From 20adbaf36b34705f01c5020e5c83b2becbf18422 Mon Sep 17 00:00:00 2001
From: Steven Fackler <sfackler@gmail.com>
Date: Sat, 12 Oct 2019 18:01:27 -0700
Subject: [PATCH] Fix build for real

---
 postgres-types/src/serde_json_1.rs | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/postgres-types/src/serde_json_1.rs b/postgres-types/src/serde_json_1.rs
index c6c35b00..7b8cfe8f 100644
--- a/postgres-types/src/serde_json_1.rs
+++ b/postgres-types/src/serde_json_1.rs
@@ -1,4 +1,4 @@
-use bytes::BytesMut;
+use bytes::{BufMut, BytesMut};
 use serde_1::{Deserialize, Serialize};
 use serde_json_1::Value;
 use std::error::Error;
@@ -7,6 +7,30 @@ use std::io::Read;
 
 use crate::{FromSql, IsNull, ToSql, Type};
 
+// https://github.com/tokio-rs/bytes/issues/170
+struct B<'a>(&'a mut BytesMut);
+
+impl<'a> BufMut for B<'a> {
+    #[inline]
+    fn remaining_mut(&self) -> usize {
+        usize::max_value() - self.0.len()
+    }
+
+    #[inline]
+    unsafe fn advance_mut(&mut self, cnt: usize) {
+        self.0.advance_mut(cnt);
+    }
+
+    #[inline]
+    unsafe fn bytes_mut(&mut self) -> &mut [u8] {
+        if !self.0.has_remaining_mut() {
+            self.0.reserve(64);
+        }
+
+        self.0.bytes_mut()
+    }
+}
+
 /// A wrapper type to allow arbitrary `Serialize`/`Deserialize` types to convert to Postgres JSON values.
 #[derive(Debug)]
 pub struct Json<T>(pub T);
@@ -42,9 +66,9 @@ where
         out: &mut BytesMut,
     ) -> Result<IsNull, Box<dyn Error + Sync + Send>> {
         if *ty == Type::JSONB {
-            out.push(1);
+            B(out).put_u8(1);
         }
-        serde_json_1::ser::to_writer(out, &self.0)?;
+        serde_json_1::ser::to_writer(B(out).writer(), &self.0)?;
         Ok(IsNull::No)
     }