⚡ perf(vscode): 预览发文档后在后台问语言扩展的请求排队发：同时在途最多 4 个、离视口近的先问、文档改了排着的作废，看得见的中文名先交

vscode/src/codeReader/editor/previewEditor.ts

@@ -30,6 +30,7 @@ import { DefinitionKinds } from '../definitionKinds'
 import { PreviewDiff } from '../diff/previewDiff'
 import { blockReplacement } from '../editText'
 import { locate } from '../folderStore'
+import { LanguageRequests } from '../languageRequests'
 import { definitionFor, symbolAt, symbolOccurrences } from '../localSymbols'
 import { DocumentNames, resolveNames } from '../nameResolution'
 import { PATH_ASK_ANCHOR } from '../qa/pathQa'
@@ -208,7 +209,9 @@ class Preview {
   visibleLine: number | undefined
   /** 最近一次发出去的文档（版本、块树、源码）：问 AI 时按块的记号在里面找那块代码，对比基准变了时拿它重新比 */
   private sent: SentDocument | undefined
-  /** 能看调用树的块（函数、类、接口卡片）落在几棵调用树里。文档发出去之后再数，不挡住第一次预览；同一版文档数过的页面重新加载后接着用 */
+  /** 发文档后在后台问语言扩展的请求（中文名、库规则查的定义、调用的种类）排队发：在途的有上限，离视口近的先发，文档改了排着的作废 */
+  private readonly requests = new LanguageRequests(() => this.document.version, () => this.visibleLine)
+  /** 能看调用树的块（函数、类、接口卡片）落在几棵调用树里。文档发出去之后再数，不挡住第一次预览，离视口近的先数；同一版文档数过的页面重新加载后接着用 */
   private readonly callTrees = new CallTreeSession(
     message => this.post(message),
     () => {
@@ -220,6 +223,7 @@ class Preview {
         load: (block, cancelled) => loadBlockCalls(this.document, block, this.owner.indexed, cancelled),
       }
     },
+    offset => this.requests.distance(this.document.positionAt(offset).line),
   )
 
   /** 最近一次发出去的文档里语言插件自己认得出的名字（LanguageAdapter.symbols）：语言扩展查不到定义、各处出现时用 */
@@ -430,9 +434,9 @@ class Preview {
       void this.diff.update(this.sent)
     // 文档在解析期间又改了的，等下一次发文档再查
     if (version === this.document.version) {
-      this.names.resolve(version, report => resolveNames(displayNames, message.blocks, this.nameSources(), report))
-      this.lookups.resolve(version, session.requests(), this.lookupSources())
-      this.callees.resolve(version, callees.requests(), offset => this.calleeKind(offset))
+      this.names.resolve(version, report => resolveNames(displayNames, message.blocks, this.nameSources(version), report))
+      this.lookups.resolve(version, session.requests(), this.lookupSources(version))
+      this.callees.resolve(version, callees.requests(), offset => this.queued(version, offset, () => this.calleeKind(offset), undefined))
       this.callTrees.documentSent()
     }
   }
@@ -501,25 +505,31 @@ class Preview {
       .map(({ uri, range }) => ({ uri: uri.toString(), line: range.start.line, character: range.start.character }))
   }
 
-  /** 找中文名落在哪些名字上时问的：这份文档的语言扩展、工作区里的中文名索引。 */
-  private nameSources(): NameSources {
+  /** 找 version 这一版的中文名落在哪些名字上时问的：这份文档的语言扩展（排队问）、工作区里的中文名索引、页面的视口。 */
+  private nameSources(version: number): NameSources {
     const { document } = this
     return {
       uri: document.uri.toString(),
-      occurrences: async offset => (await this.occurrences(offset)).map(({ start, end }) => ({ start, end })),
-      definitions: offset => this.definitionStarts(offset),
+      occurrences: offset => this.queued(version, offset, async () => (await this.occurrences(offset)).map(({ start, end }) => ({ start, end })), []),
+      definitions: offset => this.queued(version, offset, () => this.definitionStarts(offset), []),
       indexed: name => this.owner.indexedNames(document.languageId, name),
+      visible: offset => this.requests.visible(document.positionAt(offset).line),
     }
   }
 
-  /** 查库规则问的名字时问的：规则的工作区索引、这份文档的语言扩展。 */
-  private lookupSources(): LookupSources {
+  /** 查 version 这一版库规则问的名字时问的：规则的工作区索引、这份文档的语言扩展（排队问）。 */
+  private lookupSources(version: number): LookupSources {
     return {
       find: (index, key) => this.owner.indexed(index, key),
-      definitions: offset => this.definitionStarts(offset),
+      definitions: offset => this.queued(version, offset, () => this.definitionStarts(offset), []),
     }
   }
 
+  /** 排进后台请求的队（见 LanguageRequests）：version 这一版文档 offset 处要问的，没发就作废的交回 dropped（当语言扩展没答）。 */
+  private queued<T>(version: number, offset: number, request: () => Promise<T>, dropped: T): Promise<T> {
+    return this.requests.run(version, this.document.positionAt(offset).line, request, dropped)
+  }
+
   /** 跳到高亮着的名字的下一处 / 上一处出现；页面还没 ready 就算了（还没有高亮）。 */
   moveOccurrence(step: 1 | -1): void {
     if (this.ready)
@@ -552,6 +562,7 @@ class Preview {
 
   dispose(): void {
     this.callTrees.dispose()
+    this.requests.dispose()
     clearTimeout(this.timer)
     this.names.dispose()
     this.lookups.dispose()