Improve buffering performance

Cargo.lock

@@ -1043,6 +1043,7 @@ name = "sailfish"
 version = "0.1.0"
 dependencies = [
  "ryu 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1347,6 +1348,11 @@ dependencies = [
  "percent-encoding 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "version_check"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"
@@ -1561,6 +1567,7 @@ dependencies = [
 "checksum unicode-segmentation 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e83e153d1053cbb5a118eeff7fd5be06ed99153f00dbcd8ae310c5fb2b22edc0"
 "checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
 "checksum url 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "829d4a8476c35c9bf0bbce5a3b23f4106f79728039b726d292bb93bc106787cb"
+"checksum version_check 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 "checksum wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)" = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 "checksum widestring 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "effc0e4ff8085673ea7b9b2e3c73f6bd4d118810c9009ed8f1e16bd96c331db6"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"

sailfish/Cargo.toml

@@ -14,3 +14,6 @@ edition = "2018"
 
 [dependencies]
 ryu = "1.0.4"
+
+[build-dependencies]
+version_check = "0.9.2"

sailfish/build.rs

@@ -0,0 +1,5 @@
+fn main() {
+    if version_check::is_feature_flaggable() == Some(true) {
+        println!("cargo:rustc-cfg=sailfish_nightly");
+    }
+}

sailfish/src/lib.rs

@@ -34,6 +34,7 @@
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/Kogia-sima/sailfish/master/resources/icon.png"
 )]
+#![cfg_attr(sailfish_nightly, feature(core_intrinsics))]
 
 pub mod runtime;
 

sailfish/src/runtime/buffer.rs

@@ -4,6 +4,20 @@ use std::mem::{align_of, ManuallyDrop};
 use std::ops::{Add, AddAssign};
 use std::ptr;
 
+#[cfg(sailfish_nightly)]
+macro_rules! unlikely {
+    ($val:expr) => {
+        std::intrinsics::unlikely($val)
+    };
+}
+
+#[cfg(not(sailfish_nightly))]
+macro_rules! unlikely {
+    ($val:expr) => {
+        $val
+    };
+}
+
 /// Buffer for rendered contents
 ///
 /// This struct is quite simular to `String`, but some methods are
@@ -86,7 +100,7 @@ impl Buffer {
 
     #[inline]
     pub fn reserve(&mut self, size: usize) {
-        if size > self.capacity - self.len {
+        if unlikely!(self.len + size > self.capacity) {
             self.reserve_internal(size);
         }
     }
@@ -105,9 +119,7 @@ impl Buffer {
     #[inline]
     pub fn push_str(&mut self, data: &str) {
         let size = data.len();
-        if size > self.capacity - self.len {
-            self.reserve_internal(size);
-        }
+        self.reserve(size);
         unsafe {
             let p = self.data.add(self.len);
             std::ptr::copy_nonoverlapping(data.as_ptr(), p, size);
@@ -121,28 +133,31 @@ impl Buffer {
         self.push_str(data.encode_utf8(&mut buf));
     }
 
-    #[inline(never)]
+    #[inline]
     fn reserve_internal(&mut self, size: usize) {
         unsafe {
             let new_capacity = std::cmp::max(self.capacity * 2, self.len + size);
-            self.realloc(new_capacity);
+            self.data = self.realloc(new_capacity);
             self.capacity = new_capacity;
         }
     }
 
-    unsafe fn realloc(&mut self, cap: usize) {
-        if self.capacity == 0 {
+    #[inline]
+    unsafe fn realloc(&self, cap: usize) -> *mut u8 {
+        let data = if unlikely!(self.capacity == 0) {
             let new_layout = Layout::from_size_align_unchecked(cap, 1);
-            self.data = alloc(new_layout);
+            alloc(new_layout)
         } else {
-            assert!(cap <= std::usize::MAX / 2, "capacity is too large");
+            debug_assert!(cap <= std::usize::MAX / 2, "capacity is too large");
             let old_layout = Layout::from_size_align_unchecked(self.capacity, 1);
-            self.data = realloc(self.data, old_layout, cap);
-        }
+            realloc(self.data, old_layout, cap)
+        };
 
-        if self.data.is_null() {
+        if data.is_null() {
             handle_alloc_error(Layout::from_size_align_unchecked(cap, 1));
         }
+
+        data
     }
 }
 

sailfish/src/runtime/mod.rs

@@ -55,3 +55,20 @@ impl Context {
         Ok(self.buf.into_string())
     }
 }
+
+// #[inline(never)]
+// pub fn _instantiate(table: Vec<Vec<usize>>) -> String {
+//     let mut buffer = Buffer::with_capacity(130000);
+//     buffer.push_str("<table>");
+//     for r1 in table {
+//         buffer.push_str("<tr><td>");
+//         for r2 in r1 {
+//             let _ = (&r2).render(&mut buffer);
+//             buffer.push_str("</td><td>");
+//         }
+//         unsafe { buffer.set_len(buffer.len() - 4) }
+//         buffer.push_str("</tr>");
+//     }
+//     buffer.push_str("</table>");
+//     buffer.into_string()
+// }