Visitor Class — react Architecture

Source Code

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidatePreservedManualMemoization.ts lines 318–605

class Visitor extends ReactiveFunctionVisitor<VisitorState> {
  /**
   * Records all completed scopes (regardless of transitive memoization
   * of scope dependencies)
   *
   * Both @scopes and @prunedScopes are live sets. We rely on iterating
   * the reactive-ir in evaluation order, as they are used to determine
   * whether scope dependencies / declarations have completed mutation.
   */
  scopes: Set<ScopeId> = new Set();
  prunedScopes: Set<ScopeId> = new Set();
  temporaries: Map<IdentifierId, ManualMemoDependency> = new Map();

  /**
   * Recursively visit values and instructions to collect declarations
   * and property loads.
   * @returns a @{ManualMemoDependency} representing the variable +
   * property reads represented by @value
   */
  recordDepsInValue(value: ReactiveValue, state: VisitorState): void {
    switch (value.kind) {
      case 'SequenceExpression': {
        for (const instr of value.instructions) {
          this.visitInstruction(instr, state);
        }
        this.recordDepsInValue(value.value, state);
        break;
      }
      case 'OptionalExpression': {
        this.recordDepsInValue(value.value, state);
        break;
      }
      case 'ConditionalExpression': {
        this.recordDepsInValue(value.test, state);
        this.recordDepsInValue(value.consequent, state);
        this.recordDepsInValue(value.alternate, state);
        break;
      }
      case 'LogicalExpression': {
        this.recordDepsInValue(value.left, state);
        this.recordDepsInValue(value.right, state);
        break;
      }
      default: {
        collectMaybeMemoDependencies(value, this.temporaries, false);
        if (
          value.kind === 'StoreLocal' ||
          value.kind === 'StoreContext' ||
          value.kind === 'Destructure'
        ) {
          for (const storeTarget of eachInstructionValueLValue(value)) {
            state.manualMemoState?.decls.add(
              storeTarget.identifier.declarationId,
            );
            if (storeTarget.identifier.name?.kind === 'named') {
              this.temporaries.set(storeTarget.identifier.id, {
                root: {
                  kind: 'NamedLocal',
                  value: storeTarget,
                  constant: false,
                },
                path: [],
                loc: storeTarget.loc,
              });
            }
          }
        }
        break;
      }
    }
  }

  recordTemporaries(instr: ReactiveInstruction, state: VisitorState): void {
    const temporaries = this.temporaries;
    const {lvalue, value} = instr;
    const lvalId = lvalue?.identifier.id;
    if (lvalId != null && temporaries.has(lvalId)) {
      return;
    }
    const isNamedLocal = lvalue?.identifier.name?.kind === 'named';
    if (lvalue !== null && isNamedLocal && state.manualMemoState != null) {