ampache_react/app/reducers/entities.js

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/**
* This implements the global entities reducer.
*/
// NPM imports
import Immutable from "immutable";
// Local imports
import { createReducer } from "../utils";
// Models
import { stateRecord } from "../models/entities";
// Actions
import {
API_REQUEST,
API_FAILURE,
PUSH_ENTITIES,
INCREMENT_REFCOUNT,
DECREMENT_REFCOUNT,
INVALIDATE_STORE,
} from "../actions";
/**
* Helper methods
*/
/**
* Update the reference counter for a given item.
*
* Do not do any garbage collection.
*
* @param state The state object to update.
* @param keyPath The keyPath to update, from the refCount key.
* @param incr The increment (or decrement) for the reference counter.
*
* @return An updated state.
*/
function updateRefCount(state, keyPath, incr) {
// Prepend refCounts to keyPath
const refCountKeyPath = Array.concat(["refCounts"], keyPath);
// Get updated value
let newRefCount = state.getIn(refCountKeyPath) + incr;
if (isNaN(newRefCount)) {
// If NaN, reference does not exist, so set it to ±1
newRefCount = Math.sign(incr);
}
// Update state
return state.setIn(refCountKeyPath, newRefCount);
}
/**
* Update the reference counter of a given entity, taking into account the
* nested objects.
*
* Do not do any garbage collection.
*
* @param state The state object to update.
* @param itemName The type of the entity object.
* @param id The id of the entity.
* @param entity The entity object, as Immutable.
* @param incr The increment (or decrement) for the reference counter.
*
* @return An updated state.
*/
function updateEntityRefCount(state, itemName, id, entity, incr) {
let newState = state;
let albums = null;
let tracks = null;
switch (itemName) {
case "artist":
// Update artist refCount
newState = updateRefCount(newState, ["artist", id], incr);
// Update nested albums refCount
albums = entity.get("albums");
if (Immutable.List.isList(albums)) {
albums.forEach(function (id) {
newState = updateRefCount(newState, ["album", id], incr);
});
}
// Update nested tracks refCount
tracks = entity.get("songs");
if (Immutable.List.isList(tracks)) {
tracks.forEach(function (id) {
newState = updateRefCount(newState, ["song", id], incr);
});
}
break;
case "album":
// Update album refCount
newState = updateRefCount(newState, ["album", id], incr);
// Update nested artist refCount
newState = updateRefCount(newState, ["artist", entity.get("artist")], incr);
// Update nested tracks refCount
tracks = entity.get("tracks");
if (Immutable.List.isList(tracks)) {
tracks.forEach(function (id) {
newState = updateRefCount(newState, ["song", id], incr);
});
}
break;
case "song":
// Update track refCount
newState = updateRefCount(newState, ["song", id], incr);
// Update nested artist refCount
newState = updateRefCount(newState, ["artist", entity.get("artist")], incr);
// Update nested album refCount
newState = updateRefCount(newState, ["album", entity.get("album")], incr);
break;
default:
// Just update the entity, no nested entities
newState = updateRefCount(newState, [itemName, id], incr);
break;
}
return newState;
}
/**
*
*/
function garbageCollection(state) {
let newState = state;
state.refCounts.forEach(function (refCounts, itemName) {
refCounts.forEach(function (refCount, id) {
if (refCount < 1) {
// Garbage collection
newState = newState.deleteIn(["entities", itemName, id]);
newState = newState.deleteIn(["refCounts", itemName, id]);
}
});
});
return newState;
}
/**
* Initial state
*/
var initialState = new stateRecord();
/**
* Reducer
*/
export default createReducer(initialState, {
[API_REQUEST]: (state) => {
return (
state
.set("isFetching", true)
.set("error", null)
);
},
[API_FAILURE]: (state, payload) => {
return (
state
.set("isFetching", false)
.set("error", payload.error)
);
},
[PUSH_ENTITIES]: (state, payload) => {
let newState = state;
// Unset error and isFetching
newState = state.set("isFetching", false).set("error", payload.error);
// Merge entities
newState = newState.mergeIn(["entities"], payload.entities);
// Increment reference counter
payload.refCountType.forEach(function (itemName) {
const entities = payload.entities[itemName];
for (let id in entities) {
const entity = newState.getIn(["entities", itemName, id]);
newState = updateEntityRefCount(newState, itemName, id, entity, 1);
}
});
return newState;
},
[INCREMENT_REFCOUNT]: (state, payload) => {
let newState = state;
// Increment reference counter
for (let itemName in payload.entities) {
const entities = payload.entities[itemName];
entities.forEach(function (id) {
const entity = newState.getIn(["entities", itemName, id]);
newState = updateEntityRefCount(newState, itemName, id, entity, 1);
});
}
return newState;
},
[DECREMENT_REFCOUNT]: (state, payload) => {
let newState = state;
// Decrement reference counter
for (let itemName in payload.entities) {
const entities = payload.entities[itemName];
entities.forEach(function (id) {
const entity = newState.getIn(["entities", itemName, id]);
newState = updateEntityRefCount(newState, itemName, id, entity, -1);
});
}
// Perform garbage collection
newState = garbageCollection(newState);
return newState;
},
[INVALIDATE_STORE]: () => {
return new stateRecord();
},
});