comitium/core/structs.go

// Copyright (C) 2021 nytpu
// SPDX-License-Identifier: AGPL-3.0-or-later
// For more license details, see LICENSE or <https://www.gnu.org/licenses/agpl-3.0.html>.

// This file incorporates code from makeworlds's amfora:
// https://github.com/makeworld-the-better-one/amfora/blob/master/subscriptions/structs.go
// Original source is Copyright 2020 makeworld and is licensed under the
// terms of the GNU General Public License Version 3.0.
// https://www.gnu.org/licenses/gpl-3.0-standalone.html

// package core implements the structs and other necessary resources for storing
// and managing feeds and pages
package core

import (
	"net/url"
	"sync"
	"time"

	"github.com/mmcdole/gofeed"
)

// jsonData is used for both reading from json and for storing the global feeds
// map. contains read mutexes so concurrency can be used.
type jsonData struct {
	Feeds map[url.URL]*Feed `json:"feeds,omitempty"`
	Pages map[url.URL]*Page `json:"pages,omitempty"`

	feedsMu *sync.RWMutex
	pagesMu *sync.RWMutex
}

// Feed holds all the necessary fields when storing a feed
type Feed struct {
	Title    string    `json:"title,omitempty"`
	Link     *url.URL  `json:"link,omitempty"`     // link to the human-readable page for the feed. same as FeedLink for gemini feeds.
	FeedLink *url.URL  `json:"feedlink,omitempty"` // link to the feed itself.
	Updated  time.Time `json:"updated,omitempty"`
	Items    []*Item   `json:"items,omitempty"`
}

// Item is a single item from a subscripton
type Item struct {
	Title     string    `json:"title,omitempty"` // if empty, use Link as title
	Content   string    `json:"content,omitempty"`
	Link      *url.URL  `json:"link,omitempty"`
	Published time.Time `json:"updated,omitempty"`
}

// Page holds all the necessary fields when storing a page being watched for
// changes.
type Page struct {
	Title   string    `json:"title,omitempty"`
	Link    *url.URL  `json:"link,omitempty"`
	Updated time.Time `json:"updated,omitempty"`
	Hash    string    `json:"hash,omitempty"`
}

// gofeedConvert converts a gofeed.Feed into a Feed struct
func GofeedConvert(f *gofeed.Feed, title string) (*Feed, error) {
	new := &Feed{}

	if title != "" {
		new.Title = title
	} else {
		new.Title = f.Title
	}
	new.Updated = *f.UpdatedParsed
	var err error
	new.Link, err = url.ParseRequestURI(f.Link)
	if err != nil {
		return nil, err
	}
	new.FeedLink, err = url.ParseRequestURI(f.FeedLink)
	if err != nil {
		return nil, err
	}

	for _, v := range f.Items {
		item := &Item{}
		item.Title = v.Title
		item.Content = v.Content
		item.Published = *v.PublishedParsed
		item.Link, err = url.ParseRequestURI(f.FeedLink)
		if err != nil {
			return nil, err
		}

		new.Items = append(new.Items, item)
	}

	return new, nil
}

// Implement sort.Interface for Feed

// Len returns the length of Items.
func (f *Feed) Len() int {
	return len(f.Items)
}

// Less compares Published of Items[i], Items[k] and returns true if Items[i] is
// before Items[j].
func (f *Feed) Less(i, j int) {
	return f.Items[i].Published.Before(f.Items[j].Published)
}

// Swap swaps Items[i] and Items[j].
func (f *Feed) Swap(i, j int) {
	f.Items[i], f.Items[j] = f.Items[j], f.Items[i]
}

// Lock locks both feed and page mutexes.
func (j *jsonData) Lock() {
	j.feedsMu.Lock()
	j.pagesMu.Lock()
}

// Unlock unlocks both feed and page mutexes.
func (j *jsonData) Unlock() {
	j.feedsMu.Unlock()
	j.pagesMu.Unlock()
}

// RLock read-locks both feed and page mutexes.
func (j *jsonData) RLock() {
	j.feedsMu.RLock()
	j.pagesMu.RLock()
}

// RUnlock read-unlocks both feed and page mutexes.
func (j *jsonData) RUnlock() {
	j.feedsMu.RUnlock()
	j.pagesMu.RUnlock()
}

// PageEntry is a single item on a subscriptions page. It is used for both feeds
// and pages.
type PageEntry struct {
	Prefix    string // whatever goes before the post title to identify the feed.
	Title     string // article/entry title
	URL       string
	Published time.Time
}

// PageEntries is reverse chronological list of entries used when generating subs.
type PageEntries struct {
	Entries []*PageEntry
}

// Implement sort.Interface for PageEntries

// Len returns the length of Entries
func (e *PageEntries) Len() int {
	return len(e.Entries)
}

// Less compares the Published if Entries[i], Entries[j] and returns true if
// Entries[i] is /after/ Entries[j] (for reverse chronological sorting)
func (e *PageEntries) Less(i, j int) bool {
	return e.Entries[i].Published.After(e.Entries[j].Published)
}

// Swap swaps Entries[i] and Entries[j]
func (e *PageEntries) Swap(i, j int) {
	e.Entries[i], e.Entries[j] = e.Entries[j], e.Entries[i]
}