From c01f39aefb842a38401d511a43b301dcf8ea73ae Mon Sep 17 00:00:00 2001
From: Piotr Jastrzebski <haaawk@gmail.com>
Date: Sun, 7 Jul 2024 18:51:44 +0200
Subject: [PATCH] Make it possible to get row values as &str

This allows to avoid some unneeded copies and allocations.

Signed-off-by: Piotr Jastrzebski <haaawk@gmail.com>
---
 core/lib.rs   |  6 +++---
 core/types.rs | 23 ++++++++++++++++-------
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/core/lib.rs b/core/lib.rs
index 39de5871b..9f54d4d83 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -65,12 +65,12 @@ impl Database {
             loop {
                 match rows.next()? {
                     RowResult::Row(row) => {
-                        let ty = row.get::<String>(0)?;
+                        let ty = row.get::<&str>(0)?;
                         if ty != "table" {
                             continue;
                         }
                         let root_page: i64 = row.get::<i64>(3)?;
-                        let sql: String = row.get::<String>(4)?;
+                        let sql: &str = row.get::<&str>(4)?;
                         let table = schema::BTreeTable::from_sql(&sql, root_page as usize)?;
                         schema.add_table(Rc::new(table));
                     }
@@ -242,7 +242,7 @@ pub struct Row<'a> {
 }
 
 impl<'a> Row<'a> {
-    pub fn get<T: crate::types::FromValue>(&self, idx: usize) -> Result<T> {
+    pub fn get<T: crate::types::FromValue<'a> + 'a>(&self, idx: usize) -> Result<T> {
         let value = &self.values[idx];
         T::from_value(value)
     }
diff --git a/core/types.rs b/core/types.rs
index f48449953..4bfce889c 100644
--- a/core/types.rs
+++ b/core/types.rs
@@ -165,14 +165,14 @@ pub fn to_value(value: &OwnedValue) -> Value<'_> {
     }
 }
 
-pub trait FromValue {
-    fn from_value(value: &Value) -> Result<Self>
+pub trait FromValue<'a> {
+    fn from_value(value: &Value<'a>) -> Result<Self>
     where
-        Self: Sized;
+        Self: Sized + 'a;
 }
 
-impl FromValue for i64 {
-    fn from_value(value: &Value) -> Result<Self> {
+impl<'a> FromValue<'a> for i64 {
+    fn from_value(value: &Value<'a>) -> Result<Self> {
         match value {
             Value::Integer(i) => Ok(*i),
             _ => anyhow::bail!("Expected integer value"),
@@ -180,8 +180,8 @@ impl FromValue for i64 {
     }
 }
 
-impl FromValue for String {
-    fn from_value(value: &Value) -> Result<Self> {
+impl<'a> FromValue<'a> for String {
+    fn from_value(value: &Value<'a>) -> Result<Self> {
         match value {
             Value::Text(s) => Ok(s.to_string()),
             _ => anyhow::bail!("Expected text value"),
@@ -189,6 +189,15 @@ impl FromValue for String {
     }
 }
 
+impl<'a> FromValue<'a> for &'a str {
+    fn from_value(value: &Value<'a>) -> Result<&'a str> {
+        match value {
+            Value::Text(s) => Ok(&s),
+            _ => anyhow::bail!("Expected text value"),
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct Record<'a> {
     pub values: Vec<Value<'a>>,