From b878855bc3396c78eaff9daf20bb0d3b07fd9142 Mon Sep 17 00:00:00 2001
From: Sunjay Varma <varma.sunjay@gmail.com>
Date: Sat, 28 Sep 2019 22:43:52 -0400
Subject: [PATCH] **CHANGES** extend trait in order to allow FromStream impls
 for String

---
 src/lib.rs                |   1 +
 src/stream/extend.rs      |   2 +-
 src/string/extend.rs      |  60 ++++++++++++++++++++++
 src/string/from_stream.rs | 104 ++++++++++++++++++++++++++++++++++++++
 src/string/mod.rs         |   9 ++++
 5 files changed, 175 insertions(+), 1 deletion(-)
 create mode 100644 src/string/extend.rs
 create mode 100644 src/string/from_stream.rs
 create mode 100644 src/string/mod.rs

diff --git a/src/lib.rs b/src/lib.rs
index ba0326ac..f64fdbc2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -68,6 +68,7 @@ cfg_if! {
         mod vec;
         mod result;
         mod option;
+        mod string;
     }
 }
 
diff --git a/src/stream/extend.rs b/src/stream/extend.rs
index b960dacf..47dc828f 100644
--- a/src/stream/extend.rs
+++ b/src/stream/extend.rs
@@ -33,7 +33,7 @@ pub trait Extend<A> {
     fn stream_extend<'a, T: IntoStream<Item = A> + 'a>(
         &'a mut self,
         stream: T,
-    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>;
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> where A: 'a;
 }
 
 impl Extend<()> for () {
diff --git a/src/string/extend.rs b/src/string/extend.rs
new file mode 100644
index 00000000..71d14a32
--- /dev/null
+++ b/src/string/extend.rs
@@ -0,0 +1,60 @@
+use std::pin::Pin;
+use std::borrow::Cow;
+
+use crate::prelude::*;
+use crate::stream::{Extend, IntoStream};
+
+impl Extend<char> for String {
+    fn stream_extend<'a, S: IntoStream<Item = char> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        let stream = stream.into_stream();
+        //TODO: Add this back in when size_hint is added to stream
+        // let (lower_bound, _) = stream.size_hint();
+        // self.reserve(lower_bound);
+
+        //TODO: This can just be: stream.for_each(move |c| self.push(c))
+        Box::pin(stream.fold((), move |(), c| self.push(c)))
+    }
+}
+
+impl<'b> Extend<&'b char> for String {
+    fn stream_extend<'a, S: IntoStream<Item = &'b char> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> where 'b: 'a {
+        //TODO: Box::pin(stream.into_stream().copied())
+        unimplemented!()
+    }
+}
+
+impl<'b> Extend<&'b str> for String {
+    fn stream_extend<'a, S: IntoStream<Item = &'b str> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> where 'b: 'a {
+        //TODO: This can just be: stream.into_stream().for_each(move |s| self.push_str(s))
+        Box::pin(stream.into_stream().fold((), move |(), s| self.push_str(s)))
+    }
+}
+
+impl Extend<String> for String {
+    fn stream_extend<'a, S: IntoStream<Item = String> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        //TODO: This can just be: stream.into_stream().for_each(move |s| self.push_str(&s))
+        Box::pin(stream.into_stream().fold((), move |(), s| self.push_str(&s)))
+    }
+}
+
+impl<'b> Extend<Cow<'b, str>> for String {
+    fn stream_extend<'a, S: IntoStream<Item = Cow<'b, str>> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> where 'b: 'a {
+        //TODO: This can just be: stream.into_stream().for_each(move |s| self.push_str(&s))
+        Box::pin(stream.into_stream().fold((), move |(), s| self.push_str(&s)))
+    }
+}
diff --git a/src/string/from_stream.rs b/src/string/from_stream.rs
new file mode 100644
index 00000000..7d3bc5bd
--- /dev/null
+++ b/src/string/from_stream.rs
@@ -0,0 +1,104 @@
+use std::pin::Pin;
+use std::borrow::Cow;
+
+use crate::stream::{FromStream, IntoStream, Extend};
+
+impl FromStream<char> for String {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = char>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = String::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}
+
+impl<'b> FromStream<&'b char> for String {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = &'b char>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = String::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}
+
+impl<'b> FromStream<&'b str> for String {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = &'b str>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = String::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}
+
+impl FromStream<String> for String {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = String>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = String::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}
+
+impl<'b> FromStream<Cow<'b, str>> for String {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = Cow<'b, str>>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = String::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}
diff --git a/src/string/mod.rs b/src/string/mod.rs
new file mode 100644
index 00000000..e382fcf2
--- /dev/null
+++ b/src/string/mod.rs
@@ -0,0 +1,9 @@
+//! The Rust core string library
+//!
+//! This library provides a UTF-8 encoded, growable string.
+
+mod extend;
+mod from_stream;
+
+#[doc(inline)]
+pub use std::string::String;