pad(afterLine, dv.afterNumDigits)))
+					}
+					b.WriteString(afterFullContentStyle.Render(
+						ls.Symbol.Render(ternary(leadingEllipsis, "+…", "+ ")) +
+							ls.Code.Width(dv.codeWidth+btoi(dv.extraColOnAfter)).Render(content),
+					))
 				}
-				write(afterFullContentStyle.Render(
-					ls.Symbol.Render(ternary(leadingEllipsis, "+…", "+ ")) +
-						ls.Code.Width(dv.codeWidth+btoi(dv.extraColOnAfter)).Render(content),
-				))
 				afterLine++
 			}
 
-			write("\n")
+			if shouldWrite() {
+				b.WriteRune('\n')
+			}
 
 			printedLines++
 		}
 	}
 
 	for printedLines < dv.height {
-		ls := dv.style.MissingLine
-		if dv.lineNumbers {
-			write(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
-		}
-		write(ls.Code.Width(dv.fullCodeWidth).Render(" "))
-		if dv.lineNumbers {
-			write(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+		if shouldWrite() {
+			ls := dv.style.MissingLine
+			if dv.lineNumbers {
+				b.WriteString(ls.LineNumber.Render(pad(" ", dv.beforeNumDigits)))
+			}
+			b.WriteString(ls.Code.Width(dv.fullCodeWidth).Render(" "))
+			if dv.lineNumbers {
+				b.WriteString(ls.LineNumber.Render(pad(" ", dv.afterNumDigits)))
+			}
+			b.WriteString(ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render(" "))
+			b.WriteRune('\n')
 		}
-		write(ls.Code.Width(dv.fullCodeWidth + btoi(dv.extraColOnAfter)).Render(" "))
-		write("\n")
 		printedLines++
 	}