limu/src/core/scope.ts

A fast js lib of immutable data, based on shallow copy on read and mark modified on write mechanism

/*---------------------------------------------------------------------------------------------
 *  Licensed under the MIT License.
 *
 *  @Author: fantasticsoul
 *--------------------------------------------------------------------------------------------*/
import type { DraftMeta, IApiCtx } from '../inner-types';
import { ARRAY, MAP, SET } from '../support/consts';
import { deepDrill, isObject } from '../support/util';
import { clearMultiRefData, getDraftMeta, getDraftMetaByCtx, getMetaVer, getMultiRefPaths, resetMultiRefData } from './meta';
import { getKeyStrByPath, getVal, setVal } from './path-util';

function ressignArrayItem(listMeta: DraftMeta, itemMeta: DraftMeta, ctx: { targetNode: any; key: any }) {
  const { copy, isArrOrderChanged } = listMeta;
  const { targetNode, key } = ctx;
  // 数组顺序已变化
  if (isArrOrderChanged) {
    // fix issue https://github.com/tnfe/limu/issues/13
    // 元素经过 sort 后，可能已变成 proxy 对象，所以这里需要比较 copy 和 proxyVal
    const index = copy.findIndex((item: any) => item === itemMeta.copy || item === itemMeta.proxyVal);
    if (index >= 0) {
      copy[index] = targetNode;
    }
    return;
  }

  copy[key] = targetNode;
}

export function isInSameScope(mayDraftProxy: any, callerScopeVer: string) {
  if (!isObject(mayDraftProxy)) {
    return true;
  }
  return getMetaVer(mayDraftProxy) === callerScopeVer;
}

export function clearScopes(rootMeta: DraftMeta, apiCtx: IApiCtx) {
  const { metaMap } = apiCtx;

  // TODO 下钻有一定的性能损耗，允许用户关闭此逻辑 findDraftNodeNewRef=false
  const drilledMap: Map<any, any> = new Map();
  apiCtx.newNodeMap.forEach((v) => {
    const { node, parent, key } = v;
    const drilledNode = drilledMap.get(node);
    if (drilledNode) {
      // 同一个节点被多个父级引用了，只需要指向自身即可，无需再次下钻
      parent[key] = drilledNode;
      return;
    }
    const item = v;
    deepDrill(node, parent, key, (obj: any, parentObj: any, key: any) => {
      const meta = getDraftMetaByCtx(obj, apiCtx);
      if (meta) {
        const { modified, copy, self } = meta;
        const targetNode = !modified ? self : copy;
        parentObj[key] = targetNode;
      }
    });
    item.target = parent[key]; // 此处可能已被替换为真正的目标节点
    drilledMap.set(node, item.target);
  });

  rootMeta.scopes.forEach((meta) => {
    const { modified, copy, parentMeta, key, self, revoke, proxyVal, isDel } = meta;
    // LABEL: WAIT TEST(2025-05-25)
    const leaveScope = () => {
      metaMap.delete(self);
      metaMap.delete(proxyVal);
      // 这里还不能将 copy 的映射删除，否则会照成以下错误，留给 js 引擎自己清理即可
      // fail at test/api/setAutoRevoke.ts -> set autoRevoke when call createDraft › read subNode
      // metaMap.delete(copy);
      revoke();
    };

    if (!copy || !parentMeta) return leaveScope();

    const targetNode = !modified ? self : copy;
    // 父节点是 Map、Set 时，parent 指向的是 ProxyItems，这里取到 copy 本体后再重新赋值
    const parentCopy = parentMeta.copy as any;
    const parentType = parentMeta.selfType;

    if (parentType === MAP) {
      parentCopy.set(key, targetNode);
      return leaveScope();
    }
    if (parentType === SET) {
      parentCopy.delete(proxyVal);
      parentCopy.add(targetNode);
      return leaveScope();
    }
    if (parentType === ARRAY) {
      ressignArrayItem(parentMeta, meta, { targetNode, key });
      return leaveScope();
    }
    if (isDel !== true) {
      parentCopy[key] = targetNode;
      return leaveScope();
    }
  });

  rootMeta.scopes.length = 0;
}

/**
 * TODO  将来使用 handleMultiRefV2 替换掉 handleMultiRef
 * @param rootMeta T
 * @param final 
 */
export function handleMultiRefV2(rootMeta: DraftMeta, final: any) {
  type Stat = { modified: boolean; keyPaths: string[][]; data: any };
  const { sourceId, proxyVal } = rootMeta;
  const keyPathsList = getMultiRefPaths(sourceId);

  const keyPathsListNew: string[][][] = [];
  const keyStr2KeyPaths: Record<string, string[][]> = {};

  for (const keyPaths of keyPathsList) {
    const resultStatMap = new Map<any, Stat>();

    const getResultStat = (val: any) => {
      let stat = resultStatMap.get(val);
      if (!stat) {
        stat = { modified: false, keyPaths: [], data: null };
        resultStatMap.set(val, stat);
      }
      return stat;
    };

    // keyPaths 里每一个路径代表上一刻记录的多引用关系，
    // 这里开始对比实际值并记录为新的多引用关系
    for (const subIdx in keyPaths) {
      const subIdxNum = Number(subIdx);
      const keyPath = keyPaths[subIdxNum];
      const { val } = getVal(proxyVal, keyPath);
      const valMeta = getDraftMeta(val);
      if (!valMeta) {
        continue;
      }

      const result = valMeta.modified ? valMeta.copy : valMeta.self;
      const stat = getResultStat(result);
      stat.keyPaths.push(keyPath);

      if (stat.modified) {
        continue;
      }

      if (valMeta.modified) {
        stat.modified = true;
        stat.data = valMeta.copy;
      } else {
        stat.data = valMeta.self;
      }
    }

    resultStatMap.forEach((stat) => {
      const { keyPaths, data } = stat;
      for (const keyPath of keyPaths) {
        // 统一指到同一个 self 或者 copy
        setVal(final, keyPath, data);
        // 记录行新的 keyStr keyPaths 映射关系
        keyStr2KeyPaths[getKeyStrByPath(keyPath)] = keyPaths;
      }
      // 添加到新的同一个数据多引用路径列表里
      keyPathsListNew.push(keyPaths);
    });
  }

  resetMultiRefData(sourceId, keyPathsListNew, keyStr2KeyPaths);
}

export function handleMultiRef(rootMeta: DraftMeta, final: any) {
  const keyPathsList = getMultiRefPaths(rootMeta.sourceId);

  let idx = -1;
  const toClearIdxList: number[] = [];
  const toClearKeyStrList: string[] = [];
  for (const keyPaths of keyPathsList) {
    idx += 1;
    let changedMeta: any = null;
    let fixedMeta: any = null;
    const results: any[] = [];
    for (const keyPath of keyPaths) {
      const { val } = getVal(rootMeta.proxyVal, keyPath);
      const valMeta = getDraftMeta(val);
      if (!valMeta) continue;

      if (valMeta.modified && !changedMeta) {
        changedMeta = valMeta;
      }

      fixedMeta = valMeta;
      results.push(valMeta.self);
    }

    // TODO  优化为分析所有 results，做部分清理，见 handleMultiRefV2
    // prev: [ r1, r2, r3, r4, r5 ] 都一样
    // now: [ r1, r2, r3 ] 一样，[ r4, r5 ] 一样
    // 需要按照新的比较结果来记录新的，目前先实现简单的下标1和2比较
    const isEq = results[0] === results[1];
    if (!isEq) {
      toClearIdxList.push(idx);
      keyPaths.forEach((keyPath) => toClearKeyStrList.push(getKeyStrByPath(keyPath)));
    } else if (changedMeta) {
      for (const keyPath of keyPaths) {
        setVal(final, keyPath, changedMeta.copy);
      }
    } else if (fixedMeta) {
      for (const keyPath of keyPaths) {
        setVal(final, keyPath, fixedMeta.self);
      }
    }
  }

  if (toClearIdxList.length) {
    clearMultiRefData(rootMeta.sourceId, toClearIdxList, toClearKeyStrList);
  }
}

export function extractFinalData(rootMeta: DraftMeta, apiCtx: IApiCtx) {
  const { self, copy, modified } = rootMeta;
  let final = self;
  // 有 copy 不一定有修改行为，这里需做双重判断
  if (copy && modified) {
    final = rootMeta.copy;
  }
  // 这里 handleMultiRef 和 clearScopes 顺序很重要，必须先处理多引用，再清理 scopes
  handleMultiRef(rootMeta, final);
  // if put this on first line, fail at test/set-other/update-object-item.ts
  clearScopes(rootMeta, apiCtx);
  return final;
}

export function recordVerScope(meta: DraftMeta) {
  meta.rootMeta.scopes.push(meta);
}