audiobookshelf-pgodwin/server/libs/njodb/objects.js

609 lines
17 KiB
JavaScript

"use strict";
const {
convertSize,
max,
min
} = require("./utils");
const Randomizer = (data, replacement) => {
var mutable = [...data];
if (replacement === undefined || typeof replacement !== "boolean") replacement = true;
function _next() {
var selection;
const index = Math.floor(Math.random() * mutable.length);
if (replacement) {
selection = mutable.slice(index, index + 1)[0];
} else {
selection = mutable.splice(index, 1)[0];
if (mutable.length === 0) mutable = [...data];
}
return selection;
}
return {
next: _next
};
};
const Result = (type) => {
var _result;
switch (type) {
case "stats":
_result = {
size: 0,
lines: 0,
records: 0,
errors: [],
blanks: 0,
created: undefined,
modified: undefined,
start: Date.now(),
end: undefined,
elapsed: 0
};
break;
case "distribute":
_result = {
stores: undefined,
records: 0,
errors: [],
start: Date.now(),
end: undefined,
elapsed: undefined
};
break;
case "insert":
_result = {
inserted: 0,
start: Date.now(),
end: undefined,
elapsed: 0
};
break;
case "insertFile":
_result = {
lines: 0,
inserted: 0,
errors: [],
blanks: 0,
start: Date.now(),
end: undefined
};
break;
case "select":
_result = {
lines: 0,
selected: 0,
ignored: 0,
errors: [],
blanks: 0,
start: Date.now(),
end: undefined,
elapsed: 0,
data: [],
};
break;
case "update":
_result = {
lines: 0,
selected: 0,
updated: 0,
unchanged: 0,
errors: [],
blanks: 0,
start: Date.now(),
end: undefined,
elapsed: 0,
data: [],
records: []
};
break;
case "delete":
_result = {
lines: 0,
deleted: 0,
retained: 0,
errors: [],
blanks: 0,
start: Date.now(),
end: undefined,
elapsed: 0,
data: [],
records: []
};
break;
case "aggregate":
_result = {
lines: 0,
aggregates: {},
indexed: 0,
unindexed: 0,
errors: [],
blanks: 0,
start: Date.now(),
end: undefined,
elapsed: 0
};
break;
}
return _result;
}
const Reduce = (type) => {
var _reduce;
switch (type) {
case "stats":
_reduce = Object.assign(Result("stats"), {
stores: 0,
min: undefined,
max: undefined,
mean: undefined,
var: undefined,
std: undefined,
m2: 0
});
break;
case "drop":
_reduce = {
dropped: false,
start: Date.now(),
end: 0,
elapsed: 0
};
break;
case "aggregate":
_reduce = Object.assign(Result("aggregate"), {
data: []
});
break;
default:
_reduce = Result(type);
break;
}
_reduce.details = undefined;
return _reduce;
};
const Handler = (type, ...functions) => {
var _results = Result(type);
const _next = (record, writer) => {
record = new Record(record);
_results.lines++;
if (record.length === 0) {
_results.blanks++;
} else {
if (record.data) {
switch (type) {
case "stats":
statsHandler(record, _results);
break;
case "select":
selectHandler(record, functions[0], functions[1], _results);
break;
case "update":
updateHandler(record, functions[0], functions[1], writer, _results);
break;
case "delete":
deleteHandler(record, functions[0], writer, _results);
break;
case "aggregate":
aggregateHandler(record, functions[0], functions[1], functions[2], _results);
break;
}
} else {
_results.errors.push({ error: record.error, line: _results.lines, data: record.source });
if (type === "update" || type === "delete") {
if (writer) {
writer.write(record.source + "\n");
} else {
_results.data.push(record.source);
}
}
}
}
};
const _return = () => {
_results.end = Date.now();
_results.elapsed = _results.end - _results.start;
return _results;
}
return {
next: _next,
return: _return
};
};
const statsHandler = (record, results) => {
results.records++;
return results;
};
const selectHandler = (record, selecter, projecter, results) => {
if (record.select(selecter)) {
if (projecter) {
results.data.push(record.project(projecter));
} else {
results.data.push(record.data);
}
results.selected++;
} else {
results.ignored++;
}
};
const updateHandler = (record, selecter, updater, writer, results) => {
if (record.select(selecter)) {
results.selected++;
if (record.update(updater)) {
results.updated++;
results.records.push(record.data);
} else {
results.unchanged++;
}
} else {
results.unchanged++;
}
if (writer) {
writer.write(JSON.stringify(record.data) + "\n");
} else {
results.data.push(JSON.stringify(record.data));
}
};
const deleteHandler = (record, selecter, writer, results) => {
if (record.select(selecter)) {
results.deleted++;
results.records.push(record.data);
} else {
results.retained++;
if (writer) {
writer.write(JSON.stringify(record.data) + "\n");
} else {
results.data.push(JSON.stringify(record.data));
}
}
};
const aggregateHandler = (record, selecter, indexer, projecter, results) => {
if (record.select(selecter)) {
const index = record.index(indexer);
if (!index) {
results.unindexed++;
} else {
var projection;
var fields;
if (results.aggregates[index]) {
results.aggregates[index].count++;
} else {
results.aggregates[index] = {
count: 1,
aggregates: {}
};
}
if (projecter) {
projection = record.project(projecter);
fields = Object.keys(projection);
} else {
projection = record.data;
fields = Object.keys(record.data);
}
for (const field of fields) {
if (projection[field] !== undefined) {
if (results.aggregates[index].aggregates[field]) {
accumulateAggregate(results.aggregates[index].aggregates[field], projection[field]);
} else {
results.aggregates[index].aggregates[field] = {
min: projection[field],
max: projection[field],
count: 1
};
if (typeof projection[field] === "number") {
results.aggregates[index].aggregates[field]["sum"] = projection[field];
results.aggregates[index].aggregates[field]["mean"] = projection[field];
results.aggregates[index].aggregates[field]["m2"] = 0;
}
}
}
}
results.indexed++;
}
}
}
const accumulateAggregate = (index, projection) => {
index["min"] = min(index["min"], projection);
index["max"] = max(index["max"], projection);
index["count"]++;
// Welford's algorithm
if (typeof projection === "number") {
const delta1 = projection - index["mean"];
index["sum"] += projection;
index["mean"] += delta1 / index["count"];
const delta2 = projection - index["mean"];
index["m2"] += delta1 * delta2;
}
return index;
};
class Record {
constructor(record) {
this.source = record.trim();
this.length = this.source.length
this.data = {};
this.error = "";
try {
this.data = JSON.parse(this.source)
} catch (e) {
this.data = undefined;
this.error = e.message;
}
}
}
Record.prototype.select = function (selecter) {
var result;
try {
result = selecter(this.data);
} catch {
return false;
}
if (typeof result !== "boolean") {
throw new TypeError("Selecter must return a boolean");
} else {
return result;
}
};
Record.prototype.update = function (updater) {
var result;
try {
result = updater(this.data);
} catch {
return false;
}
if (typeof result !== "object") {
throw new TypeError("Updater must return an object");
} else {
this.data = result;
return true;
}
}
Record.prototype.project = function (projecter) {
var result;
try {
result = projecter(this.data);
} catch {
return undefined;
}
if (Array.isArray(result) || typeof result !== "object") {
throw new TypeError("Projecter must return an object");
} else {
return result;
}
};
Record.prototype.index = function (indexer) {
try {
return indexer(this.data);
} catch {
return undefined;
}
};
const Reducer = (type, results) => {
var _reduce = Reduce(type);
var i = 0;
var aggregates = {};
for (const result of results) {
switch (type) {
case "stats":
statsReducer(_reduce, result, i);
break;
case "insert":
insertReducer(_reduce, result);
break;
case "select":
selectReducer(_reduce, result);
break;
case "update":
updateReducer(_reduce, result);
break;
case "delete":
deleteReducer(_reduce, result);
break;
case "aggregate":
aggregateReducer(_reduce, result, aggregates);
break
}
if (type === "stats") {
_reduce.stores++;
i++;
}
if (type === "drop") {
_reduce.dropped = true;
} else if (type !== "insert") {
_reduce.lines += result.lines;
_reduce.errors = _reduce.errors.concat(result.errors);
_reduce.blanks += result.blanks;
}
_reduce.start = min(_reduce.start, result.start);
_reduce.end = max(_reduce.end, result.end);
}
if (type === "stats") {
_reduce.size = convertSize(_reduce.size);
_reduce.var = _reduce.m2 / (results.length);
_reduce.std = Math.sqrt(_reduce.m2 / (results.length));
delete _reduce.m2;
} else if (type === "aggregate") {
for (const index of Object.keys(aggregates)) {
var aggregate = {
index: index,
count: aggregates[index].count,
aggregates: []
};
for (const field of Object.keys(aggregates[index].aggregates)) {
delete aggregates[index].aggregates[field].m2;
aggregate.aggregates.push({ field: field, data: aggregates[index].aggregates[field] });
}
_reduce.data.push(aggregate);
}
delete _reduce.aggregates;
}
_reduce.elapsed = _reduce.end - _reduce.start;
_reduce.details = results;
return _reduce;
};
const statsReducer = (reduce, result, i) => {
reduce.size += result.size;
reduce.records += result.records;
reduce.min = min(reduce.min, result.records);
reduce.max = max(reduce.max, result.records);
if (reduce.mean === undefined) reduce.mean = result.records;
const delta1 = result.records - reduce.mean;
reduce.mean += delta1 / (i + 2);
const delta2 = result.records - reduce.mean;
reduce.m2 += delta1 * delta2;
reduce.created = min(reduce.created, result.created);
reduce.modified = max(reduce.modified, result.modified);
};
const insertReducer = (reduce, result) => {
reduce.inserted += result.inserted;
};
const selectReducer = (reduce, result) => {
reduce.selected += result.selected;
reduce.ignored += result.ignored;
reduce.data = reduce.data.concat(result.data);
delete result.data;
};
const updateReducer = (reduce, result) => {
reduce.selected += result.selected;
reduce.updated += result.updated;
reduce.unchanged += result.unchanged;
};
const deleteReducer = (reduce, result) => {
reduce.deleted += result.deleted;
reduce.retained += result.retained;
};
const aggregateReducer = (reduce, result, aggregates) => {
reduce.indexed += result.indexed;
reduce.unindexed += result.unindexed;
const indexes = Object.keys(result.aggregates);
for (const index of indexes) {
if (aggregates[index]) {
aggregates[index].count += result.aggregates[index].count;
} else {
aggregates[index] = {
count: result.aggregates[index].count,
aggregates: {}
};
}
const fields = Object.keys(result.aggregates[index].aggregates);
for (const field of fields) {
const aggregateObject = aggregates[index].aggregates[field];
const resultObject = result.aggregates[index].aggregates[field];
if (aggregateObject) {
reduceAggregate(aggregateObject, resultObject);
} else {
aggregates[index].aggregates[field] = {
min: resultObject["min"],
max: resultObject["max"],
count: resultObject["count"]
};
if (resultObject["m2"] !== undefined) {
aggregates[index].aggregates[field]["sum"] = resultObject["sum"];
aggregates[index].aggregates[field]["mean"] = resultObject["mean"];
aggregates[index].aggregates[field]["varp"] = resultObject["m2"] / resultObject["count"];
aggregates[index].aggregates[field]["vars"] = resultObject["m2"] / (resultObject["count"] - 1);
aggregates[index].aggregates[field]["stdp"] = Math.sqrt(resultObject["m2"] / resultObject["count"]);
aggregates[index].aggregates[field]["stds"] = Math.sqrt(resultObject["m2"] / (resultObject["count"] - 1));
aggregates[index].aggregates[field]["m2"] = resultObject["m2"];
}
}
}
}
delete result.aggregates;
};
const reduceAggregate = (aggregate, result) => {
const n = aggregate["count"] + result["count"];
aggregate["min"] = min(aggregate["min"], result["min"]);
aggregate["max"] = max(aggregate["max"], result["max"]);
// Parallel version of Welford's algorithm
if (result["m2"] !== undefined) {
const delta = result["mean"] - aggregate["mean"];
const m2 = aggregate["m2"] + result["m2"] + (Math.pow(delta, 2) * ((aggregate["count"] * result["count"]) / n));
aggregate["m2"] = m2;
aggregate["varp"] = m2 / n;
aggregate["vars"] = m2 / (n - 1);
aggregate["stdp"] = Math.sqrt(m2 / n);
aggregate["stds"] = Math.sqrt(m2 / (n - 1));
}
if (result["sum"] !== undefined) {
aggregate["mean"] = (aggregate["sum"] + result["sum"]) / n;
aggregate["sum"] += result["sum"];
}
aggregate["count"] = n;
};
exports.Randomizer = Randomizer;
exports.Result = Result;
exports.Reduce = Reduce;
exports.Handler = Handler;
exports.Reducer = Reducer;