fs: consistent constants use and cleanup

* only require('buffer') once
* use constants directly
* fix incorrect constants
PR-URL: #20765
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ron Korving <ron@ronkorving.nl>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: jasnell

lib/fs.js

@@ -24,16 +24,31 @@
 
 'use strict';
 
-constconstants=process.binding('constants').fs;
-const{S_IFIFO,S_IFLNK,S_IFMT,S_IFREG,S_IFSOCK}=constants;
+const{fs: constants}=process.binding('constants');
+const{
+S_IFIFO,
+S_IFLNK,
+S_IFMT,
+S_IFREG,
+S_IFSOCK,
+F_OK,
+R_OK,
+W_OK,
+X_OK,
+O_WRONLY,
+O_SYMLINK,
+UV_FS_COPYFILE_EXCL,
+UV_FS_COPYFILE_FICLONE,
+UV_FS_COPYFILE_FICLONE_FORCE
+}=constants;
 constutil=require('util');
 constpathModule=require('path');
 const{ isUint8Array }=require('internal/util/types');
 const{ createPromise, promiseResolve }=process.binding('util');
 
 constbinding=process.binding('fs');
 constfs=exports;
-const{ Buffer }=require('buffer');
+const{ Buffer, kMaxLength}=require('buffer');
 consterrors=require('internal/errors');
 const{
 ERR_FS_FILE_TOO_LARGE,
@@ -58,6 +73,7 @@ const {
  preprocessSymlinkDestination,
  Stats,
  getStatsFromBinding,
+ realpathCacheKey,
  stringToFlags,
  stringToSymlinkType,
  toUnixTimestamp,
@@ -103,7 +119,6 @@ function lazyAssert() {
 }
 
 constkMinPoolSpace=128;
-const{ kMaxLength }=require('buffer');
 
 constisWindows=process.platform==='win32';
 
@@ -179,16 +194,16 @@ function isFileType(stats, fileType) {
 
 // Don't allow mode to accidentally be overwritten.
 Object.defineProperties(fs,{
-F_OK: {enumerable: true,value: constants.F_OK||0},
-R_OK: {enumerable: true,value: constants.R_OK||0},
-W_OK: {enumerable: true,value: constants.W_OK||0},
-X_OK: {enumerable: true,value: constants.X_OK||0},
+F_OK: {enumerable: true,value: F_OK||0},
+R_OK: {enumerable: true,value: R_OK||0},
+W_OK: {enumerable: true,value: W_OK||0},
+X_OK: {enumerable: true,value: X_OK||0},
 });
 
 fs.access=function(path,mode,callback){
 if(typeofmode==='function'){
 callback=mode;
-mode=fs.F_OK;
+mode=F_OK;
 }
 
 path=getPathFromURL(path);
@@ -205,7 +220,7 @@ fs.accessSync = function(path, mode) {
 validatePath(path);
 
 if(mode===undefined)
-mode=fs.F_OK;
+mode=F_OK;
 else
 mode=mode|0;
 
@@ -222,7 +237,7 @@ fs.exists = function(path, callback) {
 }
 
 try{
-fs.access(path,fs.FS_OK,suppressedCallback);
+fs.access(path,F_OK,suppressedCallback);
 }catch(err){
 returncallback(false);
 }
@@ -244,7 +259,7 @@ Object.defineProperty(fs.exists, internalUtil.promisify.custom, {
 // TODO(joyeecheung): deprecate the never-throw-on-invalid-arguments behavior
 fs.existsSync=function(path){
 try{
-fs.accessSync(path,fs.FS_OK);
+fs.accessSync(path,F_OK);
 returntrue;
 }catch(e){
 returnfalse;
@@ -1054,10 +1069,10 @@ fs.fchmodSync = function(fd, mode) {
 handleErrorFromBinding(ctx);
 };
 
-if(constants.O_SYMLINK!==undefined){
+if(O_SYMLINK!==undefined){
 fs.lchmod=function(path,mode,callback){
 callback=maybeCallback(callback);
-fs.open(path,constants.O_WRONLY|constants.O_SYMLINK,function(err,fd){
+fs.open(path,O_WRONLY|O_SYMLINK,function(err,fd){
 if(err){
 callback(err);
 return;
@@ -1073,7 +1088,7 @@ if (constants.O_SYMLINK !== undefined) {
 };
 
 fs.lchmodSync=function(path,mode){
-constfd=fs.openSync(path,constants.O_WRONLY|constants.O_SYMLINK);
+constfd=fs.openSync(path,O_WRONLY|O_SYMLINK);
 
 // Prefer to return the chmod error, if one occurs,
 // but still try to close, and report closing errors if they occur.
@@ -1110,10 +1125,10 @@ fs.chmodSync = function(path, mode) {
 handleErrorFromBinding(ctx);
 };
 
-if(constants.O_SYMLINK!==undefined){
+if(O_SYMLINK!==undefined){
 fs.lchown=function(path,uid,gid,callback){
 callback=maybeCallback(callback);
-fs.open(path,constants.O_WRONLY|constants.O_SYMLINK,function(err,fd){
+fs.open(path,O_WRONLY|O_SYMLINK,function(err,fd){
 if(err){
 callback(err);
 return;
@@ -1129,7 +1144,7 @@ if (constants.O_SYMLINK !== undefined) {
 };
 
 fs.lchownSync=function(path,uid,gid){
-constfd=fs.openSync(path,constants.O_WRONLY|constants.O_SYMLINK);
+constfd=fs.openSync(path,O_WRONLY|O_SYMLINK);
 letret;
 try{
 ret=fs.fchownSync(fd,uid,gid);
@@ -1631,7 +1646,7 @@ fs.realpathSync = function realpathSync(p, options) {
 validatePath(p);
 p=pathModule.resolve(p);
 
-constcache=options[internalFS.realpathCacheKey];
+constcache=options[realpathCacheKey];
 constmaybeCachedResult=cache&&cache.get(p);
 if(maybeCachedResult){
 returnmaybeCachedResult;
@@ -1936,14 +1951,14 @@ fs.mkdtempSync = function(prefix, options) {
 
 // Define copyFile() flags.
 Object.defineProperties(fs.constants,{
-COPYFILE_EXCL: {enumerable: true,value: constants.UV_FS_COPYFILE_EXCL},
+COPYFILE_EXCL: {enumerable: true,value: UV_FS_COPYFILE_EXCL},
 COPYFILE_FICLONE: {
 enumerable: true,
-value: constants.UV_FS_COPYFILE_FICLONE
+value: UV_FS_COPYFILE_FICLONE
 },
 COPYFILE_FICLONE_FORCE: {
 enumerable: true,
-value: constants.UV_FS_COPYFILE_FICLONE_FORCE
+value: UV_FS_COPYFILE_FICLONE_FORCE
 }
 });