refactor(backend): fix paginator api

mdcpp · Jul 11, 2024 · 226503b · 226503b
1 parent a4d5067
commit 226503b
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Showing 3 changed files with 28 additions and 19 deletions.
diff --git a/backend/src/endpoint/problem.rs b/backend/src/endpoint/problem.rs
@@ -47,7 +47,7 @@ impl Problem for ArcServer {
     ) -> Result<Response<ListProblemResponse>, Status> {
         let (auth, req) = self
             .parse_request_fn(req, |req| {
-                ((req.size.saturating_abs() as u64) + req.offset / 5 + 2)
+                ((req.size as u64) + req.offset.saturating_abs() as u64 / 5 + 2)
                     .try_into()
                     .unwrap_or(u32::MAX)
             })

diff --git a/backend/src/entity/problem.rs b/backend/src/entity/problem.rs
@@ -4,7 +4,6 @@
 use std::ops::Deref;
 
 use super::*;
-use crate::entity::problem::Paginator::Parent;
 use crate::entity::util::paginator::{Pager, Remain};
 use crate::union;
 use grpc::backend::list_problem_request::Sort;
@@ -412,7 +411,17 @@ impl<'a> WithAuth<'a, Paginator> {
 }
 
 impl<'a, 'b> WithDB<'a, WithAuth<'b, Paginator>> {
-    pub async fn fetch(&mut self, size: i64, offset: u64) -> Result<Vec<PartialModel>, Error> {
+    pub async fn fetch(&mut self, size: u64, offset: i64) -> Result<Vec<PartialModel>, Error> {
+        let size = size.min((i64::MAX - 1) as u64) as i64;
+        if offset < 0 {
+            self.fetch_inner(-size, (-offset).saturating_sub(size) as u64)
+                .await
+                .map(|x| x.into_iter().rev().collect())
+        } else {
+            self.fetch_inner(size, offset as u64).await
+        }
+    }
+    async fn fetch_inner(&mut self, size: i64, offset: u64) -> Result<Vec<PartialModel>, Error> {
         let db = self.0;
         let auth = self.1 .0;
         macro_rules! write_back_with_list {

diff --git a/grpc/proto/backend.proto b/grpc/proto/backend.proto
@@ -128,8 +128,8 @@ message ListProblemRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 message ListProblemResponse {
@@ -192,8 +192,8 @@ message ListSubmitRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 message ListSubmitResponse {
@@ -276,8 +276,8 @@ message ListAnnouncementRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 service Announcement {
@@ -348,8 +348,8 @@ message ListEducationRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 service Education {
@@ -421,8 +421,8 @@ message ListTestcaseRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 // Testcase
@@ -527,8 +527,8 @@ message ListContestRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 message Users { repeated UserRank list = 1; }
@@ -607,8 +607,8 @@ message ListUserRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 service User {
@@ -681,8 +681,8 @@ message ListChatRequest {
     Create create = 1;
     string paginator = 2;
   }
-  required int64 size = 3;
-  required uint64 offset = 4;
+  required uint64 size = 3;
+  required int64 offset = 4;
 }
 
 service Chat {