Add Big Requests Extension

Cargo.toml

@@ -16,8 +16,15 @@ keywords = [ "x11", "xorg", "xproto", "xrs", "window" ]
 categories = [ "data-structures", "api-bindings", "encoding" ]
 
 [features]
+default = ["big-requests"]
 try = []
 
+# Protocol Extentions
+
+# Big Requests
+# https://www.x.org/releases/X11R7.7/doc/bigreqsproto/bigreq.html
+big-requests = []
+
 [workspace]
 # XRB is defined as a workspace that automatically includes all its path
 # dependencies. Currently, that means `xrb-proc-macros` and `cornflakes`.

src/big_requests.rs

@@ -0,0 +1,8 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//! Request to enable extended length field in the protocol.
+
+pub mod reply;
+pub mod request;

src/big_requests/reply.rs

@@ -0,0 +1,22 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+extern crate self as xrb;
+
+use crate::{big_requests::request, message::Reply};
+use derivative::Derivative;
+use xrbk_macro::derive_xrb;
+
+derive_xrb! {
+	#[derive(Derivative, Debug, X11Size, Readable, Writable)]
+	#[derivative(Hash, PartialEq, Eq)]
+	pub struct EnableBigRequests: Reply for request::EnableBigRequests {
+		#[sequence]
+		#[derivative(Hash = "ignore", PartialEq = "ignore")]
+		pub sequence: u16,
+
+		pub maximum_request_length: u32,
+		[_; 2],
+	}
+}

src/big_requests/request.rs

@@ -0,0 +1,15 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+extern crate self as xrb;
+
+use crate::{big_requests::reply, message::Request};
+use derivative::Derivative;
+use xrbk_macro::derive_xrb;
+
+derive_xrb! {
+	#[derive(Derivative, Debug, X11Size, Readable, Writable)]
+	#[derivative(Hash, PartialEq, Eq)]
+	pub struct EnableBigRequests: Request(0 /* TODO: extensions use dynamic major opcodes */) -> reply::EnableBigRequests {}
+}

src/lib.rs

@@ -87,3 +87,8 @@ pub mod connection;
 pub mod message;
 pub mod unit;
 pub mod x11;
+
+// Protocol Extensions
+
+#[cfg(feature = "big-requests")]
+pub mod big_requests;

src/message.rs

@@ -123,6 +123,7 @@ pub trait Request: X11Size + Writable {
 	///     }
 	/// }
 	/// ```
+	#[cfg(not(feature = "big-requests"))]
 	#[allow(clippy::cast_possible_truncation)]
 	fn length(&self) -> u16 {
 		let size = self.x11_size();
@@ -135,6 +136,20 @@ pub trait Request: X11Size + Writable {
 
 		(size / 4) as u16
 	}
+
+	#[cfg(feature = "big-requests")]
+	#[allow(clippy::cast_possible_truncation)]
+	fn length(&self) -> u32 {
+		let size = self.x11_size();
+
+		assert_eq!(
+			size % 4,
+			0,
+			"expected Request size to be a multiple of 4, found {size}"
+		);
+
+		(size / 4) as u32
+	}
 }
 
 /// The result of sending a [request].

src/x11/request/graphics.rs

@@ -86,6 +86,24 @@ request_error! {
 	}
 }
 
+/// Writes the length of the request to the provided buffer.
+fn write_size(request: &impl Request, buf: &mut impl BufMut) {
+	#[cfg(not(feature = "big-requests"))]
+	buf.put_u16(request.length());
+	#[cfg(feature = "big-requests")]
+	{
+		let length = request.length();
+		match u16::try_from(length) {
+			Ok(length) => buf.put_u16(length),
+			// length is too big for u16, using the extended length field
+			Err(_) => {
+				buf.put_u16(0);
+				buf.put_u32(length);
+			},
+		}
+	}
+}
+
 derive_xrb! {
 	/// A [request] that clears a particular area of a [window].
 	///
@@ -2102,7 +2120,7 @@ impl Writable for DrawText8 {
 		buf.put_u8(Self::MAJOR_OPCODE);
 		// Unused metabyte position.
 		buf.put_u8(0);
-		buf.put_u16(self.length());
+		write_size(self, buf);
 
 		self.target.write_to(buf)?;
 		self.graphics_context.write_to(buf)?;
@@ -2470,7 +2488,7 @@ impl Writable for DrawText16 {
 		buf.put_u8(Self::MAJOR_OPCODE);
 		// Unused metabyte position.
 		buf.put_u8(0);
-		buf.put_u16(self.length());
+		write_size(self, buf);
 
 		self.target.write_to(buf)?;
 		self.graphics_context.write_to(buf)?;

src/x11/request/input.rs

@@ -21,6 +21,7 @@ use xrbk::{
 	ReadResult,
 	Readable,
 	Writable,
+	WriteError,
 	WriteResult,
 	X11Size,
 };
@@ -1439,7 +1440,15 @@ impl<const KEYSYMS_PER_KEYCODE: usize> Writable for ChangeKeyboardMapping<KEYSYM
 	#[allow(clippy::cast_possible_truncation)]
 	fn write_to(&self, buf: &mut impl BufMut) -> WriteResult {
 		// Limit `buf` by the length (converted to bytes).
+		#[cfg(not(feature = "big-requests"))]
 		let buf = &mut buf.limit(usize::from(self.length()) * 4);
+		#[cfg(feature = "big-requests")]
+		let size = match usize::try_from(self.length()) {
+			Ok(size) => size * 4,
+
+			Err(error) => return Err(WriteError::Other(Box::new(error))),
+		};
+		let buf = &mut buf.limit(size);
 
 		// The major opcode.
 		Self::MAJOR_OPCODE.write_to(buf)?;

xrbk_macro/src/definition/expansion/message_trait.rs

@@ -55,10 +55,17 @@ impl Request {
 						#minor_opcode
 					};
 
+					#[cfg(not(feature = "big-requests"))]
 					#[allow(clippy::cast_possible_truncation)]
 					fn length(&self) -> u16 {
 						(<Self as ::xrbk::X11Size>::x11_size(self) / 4) as u16
 					}
+
+					#[cfg(feature = "big-requests")]
+					#[allow(clippy::cast_possible_truncation)]
+					fn length(&self) -> u32 {
+						(<Self as ::xrbk::X11Size>::x11_size(self) / 4) as u32
+					}
 				}
 			)
 		});

xrbk_macro/src/definition/expansion/readable.rs

@@ -128,7 +128,14 @@ impl Request {
 					// read.
 					#metabyte
 					// Read the request's length.
+					#[cfg(not(feature = "big-requests"))]
 					let length = <_ as ::xrbk::Buf>::get_u16(buf);
+					#[cfg(feature = "big-requests")]
+					let length = match <_ as ::xrbk::Buf>::get_u16(buf) as u32 {
+						0 => <_ as ::xrbk::Buf>::get_u32(buf),
+						length => length,
+					};
+
 					let buf = &mut <_ as ::xrbk::Buf>::take(
 						buf,
 						((length - 1) as usize) * 4,

xrbk_macro/src/definition/expansion/writable.rs

@@ -137,10 +137,32 @@ impl Request {
 					// Metabyte position
 					#metabyte
 					// Length
+					#[cfg(not(feature = "big-requests"))]
 					<_ as ::xrbk::BufMut>::put_u16(
 						buf,
 						<Self as xrb::message::Request>::length(&self),
 					);
+					#[cfg(feature = "big-requests")]
+					{
+						let length = <Self as xrb::message::Request>::length(&self);
+						match u16::try_from(length) {
+							Ok(length) => <_ as ::xrbk::BufMut>::put_u16(
+								buf,
+								length
+							),
+							// length is too big for u16, using the extended length field
+							Err(_) => {
+								<_ as ::xrbk::BufMut>::put_u16(
+									buf,
+									0,
+								);
+								<_ as ::xrbk::BufMut>::put_u32(
+									buf,
+									length,
+								);
+							},
+						}
+					}
 
 					// Other elements
 					#writes