From 9b04250ec3051d262ebaf7b7e262507996118a67 Mon Sep 17 00:00:00 2001
From: Ivan Kalinin <i.kalinin@dexpa.io>
Date: Thu, 28 Nov 2024 17:01:12 +0100
Subject: [PATCH] Simplify `TlPacket`

---
 proc/src/tl_write.rs |  6 +++---
 src/hasher.rs        | 10 ++++++++--
 src/lib.rs           |  5 +++++
 src/traits.rs        | 28 ++++++++++++++--------------
 4 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/proc/src/tl_write.rs b/proc/src/tl_write.rs
index 48c3df6..419b2a6 100644
--- a/proc/src/tl_write.rs
+++ b/proc/src/tl_write.rs
@@ -342,10 +342,10 @@ where
 
                     if field.attrs.signature {
                         quote! {
-                        if <P_ as _tl_proto::TlPacket>::TARGET == _tl_proto::TlTarget::Packet {
-                            #write_to
-                        } else {
+                        if _tl_proto::__internal::unlikely(<P_ as _tl_proto::TlPacket>::ignore_signature(__packet)) {
                             <&[u8] as _tl_proto::TlWrite>::write_to::<P_>(&[].as_ref(), __packet);
+                        } else {
+                            #write_to
                         }
                     }
                     } else {
diff --git a/src/hasher.rs b/src/hasher.rs
index 1d2d890..d398ec1 100644
--- a/src/hasher.rs
+++ b/src/hasher.rs
@@ -29,7 +29,10 @@ impl<T> TlPacket for DigestWriter<'_, T>
 where
     T: digest::Update,
 {
-    const TARGET: TlTarget = TlTarget::Hasher;
+    #[inline(always)]
+    fn ignore_signature(&self) -> bool {
+        true
+    }
 
     #[inline(always)]
     fn write_u32(&mut self, data: u32) {
@@ -69,7 +72,10 @@ where
 struct HashWriter<'a>(pub &'a mut dyn Hasher);
 
 impl<'a> TlPacket for HashWriter<'a> {
-    const TARGET: TlTarget = TlTarget::Hasher;
+    #[inline(always)]
+    fn ignore_signature(&self) -> bool {
+        true
+    }
 
     #[inline(always)]
     fn write_u32(&mut self, data: u32) {
diff --git a/src/lib.rs b/src/lib.rs
index a0b2697..1d00bb8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -132,3 +132,8 @@ where
 {
     hash(data.into_boxed())
 }
+
+#[doc(hidden)]
+pub mod __internal {
+    pub use crate::util::unlikely;
+}
diff --git a/src/traits.rs b/src/traits.rs
index b5a6682..6608988 100644
--- a/src/traits.rs
+++ b/src/traits.rs
@@ -132,8 +132,8 @@ where
 
 /// TL packet interface.
 pub trait TlPacket {
-    /// TL packet type.
-    const TARGET: TlTarget;
+    /// Whether this packet type excludes signatures.
+    fn ignore_signature(&self) -> bool;
 
     /// Writes `u32` to the packet.
     fn write_u32(&mut self, data: u32);
@@ -148,7 +148,10 @@ pub trait TlPacket {
 }
 
 impl TlPacket for Vec<u8> {
-    const TARGET: TlTarget = TlTarget::Packet;
+    #[inline(always)]
+    fn ignore_signature(&self) -> bool {
+        false
+    }
 
     #[inline(always)]
     fn write_u32(&mut self, data: u32) {
@@ -178,7 +181,10 @@ impl TlPacket for Vec<u8> {
 
 #[cfg(feature = "bytes")]
 impl TlPacket for bytes::BytesMut {
-    const TARGET: TlTarget = TlTarget::Packet;
+    #[inline(always)]
+    fn ignore_signature(&self) -> bool {
+        false
+    }
 
     #[inline(always)]
     fn write_u32(&mut self, data: u32) {
@@ -241,7 +247,10 @@ impl<W> IoWriter<W> {
 }
 
 impl<W: std::io::Write> TlPacket for IoWriter<W> {
-    const TARGET: TlTarget = TlTarget::Packet;
+    #[inline(always)]
+    fn ignore_signature(&self) -> bool {
+        false
+    }
 
     #[inline(always)]
     fn write_u32(&mut self, data: u32) {
@@ -275,15 +284,6 @@ impl<W: std::io::Write> TlPacket for IoWriter<W> {
     }
 }
 
-/// TL packet type.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-pub enum TlTarget {
-    /// Ordinary packet (bytes).
-    Packet,
-    /// Hasher packet (to compute TL hash without allocations).
-    Hasher,
-}
-
 /// TL result wrapper.
 pub type TlResult<T> = Result<T, TlError>;