internet-programming/lab3/node_modules/file-entry-cache/cache.js

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2023-11-02 02:38:40 +04:00
var path = require('path');
var crypto = require('crypto');
module.exports = {
createFromFile: function (filePath, useChecksum) {
var fname = path.basename(filePath);
var dir = path.dirname(filePath);
return this.create(fname, dir, useChecksum);
},
create: function (cacheId, _path, useChecksum) {
var fs = require('fs');
var flatCache = require('flat-cache');
var cache = flatCache.load(cacheId, _path);
var normalizedEntries = {};
var removeNotFoundFiles = function removeNotFoundFiles() {
const cachedEntries = cache.keys();
// remove not found entries
cachedEntries.forEach(function remover(fPath) {
try {
fs.statSync(fPath);
} catch (err) {
if (err.code === 'ENOENT') {
cache.removeKey(fPath);
}
}
});
};
removeNotFoundFiles();
return {
/**
* the flat cache storage used to persist the metadata of the `files
* @type {Object}
*/
cache: cache,
/**
* Given a buffer, calculate md5 hash of its content.
* @method getHash
* @param {Buffer} buffer buffer to calculate hash on
* @return {String} content hash digest
*/
getHash: function (buffer) {
return crypto.createHash('md5').update(buffer).digest('hex');
},
/**
* Return whether or not a file has changed since last time reconcile was called.
* @method hasFileChanged
* @param {String} file the filepath to check
* @return {Boolean} wheter or not the file has changed
*/
hasFileChanged: function (file) {
return this.getFileDescriptor(file).changed;
},
/**
* given an array of file paths it return and object with three arrays:
* - changedFiles: Files that changed since previous run
* - notChangedFiles: Files that haven't change
* - notFoundFiles: Files that were not found, probably deleted
*
* @param {Array} files the files to analyze and compare to the previous seen files
* @return {[type]} [description]
*/
analyzeFiles: function (files) {
var me = this;
files = files || [];
var res = {
changedFiles: [],
notFoundFiles: [],
notChangedFiles: [],
};
me.normalizeEntries(files).forEach(function (entry) {
if (entry.changed) {
res.changedFiles.push(entry.key);
return;
}
if (entry.notFound) {
res.notFoundFiles.push(entry.key);
return;
}
res.notChangedFiles.push(entry.key);
});
return res;
},
getFileDescriptor: function (file) {
var fstat;
try {
fstat = fs.statSync(file);
} catch (ex) {
this.removeEntry(file);
return { key: file, notFound: true, err: ex };
}
if (useChecksum) {
return this._getFileDescriptorUsingChecksum(file);
}
return this._getFileDescriptorUsingMtimeAndSize(file, fstat);
},
_getFileDescriptorUsingMtimeAndSize: function (file, fstat) {
var meta = cache.getKey(file);
var cacheExists = !!meta;
var cSize = fstat.size;
var cTime = fstat.mtime.getTime();
var isDifferentDate;
var isDifferentSize;
if (!meta) {
meta = { size: cSize, mtime: cTime };
} else {
isDifferentDate = cTime !== meta.mtime;
isDifferentSize = cSize !== meta.size;
}
var nEntry = (normalizedEntries[file] = {
key: file,
changed: !cacheExists || isDifferentDate || isDifferentSize,
meta: meta,
});
return nEntry;
},
_getFileDescriptorUsingChecksum: function (file) {
var meta = cache.getKey(file);
var cacheExists = !!meta;
var contentBuffer;
try {
contentBuffer = fs.readFileSync(file);
} catch (ex) {
contentBuffer = '';
}
var isDifferent = true;
var hash = this.getHash(contentBuffer);
if (!meta) {
meta = { hash: hash };
} else {
isDifferent = hash !== meta.hash;
}
var nEntry = (normalizedEntries[file] = {
key: file,
changed: !cacheExists || isDifferent,
meta: meta,
});
return nEntry;
},
/**
* Return the list o the files that changed compared
* against the ones stored in the cache
*
* @method getUpdated
* @param files {Array} the array of files to compare against the ones in the cache
* @returns {Array}
*/
getUpdatedFiles: function (files) {
var me = this;
files = files || [];
return me
.normalizeEntries(files)
.filter(function (entry) {
return entry.changed;
})
.map(function (entry) {
return entry.key;
});
},
/**
* return the list of files
* @method normalizeEntries
* @param files
* @returns {*}
*/
normalizeEntries: function (files) {
files = files || [];
var me = this;
var nEntries = files.map(function (file) {
return me.getFileDescriptor(file);
});
//normalizeEntries = nEntries;
return nEntries;
},
/**
* Remove an entry from the file-entry-cache. Useful to force the file to still be considered
* modified the next time the process is run
*
* @method removeEntry
* @param entryName
*/
removeEntry: function (entryName) {
delete normalizedEntries[entryName];
cache.removeKey(entryName);
},
/**
* Delete the cache file from the disk
* @method deleteCacheFile
*/
deleteCacheFile: function () {
cache.removeCacheFile();
},
/**
* remove the cache from the file and clear the memory cache
*/
destroy: function () {
normalizedEntries = {};
cache.destroy();
},
_getMetaForFileUsingCheckSum: function (cacheEntry) {
var contentBuffer = fs.readFileSync(cacheEntry.key);
var hash = this.getHash(contentBuffer);
var meta = Object.assign(cacheEntry.meta, { hash: hash });
delete meta.size;
delete meta.mtime;
return meta;
},
_getMetaForFileUsingMtimeAndSize: function (cacheEntry) {
var stat = fs.statSync(cacheEntry.key);
var meta = Object.assign(cacheEntry.meta, {
size: stat.size,
mtime: stat.mtime.getTime(),
});
delete meta.hash;
return meta;
},
/**
* Sync the files and persist them to the cache
* @method reconcile
*/
reconcile: function (noPrune) {
removeNotFoundFiles();
noPrune = typeof noPrune === 'undefined' ? true : noPrune;
var entries = normalizedEntries;
var keys = Object.keys(entries);
if (keys.length === 0) {
return;
}
var me = this;
keys.forEach(function (entryName) {
var cacheEntry = entries[entryName];
try {
var meta = useChecksum
? me._getMetaForFileUsingCheckSum(cacheEntry)
: me._getMetaForFileUsingMtimeAndSize(cacheEntry);
cache.setKey(entryName, meta);
} catch (err) {
// if the file does not exists we don't save it
// other errors are just thrown
if (err.code !== 'ENOENT') {
throw err;
}
}
});
cache.save(noPrune);
},
};
},
};