147 lines
3.9 KiB
Rust
147 lines
3.9 KiB
Rust
use uuid::Uuid;
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#[derive(Debug)]
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pub(crate) enum PageSource {
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NewerThan(Uuid),
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OlderThan(Uuid),
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}
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#[derive(Debug)]
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pub(crate) struct PageNum {
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pub(crate) page: usize,
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}
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#[derive(Debug)]
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pub(crate) struct Page {
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pub(crate) items: Vec<Uuid>,
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pub(crate) next: Option<Uuid>,
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pub(crate) prev: Option<Uuid>,
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pub(crate) reset: bool,
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}
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#[derive(Debug)]
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pub(crate) struct SearchPage {
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pub(crate) items: Vec<Uuid>,
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pub(crate) next: Option<usize>,
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pub(crate) prev: Option<usize>,
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pub(crate) term: String,
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}
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pub trait Pagination {
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fn from_max<'a>(&'a mut self, max: Uuid) -> Box<dyn DoubleEndedIterator<Item = Uuid> + 'a>;
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fn from_min<'a>(&'a mut self, min: Uuid) -> Box<dyn DoubleEndedIterator<Item = Uuid> + 'a>;
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fn from_start<'a>(&'a mut self) -> Box<dyn DoubleEndedIterator<Item = Uuid> + 'a>;
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}
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pub trait SearchPagination {
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fn from_term<'a>(&'a mut self, term: &'a str)
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-> Box<dyn DoubleEndedIterator<Item = Uuid> + 'a>;
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}
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impl Page {
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pub(crate) fn from_pagination(
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mut pagination: impl Pagination,
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per_page: usize,
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source: Option<PageSource>,
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) -> Self {
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let mut items: Vec<Uuid>;
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let mut next = None;
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let mut prev = None;
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let mut reset = false;
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match source {
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Some(PageSource::OlderThan(max)) => {
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items = pagination.from_max(max).take(per_page + 1).collect();
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if let Some(item) = items.get(0) {
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prev = Some(*item);
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} else {
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reset = true;
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}
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if items.len() == per_page + 1 {
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items.pop();
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next = Some(items[per_page.saturating_sub(1)]);
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}
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}
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Some(PageSource::NewerThan(min)) => {
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let mut tmp_items: Vec<_> = pagination.from_min(min).take(per_page + 2).collect();
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if tmp_items.len() == per_page + 2 {
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tmp_items.pop();
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prev = Some(tmp_items[per_page]);
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}
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items = tmp_items.into_iter().rev().collect();
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items.pop();
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if let Some(item) = items.get(items.len().saturating_sub(1)) {
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next = Some(*item);
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} else {
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reset = true;
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}
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}
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None => {
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items = pagination.from_start().take(per_page + 1).collect();
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if items.len() == per_page + 1 {
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items.pop();
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next = Some(items[per_page.saturating_sub(1)]);
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}
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}
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}
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Page {
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items,
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next,
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prev,
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reset,
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}
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}
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}
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impl SearchPage {
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pub(crate) fn from_pagination(
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mut pagination: impl SearchPagination,
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per_page: usize,
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term: String,
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page: Option<PageNum>,
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) -> Self {
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let mut items: Vec<Uuid>;
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let mut next = None;
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let mut prev = None;
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match page {
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Some(PageNum { page }) => {
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let page = page.saturating_sub(1);
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items = pagination
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.from_term(&term)
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.skip(page * per_page)
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.take(per_page + 1)
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.collect();
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if page > 0 {
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prev = Some(page);
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}
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if items.len() == per_page + 1 {
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items.pop();
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next = Some(page + 2);
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}
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}
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None => {
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items = pagination.from_term(&term).take(per_page + 1).collect();
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if items.len() == per_page + 1 {
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items.pop();
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next = Some(2);
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}
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}
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}
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SearchPage {
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items,
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next,
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prev,
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term,
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}
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}
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}
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