storage: simplify pagination

crates/storage/src/compat/sso_login.rs

@@ -22,7 +22,7 @@ use url::Url;
 use uuid::Uuid;
 
 use crate::{
-    pagination::{process_page, Page, QueryBuilderExt},
+    pagination::{Page, QueryBuilderExt},
     tracing::ExecuteExt,
     Clock, DatabaseError, DatabaseInconsistencyError, LookupResultExt,
 };
@@ -379,19 +379,13 @@ impl<'c> CompatSsoLoginRepository for PgCompatSsoLoginRepository<'c> {
             .push_bind(Uuid::from(user.id))
             .generate_pagination("cl.compat_sso_login_id", before, after, first, last)?;
 
-        let page: Vec<CompatSsoLoginLookup> = query
+        let edges: Vec<CompatSsoLoginLookup> = query
             .build_query_as()
             .traced()
             .fetch_all(&mut *self.conn)
             .await?;
 
-        let (has_previous_page, has_next_page, edges) = process_page(page, first, last)?;
+        let page = Page::process(edges, first, last)?.try_map(CompatSsoLogin::try_from)?;
-
+        Ok(page)
-        let edges: Result<Vec<_>, _> = edges.into_iter().map(TryInto::try_into).collect();
-        Ok(Page {
-            has_next_page,
-            has_previous_page,
-            edges: edges?,
-        })
     }
 }

crates/storage/src/oauth2/session.rs

@@ -21,7 +21,7 @@ use ulid::Ulid;
 use uuid::Uuid;
 
 use crate::{
-    pagination::{process_page, Page, QueryBuilderExt},
+    pagination::{Page, QueryBuilderExt},
     tracing::ExecuteExt,
     Clock, DatabaseError, DatabaseInconsistencyError, LookupResultExt,
 };
@@ -271,15 +271,7 @@ impl<'c> OAuth2SessionRepository for PgOAuth2SessionRepository<'c> {
             .fetch_all(&mut *self.conn)
             .await?;
 
-        let (has_previous_page, has_next_page, edges) = process_page(edges, first, last)?;
+        let page = Page::process(edges, first, last)?.try_map(Session::try_from)?;
-
+        Ok(page)
-        let edges: Result<Vec<_>, DatabaseInconsistencyError> =
-            edges.into_iter().map(Session::try_from).collect();
-
-        Ok(Page {
-            has_next_page,
-            has_previous_page,
-            edges: edges?,
-        })
     }
 }

crates/storage/src/pagination.rs

@@ -82,41 +82,71 @@ where
     Ok(())
 }
 
-/// Process a page returned by a paginated query
-pub fn process_page<T>(
-    mut page: Vec<T>,
-    first: Option<usize>,
-    last: Option<usize>,
-) -> Result<(bool, bool, Vec<T>), InvalidPagination> {
-    let limit = match (first, last) {
-        (Some(count), _) | (_, Some(count)) => count,
-        _ => return Err(InvalidPagination),
-    };
-
-    let is_full = page.len() == (limit + 1);
-    if is_full {
-        page.pop();
-    }
-
-    let (has_previous_page, has_next_page) = if first.is_some() {
-        (false, is_full)
-    } else if last.is_some() {
-        // 6. If the last argument is provided, I reverse the order of the results
-        page.reverse();
-        (is_full, false)
-    } else {
-        unreachable!()
-    };
-
-    Ok((has_previous_page, has_next_page, page))
-}
-
 pub struct Page<T> {
     pub has_next_page: bool,
     pub has_previous_page: bool,
     pub edges: Vec<T>,
 }
 
+impl<T> Page<T> {
+    /// Process a page returned by a paginated query
+    pub fn process(
+        mut edges: Vec<T>,
+        first: Option<usize>,
+        last: Option<usize>,
+    ) -> Result<Self, InvalidPagination> {
+        let limit = match (first, last) {
+            (Some(count), _) | (_, Some(count)) => count,
+            _ => return Err(InvalidPagination),
+        };
+
+        let is_full = edges.len() == (limit + 1);
+        if is_full {
+            edges.pop();
+        }
+
+        let (has_previous_page, has_next_page) = if first.is_some() {
+            (false, is_full)
+        } else if last.is_some() {
+            // 6. If the last argument is provided, I reverse the order of the results
+            edges.reverse();
+            (is_full, false)
+        } else {
+            unreachable!()
+        };
+
+        Ok(Page {
+            has_next_page,
+            has_previous_page,
+            edges,
+        })
+    }
+
+    pub fn map<F, T2>(self, f: F) -> Page<T2>
+    where
+        F: FnMut(T) -> T2,
+    {
+        let edges = self.edges.into_iter().map(f).collect();
+        Page {
+            has_next_page: self.has_next_page,
+            has_previous_page: self.has_previous_page,
+            edges,
+        }
+    }
+
+    pub fn try_map<F, E, T2>(self, f: F) -> Result<Page<T2>, E>
+    where
+        F: FnMut(T) -> Result<T2, E>,
+    {
+        let edges: Result<Vec<T2>, E> = self.edges.into_iter().map(f).collect();
+        Ok(Page {
+            has_next_page: self.has_next_page,
+            has_previous_page: self.has_previous_page,
+            edges: edges?,
+        })
+    }
+}
+
 impl<T> Page<T> {}
 
 pub trait QueryBuilderExt {

crates/storage/src/upstream_oauth2/link.rs

@@ -21,7 +21,7 @@ use ulid::Ulid;
 use uuid::Uuid;
 
 use crate::{
-    pagination::{process_page, Page, QueryBuilderExt},
+    pagination::{Page, QueryBuilderExt},
     tracing::ExecuteExt,
     Clock, DatabaseError, LookupResultExt,
 };
@@ -297,19 +297,13 @@ impl<'c> UpstreamOAuthLinkRepository for PgUpstreamOAuthLinkRepository<'c> {
             .push_bind(Uuid::from(user.id))
             .generate_pagination("upstream_oauth_link_id", before, after, first, last)?;
 
-        let page: Vec<LinkLookup> = query
+        let edges: Vec<LinkLookup> = query
             .build_query_as()
             .traced()
             .fetch_all(&mut *self.conn)
             .await?;
 
-        let (has_previous_page, has_next_page, edges) = process_page(page, first, last)?;
+        let page = Page::process(edges, first, last)?.map(UpstreamOAuthLink::from);
-
+        Ok(page)
-        let edges: Vec<_> = edges.into_iter().map(Into::into).collect();
-        Ok(Page {
-            has_next_page,
-            has_previous_page,
-            edges,
-        })
     }
 }

crates/storage/src/upstream_oauth2/provider.rs

@@ -23,7 +23,7 @@ use ulid::Ulid;
 use uuid::Uuid;
 
 use crate::{
-    pagination::{process_page, Page, QueryBuilderExt},
+    pagination::{Page, QueryBuilderExt},
     tracing::ExecuteExt,
     Clock, DatabaseError, DatabaseInconsistencyError, LookupResultExt,
 };
@@ -266,20 +266,14 @@ impl<'c> UpstreamOAuthProviderRepository for PgUpstreamOAuthProviderRepository<'
 
         query.generate_pagination("upstream_oauth_provider_id", before, after, first, last)?;
 
-        let page: Vec<ProviderLookup> = query
+        let edges: Vec<ProviderLookup> = query
             .build_query_as()
             .traced()
             .fetch_all(&mut *self.conn)
             .await?;
 
-        let (has_previous_page, has_next_page, edges) = process_page(page, first, last)?;
+        let page = Page::process(edges, first, last)?.try_map(TryInto::try_into)?;
-
+        Ok(page)
-        let edges: Result<Vec<_>, _> = edges.into_iter().map(TryInto::try_into).collect();
-        Ok(Page {
-            has_next_page,
-            has_previous_page,
-            edges: edges?,
-        })
     }
 
     #[tracing::instrument(

crates/storage/src/user/email.rs

@@ -21,7 +21,7 @@ use ulid::Ulid;
 use uuid::Uuid;
 
 use crate::{
-    pagination::{process_page, Page, QueryBuilderExt},
+    pagination::{Page, QueryBuilderExt},
     tracing::ExecuteExt,
     Clock, DatabaseError, DatabaseInconsistencyError, LookupResultExt,
 };
@@ -315,15 +315,8 @@ impl<'c> UserEmailRepository for PgUserEmailRepository<'c> {
             .fetch_all(&mut *self.conn)
             .await?;
 
-        let (has_previous_page, has_next_page, edges) = process_page(edges, first, last)?;
+        let page = Page::process(edges, first, last)?.map(UserEmail::from);
-
+        Ok(page)
-        let edges = edges.into_iter().map(Into::into).collect();
-
-        Ok(Page {
-            has_next_page,
-            has_previous_page,
-            edges,
-        })
     }
 
     #[tracing::instrument(

crates/storage/src/user/session.rs

@@ -21,7 +21,7 @@ use ulid::Ulid;
 use uuid::Uuid;
 
 use crate::{
-    pagination::{process_page, Page, QueryBuilderExt},
+    pagination::{Page, QueryBuilderExt},
     tracing::ExecuteExt,
     Clock, DatabaseError, DatabaseInconsistencyError, LookupResultExt,
 };
@@ -91,19 +91,19 @@ struct SessionLookup {
     last_authd_at: Option<DateTime<Utc>>,
 }
 
-impl TryInto<BrowserSession> for SessionLookup {
+impl TryFrom<SessionLookup> for BrowserSession {
     type Error = DatabaseInconsistencyError;
 
-    fn try_into(self) -> Result<BrowserSession, Self::Error> {
+    fn try_from(value: SessionLookup) -> Result<Self, Self::Error> {
-        let id = Ulid::from(self.user_id);
+        let id = Ulid::from(value.user_id);
         let user = User {
             id,
-            username: self.user_username,
+            username: value.user_username,
             sub: id.to_string(),
-            primary_user_email_id: self.user_primary_user_email_id.map(Into::into),
+            primary_user_email_id: value.user_primary_user_email_id.map(Into::into),
         };
 
-        let last_authentication = match (self.last_authentication_id, self.last_authd_at) {
+        let last_authentication = match (value.last_authentication_id, value.last_authd_at) {
             (Some(id), Some(created_at)) => Some(Authentication {
                 id: id.into(),
                 created_at,
@@ -117,10 +117,10 @@ impl TryInto<BrowserSession> for SessionLookup {
         };
 
         Ok(BrowserSession {
-            id: self.user_session_id.into(),
+            id: value.user_session_id.into(),
             user,
-            created_at: self.user_session_created_at,
+            created_at: value.user_session_created_at,
-            finished_at: self.user_session_finished_at,
+            finished_at: value.user_session_finished_at,
             last_authentication,
         })
     }
@@ -292,20 +292,14 @@ impl<'c> BrowserSessionRepository for PgBrowserSessionRepository<'c> {
             .push_bind(Uuid::from(user.id))
             .generate_pagination("s.user_session_id", before, after, first, last)?;
 
-        let page: Vec<SessionLookup> = query
+        let edges: Vec<SessionLookup> = query
             .build_query_as()
             .traced()
             .fetch_all(&mut *self.conn)
             .await?;
 
-        let (has_previous_page, has_next_page, edges) = process_page(page, first, last)?;
+        let page = Page::process(edges, first, last)?.try_map(BrowserSession::try_from)?;
-
+        Ok(page)
-        let edges: Result<Vec<_>, _> = edges.into_iter().map(TryInto::try_into).collect();
-        Ok(Page {
-            has_previous_page,
-            has_next_page,
-            edges: edges?,
-        })
     }
 
     #[tracing::instrument(