Delete associated favorites when deleting a cipher or user

This prevents foreign key constraint violations.

src/db/models/favorite.rs

@@ -0,0 +1,83 @@
+use super::{Cipher, User};
+
+db_object! {
+    #[derive(Debug, Identifiable, Queryable, Insertable, Associations)]
+    #[table_name = "favorites"]
+    #[belongs_to(User, foreign_key = "user_uuid")]
+    #[belongs_to(Cipher, foreign_key = "cipher_uuid")]
+    #[primary_key(user_uuid, cipher_uuid)]
+    pub struct Favorite {
+        pub user_uuid: String,
+        pub cipher_uuid: String,
+    }
+}
+
+use crate::db::DbConn;
+
+use crate::api::EmptyResult;
+use crate::error::MapResult;
+
+impl Favorite {
+    // Returns whether the specified cipher is a favorite of the specified user.
+    pub fn is_favorite(cipher_uuid: &str, user_uuid: &str, conn: &DbConn) -> bool {
+        db_run!{ conn: {
+            let query = favorites::table
+                .filter(favorites::cipher_uuid.eq(cipher_uuid))
+                .filter(favorites::user_uuid.eq(user_uuid))
+                .count();
+
+            query.first::<i64>(conn).ok().unwrap_or(0) != 0
+        }}
+    }
+
+    // Sets whether the specified cipher is a favorite of the specified user.
+    pub fn set_favorite(favorite: bool, cipher_uuid: &str, user_uuid: &str, conn: &DbConn) -> EmptyResult {
+        let (old, new) = (Self::is_favorite(cipher_uuid, user_uuid, &conn), favorite);
+        match (old, new) {
+            (false, true) => {
+                User::update_uuid_revision(user_uuid, &conn);
+                db_run!{ conn: {
+                    diesel::insert_into(favorites::table)
+                        .values((
+                            favorites::user_uuid.eq(user_uuid),
+                            favorites::cipher_uuid.eq(cipher_uuid),
+                        ))
+                        .execute(conn)
+                        .map_res("Error adding favorite")
+                    }}
+            }
+            (true, false) => {
+                User::update_uuid_revision(user_uuid, &conn);
+                db_run!{ conn: {
+                    diesel::delete(
+                        favorites::table
+                            .filter(favorites::user_uuid.eq(user_uuid))
+                            .filter(favorites::cipher_uuid.eq(cipher_uuid))
+                    )
+                    .execute(conn)
+                    .map_res("Error removing favorite")
+                }}
+            }
+            // Otherwise, the favorite status is already what it should be.
+            _ => Ok(())
+        }
+    }
+
+    // Delete all favorite entries associated with the specified cipher.
+    pub fn delete_all_by_cipher(cipher_uuid: &str, conn: &DbConn) -> EmptyResult {
+        db_run! { conn: {
+            diesel::delete(favorites::table.filter(favorites::cipher_uuid.eq(cipher_uuid)))
+                .execute(conn)
+                .map_res("Error removing favorites by cipher")
+        }}
+    }
+
+    // Delete all favorite entries associated with the specified user.
+    pub fn delete_all_by_user(user_uuid: &str, conn: &DbConn) -> EmptyResult {
+        db_run! { conn: {
+            diesel::delete(favorites::table.filter(favorites::user_uuid.eq(user_uuid)))
+                .execute(conn)
+                .map_res("Error removing favorites by user")
+        }}
+    }
+}