From 9adb59bcdb61a06792bec1bee468a900ad5118f5 Mon Sep 17 00:00:00 2001 From: Philippe Antoine Date: Thu, 16 Mar 2023 09:20:40 +0100 Subject: [PATCH] http2: faster when reducing dynamic headers size avoid quadratic complexity from removing the first element and copying all the contents a big number fo times. Ticket: #5909 --- rust/src/http2/parser.rs | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/rust/src/http2/parser.rs b/rust/src/http2/parser.rs index 6ed570e09a..7c8c88101e 100644 --- a/rust/src/http2/parser.rs +++ b/rust/src/http2/parser.rs @@ -456,7 +456,8 @@ fn http2_parse_headers_block_literal_incindex<'a>( } else { dyn_headers.table.push(headcopy); } - while dyn_headers.current_size > dyn_headers.max_size && !dyn_headers.table.is_empty() + while dyn_headers.current_size > dyn_headers.max_size + && !dyn_headers.table.is_empty() { dyn_headers.current_size -= 32 + dyn_headers.table[0].name.len() + dyn_headers.table[0].value.len(); @@ -539,13 +540,16 @@ fn http2_parse_headers_block_dynamic_size<'a>( if (maxsize2 as usize) < dyn_headers.max_size { //dyn_headers.max_size is updated later with all headers //may evict entries - while dyn_headers.current_size > (maxsize2 as usize) && !dyn_headers.table.is_empty() { + let mut toremove = 0; + while dyn_headers.current_size > (maxsize2 as usize) && toremove < dyn_headers.table.len() { // we check dyn_headers.table as we may be in best effort // because the previous maxsize was too big for us to retain all the headers - dyn_headers.current_size -= - 32 + dyn_headers.table[0].name.len() + dyn_headers.table[0].value.len(); - dyn_headers.table.remove(0); + dyn_headers.current_size -= 32 + + dyn_headers.table[toremove].name.len() + + dyn_headers.table[toremove].value.len(); + toremove += 1; } + dyn_headers.table.drain(0..toremove); } return Ok(( i3, -- 2.47.2