capnpc-ts/src/file.ts

Cap'n Proto schema compiler for TypeScript.

import * as capnp from "capnp-ts";
import * as s from "capnp-ts/src/std/schema.capnp.js";
import { format } from "capnp-ts/src/util";
import initTrace from "debug";

import { CodeGeneratorFileContext } from "./code-generator-file-context";
import { ConcreteListType } from "./constants";
import * as E from "./errors";
import * as util from "./util";

const trace = initTrace("capnpc:file");
trace("load");

export function compareCodeOrder(a: { getCodeOrder(): number }, b: { getCodeOrder(): number }): number {
  return a.getCodeOrder() - b.getCodeOrder();
}

export function getConcreteListType(ctx: CodeGeneratorFileContext, type: s.Type): string {
  if (!type.isList()) return getJsType(ctx, type, false);

  const elementType = type.getList().getElementType();
  const elementTypeWhich = elementType.which();

  if (elementTypeWhich === s.Type.LIST) {
    return `capnp.PointerList(${getConcreteListType(ctx, elementType)})`;
  } else if (elementTypeWhich === s.Type.STRUCT) {
    const structNode = lookupNode(ctx, elementType.getStruct().getTypeId());

    if (structNode.getStruct().getPreferredListEncoding() !== s.ElementSize.INLINE_COMPOSITE) {
      throw new Error(E.GEN_FIELD_NON_INLINE_STRUCT_LIST);
    }

    return `capnp.CompositeList(${getJsType(ctx, elementType, false)})`;
  }

  return ConcreteListType[elementTypeWhich];
}

export function getDisplayNamePrefix(node: s.Node): string {
  return node.getDisplayName().substr(node.getDisplayNamePrefixLength());
}

export function getFullClassName(node: s.Node): string {
  return node.getDisplayName().split(":")[1].split(".").map(util.c2t).join("_");
}

export function getJsType(ctx: CodeGeneratorFileContext, type: s.Type, constructor: boolean): string {
  const whichType = type.which();

  switch (whichType) {
    case s.Type.ANY_POINTER:
      return "capnp.Pointer";

    case s.Type.BOOL:
      return "boolean";

    case s.Type.DATA:
      return "capnp.Data";

    case s.Type.ENUM:
      return getFullClassName(lookupNode(ctx, type.getEnum().getTypeId()));

    case s.Type.FLOAT32:
    case s.Type.FLOAT64:
    case s.Type.INT16:
    case s.Type.INT32:
    case s.Type.INT8:
    case s.Type.UINT16:
    case s.Type.UINT32:
    case s.Type.UINT8:
      return "number";

    case s.Type.INT64:
      return "capnp.Int64";

    case s.Type.INTERFACE:
      return "capnp.Interface";

    case s.Type.LIST:
      return `capnp.List${constructor ? "Ctor" : ""}<${getJsType(ctx, type.getList().getElementType(), false)}>`;

    case s.Type.STRUCT: {
      const c = getFullClassName(lookupNode(ctx, type.getStruct().getTypeId()));

      return constructor ? `capnp.StructCtor<${c}>` : c;
    }
    case s.Type.UINT64:
      return "capnp.Uint64";

    case s.Type.TEXT:
      return "string";

    case s.Type.VOID:
      return "capnp.Void";

    default:
      throw new Error(format(E.GEN_UNKNOWN_TYPE, whichType));
  }
}

export function getUnnamedUnionFields(node: s.Node): s.Field[] {
  if (!node.isStruct()) return [];

  return node
    .getStruct()
    .getFields()
    .filter((f) => f.getDiscriminantValue() !== s.Field.NO_DISCRIMINANT);
}

export function hasNode(ctx: CodeGeneratorFileContext, lookup: { getId(): capnp.Uint64 } | capnp.Uint64): boolean {
  const id = lookup instanceof capnp.Uint64 ? lookup : lookup.getId();

  return ctx.nodes.some((n) => n.getId().equals(id));
}

export function loadRequestedFile(
  req: s.CodeGeneratorRequest,
  file: s.CodeGeneratorRequest_RequestedFile
): CodeGeneratorFileContext {
  trace("compile(%s, %s)", req, file);

  const ctx = new CodeGeneratorFileContext(req, file);

  const schema = lookupNode(ctx, file.getId());

  ctx.tsPath = schema.getDisplayName() + ".ts";

  return ctx;
}

export function lookupNode(ctx: CodeGeneratorFileContext, lookup: { getId(): capnp.Uint64 } | capnp.Uint64): s.Node {
  const id = lookup instanceof capnp.Uint64 ? lookup : lookup.getId();
  const node = ctx.nodes.find((n) => n.getId().equals(id));

  if (node === undefined) throw new Error(format(E.GEN_NODE_LOOKUP_FAIL, id));

  return node;
}

/**
 * Determine whether the given field needs a concrete list class: this is currently the case for composite lists
 * (`capnp.CompositeList`) and lists of lists (`capnp.PointerList`).
 *
 * @param {s.Field} field The field to check.
 * @returns {boolean} Returns `true` if the field requires a concrete list class initializer.
 */

export function needsConcreteListClass(field: s.Field): boolean {
  if (!field.isSlot()) return false;

  const slotType = field.getSlot().getType();

  if (!slotType.isList()) return false;

  const elementType = slotType.getList().getElementType();

  return elementType.isStruct() || elementType.isList();
}