1 | use std::collections::HashSet; |
2 | use syn::{punctuated::Punctuated, Expr, Ident, LitInt, LitStr, Path, Token}; |
3 | |
4 | use proc_macro2::TokenStream; |
5 | use quote::{quote, quote_spanned, ToTokens}; |
6 | use syn::ext::IdentExt as _; |
7 | use syn::parse::{Parse, ParseStream}; |
8 | |
9 | /// Arguments to `#[instrument(err(...))]` and `#[instrument(ret(...))]` which describe how the |
10 | /// return value event should be emitted. |
11 | #[derive(Clone, Default, Debug)] |
12 | pub(crate) struct EventArgs { |
13 | level: Option<Level>, |
14 | pub(crate) mode: FormatMode, |
15 | } |
16 | |
17 | #[derive(Clone, Default, Debug)] |
18 | pub(crate) struct InstrumentArgs { |
19 | level: Option<Level>, |
20 | pub(crate) name: Option<LitStr>, |
21 | target: Option<LitStr>, |
22 | pub(crate) parent: Option<Expr>, |
23 | pub(crate) follows_from: Option<Expr>, |
24 | pub(crate) skips: HashSet<Ident>, |
25 | pub(crate) skip_all: bool, |
26 | pub(crate) fields: Option<Fields>, |
27 | pub(crate) err_args: Option<EventArgs>, |
28 | pub(crate) ret_args: Option<EventArgs>, |
29 | /// Errors describing any unrecognized parse inputs that we skipped. |
30 | parse_warnings: Vec<syn::Error>, |
31 | } |
32 | |
33 | impl InstrumentArgs { |
34 | pub(crate) fn level(&self) -> Level { |
35 | self.level.clone().unwrap_or(Level::Info) |
36 | } |
37 | |
38 | pub(crate) fn target(&self) -> impl ToTokens { |
39 | if let Some(ref target) = self.target { |
40 | quote!(#target) |
41 | } else { |
42 | quote!(module_path!()) |
43 | } |
44 | } |
45 | |
46 | /// Generate "deprecation" warnings for any unrecognized attribute inputs |
47 | /// that we skipped. |
48 | /// |
49 | /// For backwards compatibility, we need to emit compiler warnings rather |
50 | /// than errors for unrecognized inputs. Generating a fake deprecation is |
51 | /// the only way to do this on stable Rust right now. |
52 | pub(crate) fn warnings(&self) -> impl ToTokens { |
53 | let warnings = self.parse_warnings.iter().map(|err| { |
54 | let msg = format!("found unrecognized input, {}" , err); |
55 | let msg = LitStr::new(&msg, err.span()); |
56 | // TODO(eliza): This is a bit of a hack, but it's just about the |
57 | // only way to emit warnings from a proc macro on stable Rust. |
58 | // Eventually, when the `proc_macro::Diagnostic` API stabilizes, we |
59 | // should definitely use that instead. |
60 | quote_spanned! {err.span()=> |
61 | #[warn(deprecated)] |
62 | { |
63 | #[deprecated(since = "not actually deprecated" , note = #msg)] |
64 | const TRACING_INSTRUMENT_WARNING: () = (); |
65 | let _ = TRACING_INSTRUMENT_WARNING; |
66 | } |
67 | } |
68 | }); |
69 | quote! { |
70 | { #(#warnings)* } |
71 | } |
72 | } |
73 | } |
74 | |
75 | impl Parse for InstrumentArgs { |
76 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
77 | let mut args = Self::default(); |
78 | while !input.is_empty() { |
79 | let lookahead = input.lookahead1(); |
80 | if lookahead.peek(kw::name) { |
81 | if args.name.is_some() { |
82 | return Err(input.error("expected only a single `name` argument" )); |
83 | } |
84 | let name = input.parse::<StrArg<kw::name>>()?.value; |
85 | args.name = Some(name); |
86 | } else if lookahead.peek(LitStr) { |
87 | // XXX: apparently we support names as either named args with an |
88 | // sign, _or_ as unnamed string literals. That's weird, but |
89 | // changing it is apparently breaking. |
90 | if args.name.is_some() { |
91 | return Err(input.error("expected only a single `name` argument" )); |
92 | } |
93 | args.name = Some(input.parse()?); |
94 | } else if lookahead.peek(kw::target) { |
95 | if args.target.is_some() { |
96 | return Err(input.error("expected only a single `target` argument" )); |
97 | } |
98 | let target = input.parse::<StrArg<kw::target>>()?.value; |
99 | args.target = Some(target); |
100 | } else if lookahead.peek(kw::parent) { |
101 | if args.target.is_some() { |
102 | return Err(input.error("expected only a single `parent` argument" )); |
103 | } |
104 | let parent = input.parse::<ExprArg<kw::parent>>()?; |
105 | args.parent = Some(parent.value); |
106 | } else if lookahead.peek(kw::follows_from) { |
107 | if args.target.is_some() { |
108 | return Err(input.error("expected only a single `follows_from` argument" )); |
109 | } |
110 | let follows_from = input.parse::<ExprArg<kw::follows_from>>()?; |
111 | args.follows_from = Some(follows_from.value); |
112 | } else if lookahead.peek(kw::level) { |
113 | if args.level.is_some() { |
114 | return Err(input.error("expected only a single `level` argument" )); |
115 | } |
116 | args.level = Some(input.parse()?); |
117 | } else if lookahead.peek(kw::skip) { |
118 | if !args.skips.is_empty() { |
119 | return Err(input.error("expected only a single `skip` argument" )); |
120 | } |
121 | if args.skip_all { |
122 | return Err(input.error("expected either `skip` or `skip_all` argument" )); |
123 | } |
124 | let Skips(skips) = input.parse()?; |
125 | args.skips = skips; |
126 | } else if lookahead.peek(kw::skip_all) { |
127 | if args.skip_all { |
128 | return Err(input.error("expected only a single `skip_all` argument" )); |
129 | } |
130 | if !args.skips.is_empty() { |
131 | return Err(input.error("expected either `skip` or `skip_all` argument" )); |
132 | } |
133 | let _ = input.parse::<kw::skip_all>()?; |
134 | args.skip_all = true; |
135 | } else if lookahead.peek(kw::fields) { |
136 | if args.fields.is_some() { |
137 | return Err(input.error("expected only a single `fields` argument" )); |
138 | } |
139 | args.fields = Some(input.parse()?); |
140 | } else if lookahead.peek(kw::err) { |
141 | let _ = input.parse::<kw::err>(); |
142 | let err_args = EventArgs::parse(input)?; |
143 | args.err_args = Some(err_args); |
144 | } else if lookahead.peek(kw::ret) { |
145 | let _ = input.parse::<kw::ret>()?; |
146 | let ret_args = EventArgs::parse(input)?; |
147 | args.ret_args = Some(ret_args); |
148 | } else if lookahead.peek(Token![,]) { |
149 | let _ = input.parse::<Token![,]>()?; |
150 | } else { |
151 | // We found a token that we didn't expect! |
152 | // We want to emit warnings for these, rather than errors, so |
153 | // we'll add it to the list of unrecognized inputs we've seen so |
154 | // far and keep going. |
155 | args.parse_warnings.push(lookahead.error()); |
156 | // Parse the unrecognized token tree to advance the parse |
157 | // stream, and throw it away so we can keep parsing. |
158 | let _ = input.parse::<proc_macro2::TokenTree>(); |
159 | } |
160 | } |
161 | Ok(args) |
162 | } |
163 | } |
164 | |
165 | impl EventArgs { |
166 | pub(crate) fn level(&self, default: Level) -> Level { |
167 | self.level.clone().unwrap_or(default) |
168 | } |
169 | } |
170 | |
171 | impl Parse for EventArgs { |
172 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
173 | if !input.peek(syn::token::Paren) { |
174 | return Ok(Self::default()); |
175 | } |
176 | let content; |
177 | let _ = syn::parenthesized!(content in input); |
178 | let mut result = Self::default(); |
179 | let mut parse_one_arg = |
180 | || { |
181 | let lookahead = content.lookahead1(); |
182 | if lookahead.peek(kw::level) { |
183 | if result.level.is_some() { |
184 | return Err(content.error("expected only a single `level` argument" )); |
185 | } |
186 | result.level = Some(content.parse()?); |
187 | } else if result.mode != FormatMode::default() { |
188 | return Err(content.error("expected only a single format argument" )); |
189 | } else if let Some(ident) = content.parse::<Option<Ident>>()? { |
190 | match ident.to_string().as_str() { |
191 | "Debug" => result.mode = FormatMode::Debug, |
192 | "Display" => result.mode = FormatMode::Display, |
193 | _ => return Err(syn::Error::new( |
194 | ident.span(), |
195 | "unknown event formatting mode, expected either `Debug` or `Display`" , |
196 | )), |
197 | } |
198 | } |
199 | Ok(()) |
200 | }; |
201 | parse_one_arg()?; |
202 | if !content.is_empty() { |
203 | if content.lookahead1().peek(Token![,]) { |
204 | let _ = content.parse::<Token![,]>()?; |
205 | parse_one_arg()?; |
206 | } else { |
207 | return Err(content.error("expected `,` or `)`" )); |
208 | } |
209 | } |
210 | Ok(result) |
211 | } |
212 | } |
213 | |
214 | struct StrArg<T> { |
215 | value: LitStr, |
216 | _p: std::marker::PhantomData<T>, |
217 | } |
218 | |
219 | impl<T: Parse> Parse for StrArg<T> { |
220 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
221 | let _ = input.parse::<T>()?; |
222 | let _ = input.parse::<Token![=]>()?; |
223 | let value = input.parse()?; |
224 | Ok(Self { |
225 | value, |
226 | _p: std::marker::PhantomData, |
227 | }) |
228 | } |
229 | } |
230 | |
231 | struct ExprArg<T> { |
232 | value: Expr, |
233 | _p: std::marker::PhantomData<T>, |
234 | } |
235 | |
236 | impl<T: Parse> Parse for ExprArg<T> { |
237 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
238 | let _ = input.parse::<T>()?; |
239 | let _ = input.parse::<Token![=]>()?; |
240 | let value = input.parse()?; |
241 | Ok(Self { |
242 | value, |
243 | _p: std::marker::PhantomData, |
244 | }) |
245 | } |
246 | } |
247 | |
248 | struct Skips(HashSet<Ident>); |
249 | |
250 | impl Parse for Skips { |
251 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
252 | let _ = input.parse::<kw::skip>(); |
253 | let content; |
254 | let _ = syn::parenthesized!(content in input); |
255 | let names = content.parse_terminated(Ident::parse_any, Token![,])?; |
256 | let mut skips = HashSet::new(); |
257 | for name in names { |
258 | if skips.contains(&name) { |
259 | return Err(syn::Error::new( |
260 | name.span(), |
261 | "tried to skip the same field twice" , |
262 | )); |
263 | } else { |
264 | skips.insert(name); |
265 | } |
266 | } |
267 | Ok(Self(skips)) |
268 | } |
269 | } |
270 | |
271 | #[derive(Clone, Debug, Hash, PartialEq, Eq)] |
272 | pub(crate) enum FormatMode { |
273 | Default, |
274 | Display, |
275 | Debug, |
276 | } |
277 | |
278 | impl Default for FormatMode { |
279 | fn default() -> Self { |
280 | FormatMode::Default |
281 | } |
282 | } |
283 | |
284 | #[derive(Clone, Debug)] |
285 | pub(crate) struct Fields(pub(crate) Punctuated<Field, Token![,]>); |
286 | |
287 | #[derive(Clone, Debug)] |
288 | pub(crate) struct Field { |
289 | pub(crate) name: Punctuated<Ident, Token![.]>, |
290 | pub(crate) value: Option<Expr>, |
291 | pub(crate) kind: FieldKind, |
292 | } |
293 | |
294 | #[derive(Clone, Debug, Eq, PartialEq)] |
295 | pub(crate) enum FieldKind { |
296 | Debug, |
297 | Display, |
298 | Value, |
299 | } |
300 | |
301 | impl Parse for Fields { |
302 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
303 | let _ = input.parse::<kw::fields>(); |
304 | let content; |
305 | let _ = syn::parenthesized!(content in input); |
306 | let fields = content.parse_terminated(Field::parse, Token![,])?; |
307 | Ok(Self(fields)) |
308 | } |
309 | } |
310 | |
311 | impl ToTokens for Fields { |
312 | fn to_tokens(&self, tokens: &mut TokenStream) { |
313 | self.0.to_tokens(tokens) |
314 | } |
315 | } |
316 | |
317 | impl Parse for Field { |
318 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
319 | let mut kind = FieldKind::Value; |
320 | if input.peek(Token![%]) { |
321 | input.parse::<Token![%]>()?; |
322 | kind = FieldKind::Display; |
323 | } else if input.peek(Token![?]) { |
324 | input.parse::<Token![?]>()?; |
325 | kind = FieldKind::Debug; |
326 | }; |
327 | let name = Punctuated::parse_separated_nonempty_with(input, Ident::parse_any)?; |
328 | let value = if input.peek(Token![=]) { |
329 | input.parse::<Token![=]>()?; |
330 | if input.peek(Token![%]) { |
331 | input.parse::<Token![%]>()?; |
332 | kind = FieldKind::Display; |
333 | } else if input.peek(Token![?]) { |
334 | input.parse::<Token![?]>()?; |
335 | kind = FieldKind::Debug; |
336 | }; |
337 | Some(input.parse()?) |
338 | } else { |
339 | None |
340 | }; |
341 | Ok(Self { name, value, kind }) |
342 | } |
343 | } |
344 | |
345 | impl ToTokens for Field { |
346 | fn to_tokens(&self, tokens: &mut TokenStream) { |
347 | if let Some(ref value) = self.value { |
348 | let name = &self.name; |
349 | let kind = &self.kind; |
350 | tokens.extend(quote! { |
351 | #name = #kind #value |
352 | }) |
353 | } else if self.kind == FieldKind::Value { |
354 | // XXX(eliza): I don't like that fields without values produce |
355 | // empty fields rather than local variable shorthand...but, |
356 | // we've released a version where field names without values in |
357 | // `instrument` produce empty field values, so changing it now |
358 | // is a breaking change. agh. |
359 | let name = &self.name; |
360 | tokens.extend(quote!(#name = tracing::field::Empty)) |
361 | } else { |
362 | self.kind.to_tokens(tokens); |
363 | self.name.to_tokens(tokens); |
364 | } |
365 | } |
366 | } |
367 | |
368 | impl ToTokens for FieldKind { |
369 | fn to_tokens(&self, tokens: &mut TokenStream) { |
370 | match self { |
371 | FieldKind::Debug => tokens.extend(quote! { ? }), |
372 | FieldKind::Display => tokens.extend(quote! { % }), |
373 | _ => {} |
374 | } |
375 | } |
376 | } |
377 | |
378 | #[derive(Clone, Debug)] |
379 | pub(crate) enum Level { |
380 | Trace, |
381 | Debug, |
382 | Info, |
383 | Warn, |
384 | Error, |
385 | Path(Path), |
386 | } |
387 | |
388 | impl Parse for Level { |
389 | fn parse(input: ParseStream<'_>) -> syn::Result<Self> { |
390 | let _ = input.parse::<kw::level>()?; |
391 | let _ = input.parse::<Token![=]>()?; |
392 | let lookahead = input.lookahead1(); |
393 | if lookahead.peek(LitStr) { |
394 | let str: LitStr = input.parse()?; |
395 | match str.value() { |
396 | s if s.eq_ignore_ascii_case("trace" ) => Ok(Level::Trace), |
397 | s if s.eq_ignore_ascii_case("debug" ) => Ok(Level::Debug), |
398 | s if s.eq_ignore_ascii_case("info" ) => Ok(Level::Info), |
399 | s if s.eq_ignore_ascii_case("warn" ) => Ok(Level::Warn), |
400 | s if s.eq_ignore_ascii_case("error" ) => Ok(Level::Error), |
401 | _ => Err(input.error( |
402 | "unknown verbosity level, expected one of \"trace \", \ |
403 | \"debug \", \"info \", \"warn \", or \"error \", or a number 1-5" , |
404 | )), |
405 | } |
406 | } else if lookahead.peek(LitInt) { |
407 | fn is_level(lit: &LitInt, expected: u64) -> bool { |
408 | match lit.base10_parse::<u64>() { |
409 | Ok(value) => value == expected, |
410 | Err(_) => false, |
411 | } |
412 | } |
413 | let int: LitInt = input.parse()?; |
414 | match &int { |
415 | i if is_level(i, 1) => Ok(Level::Trace), |
416 | i if is_level(i, 2) => Ok(Level::Debug), |
417 | i if is_level(i, 3) => Ok(Level::Info), |
418 | i if is_level(i, 4) => Ok(Level::Warn), |
419 | i if is_level(i, 5) => Ok(Level::Error), |
420 | _ => Err(input.error( |
421 | "unknown verbosity level, expected one of \"trace \", \ |
422 | \"debug \", \"info \", \"warn \", or \"error \", or a number 1-5" , |
423 | )), |
424 | } |
425 | } else if lookahead.peek(Ident) { |
426 | Ok(Self::Path(input.parse()?)) |
427 | } else { |
428 | Err(lookahead.error()) |
429 | } |
430 | } |
431 | } |
432 | |
433 | impl ToTokens for Level { |
434 | fn to_tokens(&self, tokens: &mut TokenStream) { |
435 | match self { |
436 | Level::Trace => tokens.extend(quote!(tracing::Level::TRACE)), |
437 | Level::Debug => tokens.extend(quote!(tracing::Level::DEBUG)), |
438 | Level::Info => tokens.extend(quote!(tracing::Level::INFO)), |
439 | Level::Warn => tokens.extend(quote!(tracing::Level::WARN)), |
440 | Level::Error => tokens.extend(quote!(tracing::Level::ERROR)), |
441 | Level::Path(ref pat) => tokens.extend(quote!(#pat)), |
442 | } |
443 | } |
444 | } |
445 | |
446 | mod kw { |
447 | syn::custom_keyword!(fields); |
448 | syn::custom_keyword!(skip); |
449 | syn::custom_keyword!(skip_all); |
450 | syn::custom_keyword!(level); |
451 | syn::custom_keyword!(target); |
452 | syn::custom_keyword!(parent); |
453 | syn::custom_keyword!(follows_from); |
454 | syn::custom_keyword!(name); |
455 | syn::custom_keyword!(err); |
456 | syn::custom_keyword!(ret); |
457 | } |
458 | |