const { LRUCache } = require('lru-cache')
|
const { getHeapStatistics } = require('node:v8')
|
const { log } = require('proc-log')
|
|
// This is an in-memory cache that Pacote uses for packuments.
|
// Packuments are usually cached on disk. This allows for rapid re-requests
|
// of the same packument to bypass disk reads. The tradeoff here is memory
|
// usage for disk reads.
|
class PackumentCache extends LRUCache {
|
static #heapLimit = Math.floor(getHeapStatistics().heap_size_limit)
|
|
#sizeKey
|
#disposed = new Set()
|
|
#log (...args) {
|
log.silly('packumentCache', ...args)
|
}
|
|
constructor ({
|
// How much of this.#heapLimit to take up
|
heapFactor = 0.25,
|
// How much of this.#maxSize we allow any one packument to take up
|
// Anything over this is not cached
|
maxEntryFactor = 0.5,
|
sizeKey = '_contentLength',
|
} = {}) {
|
const maxSize = Math.floor(PackumentCache.#heapLimit * heapFactor)
|
const maxEntrySize = Math.floor(maxSize * maxEntryFactor)
|
super({
|
maxSize,
|
maxEntrySize,
|
sizeCalculation: (p) => {
|
// Don't cache if we dont know the size
|
// Some versions of pacote set this to `0`, newer versions set it to `null`
|
if (!p[sizeKey]) {
|
return maxEntrySize + 1
|
}
|
if (p[sizeKey] < 10_000) {
|
return p[sizeKey] * 2
|
}
|
if (p[sizeKey] < 1_000_000) {
|
return Math.floor(p[sizeKey] * 1.5)
|
}
|
// It is less beneficial to store a small amount of super large things
|
// at the cost of all other packuments.
|
return maxEntrySize + 1
|
},
|
dispose: (v, k) => {
|
this.#disposed.add(k)
|
this.#log(k, 'dispose')
|
},
|
})
|
this.#sizeKey = sizeKey
|
this.#log(`heap:${PackumentCache.#heapLimit} maxSize:${maxSize} maxEntrySize:${maxEntrySize}`)
|
}
|
|
set (k, v, ...args) {
|
// we use disposed only for a logging signal if we are setting packuments that
|
// have already been evicted from the cache previously. logging here could help
|
// us tune this in the future.
|
const disposed = this.#disposed.has(k)
|
/* istanbul ignore next - this doesnt happen consistently so hard to test without resorting to unit tests */
|
if (disposed) {
|
this.#disposed.delete(k)
|
}
|
this.#log(k, 'set', `size:${v[this.#sizeKey]} disposed:${disposed}`)
|
return super.set(k, v, ...args)
|
}
|
|
has (k, ...args) {
|
const has = super.has(k, ...args)
|
this.#log(k, `cache-${has ? 'hit' : 'miss'}`)
|
return has
|
}
|
}
|
|
module.exports = PackumentCache
|
