ffi/lib/foreign_function.js

A foreign function interface (FFI) for Node.js

/**
 * Module dependencies.
 */

var CIF = require('./cif')
  , _ForeignFunction = require('./_foreign_function')
  , debug = require('debug')('ffi:ForeignFunction')
  , assert = require('assert')
  , ref = require('ref')

/**
 * Represents a foreign function in another library. Manages all of the aspects
 * of function execution, including marshalling the data parameters for the
 * function into native types and also unmarshalling the return from function
 * execution.
 */

function ForeignFunction (funcPtr, returnType, argTypes, abi) {
  debug('creating new ForeignFunction', funcPtr)

  // check args
  assert(Buffer.isBuffer(funcPtr), 'expected Buffer as first argument')
  assert(!!returnType, 'expected a return "type" object as the second argument')
  assert(Array.isArray(argTypes), 'expected Array of arg "type" objects as the third argument')

  // normalize the "types" (they could be strings,
  // so turn into real type instances)
  returnType = ref.coerceType(returnType)
  argTypes = argTypes.map(ref.coerceType)

  // create the `ffi_cif *` instance
  var cif = CIF(returnType, argTypes, abi)

  // create and return the JS proxy function
  return _ForeignFunction(cif, funcPtr, returnType, argTypes)
}
module.exports = ForeignFunction