85 lines
2.5 KiB
JavaScript
85 lines
2.5 KiB
JavaScript
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'use strict';
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/**
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* Module dependencies.
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*/
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const Type = require('./type');
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const assert = require('assert');
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const debug = require('debug')('ffi:cif_var');
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const ref = require('ref-napi');
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const bindings = require('./bindings');
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const POINTER_SIZE = ref.sizeof.pointer;
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const ffi_prep_cif_var = bindings.ffi_prep_cif_var;
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const FFI_CIF_SIZE = bindings.FFI_CIF_SIZE;
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const FFI_DEFAULT_ABI = bindings.FFI_DEFAULT_ABI;
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// status codes
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const FFI_OK = bindings.FFI_OK;
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const FFI_BAD_TYPEDEF = bindings.FFI_BAD_TYPEDEF;
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const FFI_BAD_ABI = bindings.FFI_BAD_ABI;
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/**
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* JS wrapper for the `ffi_prep_cif_var` function.
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* Returns a Buffer instance representing a variadic `ffi_cif *` instance.
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*/
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function CIF_var (rtype, types, numFixedArgs, abi) {
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debug('creating `ffi_cif *` instance with `ffi_prep_cif_var()`');
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// the return and arg types are expected to be coerced at this point...
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assert(!!rtype, 'expected a return "type" object as the first argument');
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assert(Array.isArray(types), 'expected an Array of arg "type" objects as the second argument');
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assert(numFixedArgs >= 1, 'expected the number of fixed arguments to be at least 1');
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// the buffer that will contain the return `ffi_cif *` instance
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const cif = Buffer.alloc(FFI_CIF_SIZE);
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const numTotalArgs = types.length;
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const _argtypesptr = Buffer.alloc(numTotalArgs * POINTER_SIZE);
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const _rtypeptr = Type(rtype);
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for (let i = 0; i < numTotalArgs; i++) {
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const ffiType = Type(types[i]);
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_argtypesptr.writePointer(ffiType, i * POINTER_SIZE);
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}
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// prevent GC of the arg type and rtn type buffers (not sure if this is required)
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cif.rtnTypePtr = _rtypeptr;
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cif.argTypesPtr = _argtypesptr;
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if (typeof abi === 'undefined') {
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debug('no ABI specified (this is OK), using FFI_DEFAULT_ABI');
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abi = FFI_DEFAULT_ABI;
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}
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const status = ffi_prep_cif_var(cif, numFixedArgs, numTotalArgs, _rtypeptr, _argtypesptr, abi);
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if (status !== FFI_OK) {
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switch (status) {
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case FFI_BAD_TYPEDEF:
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{
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const err = new Error('ffi_prep_cif_var() returned an FFI_BAD_TYPEDEF error');
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err.code = 'FFI_BAD_TYPEDEF';
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err.errno = status;
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throw err;
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}
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case FFI_BAD_ABI:
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{
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const err = new Error('ffi_prep_cif_var() returned an FFI_BAD_ABI error');
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err.code = 'FFI_BAD_ABI';
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err.errno = status;
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throw err;
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}
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default:
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{
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const err = new Error('ffi_prep_cif_var() returned an error: ' + status);
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err.errno = status;
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throw err;
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}
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}
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}
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return cif;
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}
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module.exports = CIF_var;
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