rea/src/native/AppleDispatchCoverage.ts

import type { ObjcSwiftMetadata } from "../domain/native/objcSwiftMetadata.js";
import type { PointerFixups } from "./AppleMachoFixups.js";
import type { DecodeIssue } from "./AppleDispatchDecodeFacts.js";
import type { FacetDecodeFacts } from "./AppleDispatchDecodeFacts.js";

const describeFixups = (fixups: PointerFixups): string => {
  const unread =
    fixups.unreadRebaseBytes > 0
      ? `LC_DYLD_INFO rebase opcodes were not decoded (${fixups.unreadRebaseBytes} bytes)`
      : undefined;
  const kind =
    fixups.kind === "chained"
      ? `chained fixups: ${fixups.formats.join(", ") || "no fixup segments"}`
      : fixups.kind === "dyld-info"
        ? "LC_DYLD_INFO bind opcodes"
        : unread === undefined
          ? "no fixup load commands"
          : undefined;
  return [unread, kind].filter((line) => line !== undefined).join("; ");
};

/** Append the per-facet coverage of one Apple dispatch metadata decode. */
export const pushDispatchCoverage = (input: {
  readonly result: ObjcSwiftMetadata;
  readonly failures: readonly string[];
  readonly categoryIssues: readonly DecodeIssue[];
  readonly examined: number;
  readonly categoriesExamined: number;
  readonly truncated: boolean;
  readonly fixups: PointerFixups;
  readonly vtables: FacetDecodeFacts;
  readonly swift: FacetDecodeFacts;
}): void => {
  const {
    result,
    failures,
    categoryIssues,
    examined,
    categoriesExamined,
    truncated,
    fixups,
    vtables,
    swift,
  } = input;
  const classOwnedMethods = result.objc_dispatch_implementations.filter(
    ({ category }) => category === undefined,
  );
  const classRecords = [
    ...result.objc_classes.flatMap((record) =>
      record.decode?.status === "decoded"
        ? []
        : [
            `class ${record.name}: ${record.decode?.reason ?? record.decode?.status ?? "decode_status_missing"}`,
          ],
    ),
    ...result.objc_protocol_records.flatMap((record) =>
      record.decode.status === "decoded"
        ? []
        : [
            `protocol ${record.name}: ${record.decode.reason ?? record.decode.status}`,
          ],
    ),
    ...classOwnedMethods.flatMap((record) =>
      record.decode.status === "decoded"
        ? []
        : [
            `method ${record.class_name} ${record.method_type} ${record.selector}: ${record.decode.reason ?? record.decode.status}`,
          ],
    ),
    ...result.objc_ivars.flatMap((record) =>
      record.decode.status === "decoded"
        ? []
        : [
            `ivar ${record.class_name}.${record.name}: ${record.decode.reason ?? record.decode.status}`,
          ],
    ),
  ];
  const classReasons = [
    ...failures,
    ...classRecords,
    ...(truncated ? ["max_records_reached"] : []),
  ];
  const categoryMethods = result.objc_dispatch_implementations.filter(
    ({ category }) => category !== undefined,
  );
  const categoryMethodReasons = categoryMethods.flatMap((record) =>
    record.decode.status === "decoded"
      ? []
      : [
          `category method ${record.category} ${record.class_name} ${record.method_type} ${record.selector}: ${record.decode.reason ?? record.decode.status}`,
        ],
  );
  result.coverage.push({
    facet: "objc_class_method_ivar_metadata",
    status: classReasons.length > 0 ? "partial" : "complete",
    reason: classReasons.join("; ") || null,
    examined,
    decoded: result.objc_classes.filter(
      ({ decode }) => decode?.status === "decoded",
    ).length,
  });
  result.coverage.push({
    facet: "binary_relative_pointers",
    status:
      truncated ||
      result.relative_pointers.some((item) => item.decode.status !== "decoded")
        ? "partial"
        : "complete",
    reason: truncated
      ? "max_records_reached"
      : result.relative_pointers.some(
            (item) => item.decode.status !== "decoded",
          )
        ? "relative_pointer_targets_unresolved"
        : null,
    examined: result.relative_pointers.length,
    decoded: result.relative_pointers.filter(
      (item) => item.decode.status === "decoded",
    ).length,
  });
  const categoryFailures = categoryIssues.map(
    ({ code, location, message }) =>
      `${code}${location === undefined ? "" : ` at ${location}`}: ${message}`,
  );
  result.coverage.push({
    facet: "objc_properties_categories",
    status:
      truncated ||
      categoryFailures.length > 0 ||
      result.objc_categories.some(
        ({ decode }) => decode.status !== "decoded",
      ) ||
      categoryMethodReasons.length > 0
        ? "partial"
        : "complete",
    reason:
      [
        ...categoryFailures,
        ...categoryMethodReasons,
        ...(truncated ? ["max_records_reached"] : []),
      ].join("; ") || null,
    examined: categoriesExamined,
    decoded: result.objc_categories.filter(
      ({ decode }) => decode.status === "decoded",
    ).length,
  });
  const fixupReason = [
    describeFixups(fixups),
    ...fixups.issues.map(
      ({ code, location, message }) =>
        `${code}${location === undefined ? "" : ` at ${location}`}: ${message}`,
    ),
  ]
    .filter((line) => line.length > 0)
    .join("; ");
  result.coverage.push({
    facet: "pointer_fixups",
    status:
      fixups.issues.length > 0 || fixups.unreadRebaseBytes > 0
        ? "partial"
        : fixups.examined === 0
          ? "unsupported"
          : "complete",
    reason: fixupReason.length > 0 ? fixupReason : null,
    examined: fixups.examined,
    decoded: fixups.decoded,
  });
  result.coverage.push({
    facet: "swift_generic_resilient_witnesses_overrides_async_coroutines",
    status: "unsupported",
    reason:
      "This reader admits simple Swift conformance/static witness records and non-generic, non-resilient class vtables; generic/resilient tables and other Swift metadata families are not decoded",
    examined: 0,
    decoded: 0,
  });
  result.coverage.push({
    facet: "swift_conformances_static_witness_slots",
    status:
      swift.exhaustive &&
      !truncated &&
      !result.swift_conformances.some(
        ({ decode }) => decode.status !== "decoded",
      ) &&
      !result.swift_dispatch_slots.some(
        ({ table_kind, decode }) =>
          table_kind === "witness_table" && decode.status !== "decoded",
      )
        ? "complete"
        : "partial",
    reason:
      [
        ...swift.issues.map(formatIssue),
        ...(truncated ? ["max_records_reached"] : []),
        ...(result.swift_conformances.some(
          ({ decode }) => decode.status !== "decoded",
        ) ||
        result.swift_dispatch_slots.some(
          ({ table_kind, decode }) =>
            table_kind === "witness_table" && decode.status !== "decoded",
        )
          ? ["swift_records_unresolved"]
          : []),
      ].join("; ") || null,
    examined: swift.examined,
    decoded: swift.decoded,
  });
  result.coverage.push({
    facet: "swift_class_vtable_descriptors",
    status:
      vtables.exhaustive &&
      !truncated &&
      !result.swift_dispatch_slots.some(
        ({ table_kind, decode }) =>
          table_kind === "class_vtable" && decode.status !== "decoded",
      )
        ? "complete"
        : "partial",
    reason:
      [
        ...vtables.issues.map(formatIssue),
        ...(truncated ? ["max_records_reached"] : []),
        ...(result.swift_dispatch_slots.some(
          ({ table_kind, decode }) =>
            table_kind === "class_vtable" && decode.status !== "decoded",
        )
          ? ["vtable_implementations_unresolved"]
          : []),
      ].join("; ") || null,
    examined: vtables.examined,
    decoded: vtables.decoded,
  });
};

const formatIssue = ({ code, location, message }: DecodeIssue): string =>
  `${code}${location === undefined ? "" : ` at ${location}`}: ${message}`;