add pagination cursor

crates/db_schema/src/newtypes.rs

@@ -89,19 +89,19 @@ pub struct PersonMentionId(i32);
 #[cfg_attr(feature = "full", derive(DieselNewType, TS))]
 #[cfg_attr(feature = "full", ts(export))]
 /// The comment report id.
-pub struct CommentReportId(i32);
+pub struct CommentReportId(pub i32);
 
 #[derive(Debug, Copy, Clone, Hash, Eq, PartialEq, Serialize, Deserialize, Default)]
 #[cfg_attr(feature = "full", derive(DieselNewType, TS))]
 #[cfg_attr(feature = "full", ts(export))]
 /// The post report id.
-pub struct PostReportId(i32);
+pub struct PostReportId(pub i32);
 
 #[derive(Debug, Copy, Clone, Hash, Eq, PartialEq, Serialize, Deserialize, Default)]
 #[cfg_attr(feature = "full", derive(DieselNewType, TS))]
 #[cfg_attr(feature = "full", ts(export))]
 /// The private message report id.
-pub struct PrivateMessageReportId(i32);
+pub struct PrivateMessageReportId(pub i32);
 
 #[derive(Debug, Copy, Clone, Hash, Eq, PartialEq, Serialize, Deserialize, Default)]
 #[cfg_attr(feature = "full", derive(DieselNewType, TS))]

crates/db_views/src/report_combined_view.rs

@@ -3,6 +3,7 @@ use crate::structs::{
   LocalUserView,
   PostReportView,
   PrivateMessageReportView,
+  ReportCombinedPaginationCursor,
   ReportCombinedView,
   ReportCombinedViewInternal,
 };
@@ -13,6 +14,7 @@ use diesel::{
   JoinOnDsl,
   NullableExpressionMethods,
   QueryDsl,
+  SelectableHelper,
 };
 use diesel_async::RunQueryDsl;
 use lemmy_db_schema::{
@@ -36,7 +38,7 @@ use lemmy_db_schema::{
     private_message_report,
     report_combined,
   },
-  source::community::CommunityFollower,
+  source::{combined::report::ReportCombined, community::CommunityFollower},
   utils::{actions, actions_alias, functions::coalesce, get_conn, limit_and_offset, DbPool},
 };
 use lemmy_utils::error::LemmyResult;
@@ -94,6 +96,39 @@ impl ReportCombinedViewInternal {
   }
 }
 
+impl ReportCombinedPaginationCursor {
+  // get cursor for page that starts immediately after the given post
+  pub fn after_post(view: &ReportCombinedView) -> ReportCombinedPaginationCursor {
+    let (prefix, id) = match view {
+      ReportCombinedView::Comment(v) => ('C', v.comment_report.id.0),
+      ReportCombinedView::Post(v) => ('P', v.post_report.id.0),
+      ReportCombinedView::PrivateMessage(v) => ('M', v.private_message_report.id.0),
+    };
+    // hex encoding to prevent ossification
+    ReportCombinedPaginationCursor(format!("{prefix}{id:x}"))
+  }
+  pub async fn read(&self, pool: &mut DbPool<'_>) -> Result<PaginationCursorData, Error> {
+    let err_msg = || Error::QueryBuilderError("Could not parse pagination token".into());
+    let mut query = report_combined::table
+      .select(ReportCombined::as_select())
+      .into_boxed();
+    let (prefix, id_str) = self.0.split_at_checked(1).ok_or_else(err_msg)?;
+    let id = i32::from_str_radix(id_str, 16).map_err(|_| err_msg())?;
+    query = match prefix {
+      "C" => query.filter(report_combined::comment_report_id.eq(id)),
+      "P" => query.filter(report_combined::post_report_id.eq(id)),
+      "M" => query.filter(report_combined::private_message_report_id.eq(id)),
+      _ => return Err(err_msg()),
+    };
+    let token = query.first(&mut get_conn(pool).await?).await?;
+
+    Ok(PaginationCursorData(token))
+  }
+}
+
+#[derive(Clone)]
+pub struct PaginationCursorData(ReportCombined);
+
 #[derive(Default)]
 pub struct ReportCombinedQuery {
   pub community_id: Option<CommunityId>,

crates/db_views/src/structs.rs

@@ -126,6 +126,12 @@ pub struct PostReportView {
 #[cfg_attr(feature = "full", ts(export))]
 pub struct PaginationCursor(pub String);
 
+/// like PaginationCursor but for the report_combined table
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "full", derive(ts_rs::TS))]
+#[cfg_attr(feature = "full", ts(export))]
+pub struct ReportCombinedPaginationCursor(pub String);
+
 #[skip_serializing_none]
 #[derive(Debug, PartialEq, Serialize, Deserialize, Clone)]
 #[cfg_attr(feature = "full", derive(TS, Queryable))]