⚡ 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/occurrences.test.ts

@@ -36,14 +36,14 @@ function find(occ: OccurrenceHighlight, offset: number, text: string): void {
 describe('occurrences：哪些段画高亮', () => {
   it('段在源码里的范围和一处出现重叠就画，边界相接不算，没有下标的不画', () => {
     const occurrences = [at(10, 18)]
-    expect(segmentOccurrence(name('ALPHABET', 10), occurrences)).toBe('normal')
-    expect(segmentOccurrence(name('x', 2), occurrences)).toBeUndefined()
-    expect(segmentOccurrence(name('ab', 8), occurrences)).toBeUndefined()
-    expect(segmentOccurrence(name('ab', 18), occurrences)).toBeUndefined()
-    expect(segmentOccurrence(name('ab', 17), occurrences)).toBe('normal')
-    expect(segmentOccurrence({ text: '常量', role: 'storage' }, occurrences)).toBeUndefined()
+    expect(segmentOccurrence(name('ALPHABET', 10), 0, occurrences)).toBe('normal')
+    expect(segmentOccurrence(name('x', 2), 0, occurrences)).toBeUndefined()
+    expect(segmentOccurrence(name('ab', 8), 0, occurrences)).toBeUndefined()
+    expect(segmentOccurrence(name('ab', 18), 0, occurrences)).toBeUndefined()
+    expect(segmentOccurrence(name('ab', 17), 0, occurrences)).toBe('normal')
+    expect(segmentOccurrence({ text: '常量', role: 'storage' }, 0, occurrences)).toBeUndefined()
     // 整段字符串比名字长：出现落在字符串里面也算
-    expect(segmentOccurrence({ text: '\'./util\'', role: 'string', offset: 9 }, occurrences)).toBe('normal')
+    expect(segmentOccurrence({ text: '\'./util\'', role: 'string', offset: 9 }, 0, occurrences)).toBe('normal')
   })
 
   it('出现很多、乱序、有长有短还互相重叠时，结果和逐处比一样', () => {
@@ -63,7 +63,7 @@ describe('occurrences：哪些段画高亮', () => {
     })
     for (let offset = 0; offset < 2020; offset += 3) {
       const segment = name('x'.repeat(1 + (offset % 7)), offset)
-      expect(segmentOccurrence(segment, occurrences), `offset ${offset}`).toBe(brute(segment, occurrences))
+      expect(segmentOccurrence(segment, 0, occurrences), `offset ${offset}`).toBe(brute(segment, occurrences))
     }
   })
 
@@ -71,18 +71,28 @@ describe('occurrences：哪些段画高亮', () => {
     expect(occurrenceStyle('write')).toBe('strong')
     expect(occurrenceStyle('read')).toBe('normal')
     expect(occurrenceStyle('text')).toBe('normal')
-    expect(segmentOccurrence(name('a', 0), [at(0, 1, 'text')])).toBe('normal')
-    expect(segmentOccurrence(name('a', 0), [at(0, 1, 'read'), at(0, 1, 'write')])).toBe('strong')
+    expect(segmentOccurrence(name('a', 0), 0, [at(0, 1, 'text')])).toBe('normal')
+    expect(segmentOccurrence(name('a', 0), 0, [at(0, 1, 'read'), at(0, 1, 'write')])).toBe('strong')
   })
 
   it('讲别处名字的段（refers，写在字符串里的参数名）按那个名字算：那个名字的出现盖住它就画、能是当前那一处，自己照抄的位置不算', () => {
     const param: Segment = { text: 'user_id', role: 'variable', offset: 40, refers: { startIndex: 100, endIndex: 107 } }
-    expect(sourceOf(param)).toEqual({ start: 100, end: 107 })
-    expect(segmentOccurrence(param, [at(100, 107, 'write')])).toBe('strong')
-    expect(segmentOccurrence(param, [at(40, 47)])).toBeUndefined()
-    expect(isCurrent(param, { name: 'user_id', occurrences: [at(100, 107)], current: 0 })).toBe(true)
-    expect(sourceOf(name('x', 3))).toEqual({ start: 3, end: 4 })
-    expect(sourceOf({ text: '常量', role: 'storage' })).toBeUndefined()
+    expect(sourceOf(param, 0)).toEqual({ start: 100, end: 107 })
+    expect(segmentOccurrence(param, 0, [at(100, 107, 'write')])).toBe('strong')
+    expect(segmentOccurrence(param, 0, [at(40, 47)])).toBeUndefined()
+    expect(isCurrent(param, 0, { name: 'user_id', occurrences: [at(100, 107)], current: 0 })).toBe(true)
+    expect(sourceOf(name('x', 3), 0)).toEqual({ start: 3, end: 4 })
+    expect(sourceOf({ text: '常量', role: 'storage' }, 0)).toBeUndefined()
+  })
+
+  it('段里的下标从所在那块的开头算：加上那块的开头（base）才是文件里的，和各处出现比、认当前那一处都按文件里的', () => {
+    const param: Segment = { text: 'user_id', role: 'variable', offset: 4, refers: { startIndex: 10, endIndex: 17 } }
+    expect(sourceOf(param, 1000)).toEqual({ start: 1010, end: 1017 })
+    expect(sourceOf(name('x', 3), 1000)).toEqual({ start: 1003, end: 1004 })
+    expect(segmentOccurrence(name('x', 3), 1000, [at(1003, 1004, 'write')])).toBe('strong')
+    expect(segmentOccurrence(name('x', 3), 1000, [at(3, 4, 'write')])).toBeUndefined()
+    expect(isCurrent(param, 1000, { name: 'user_id', occurrences: [at(1010, 1017)], current: 0 })).toBe(true)
+    expect(isCurrent(param, 0, { name: 'user_id', occurrences: [at(1010, 1017)], current: 0 })).toBe(false)
   })
 
   it('真实的 Python 译文和属性表：定义处按写入、用到的地方按读取画；点分模块名每一节各按自己的范围认', async () => {
@@ -98,7 +108,7 @@ describe('occurrences：哪些段画高亮', () => {
     const py = createPythonAdapter(WASM_DIR)
     const views = await withBlocks(py, 'python', source, blocks => toBlockViews(blocks, { source, language: py, markers: [] }, pythonZhTranslator))
     const highlighted = (occurrences: Occurrence[]): string[] => allSegments(views).flatMap((segment) => {
-      const style = segmentOccurrence(segment, occurrences)
+      const style = segmentOccurrence(segment, 0, occurrences)
       return style ? [`${segment.text}:${style}`] : []
     })
     const range = (needle: string, kind: Occurrence['kind'], from = 0): Occurrence => {
@@ -318,10 +328,10 @@ describe('occurrences：用键盘在各处出现之间跳', () => {
 
   it('当前那一处：和它重叠的段描边，别的出现、没下标的段不描', () => {
     const highlight = { name: 'ALPHABET', occurrences: [at(10, 18), at(40, 48)], current: 1 }
-    expect(isCurrent(name('ALPHABET', 40), highlight)).toBe(true)
-    expect(isCurrent(name('ALPHABET', 10), highlight)).toBe(false)
-    expect(isCurrent({ text: 'ALPHABET', role: 'plain' }, highlight)).toBe(false)
-    expect(isCurrent(name('ALPHABET', 40), { ...highlight, current: undefined })).toBe(false)
+    expect(isCurrent(name('ALPHABET', 40), 0, highlight)).toBe(true)
+    expect(isCurrent(name('ALPHABET', 10), 0, highlight)).toBe(false)
+    expect(isCurrent({ text: 'ALPHABET', role: 'plain' }, 0, highlight)).toBe(false)
+    expect(isCurrent(name('ALPHABET', 40), 0, { ...highlight, current: undefined })).toBe(false)
   })
 
   it('能不能用键盘跳：有高亮、页面有焦点、焦点不在输入框里；第一次都告诉扩展端，之后变了才告诉', () => {