纯异步nodejs文件夹(目录)复制

node.js 复制文件夹

思路:

1、callback 驱动

2、递归所有需要复制文件

3、在一定阀值下并发复制文件

var async = require("async");  
var fs = require("fs");  
var path = require("path");  
// cursively make dir   
function mkdirs(p, mode, f, made) {  
    if (typeof mode === 'function' || mode === undefined) {  
        f = mode;  
        mode = 0777 & (~process.umask());  
    }  
    if (!made)  
        made = null;  
  
    var cb = f || function () {};  
    if (typeof mode === 'string')  
        mode = parseInt(mode, 8);  
    p = path.resolve(p);  
  
    fs.mkdir(p, mode, function (er) {  
        if (!er) {  
            made = made || p;  
            return cb(null, made);  
        }  
        switch (er.code) {  
        case 'ENOENT':  
            mkdirs(path.dirname(p), mode, function (er, made) {  
                if (er) {  
                    cb(er, made);  
                } else {  
                    mkdirs(p, mode, cb, made);  
                }  
            });  
            break;  
  
            // In the case of any other error, just see if there's a dir  
            // there already.  If so, then hooray!  If not, then something  
            // is borked.  
        default:  
            fs.stat(p, function (er2, stat) {  
                // if the stat fails, then that's super weird.  
                // let the original error be the failure reason.  
                if (er2 || !stat.isDirectory()) {  
                    cb(er, made);  
                } else {  
                    cb(null, made)  
                };  
            });  
            break;  
        }  
    });  
}  
// single file copy  
function copyFile(file, toDir, cb) {  
    async.waterfall([  
            function (callback) {  
                fs.exists(toDir, function (exists) {  
                    if (exists) {  
                        callback(null, false);  
                    } else {  
                        callback(null, true);  
                    }  
                });  
            }, function (need, callback) {  
                if (need) {  
                    mkdirs(path.dirname(toDir), callback);  
                } else {  
                    callback(null, true);  
                }  
            }, function (p, callback) {  
                var reads = fs.createReadStream(file);  
                var writes = fs.createWriteStream(path.join(path.dirname(toDir), path.basename(file)));  
                reads.pipe(writes);  
                //don't forget close the  when  all the data are read  
                reads.on("end", function () {  
                    writes.end();  
                    callback(null);  
                });  
                reads.on("error", function (err) {  
                    console.log("error occur in reads");  
                    callback(true, err);  
                });  
  
            }  
        ], cb);  
  
}  
  
// cursively count the  files that need to be copied  
  
function _ccoutTask(from, to, cbw) {  
    async.waterfall([  
            function (callback) {  
                fs.stat(from, callback);  
            },  
            function (stats, callback) {  
                if (stats.isFile()) {  
                    cbw.addFile(from, to);  
                    callback(null, []);  
                } else if (stats.isDirectory()) {  
                    fs.readdir(from, callback);  
                }  
            },  
            function (files, callback) {  
                if (files.length) {  
                    for (var i = 0; i < files.length; i++) {  
                        _ccoutTask(path.join(from, files[i]), path.join(to, files[i]), cbw.increase());  
                    }  
                }  
                callback(null);  
            }  
        ], cbw);  
  
}  
// wrap the callback before counting  
function ccoutTask(from, to, cb) {  
    var files = [];  
    var count = 1;  
  
    function wrapper(err) {  
        count--;  
        if (err || count <= 0) {  
            cb(err, files)  
        }  
    }  
    wrapper.increase = function () {  
        count++;  
        return wrapper;  
    }  
    wrapper.addFile = function (file, dir) {  
        files.push({  
            file : file,  
            dir : dir  
        });  
    }  
  
    _ccoutTask(from, to, wrapper);  
}  
  
  
function copyDir(from, to, cb) {  
    if(!cb){  
      cb=function(){};  
    }  
    async.waterfall([  
            function (callback) {  
                fs.exists(from, function (exists) {  
                    if (exists) {  
                        callback(null, true);  
                    } else {  
                        console.log(from + " not exists");  
                        callback(true);  
                    }  
                });  
            },  
            function (exists, callback) {  
                fs.stat(from, callback);  
            },  
            function (stats, callback) {  
                if (stats.isFile()) {  
                    // one file copy  
                    copyFile(from, to, function (err) {  
                        if (err) {  
                            // break the waterfall  
                            callback(true);  
                        } else {  
                            callback(null, []);  
                        }  
                    });  
                } else if (stats.isDirectory()) {  
                    ccoutTask(from, to, callback);  
                }  
            },  
            function (files, callback) {      
                // prevent reaching to max file open limit            
                async.mapLimit(files, 10, function (f, cb) {  
                    copyFile(f.file, f.dir, cb);  
                }, callback);  
            }  
        ], cb);  
}  
  
var start = new Date().getTime();  
  
copyDir("F:\\gear", "F:\\gear2", function (err) {  
    if (err) {  
        console.log("error ocur");  
        console.dir(err);  
    } else {  
  
        console.log("copy ok");  
        console.log("consume time:" + (new Date().getTime() - start))  
    }  
});

 

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