Cookie: Replace TryFrom with TryParse

Instead of requiring replies to implement TryFrom<&[u8],
Error=ParseError>, this commit changes the code to instead use the
TryParse trait that we have just for this purpose.

Related-to: #478
Signed-off-by: Uli Schlachter <[email protected]>

src/connection.rs

@@ -49,7 +49,7 @@ use crate::errors::{ConnectionError, ParseError, ReplyError, ReplyOrIdError};
 use crate::protocol::xproto::Setup;
 use crate::protocol::Event;
 use crate::utils::RawFdContainer;
-use crate::x11_utils::{ExtensionInformation, X11Error};
+use crate::x11_utils::{ExtensionInformation, TryParse, X11Error};
 
 /// Number type used for referring to things that were sent to the server in responses from the
 /// server.
@@ -119,7 +119,7 @@ pub trait RequestConnection {
         fds: Vec<RawFdContainer>,
     ) -> Result<Cookie<'_, Self, R>, ConnectionError>
     where
-        R: for<'a> TryFrom<&'a [u8], Error = ParseError>;
+        R: TryParse;
 
     /// Send a request with a reply containing file descriptors to the server.
     ///
@@ -496,7 +496,7 @@ pub enum DiscardMode {
 ///
 ///     fn send_request_with_reply<R>(&self, bufs: &[IoSlice], fds: Vec<RawFdContainer>)
 ///     -> Result<Cookie<Self, R>, ConnectionError>
-///     where R: for<'a> TryFrom<&'a [u8], Error=ParseError> {
+///     where R: TryParse {
 ///         Ok(Cookie::new(self, self.send_request(bufs, fds, true, false)?))
 ///     }
 ///

src/cookie.rs

@@ -1,6 +1,6 @@
 //! Cookies are handles to future replies or errors from the X11 server.
 
-use std::convert::{TryFrom, TryInto};
+use std::convert::TryFrom;
 use std::marker::PhantomData;
 
 use crate::connection::{BufWithFds, DiscardMode, RequestConnection, RequestKind, SequenceNumber};
@@ -9,6 +9,7 @@ use crate::errors::{ConnectionError, ParseError, ReplyError};
 use crate::protocol::record::EnableContextReply;
 use crate::protocol::xproto::ListFontsWithInfoReply;
 use crate::utils::RawFdContainer;
+use crate::x11_utils::TryParse;
 
 /// A handle to a possible error from the X11 server.
 ///
@@ -144,7 +145,7 @@ where
 
 impl<C, R> Cookie<'_, C, R>
 where
-    R: for<'a> TryFrom<&'a [u8], Error = ParseError>,
+    R: TryParse,
     C: RequestConnection + ?Sized,
 {
     /// Construct a new cookie.
@@ -177,13 +178,13 @@ where
 
     /// Get the reply that the server sent.
     pub fn reply(self) -> Result<R, ReplyError> {
-        Ok(self.raw_reply()?.as_ref().try_into()?)
+        Ok(R::try_parse(self.raw_reply()?.as_ref())?.0)
     }
 
     /// Get the reply that the server sent, but have errors handled as events.
     pub fn reply_unchecked(self) -> Result<Option<R>, ConnectionError> {
         self.raw_reply_unchecked()?
-            .map(|buf| buf.as_ref().try_into())
+            .map(|buf| R::try_parse(buf.as_ref()).map(|r| r.0))
             .transpose()
             .map_err(Into::into)
     }

src/extension_manager.rs

@@ -158,7 +158,7 @@ mod test {
     use crate::cookie::{Cookie, CookieWithFds, VoidCookie};
     use crate::errors::{ConnectionError, ParseError};
     use crate::utils::RawFdContainer;
-    use crate::x11_utils::{ExtInfoProvider, ExtensionInformation};
+    use crate::x11_utils::{ExtInfoProvider, ExtensionInformation, TryParse};
 
     use super::{CheckState, ExtensionManager};
 
@@ -173,7 +173,7 @@ mod test {
             _fds: Vec<RawFdContainer>,
         ) -> Result<Cookie<'_, Self, R>, ConnectionError>
         where
-            R: for<'a> TryFrom<&'a [u8], Error = ParseError>,
+            R: TryParse,
         {
             Ok(Cookie::new(self, 1))
         }

src/rust_connection/mod.rs

@@ -14,7 +14,7 @@ use crate::extension_manager::ExtensionManager;
 use crate::protocol::bigreq::{ConnectionExt as _, EnableReply};
 use crate::protocol::xproto::{Setup, SetupRequest, GET_INPUT_FOCUS_REQUEST};
 use crate::utils::RawFdContainer;
-use crate::x11_utils::{ExtensionInformation, Serialize};
+use crate::x11_utils::{ExtensionInformation, Serialize, TryParse};
 
 mod id_allocator;
 mod inner;
@@ -451,7 +451,7 @@ impl<S: Stream> RequestConnection for RustConnection<S> {
         fds: Vec<RawFdContainer>,
     ) -> Result<Cookie<'_, Self, Reply>, ConnectionError>
     where
-        Reply: for<'a> TryFrom<&'a [u8], Error = ParseError>,
+        Reply: TryParse,
     {
         Ok(Cookie::new(
             self,

src/xcb_ffi/mod.rs

@@ -25,7 +25,7 @@ pub use crate::errors::{ConnectError, ConnectionError, ParseError, ReplyError, R
 use crate::extension_manager::ExtensionManager;
 use crate::protocol::xproto::Setup;
 use crate::utils::{CSlice, RawFdContainer};
-use crate::x11_utils::ExtensionInformation;
+use crate::x11_utils::{ExtensionInformation, TryParse};
 
 mod pending_errors;
 mod raw_ffi;
@@ -356,7 +356,7 @@ impl RequestConnection for XCBConnection {
         fds: Vec<RawFdContainer>,
     ) -> Result<Cookie<'_, Self, R>, ConnectionError>
     where
-        R: for<'a> TryFrom<&'a [u8], Error = ParseError>,
+        R: TryParse,
     {
         Ok(Cookie::new(
             self,

tests/regression_tests.rs

@@ -69,7 +69,7 @@ impl RequestConnection for FakeConnection {
         fds: Vec<RawFdContainer>,
     ) -> Result<Cookie<Self, R>, ConnectionError>
     where
-        R: for<'a> TryFrom<&'a [u8], Error = ParseError>,
+        R: TryParse,
     {
         Ok(Cookie::new(self, self.internal_send_request(bufs, fds)?))
     }

tests/resource_manager.rs

@@ -149,7 +149,7 @@ mod test {
             _: Vec<RawFdContainer>,
         ) -> Result<Cookie<'_, Self, R>, ConnectionError>
         where
-            R: for<'a> TryFrom<&'a [u8], Error = ParseError>,
+            R: TryParse,
         {
             Ok(Cookie::new(self, 42))
         }