zhenyi
821537186e
- Reorganized import statements in adapter tests for better readability - Replaced or_insert_with(Vec::new) with or_default() in test closures - Updated Cargo.lock with new dependency versions and checksums - Added TLS features to tonic dependency configuration - Included sqlx, chrono, and uuid dependencies with specific features - Added jsonwebtoken and arc-swap as project dependencies - Reformatted assertion statements to comply with line length limits - Adjusted base64 import order in engine codec module - Updated protobuf include statement formatting
115 lines
3.2 KiB
Rust
115 lines
3.2 KiB
Rust
//! Cursor-based pagination helpers for repository queries.
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//!
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//! UUID v7 IDs are time-ordered, so `WHERE id < $cursor ORDER BY id DESC`
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//! naturally yields reverse-chronological pages without OFFSET.
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use serde::{Deserialize, Serialize};
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use uuid::Uuid;
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/// Default number of items per page.
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pub const DEFAULT_PAGE_SIZE: i64 = 50;
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/// Hard upper bound on page size to prevent abuse.
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pub const MAX_PAGE_SIZE: i64 = 100;
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/// Generic cursor-based page response.
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///
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/// Returned by list operations in the repo layer. The `next_cursor`
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/// is the last item's UUID — pass it as `before` in the next request.
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#[derive(Debug, Clone, Serialize, Deserialize)]
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pub struct CursorPage<T> {
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/// Items in this page (ordered by `id DESC`).
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pub items: Vec<T>,
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/// Opaque cursor for the next page. `None` when no more results exist.
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pub next_cursor: Option<Uuid>,
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/// Whether there are more results beyond this page.
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pub has_more: bool,
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}
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impl<T> CursorPage<T> {
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/// Build a page from a raw result set that may contain one extra row.
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///
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/// If `raw_items.len() > limit`, the extra row is dropped and
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/// `has_more` is set to `true`.
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pub fn from_raw(mut raw_items: Vec<T>, limit: i64, get_id: impl Fn(&T) -> Uuid) -> Self {
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let has_more = raw_items.len() > limit as usize;
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if has_more {
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raw_items.truncate(limit as usize);
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}
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let next_cursor = if has_more {
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raw_items.last().map(get_id)
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} else {
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None
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};
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Self {
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items: raw_items,
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next_cursor,
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has_more,
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}
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}
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/// Empty page (no results).
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pub fn empty() -> Self {
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Self {
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items: Vec::new(),
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next_cursor: None,
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has_more: false,
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}
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}
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}
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/// Clamp a caller-requested limit to `[1, MAX_PAGE_SIZE]`, defaulting to `DEFAULT_PAGE_SIZE`.
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pub fn clamp_limit(limit: Option<i64>) -> i64 {
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match limit {
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Some(n) if n < 1 => DEFAULT_PAGE_SIZE,
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Some(n) if n > MAX_PAGE_SIZE => MAX_PAGE_SIZE,
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Some(n) => n,
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None => DEFAULT_PAGE_SIZE,
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_clamp_limit_none() {
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assert_eq!(clamp_limit(None), DEFAULT_PAGE_SIZE);
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}
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#[test]
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fn test_clamp_limit_zero() {
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assert_eq!(clamp_limit(Some(0)), DEFAULT_PAGE_SIZE);
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}
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#[test]
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fn test_clamp_limit_negative() {
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assert_eq!(clamp_limit(Some(-5)), DEFAULT_PAGE_SIZE);
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}
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#[test]
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fn test_clamp_limit_over_max() {
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assert_eq!(clamp_limit(Some(200)), MAX_PAGE_SIZE);
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}
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#[test]
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fn test_clamp_limit_valid() {
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assert_eq!(clamp_limit(Some(25)), 25);
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}
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#[test]
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fn test_cursor_page_empty() {
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let page: CursorPage<String> = CursorPage::empty();
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assert!(page.items.is_empty());
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assert!(!page.has_more);
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assert!(page.next_cursor.is_none());
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}
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#[test]
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fn test_cursor_page_from_raw_no_overflow() {
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let items = vec!["a".to_string(), "b".to_string()];
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let page = CursorPage::from_raw(items, 5, |_| Uuid::nil());
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assert_eq!(page.items.len(), 2);
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assert!(!page.has_more);
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}
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}
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