From ac02450b8b2c692393fe892b246d5b63ca7fc4ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Ml=C3=A1dek?= <tmladek@protonmail.ch>
Date: Fri, 12 Feb 2021 11:56:29 +0100
Subject: [PATCH] fix "OR TRUE" variant; remove Option<> from query_to_sqlite()

---
 src/database.rs | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/src/database.rs b/src/database.rs
index 191a33f..a9e96ef 100644
--- a/src/database.rs
+++ b/src/database.rs
@@ -446,11 +446,7 @@ impl Query {
 pub fn query<C: Connection<Backend = Sqlite>>(connection: &C, query: Query) -> Result<Vec<Entry>> {
     use crate::schema::data::dsl::*;
 
-    let mut db_query = data.into_boxed();
-
-    if let Some(predicate) = query_to_sqlite(&query)? {
-        db_query = db_query.filter(predicate);
-    }
+    let db_query = data.filter(query_to_sqlite(&query)?);
 
     trace!("Querying: {}", debug_query(&db_query));
 
@@ -466,7 +462,7 @@ pub fn query<C: Connection<Backend = Sqlite>>(connection: &C, query: Query) -> R
 }
 type Predicate = dyn BoxableExpression<data::table, Sqlite, SqlType = Bool>;
 
-fn query_to_sqlite(query: &Query) -> Result<Option<Box<Predicate>>> {
+fn query_to_sqlite(query: &Query) -> Result<Box<Predicate>> {
     match query {
         Query::SingleQuery(qp) => match qp {
             QueryPart::Matches(eq) => {
@@ -507,29 +503,27 @@ fn query_to_sqlite(query: &Query) -> Result<Option<Box<Predicate>>> {
                 };
 
                 match subqueries.len() {
-                    0 => Ok(None),
-                    1 => Ok(Some(subqueries.remove(0))),
+                    0 => Ok(Box::new(true.into_sql::<Bool>())),
+                    1 => Ok(subqueries.remove(0)),
                     _ => {
                         let mut result: Box<And<Box<Predicate>, Box<Predicate>>> =
                             Box::new(And::new(subqueries.remove(0), subqueries.remove(0)));
                         while subqueries.len() > 0 {
                             result = Box::new(And::new(result, subqueries.remove(0)));
                         }
-                        Ok(Some(Box::new(result)))
+                        Ok(Box::new(result))
                     }
                 }
             }
             QueryPart::Type(_) => unimplemented!("Type queries are not yet implemented."),
         },
         Query::MultiQuery(mq) => {
-            // TODO: Handle the "OR TRUE" case as well
-            let subqueries: Result<Vec<Option<Box<Predicate>>>> =
+            let subqueries: Result<Vec<Box<Predicate>>> =
                 mq.queries.iter().map(|sq| query_to_sqlite(sq)).collect();
-            let mut subqueries: Vec<Box<Predicate>> =
-                subqueries?.into_iter().filter_map(|sq| sq).collect();
+            let mut subqueries: Vec<Box<Predicate>> = subqueries?;
             match subqueries.len() {
-                0 => Ok(None),
-                1 => Ok(Some(subqueries.remove(0))),
+                0 => Ok(Box::new(true.into_sql::<Bool>())),
+                1 => Ok(subqueries.remove(0)),
                 _ => match mq.qualifier {
                     QueryQualifier::AND => {
                         let mut result: Box<And<Box<Predicate>, Box<Predicate>>> =
@@ -537,7 +531,7 @@ fn query_to_sqlite(query: &Query) -> Result<Option<Box<Predicate>>> {
                         while subqueries.len() > 0 {
                             result = Box::new(And::new(result, subqueries.remove(0)));
                         }
-                        Ok(Some(Box::new(result)))
+                        Ok(Box::new(result))
                     }
                     QueryQualifier::OR => {
                         let mut result: Box<Or<Box<Predicate>, Box<Predicate>>> =
@@ -545,7 +539,7 @@ fn query_to_sqlite(query: &Query) -> Result<Option<Box<Predicate>>> {
                         while subqueries.len() > 0 {
                             result = Box::new(Or::new(result, subqueries.remove(0)));
                         }
-                        Ok(Some(Box::new(result)))
+                        Ok(Box::new(result))
                     }
                 },
             }