1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142

use darling::FromMeta;
use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::quote;
use syn::{AttributeArgs, ItemFn};

#[derive(Debug, FromMeta)]
struct MacroArgs {
    #[darling(default)]
    printer: Option<String>,
    #[darling(default)]
    tracing: Option<bool>,
}

// struct Tracing;
// impl Drop for Tracing {
//     fn drop(&mut self) {
//         let traces = TRACES.lock().unwrap();
//         println!("Begin Dumping traces:\n-----");
//         println!("[");
//         for i in 0..traces.len() {
//             println!("    {}{}", traces[i], if i == traces.len() - 1 { "" } else { ","});
//         }
//         println!("]");
//         println!("-----\nEnd Dumping traces");
//     }
// }

use proc_macro2::TokenStream as Code;

fn codegen_tracing(options: &MacroArgs, function_name: &str) -> (Option<Code>, Option<Code>) {
    if let Some(true) = options.tracing {
        let begin = quote! {
            {
                let ts = std::time::SystemTime::now()
                    .duration_since(std::time::SystemTime::UNIX_EPOCH)
                    .unwrap()
                    .as_micros();
                timed::Trace::collect(timed::Hop { ph: timed::Phase::B, name: #function_name.to_string(), ts});
            }
        };
        let end = quote! {
            {
                let ts = std::time::SystemTime::now()
                    .duration_since(std::time::SystemTime::UNIX_EPOCH)
                    .unwrap()
                    .as_micros();
                timed::Trace::collect(timed::Hop { ph: timed::Phase::E, name: #function_name.to_string(), ts});
            }
        };
        (Some(begin), Some(end))
    } else {
        (None, None)
    }
}

fn codegen_duration(
    printer: &proc_macro2::TokenStream,
    function_name: &syn::Ident,
) -> proc_macro2::TokenStream {
    quote! {
        #printer("function={} duration={:?}", stringify!(#function_name), start.elapsed());
    }
}

fn codegen_printer(options: &MacroArgs) -> proc_macro2::TokenStream {
    let (printer, needs_bang) = match &options.printer {
        Some(printer) => {
            if printer.ends_with('!') {
                (&printer[..&printer.len() - 1], true)
            } else {
                (printer.as_str(), false)
            }
        }
        None => ("println", true),
    };

    let bang = if needs_bang {
        Some(syn::token::Bang(Span::call_site()))
    } else {
        None
    };

    let printer = syn::Ident::new(printer, Span::call_site());
    quote! {
        #printer#bang
    }
}

/// Macro that times your function execution.
#[proc_macro_attribute]
pub fn timed(args: TokenStream, input: TokenStream) -> TokenStream {
    //! ```text
    //! Call this using #[timed]
    //! It will print by default with `println!`
    //! If you want to change the printer you can use #[timed(printer = "info!")]
    //! or any other macro or function that takes in a String.`
    //! ```
    //!
    //! ```ignore
    //! #[timed(printer = "println!")]
    //! ```
    // debug!("Args {:?}", args);
    let options = syn::parse_macro_input!(args as AttributeArgs);
    let function = syn::parse_macro_input!(input as ItemFn);

    // Parse options
    let options: MacroArgs = match MacroArgs::from_list(&options) {
        Ok(v) => v,
        Err(e) => return TokenStream::from(e.write_errors()),
    };
    // debug!("Parsed options {:?}", options);

    // Parse function sig
    let ItemFn {
        attrs,
        vis,
        sig,
        block: body,
        ..
    } = &function;

    let name = &function.sig.ident;
    let printer = codegen_printer(&options);
    let print_duration = codegen_duration(&printer, &name);
    let (tracing_begin, tracing_end) = codegen_tracing(&options, &name.to_string());

    let result = quote! {
        #(#attrs)*
        #vis #sig {
           #tracing_begin
           let start = std::time::Instant::now();
           let res = { #body };
           #print_duration
           #tracing_end
           res
        }
    };

    let res: proc_macro::TokenStream = result.into();
    res
}