Fork of Tangara with customizations
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tangara-fw/src/playlist/source.cpp

145 lines
3.4 KiB

/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include "source.hpp"
#include <algorithm>
#include <functional>
#include <memory>
#include <set>
#include <variant>
#include "esp_log.h"
#include "bloom_filter.hpp"
#include "database.hpp"
#include "komihash.h"
#include "random.hpp"
#include "track.hpp"
namespace playlist {
IndexRecordSource::IndexRecordSource(
std::weak_ptr<database::Database> db,
std::shared_ptr<database::Result<database::IndexRecord>> initial)
: db_(db),
initial_page_(initial),
initial_item_(0),
current_page_(initial_page_),
current_item_(initial_item_) {}
IndexRecordSource::IndexRecordSource(
std::weak_ptr<database::Database> db,
std::shared_ptr<database::Result<database::IndexRecord>> initial,
std::size_t initial_index,
std::shared_ptr<database::Result<database::IndexRecord>> current,
std::size_t current_index)
: db_(db),
initial_page_(initial),
initial_item_(initial_index),
current_page_(current),
current_item_(current_index) {}
auto IndexRecordSource::Current() -> std::optional<database::TrackId> {
if (current_page_->values().size() <= current_item_) {
return {};
}
if (current_page_ == initial_page_ && current_item_ < initial_item_) {
return {};
}
return current_page_->values().at(current_item_)->track();
}
auto IndexRecordSource::Advance() -> std::optional<database::TrackId> {
current_item_++;
if (current_item_ >= current_page_->values().size()) {
auto next_page = current_page_->next_page();
if (!next_page) {
current_item_--;
return {};
}
auto db = db_.lock();
if (!db) {
return {};
}
current_page_.reset(db->GetPage(&*next_page).get());
current_item_ = 0;
}
return Current();
}
auto IndexRecordSource::Previous() -> std::optional<database::TrackId> {
if (current_page_ == initial_page_ && current_item_ <= initial_item_) {
return {};
}
current_item_--;
if (current_item_ < 0) {
auto prev_page = current_page_->prev_page();
if (!prev_page) {
return {};
}
auto db = db_.lock();
if (!db) {
return {};
}
current_page_.reset(db->GetPage(&*prev_page).get());
current_item_ = current_page_->values().size() - 1;
}
return Current();
}
auto IndexRecordSource::Peek(std::size_t n, std::vector<database::TrackId>* out)
-> std::size_t {
if (current_page_->values().size() <= current_item_) {
return {};
}
auto db = db_.lock();
if (!db) {
return 0;
}
std::size_t items_added = 0;
std::shared_ptr<database::Result<database::IndexRecord>> working_page =
current_page_;
std::size_t working_item = current_item_ + 1;
while (n > 0) {
if (working_item >= working_page->values().size()) {
auto next_page = current_page_->next_page();
if (!next_page) {
break;
}
// TODO(jacqueline): It would probably be a good idea to hold onto these
// peeked pages, to avoid needing to look them up again later.
working_page.reset(db->GetPage(&*next_page).get());
working_item = 0;
}
out->push_back(working_page->values().at(working_item)->track().value());
n--;
items_added++;
working_item++;
}
return items_added;
}
auto IndexRecordSource::Reset() -> void {
current_page_ = initial_page_;
current_item_ = initial_item_;
}
} // namespace playlist