79 lines
2.5 KiB
JavaScript
79 lines
2.5 KiB
JavaScript
// @ts-check
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const assert = require("assert").strict
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const mixin = require("mixin-deep")
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const {isDeepStrictEqual} = require("util")
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/** Mutates the input. */
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function kstateStripConditionals(kstate) {
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for (const [k, content] of Object.entries(kstate)) {
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// conditional for whether a key is even part of the kstate (doing this declaratively on json is hard, so represent it as a property instead.)
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if ("$if" in content) {
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if (content.$if) delete content.$if
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else delete kstate[k]
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}
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}
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return kstate
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}
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function kstateToState(kstate) {
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const events = []
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kstateStripConditionals(kstate)
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for (const [k, content] of Object.entries(kstate)) {
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const slashIndex = k.indexOf("/")
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assert(slashIndex > 0)
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const type = k.slice(0, slashIndex)
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const state_key = k.slice(slashIndex + 1)
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events.push({type, state_key, content})
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}
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return events
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}
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/**
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* @param {import("../types").Event.BaseStateEvent[]} events
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* @returns {any}
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*/
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function stateToKState(events) {
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const kstate = {}
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for (const event of events) {
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kstate[event.type + "/" + event.state_key] = event.content
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}
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return kstate
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}
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function diffKState(actual, target) {
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const diff = {}
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// go through each key that it should have
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for (const key of Object.keys(target)) {
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if (!key.includes("/")) throw new Error(`target kstate's key "${key}" does not contain a slash separator; if a blank state_key was intended, add a trailing slash to the kstate key.\ncontext: ${JSON.stringify(target)}`)
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if (key === "m.room.power_levels/") {
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// Special handling for power levels, we want to deep merge the actual and target into the final state.
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if (!(key in actual)) throw new Error(`want to apply a power levels diff, but original power level data is missing\nstarted with: ${JSON.stringify(actual)}\nwant to apply: ${JSON.stringify(target)}`)
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const temp = mixin({}, actual[key], target[key])
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if (!isDeepStrictEqual(actual[key], temp)) {
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// they differ. use the newly prepared object as the diff.
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diff[key] = temp
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}
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} else if (key in actual) {
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// diff
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if (!isDeepStrictEqual(actual[key], target[key])) {
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// they differ. use the target as the diff.
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diff[key] = target[key]
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}
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} else {
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// not present, needs to be added
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diff[key] = target[key]
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}
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// keys that are missing in "actual" will not be deleted on "target" (no action)
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}
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return diff
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}
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module.exports.kstateStripConditionals = kstateStripConditionals
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module.exports.kstateToState = kstateToState
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module.exports.stateToKState = stateToKState
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module.exports.diffKState = diffKState
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