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virtual-fs.js
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virtual-fs.js
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import _ from 'lodash'
import hash from 'lib/utils/hash'
import fs from 'lib/utils/fs'
import Promise from 'bluebird'
import { asTree } from 'treeify'
import path from 'path'
import {
debug
} from './log'
import {
isChildrenOf,
mergePaths,
calculatePathDiff
} from 'lib/utils/path'
// action types
export const WRITE_FILE = 'WRITE_FILE'
export const actionType = {
WRITE_FILE
}
export const getFileHash = ({fileName, data}) => hash(fileName + data)
export const writeFile = (fileName, data) => {
return {
type: WRITE_FILE,
payload: {
hash: getFileHash({fileName, data}),
fileName,
data
}
}
}
export const actions = {
writeFile
}
export default function createVfs (opts = {}) {
let pending = []
let cache = []
// return currentState as object
const getState = () => {
return {
pending,
cache
}
}
// pretty print cache state.
const ls = (showHash = false) => {
const tree = _.reduce(cache, (result, c) => {
let value = showHash ? c.hash : ''
if (c.isUpdated) {
value = `[updated] ${value}`
} else if (c.isNew) {
value = `[new] ${value}`
}
result = _.set(result, c.fileName.split(path.sep), value)
return result
}, {})
return asTree(tree, true, false)
}
// schedule action
const schedule = (action) => {
pending.push(action)
return action
}
const clearCache = () => {
cache = []
}
// read dest files to internal cache to reduce writeFile access.
const mount = async (dest, clean = false) => {
// skip if clean = true or already mounted(cache is not empty)
if (!clean || !_.isEmpty(cache)) return
// read dest files first to force clean destination directories
const files = await fs.listFiles([path.join(dest, '**/*.js'), '!**/_*/**'])
// read old files to cache by simulating writeFile.
await Promise.map(files, async (file) => {
const data = await fs.readFile(file)
schedule(writeFile(file, data))
})
// dryRun and readFiles into cache.
await perform(true)
}
// run pending action.
const perform = async (dryRun = opts.dryRun || false, clean = false) => {
// keep oldCache
const oldCache = cache
// Clear cache for record newly applied changes at this iteration.
clearCache()
debug('[debug] oldCache = ', oldCache);
await Promise.map(pending, async (action) => {
let result = true
if (action.type === WRITE_FILE) {
// update cache by fileName if found (for handling multiple writeFile call for same file at same perform call.)
const foundIndex = _.findIndex(cache, (c) => c.fileName === action.payload.fileName)
if (foundIndex > -1) {
cache.splice(foundIndex, 1) // remove file by name
}
const payload = {fileName: action.payload.fileName, hash: action.payload.hash}
cache.push(payload) // and push file to cache
// skip iteration if file not changed.
if (_.some(oldCache, (c) => c.hash === getFileHash(action.payload))) return true
// treat as update if file already exists in cache.
let isUpdate = false
if (_.some(oldCache, (c) => c.fileName === action.payload.fileName)) {
isUpdate = true
}
if (!dryRun) {
// write changes to file if necessary.
if (isUpdate) {
result = await fs.updateFileByPragma(action.payload.fileName, action.payload.data)
payload['isUpdated'] = true // mark updated
} else {
result = await fs.updateFileByPragma(action.payload.fileName, action.payload.data)
payload['isNew'] = true // mark updated
}
}
}
return result
}, {concurrency: 1})
// mark as done.
pending = []
debug('[debug] cache = ', cache);
const deletedFiles = _.differenceBy(oldCache, cache, 'fileName')
// remove unused file.
await Promise.map(deletedFiles, async ({fileName}) => {
if (!dryRun) {
return await fs.remove(fileName, clean)
}
return await true
})
// list deleted directory name.
const deletedDirs = mergePaths(_.map(deletedFiles, ({fileName}) => path.dirname(fileName)))
const cachedDirs = mergePaths(_.map(cache, ({fileName}) => path.dirname(fileName)))
const emptyDeletedDirs = _.compact(_.zipWith(deletedDirs, cachedDirs, (deleted, cached) => {
if (!deleted || !cached) return // ensure both exists
// treat as empty if deleted directory satisfy following condition.
// - has no children of cached folder
// - is not cached folder (!==)
if (!isChildrenOf(cached, deleted) && cached !== deleted) {
return calculatePathDiff(cached, deleted)
}
}))
return await Promise.map(emptyDeletedDirs, async (dir) => {
if (!dryRun) {
return await fs.remove(dir, clean)
}
return await true
})
}
// expose wrapped actions(like mapDispatchToProps of redux :))
const wrappedActions = _.reduce(actions, (result, fn, action) => {
// wrap action by schedule with same arguments
result[action] = function () {
return schedule(fn.call(this, ...arguments))
}
return result
}, {})
return {
getState,
schedule,
mount,
clearCache,
perform,
ls,
...wrappedActions
}
}