⚡ perf(vscode): 代码阅读预览发给页面的块只记相对位置：块在源码里占的地方记成离前一块多远、自己多长，块里名字的下标从块的开头算，页面从文件开头累加回文件里的位置、和扩展端打交道的地方都在一处换算；靠前改了代码，后面内容没变的块发过去一模一样，扩展端自己的块和发给页面的块分成两种类型

vscode/webview-ui/src/codeReader/diffView.ts

@@ -1,4 +1,5 @@
-import type { BlockView, ChangedBlock, DiffStats, DocumentDiff, RemovedView } from './types'
+import type { Placement } from './placement'
+import type { BlockView, CardView, ChangedBlock, DiffStats, DocumentDiff, RemovedView } from './types'
 import { inlineText } from './segments'
 import { unfoldToShow } from './viewState'
 
@@ -63,7 +64,7 @@ export function statsParts(stats: DiffStats): { change: keyof DiffStats, text: s
 }
 
 /** 删掉的块收起时写的名字：属性表是第一行的值（函数名、变量名、导入的来源），一行译文是译文；只取第一行。 */
-export function removedTitle(block: BlockView): string {
+export function removedTitle(block: CardView): string {
   const text = 'properties' in block
     ? block.properties[0] && ('markdown' in block.properties[0].value ? block.properties[0].value.markdown : inlineText(block.properties[0].value))
     : 'markdown' in block.translation ? block.translation.markdown : inlineText(block.translation)
@@ -140,8 +141,8 @@ export interface ChangeStop {
   ancestors: string[]
 }
 
-/** 页面上的各处改动（见 ChangeStop）；hidden 里的块（被筛掉的）连同子孙不算。 */
-export function changeStops(blocks: readonly BlockView[], tree: DiffTree, hidden: ReadonlySet<string>): ChangeStop[] {
+/** 页面上的各处改动（见 ChangeStop，行号是文件里的，按 placement 换算）；hidden 里的块（被筛掉的）连同子孙不算。 */
+export function changeStops(blocks: readonly BlockView[], placement: Placement, tree: DiffTree, hidden: ReadonlySet<string>): ChangeStop[] {
   const stops: ChangeStop[] = []
   /** 一层块：owner 是父块 id（顶层 ''），ancestorsOf 给出要让某个子块看得见得展开的，removedAncestors 是这一层删掉的块要展开的 */
   const visit = (list: readonly BlockView[], owner: string, ancestorsOf: (block: BlockView) => string[], removedAncestors: string[]): void => {
@@ -154,11 +155,13 @@ export function changeStops(blocks: readonly BlockView[], tree: DiffTree, hidden
     for (const block of list) {
       const ancestors = ancestorsOf(block)
       const change = hidden.has(block.id) ? undefined : tree.changes.get(block.id)
-      if (change?.change === 'add' && change.outermost)
-        stops.push({ id: block.id, change: 'add', from: block.startLine, to: block.endLine, ancestors })
-      if (change?.change === 'mod' && change.own) {
-        const own = block.children[0] ? Math.max(block.startLine, block.children[0].startLine - 1) : block.endLine
-        stops.push({ id: block.id, change: 'mod', from: block.startLine, to: own, ancestors })
+      const place = placement.of(block.id)
+      if (place && change?.change === 'add' && change.outermost)
+        stops.push({ id: block.id, change: 'add', from: place.line, to: place.endLine, ancestors })
+      if (place && change?.change === 'mod' && change.own) {
+        const first = block.children[0] && placement.of(block.children[0].id)
+        const own = first ? Math.max(place.line, first.line - 1) : place.endLine
+        stops.push({ id: block.id, change: 'mod', from: place.line, to: own, ancestors })
       }
       if (change?.change === 'mod')
         visit(block.children, block.id, child => [...ancestors, ...unfoldToShow(block.id, child)], [...ancestors, block.id])