how to calculate hash of stylesheet

[stormslowly]

use std::hash::{Hash, Hasher};
use swc_common::{FileName, SourceMap};
use swc_common::input::StringInput;
use swc_common::sync::Lrc;
use std::borrow::Borrow;

fn main() {
    let cm: Lrc<SourceMap> = Default::default();

    let fm = cm
        .new_source_file(FileName::Real("test.css".into()), "h1 {color : red; }".to_string());
        // .new_source_file(FileName::Real("test.css".into()), "".to_string());   // OK

    let lexer = swc_css_parser::lexer::Lexer::new(StringInput::from(&*fm), None, Default::default());
    let mut parser = swc_css_parser::parser::Parser::new(lexer, Default::default());
    let stylesheet = parser.parse_all().unwrap();

    let mut hasher = std::collections::hash_map::DefaultHasher::new();
    stylesheet.hash(&mut hasher);
    let h = hasher.finish();

    println!("hash: {}", h);
}

cargo run got

    Finished dev [unoptimized + debuginfo] target(s) in 1.60s
     Running `target/debug/styleshee_hash`

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
Abort trap: 6

[kdy1]

I think it's the correct way. Did you try setting RUST_MIN_STACK?

[stormslowly]

$RUST_MIN_STACK=800000000  cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.19s
     Running `target/debug/styleshee_hash`

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
Abort trap: 6

Same error

if i run in release mode cargo run -r, cargo stucked.

and the stylesheet in example is very small .

[kdy1]

Then please post the stack trace

[stormslowly]

Stack Overflow:
   0: backtrace::backtrace::libunwind::trace
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/backtrace-0.3.69/src/backtrace/libunwind.rs:93:5
      backtrace::backtrace::trace_unsynchronized
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/backtrace-0.3.69/src/backtrace/mod.rs:66:5
   1: backtrace::backtrace::trace
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/backtrace-0.3.69/src/backtrace/mod.rs:53:14
   2: backtrace::capture::Backtrace::create
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/backtrace-0.3.69/src/capture.rs:176:9
   3: backtrace::capture::Backtrace::new
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/backtrace-0.3.69/src/capture.rs:140:22
   4: backtrace_on_stack_overflow::handle_sigsegv
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/backtrace-on-stack-overflow-0.3.0/src/lib.rs:94:40
   5: __platform_memmove
   6: <swc_css_ast::token::Token as core::hash::Hash>::hash
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/swc_css_ast-0.140.0/src/token.rs:268:17
   7: <swc_css_ast::token::Token as core::hash::Hash>::hash
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/swc_css_ast-0.140.0/src/token.rs:268:17
   8: <swc_css_ast::token::Token as core::hash::Hash>::hash
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/swc_css_ast-0.140.0/src/token.rs:268:17
   9: <swc_css_ast::token::Token as core::hash::Hash>::hash
             at /Users/me/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/swc_css_ast-0.140.0/src/token.rs:268:17
  10: <swc_css_ast::token::Token as core::hash::Hash>::hash

[stormslowly]

it repeats ...../src/token.rs:268:17 for many times; the full log file is 94M, just post the start part.

[stormslowly]

            Token::CDO
            | Token::CDC
            | Token::Colon
            | Token::Semi
            | Token::Comma
            | Token::LBracket
            | Token::RBracket
            | Token::LParen
            | Token::RParen
            | Token::LBrace
            | Token::RBrace => {
                self.hash(state);
            }

calling self.hash trigger a dead loop

[stormslowly]

i think maybe we can just delete self.hash(state); these kinds of tokens are just delimiters, so they dont need to be hashed.

[kdy1]

It should be derived I guess. Will you send a PR?