Function processFromClause

packages/db/src/query/compiler/index.ts:1038–1167

* Processes the FROM clause, handling direct collection references and subqueries. * Populates `aliasToCollectionId` and `aliasRemapping` for per-alias subscription tracking.

(
  from: CollectionRef | QueryRef | UnionFrom | UnionAll,
  allInputs: Record<string, KeyedStream>,
  collections: Record<string, Collection>,
  subscriptions: Record<string, CollectionSubscription>,
  callbacks: Record<string, LazyCollectionCallbacks>,
  lazySources: Set<string>,
  optimizableOrderByCollections: Record<string, OrderByOptimizationInfo>,
  setWindowFn: (windowFn: (options: WindowOptions) => void) => void,
  cache: QueryCache,
  queryMapping: QueryMapping,
  aliasToCollectionId: Record<string, string>,
  aliasRemapping: Record<string, string>,
  sourceWhereClauses: Map<string, BasicExpression<boolean>>,
)

 * Populates `aliasToCollectionId` and `aliasRemapping` for per-alias subscription tracking.
 */
function processFromClause(
  from: CollectionRef | QueryRef | UnionFrom | UnionAll,
  allInputs: Record<string, KeyedStream>,
  collections: Record<string, Collection>,
  subscriptions: Record<string, CollectionSubscription>,
  callbacks: Record<string, LazyCollectionCallbacks>,
  lazySources: Set<string>,
  optimizableOrderByCollections: Record<string, OrderByOptimizationInfo>,
  setWindowFn: (windowFn: (options: WindowOptions) => void) => void,
  cache: QueryCache,
  queryMapping: QueryMapping,
  aliasToCollectionId: Record<string, string>,
  aliasRemapping: Record<string, string>,
  sourceWhereClauses: Map<string, BasicExpression<boolean>>,
): {
  alias: string
  pipeline: NamespacedAndKeyedStream
  collectionId: string
  sources: Record<string, KeyedStream>
  sourceIncludes: Array<SourceInclude>
  directIncludes: Array<IncludesCompilationResult>
  isUnionFrom: boolean
} {
  if (from.type === `unionAll`) {
    return processUnionAll(
      from,
      allInputs,
      collections,
      subscriptions,
      callbacks,
      lazySources,
      optimizableOrderByCollections,
      setWindowFn,
      cache,
      queryMapping,
      aliasToCollectionId,
      aliasRemapping,
      sourceWhereClauses,
    )
  }

  if (from.type !== `unionFrom`) {
    const { alias, input, collectionId, sourceIncludes } = processFrom(
      from,
      allInputs,
      collections,
      subscriptions,
      callbacks,
      lazySources,
      optimizableOrderByCollections,
      setWindowFn,
      cache,
      queryMapping,
      aliasToCollectionId,
      aliasRemapping,
      sourceWhereClauses,
    )