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- var crypto = require("crypto");
- var mkdirp = require("mkdirp");
- var findCacheDir = require("find-cache-dir");
- var fs = require("fs");
- var os = require("os");
- var path = require("path");
- var zlib = require("zlib");
- var defaultCacheDirectory = null;
- var read = function(filename, callback) {
- return fs.readFile(filename, function(err, data) {
- if (err) {
- return callback(err);
- }
- return zlib.gunzip(data, function(err, content) {
- var result = {};
- if (err) {
- return callback(err);
- }
- try {
- result = JSON.parse(content);
- } catch (e) {
- return callback(e);
- }
- return callback(null, result);
- });
- });
- };
- var write = function(filename, result, callback) {
- var content = JSON.stringify(result);
- return zlib.gzip(content, function(err, data) {
- if (err) {
- return callback(err);
- }
- return fs.writeFile(filename, data, callback);
- });
- };
- var filename = function(source, identifier, options) {
- var hash = crypto.createHash("SHA1");
- var contents = JSON.stringify({
- source: source,
- options: options,
- identifier: identifier
- });
- hash.end(contents);
- return hash.read().toString("hex") + ".json.gz";
- };
- var handleCache = function(directory, params, callback) {
- var source = params.source;
- var options = params.options || {};
- var transform = params.transform;
- var identifier = params.identifier;
- var shouldFallback = typeof params.directory !== "string" &&
- directory !== os.tmpdir();
-
- mkdirp(directory, function(err) {
-
- if (err)
- return shouldFallback
- ? handleCache(os.tmpdir(), params, callback)
- : callback(err);
- var file = path.join(directory, filename(source, identifier, options));
- return read(file, function(err, content) {
- var result = {};
-
-
- if (!err) return callback(null, content);
-
-
- try {
- result = transform(source, options);
- } catch (error) {
- return callback(error);
- }
- return write(file, result, function(err) {
-
- if (err)
- return shouldFallback
- ? handleCache(os.tmpdir(), params, callback)
- : callback(err);
- callback(null, result);
- });
- });
- });
- };
- module.exports = function createFsCache(name) {
- return function(params, callback) {
- var directory;
- if (typeof params.directory === "string") {
- directory = params.directory;
- } else {
- if (defaultCacheDirectory === null) {
- defaultCacheDirectory = findCacheDir({
- name: name
- }) ||
- os.tmpdir();
- }
- directory = defaultCacheDirectory;
- }
- handleCache(directory, params, callback);
- };
- };
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