Method makePackedFunc

web/src/runtime.ts:2206–2239

(handle: Pointer)

  }

  private makePackedFunc(handle: Pointer): PackedFunc {
    const cell = new PackedFuncCell(handle, this.lib, this.ctx);
    const packedFunc = (...args: any): any => {
      const stack = this.lib.getOrAllocCallStack();
      const argsOffset = stack.allocRawBytes(SizeOf.TVMFFIAny * args.length);
      this.setPackedArguments(stack, args, argsOffset);
      const retOffset = stack.allocRawBytes(SizeOf.TVMFFIAny);
      // pre-store the result to be null
      stack.storeI32(retOffset, TypeIndex.kTVMFFINone);
      // clear off the extra zero padding before ptr storage
      stack.storeI32(retOffset + SizeOf.I32, 0);
      stack.commitToWasmMemory();
      this.lib.checkCall(
        (this.exports.TVMFFIFunctionCall as ctypes.FTVMFFIFunctionCall)(
          cell.getHandle(),
          stack.ptrFromOffset(argsOffset),
          args.length,
          stack.ptrFromOffset(retOffset)
        )
      );

      const ret = this.retValueToJS(stack.ptrFromOffset(retOffset), false);
      this.lib.recycleCallStack(stack);
      return ret;
    };
    // Attach attributes to the function type.
    // This is because javascript do not allow us to overload call.
    const ret: any = packedFunc;
    ret.dispose = (): void => {
      cell.dispose();
    };
    ret._tvmPackedCell = cell;
    return ret as PackedFunc;
  }

  /**
   * Creaye return value of the packed func. The value us auto-tracked for dispose.