From: Matt Corallo <git@bluematt.me>
Date: Fri, 30 Apr 2021 23:09:05 +0000 (+0000)
Subject: Resolve issues with Str introduced when it became ownable
X-Git-Tag: v0.0.98~9^2~3
X-Git-Url: http://git.bitcoin.ninja/index.cgi?p=ldk-c-bindings;a=commitdiff_plain;h=db0ed2ef02f28a8b393eb3640959587bfe1a7e52

Resolve issues with Str introduced when it became ownable

When converting from a Str to an &str, we previously took ownership
of the Str, copied the pointer to its characters to an &str and
returned the &str. This made the returned bytes always unreadable.

Further, there is now no reason to use Vec_u8Z for owned Strs, so
we swap for Str as well.
---

diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs
index 7f5a3ed..81f26bf 100644
--- a/c-bindings-gen/src/main.rs
+++ b/c-bindings-gen/src/main.rs
@@ -966,7 +966,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
 							writeln!(w, "#[no_mangle]").unwrap();
 							writeln!(w, "/// Read a {} object from a string", ident).unwrap();
 							writeln!(w, "pub extern \"C\" fn {}_from_str(s: crate::c_types::Str) -> {} {{", ident, container).unwrap();
-							writeln!(w, "\tmatch {}::from_str(s.into()) {{", resolved_path).unwrap();
+							writeln!(w, "\tmatch {}::from_str(s.into_str()) {{", resolved_path).unwrap();
 							writeln!(w, "\t\tOk(r) => {{").unwrap();
 							let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("r"), &*i.self_ty, Some(&gen_types), false);
 							write!(w, "\t\t\tcrate::c_types::CResultTempl::ok(\n\t\t\t\t").unwrap();
diff --git a/c-bindings-gen/src/types.rs b/c-bindings-gen/src/types.rs
index 395441b..d945431 100644
--- a/c-bindings-gen/src/types.rs
+++ b/c-bindings-gen/src/types.rs
@@ -842,8 +842,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
 
 			"str" if is_ref => Some("crate::c_types::Str"),
-			"String" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
-			"String" if is_ref => Some("crate::c_types::Str"),
+			"String" => Some("crate::c_types::Str"),
 
 			"std::time::Duration" => Some("u64"),
 			"std::time::SystemTime" => Some("u64"),
@@ -915,7 +914,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"[usize]" if is_ref => Some(""),
 
 			"str" if is_ref => Some(""),
-			"String" if !is_ref => Some("String::from_utf8("),
+			"String" => Some(""),
 			// Note that we'll panic for String if is_ref, as we only have non-owned memory, we
 			// cannot create a &String.
 
@@ -980,8 +979,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"[u8]" if is_ref => Some(".to_slice()"),
 			"[usize]" if is_ref => Some(".to_slice()"),
 
-			"str" if is_ref => Some(".into()"),
-			"String" if !is_ref => Some(".into_rust()).unwrap()"),
+			"str" if is_ref => Some(".into_str()"),
+			"String" => Some(".into_string()"),
 
 			"std::time::Duration" => Some(")"),
 			"std::time::SystemTime" => Some("))"),
@@ -1129,8 +1128,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"[usize]" if is_ref => Some(""),
 
 			"str" if is_ref => Some(".into()"),
-			"String" if !is_ref => Some(".into_bytes().into()"),
 			"String" if is_ref => Some(".as_str().into()"),
+			"String" => Some(".into()"),
 
 			"std::time::Duration" => Some(".as_secs()"),
 			"std::time::SystemTime" => Some(".duration_since(::std::time::SystemTime::UNIX_EPOCH).expect(\"Times must be post-1970\").as_secs()"),
diff --git a/lightning-c-bindings/src/c_types/mod.rs b/lightning-c-bindings/src/c_types/mod.rs
index b28bc80..3d45802 100644
--- a/lightning-c-bindings/src/c_types/mod.rs
+++ b/lightning-c-bindings/src/c_types/mod.rs
@@ -382,11 +382,25 @@ impl Into<Str> for &'static str {
 		Str { chars: self.as_ptr(), len: self.len(), chars_is_owned: false }
 	}
 }
-impl Into<&'static str> for Str {
-	fn into(self) -> &'static str {
+impl Str {
+	pub(crate) fn into_str(&self) -> &'static str {
 		if self.len == 0 { return ""; }
 		std::str::from_utf8(unsafe { std::slice::from_raw_parts(self.chars, self.len) }).unwrap()
 	}
+	pub(crate) fn into_string(self) -> String {
+		let bytes = if self.len == 0 {
+			Vec::new()
+		} else if self.chars_is_owned {
+			unsafe {
+				Box::from_raw(std::slice::from_raw_parts_mut(unsafe { self.chars as *mut u8 }, self.len))
+			}.into()
+		} else {
+			let mut ret = Vec::with_capacity(self.len);
+			ret.extend_from_slice(unsafe { std::slice::from_raw_parts(self.chars, self.len) });
+			ret
+		};
+		String::from_utf8(bytes).unwrap()
+	}
 }
 impl Into<Str> for String {
 	fn into(self) -> Str {