55 lines
7.0 KiB
TypeScript
55 lines
7.0 KiB
TypeScript
/**
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* 由原SHA绑定快照与稳定emit检查点提供可seek的lazy复制记录流（parserVersion=2）。
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* 没有第二份完整映射Blob；节点/引用/曲线在read某ordinal时才转换，可用readElement从索引源按需解码payload。
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* 这只是ImportSource，真正的记录摘要、依赖等待、提交和失败报告由统一runner负责。
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*/
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import type { Document, ElementRecord, CanvasRecord, Id, Registry, Json } from '../canvas-core/types.ts';
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import type { DuplicateCheckpoint } from '../canvas-core/duplicate-checkpoint.ts';
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import { createDuplicatePlanner } from '../canvas-core/duplicate-checkpoint.ts';
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import { duplicateTreeChange, duplicateEdgeChange } from '../canvas-core/duplicate.ts';
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import { fault } from '../canvas-core/values.ts';
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import { copyRegistrySignature } from './copy-snapshot.ts';
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import { duplicateImportLine } from './import-duplicate.ts';
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import type { ImportSource } from './imports.ts';
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/** A seekable record cursor over the original SHA-bound snapshot, not a second mapped Blob. */
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/** 要求 emit 起点/零输出计数与当前 registry 签名，调用 planner 复核 checkpoint 结构绑定且禁止再分配 ID。
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* 映射复制为私有 Map，但 document/registry/state 及 readElement 仍沿用调用方引用，须保持不可变/稳定。
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* sourceToken/fingerprint 的真实字节绑定由上层验证；本函数不读取文件或重新计算 SHA。
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* 构造后可按 ordinal 任意重读，read 不推进 state.emitted；持久进度由 runner 的 job.cursor 保存。 */
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export function createDuplicatePlanSource(document:Document,registry:Registry,state:DuplicateCheckpoint,fingerprint:string,readElement?:(id:Id,signal:AbortSignal)=>Promise<ElementRecord>):ImportSource{
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if(state.phase!=='emit'||state.emitted!==0||state.emittedEdges!==0||state.schemaToken!==copyRegistrySignature(document,registry))throw fault('copy_interpreter_changed');
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// Structural/source binding checks; the decoded source has already passed document validation.
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createDuplicatePlanner(document,registry,state.selection,{createId:()=>{throw fault('unstable_import_identity');},worldOffset:state.offset,...(state.mapping?{mapping:state.mapping}:{})},{sourceToken:state.sourceToken,schemaToken:state.schemaToken,checkpoint:state,topologyOnly:!!readElement});
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// 固定旧→新和新→旧映射；source key仍用原ID，输出change使用已经预留的新ID。
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const elements=new Map(state.elementIds),canvases=new Map(state.canvasIds),copiedCanvases=new Set(state.canvases),keys=new Map<Id,string>(),reverseElements=new Map(state.elementIds.map(([id,mapped])=>[mapped,id])),reverseCanvases=new Map(state.canvasIds.map(([id,mapped])=>[mapped,id]));
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for(const[id,mapped]of elements)keys.set(mapped,`element:${id}`);for(const[id,mapped]of canvases)keys.set(mapped,`canvas:${id}`);
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// Edge geometry needs mapped endpoint/owner records. Compute these on demand; retain a bounded cache.
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/** 给边计算提供原表+映射表的只读投影，get 按需转换映射 ID，每个投影最多缓存 32 项。
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* 淘汰按插入顺序，缓存命中不刷新顺序，因此是 FIFO 而非 LRU；不缓存 readElement 的完整 payload。
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* size/迭代将两组成员拼接，依赖映射不与原 ID 碰撞的 planner 合同，不能当可发布的规范文档表。 */
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function projection<T extends ElementRecord|CanvasRecord>(base:ReadonlyMap<Id,T>,reverse:ReadonlyMap<Id,Id>,kind:'element'|'canvas'):ReadonlyMap<Id,T>{
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// 未映射ID沿用原表，新ID转换源记录；缓存淘汰只影响计算成本，不改变稳定映射/源数据。
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const cache=new Map<Id,T>();const get=(id:Id):T|undefined=>{const old=reverse.get(id);if(!old)return base.get(id);const found=cache.get(id);if(found)return found;const original=base.get(old);if(!original)throw fault('invalid_copy_stream_checkpoint');const record=duplicateTreeChange(document,registry,kind,original,elements,canvases,copiedCanvases,state.offset).after as T;cache.set(id,record);if(cache.size>32)cache.delete(cache.keys().next().value!);return record;};
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/** 迭代先原记录再映射记录，keys/values/forEach均复用同一逻辑投影，不能作为发布文档表。 */
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const entries=function*():Generator<[Id,T],undefined>{yield* base;for(const id of reverse.keys())yield[id,get(id)!];return undefined;};
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const view:ReadonlyMap<Id,T>={get,has:id=>base.has(id)||reverse.has(id),size:base.size+reverse.size,entries,keys:function*():Generator<Id,undefined>{for(const[id]of entries())yield id;return undefined;},values:function*():Generator<T,undefined>{for(const[,value]of entries())yield value;return undefined;},[Symbol.iterator]:entries,forEach(fn,thisArg){for(const[id,value]of entries())fn.call(thisArg,value,id,view);}};return Object.freeze(view);
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}
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// projected只服务边端点和公共owner的坐标计算；length是tree order+edges的固定ordinal总数。
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const projected:Document={...document,elements:projection(document.elements,reverseElements,'element'),canvases:projection(document.canvases,reverseCanvases,'canvas')},length=state.order.length+state.edges.length;
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/** 前 state.order.length 项用树转换器，其余用边转换器，生成同一预映射 CopyLine。
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* readElement 可按需异步加载元素；其身份/源一致性由注入端口保证，canvas 直接从已捕获文档取。
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* 预先取消/非法 ordinal 在 try 外拒绝；try 内失败（含读取后取消）转成 ImportLine.error，runner 必须复查信号。
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* 成功检查单行 JSON 的 UTF-8 长度 ≤256KiB（不含 NDJSON 换行），不限制完整输出总字节或在单条内让出。
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* 失败不会推进此源的全局游标；是否保留失败、跳过或停止由 runner 管理。 */
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return Object.freeze({fingerprint,parserVersion:2,async read(cursor:number,signal:AbortSignal){
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if(signal.aborted)throw fault('import_aborted');if(!Number.isSafeInteger(cursor)||cursor<0||cursor>length)throw fault('invalid_import_cursor');if(cursor===length)return null;
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const task=state.order[cursor],key=task?`${task.kind}:${task.id}`:`element:${state.edges[cursor-state.order.length]}`;
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// 索引源只在此请求完整元素payload；cancel后重查signal，再生成映射/guard行并检查单条大小。
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try{const original=task?.kind==='canvas'?document.canvases.get(task.id)!:readElement?await readElement(task?.id??state.edges[cursor-state.order.length],signal):document.elements.get(task?.id??state.edges[cursor-state.order.length])!;
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if(signal.aborted)throw fault('import_aborted');const change=cursor<state.order.length?duplicateTreeChange(document,registry,task.kind,original,elements,canvases,copiedCanvases,state.offset):duplicateEdgeChange(document,registry,original as ElementRecord,elements,canvases,projected),line=duplicateImportLine(document,registry,change,keys);
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if(new TextEncoder().encode(JSON.stringify(line)).byteLength>256*1024)throw fault('record_too_large');
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return{cursor,nextCursor:cursor+1,key:line.key,value:line as unknown as Json};}catch(error){return{cursor,nextCursor:cursor+1,key,error:(error as {code?:string}).code??'copy_record_failed'};}
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}});
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}
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