1 use proc_macro2::{Span, TokenStream};
2 use quote::ToTokens;
3 use std::collections::HashMap;
4 use std::env;
5 use std::path::{Path, PathBuf};
6 use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
7 use syn::parse::{Error, Parse, ParseStream, Result};
8 use syn::punctuated::Punctuated;
9 use syn::{Token, braced, token};
10 use wasmtime_wit_bindgen::{
11     FunctionConfig, FunctionFilter, FunctionFlags, Opts, Ownership, TrappableError,
12 };
13 use wit_parser::{PackageId, Resolve, UnresolvedPackageGroup, WorldId};
14 
15 pub struct Config {
16     opts: Opts,
17     resolve: Resolve,
18     world: WorldId,
19     files: Vec<PathBuf>,
20     include_generated_code_from_file: bool,
21 }
22 
23 pub fn expand(input: &Config) -> Result<TokenStream> {
24     let mut src = match input.opts.generate(&input.resolve, input.world) {
25         Ok(s) => s,
26         Err(e) => return Err(Error::new(Span::call_site(), e.to_string())),
27     };
28 
29     if input.opts.stringify {
30         return Ok(quote::quote!(#src));
31     }
32 
33     // If a magical `WASMTIME_DEBUG_BINDGEN` environment variable is set then
34     // place a formatted version of the expanded code into a file. This file
35     // will then show up in rustc error messages for any codegen issues and can
36     // be inspected manually.
37     if input.include_generated_code_from_file
38         || input.opts.debug
39         || std::env::var("WASMTIME_DEBUG_BINDGEN").is_ok()
40     {
41         static INVOCATION: AtomicUsize = AtomicUsize::new(0);
42         let root = Path::new(env!("DEBUG_OUTPUT_DIR"));
43         let world_name = &input.resolve.worlds[input.world].name;
44         let n = INVOCATION.fetch_add(1, Relaxed);
45         let path = root.join(format!("{world_name}{n}.rs"));
46 
47         std::fs::write(&path, &src).unwrap();
48 
49         // optimistically format the code but don't require success
50         drop(
51             std::process::Command::new("rustfmt")
52                 .arg(&path)
53                 .arg("--edition=2021")
54                 .output(),
55         );
56 
57         src = format!("include!({path:?});");
58     }
59     let mut contents = src.parse::<TokenStream>().unwrap();
60 
61     // Include a dummy `include_str!` for any files we read so rustc knows that
62     // we depend on the contents of those files.
63     for file in input.files.iter() {
64         contents.extend(
65             format!("const _: &str = include_str!(r#\"{}\"#);\n", file.display())
66                 .parse::<TokenStream>()
67                 .unwrap(),
68         );
69     }
70 
71     Ok(contents)
72 }
73 
74 impl Parse for Config {
75     fn parse(input: ParseStream<'_>) -> Result<Self> {
76         let call_site = Span::call_site();
77         let mut opts = Opts::default();
78         let mut world = None;
79         let mut inline = None;
80         let mut paths = Vec::new();
81         let mut imports_configured = false;
82         let mut exports_configured = false;
83         let mut include_generated_code_from_file = false;
84 
85         if input.peek(token::Brace) {
86             let content;
87             syn::braced!(content in input);
88             let fields = Punctuated::<Opt, Token![,]>::parse_terminated(&content)?;
89             for field in fields.into_pairs() {
90                 match field.into_value() {
91                     Opt::Path(p) => {
92                         paths.extend(p.into_iter().map(|p| p.value()));
93                     }
94                     Opt::World(s) => {
95                         if world.is_some() {
96                             return Err(Error::new(s.span(), "cannot specify second world"));
97                         }
98                         world = Some(s.value());
99                     }
100                     Opt::Inline(s) => {
101                         if inline.is_some() {
102                             return Err(Error::new(s.span(), "cannot specify second source"));
103                         }
104                         inline = Some(s.value());
105                     }
106                     Opt::Debug(val) => opts.debug = val,
107                     Opt::TrappableErrorType(val) => opts.trappable_error_type = val,
108                     Opt::Ownership(val) => opts.ownership = val,
109                     Opt::Interfaces(s) => {
110                         if inline.is_some() {
111                             return Err(Error::new(s.span(), "cannot specify a second source"));
112                         }
113                         inline = Some(format!(
114                             "
115                                 package wasmtime:component-macro-synthesized;
116 
117                                 world interfaces {{
118                                     {}
119                                 }}
120                             ",
121                             s.value()
122                         ));
123 
124                         if world.is_some() {
125                             return Err(Error::new(
126                                 s.span(),
127                                 "cannot specify a world with `interfaces`",
128                             ));
129                         }
130                         world = Some("wasmtime:component-macro-synthesized/interfaces".to_string());
131 
132                         opts.only_interfaces = true;
133                     }
134                     Opt::With(val) => opts.with.extend(val),
135                     Opt::AdditionalDerives(paths) => {
136                         opts.additional_derive_attributes = paths
137                             .into_iter()
138                             .map(|p| p.into_token_stream().to_string())
139                             .collect()
140                     }
141                     Opt::Stringify(val) => opts.stringify = val,
142                     Opt::SkipMutForwardingImpls(val) => opts.skip_mut_forwarding_impls = val,
143                     Opt::RequireStoreDataSend(val) => opts.require_store_data_send = val,
144                     Opt::WasmtimeCrate(f) => {
145                         opts.wasmtime_crate = Some(f.into_token_stream().to_string())
146                     }
147                     Opt::Anyhow(val) => {
148                         opts.anyhow = val;
149                     }
150                     Opt::IncludeGeneratedCodeFromFile(i) => include_generated_code_from_file = i,
151                     Opt::Imports(config, span) => {
152                         if imports_configured {
153                             return Err(Error::new(span, "cannot specify imports configuration"));
154                         }
155                         opts.imports = config;
156                         imports_configured = true;
157                     }
158                     Opt::Exports(config, span) => {
159                         if exports_configured {
160                             return Err(Error::new(span, "cannot specify exports configuration"));
161                         }
162                         opts.exports = config;
163                         exports_configured = true;
164                     }
165                 }
166             }
167         } else {
168             world = input.parse::<Option<syn::LitStr>>()?.map(|s| s.value());
169             if input.parse::<Option<syn::token::In>>()?.is_some() {
170                 paths.push(input.parse::<syn::LitStr>()?.value());
171             }
172         }
173         let (resolve, pkgs, files) = parse_source(&paths, &inline)
174             .map_err(|err| Error::new(call_site, format!("{err:?}")))?;
175 
176         let world = resolve
177             .select_world(&pkgs, world.as_deref())
178             .map_err(|e| Error::new(call_site, format!("{e:?}")))?;
179         Ok(Config {
180             opts,
181             resolve,
182             world,
183             files,
184             include_generated_code_from_file,
185         })
186     }
187 }
188 
189 fn parse_source(
190     paths: &Vec<String>,
191     inline: &Option<String>,
192 ) -> anyhow::Result<(Resolve, Vec<PackageId>, Vec<PathBuf>)> {
193     let mut resolve = Resolve::default();
194     resolve.all_features = true;
195     let mut files = Vec::new();
196     let mut pkgs = Vec::new();
197     let root = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
198     let default = root.join("wit");
199 
200     let parse = |resolve: &mut Resolve,
201                  files: &mut Vec<PathBuf>,
202                  pkgs: &mut Vec<PackageId>,
203                  paths: &[PathBuf]|
204      -> anyhow::Result<_> {
205         for path in paths {
206             let p = root.join(path);
207             // Try to normalize the path to make the error message more understandable when
208             // the path is not correct. Fallback to the original path if normalization fails
209             // (probably return an error somewhere else).
210             let normalized_path = match std::fs::canonicalize(&p) {
211                 Ok(p) => p,
212                 Err(_) => p.to_path_buf(),
213             };
214             let (pkg, sources) = resolve.push_path(normalized_path)?;
215             pkgs.push(pkg);
216             files.extend(sources.paths().map(|p| p.to_owned()));
217         }
218         Ok(())
219     };
220 
221     if paths.is_empty() {
222         if default.exists() {
223             parse(&mut resolve, &mut files, &mut pkgs, &[default])?;
224         }
225     } else {
226         parse(
227             &mut resolve,
228             &mut files,
229             &mut pkgs,
230             &paths.iter().map(|s| s.into()).collect::<Vec<_>>(),
231         )?;
232     }
233 
234     if let Some(inline) = inline {
235         pkgs.truncate(0);
236         pkgs.push(resolve.push_group(UnresolvedPackageGroup::parse("macro-input", inline)?)?);
237     }
238 
239     Ok((resolve, pkgs, files))
240 }
241 
242 mod kw {
243     syn::custom_keyword!(inline);
244     syn::custom_keyword!(path);
245     syn::custom_keyword!(tracing);
246     syn::custom_keyword!(verbose_tracing);
247     syn::custom_keyword!(trappable_error_type);
248     syn::custom_keyword!(world);
249     syn::custom_keyword!(ownership);
250     syn::custom_keyword!(interfaces);
251     syn::custom_keyword!(with);
252     syn::custom_keyword!(except_imports);
253     syn::custom_keyword!(only_imports);
254     syn::custom_keyword!(additional_derives);
255     syn::custom_keyword!(stringify);
256     syn::custom_keyword!(skip_mut_forwarding_impls);
257     syn::custom_keyword!(require_store_data_send);
258     syn::custom_keyword!(wasmtime_crate);
259     syn::custom_keyword!(anyhow);
260     syn::custom_keyword!(include_generated_code_from_file);
261     syn::custom_keyword!(debug);
262     syn::custom_keyword!(imports);
263     syn::custom_keyword!(exports);
264     syn::custom_keyword!(store);
265     syn::custom_keyword!(trappable);
266     syn::custom_keyword!(ignore_wit);
267     syn::custom_keyword!(exact);
268     syn::custom_keyword!(task_exit);
269 }
270 
271 enum Opt {
272     World(syn::LitStr),
273     Path(Vec<syn::LitStr>),
274     Inline(syn::LitStr),
275     TrappableErrorType(Vec<TrappableError>),
276     Ownership(Ownership),
277     Interfaces(syn::LitStr),
278     With(HashMap<String, String>),
279     AdditionalDerives(Vec<syn::Path>),
280     Stringify(bool),
281     SkipMutForwardingImpls(bool),
282     RequireStoreDataSend(bool),
283     WasmtimeCrate(syn::Path),
284     Anyhow(bool),
285     IncludeGeneratedCodeFromFile(bool),
286     Debug(bool),
287     Imports(FunctionConfig, Span),
288     Exports(FunctionConfig, Span),
289 }
290 
291 impl Parse for Opt {
292     fn parse(input: ParseStream<'_>) -> Result<Self> {
293         let l = input.lookahead1();
294         if l.peek(kw::debug) {
295             input.parse::<kw::debug>()?;
296             input.parse::<Token![:]>()?;
297             Ok(Opt::Debug(input.parse::<syn::LitBool>()?.value))
298         } else if l.peek(kw::path) {
299             input.parse::<kw::path>()?;
300             input.parse::<Token![:]>()?;
301 
302             let mut paths: Vec<syn::LitStr> = vec![];
303 
304             let l = input.lookahead1();
305             if l.peek(syn::LitStr) {
306                 paths.push(input.parse()?);
307             } else if l.peek(syn::token::Bracket) {
308                 let contents;
309                 syn::bracketed!(contents in input);
310                 let list = Punctuated::<_, Token![,]>::parse_terminated(&contents)?;
311 
312                 paths.extend(list);
313             } else {
314                 return Err(l.error());
315             };
316 
317             Ok(Opt::Path(paths))
318         } else if l.peek(kw::inline) {
319             input.parse::<kw::inline>()?;
320             input.parse::<Token![:]>()?;
321             Ok(Opt::Inline(input.parse()?))
322         } else if l.peek(kw::world) {
323             input.parse::<kw::world>()?;
324             input.parse::<Token![:]>()?;
325             Ok(Opt::World(input.parse()?))
326         } else if l.peek(kw::ownership) {
327             input.parse::<kw::ownership>()?;
328             input.parse::<Token![:]>()?;
329             let ownership = input.parse::<syn::Ident>()?;
330             Ok(Opt::Ownership(match ownership.to_string().as_str() {
331                 "Owning" => Ownership::Owning,
332                 "Borrowing" => Ownership::Borrowing {
333                     duplicate_if_necessary: {
334                         let contents;
335                         braced!(contents in input);
336                         let field = contents.parse::<syn::Ident>()?;
337                         match field.to_string().as_str() {
338                             "duplicate_if_necessary" => {
339                                 contents.parse::<Token![:]>()?;
340                                 contents.parse::<syn::LitBool>()?.value
341                             }
342                             name => {
343                                 return Err(Error::new(
344                                     field.span(),
345                                     format!(
346                                         "unrecognized `Ownership::Borrowing` field: `{name}`; \
347                                          expected `duplicate_if_necessary`"
348                                     ),
349                                 ));
350                             }
351                         }
352                     },
353                 },
354                 name => {
355                     return Err(Error::new(
356                         ownership.span(),
357                         format!(
358                             "unrecognized ownership: `{name}`; \
359                              expected `Owning` or `Borrowing`"
360                         ),
361                     ));
362                 }
363             }))
364         } else if l.peek(kw::trappable_error_type) {
365             input.parse::<kw::trappable_error_type>()?;
366             input.parse::<Token![:]>()?;
367             let contents;
368             let _lbrace = braced!(contents in input);
369             let fields: Punctuated<_, Token![,]> =
370                 contents.parse_terminated(trappable_error_field_parse, Token![,])?;
371             Ok(Opt::TrappableErrorType(Vec::from_iter(fields)))
372         } else if l.peek(kw::interfaces) {
373             input.parse::<kw::interfaces>()?;
374             input.parse::<Token![:]>()?;
375             Ok(Opt::Interfaces(input.parse::<syn::LitStr>()?))
376         } else if l.peek(kw::with) {
377             input.parse::<kw::with>()?;
378             input.parse::<Token![:]>()?;
379             let contents;
380             let _lbrace = braced!(contents in input);
381             let fields: Punctuated<(String, String), Token![,]> =
382                 contents.parse_terminated(with_field_parse, Token![,])?;
383             Ok(Opt::With(HashMap::from_iter(fields)))
384         } else if l.peek(kw::additional_derives) {
385             input.parse::<kw::additional_derives>()?;
386             input.parse::<Token![:]>()?;
387             let contents;
388             syn::bracketed!(contents in input);
389             let list = Punctuated::<_, Token![,]>::parse_terminated(&contents)?;
390             Ok(Opt::AdditionalDerives(list.iter().cloned().collect()))
391         } else if l.peek(kw::stringify) {
392             input.parse::<kw::stringify>()?;
393             input.parse::<Token![:]>()?;
394             Ok(Opt::Stringify(input.parse::<syn::LitBool>()?.value))
395         } else if l.peek(kw::skip_mut_forwarding_impls) {
396             input.parse::<kw::skip_mut_forwarding_impls>()?;
397             input.parse::<Token![:]>()?;
398             Ok(Opt::SkipMutForwardingImpls(
399                 input.parse::<syn::LitBool>()?.value,
400             ))
401         } else if l.peek(kw::require_store_data_send) {
402             input.parse::<kw::require_store_data_send>()?;
403             input.parse::<Token![:]>()?;
404             Ok(Opt::RequireStoreDataSend(
405                 input.parse::<syn::LitBool>()?.value,
406             ))
407         } else if l.peek(kw::wasmtime_crate) {
408             input.parse::<kw::wasmtime_crate>()?;
409             input.parse::<Token![:]>()?;
410             Ok(Opt::WasmtimeCrate(input.parse()?))
411         } else if l.peek(kw::anyhow) {
412             input.parse::<kw::anyhow>()?;
413             input.parse::<Token![:]>()?;
414             Ok(Opt::Anyhow(input.parse::<syn::LitBool>()?.value))
415         } else if l.peek(kw::include_generated_code_from_file) {
416             input.parse::<kw::include_generated_code_from_file>()?;
417             input.parse::<Token![:]>()?;
418             Ok(Opt::IncludeGeneratedCodeFromFile(
419                 input.parse::<syn::LitBool>()?.value,
420             ))
421         } else if l.peek(kw::imports) {
422             let span = input.parse::<kw::imports>()?.span;
423             input.parse::<Token![:]>()?;
424             Ok(Opt::Imports(parse_function_config(input)?, span))
425         } else if l.peek(kw::exports) {
426             let span = input.parse::<kw::exports>()?.span;
427             input.parse::<Token![:]>()?;
428             Ok(Opt::Exports(parse_function_config(input)?, span))
429         } else {
430             Err(l.error())
431         }
432     }
433 }
434 
435 fn trappable_error_field_parse(input: ParseStream<'_>) -> Result<TrappableError> {
436     let wit_path = input.parse::<syn::LitStr>()?.value();
437     input.parse::<Token![=>]>()?;
438     let rust_type_name = input.parse::<syn::Path>()?.to_token_stream().to_string();
439     Ok(TrappableError {
440         wit_path,
441         rust_type_name,
442     })
443 }
444 
445 fn with_field_parse(input: ParseStream<'_>) -> Result<(String, String)> {
446     let interface = input.parse::<syn::LitStr>()?.value();
447     input.parse::<Token![:]>()?;
448     let start = input.span();
449     let path = input.parse::<syn::Path>()?;
450 
451     // It's not possible for the segments of a path to be empty
452     let span = start
453         .join(path.segments.last().unwrap().ident.span())
454         .unwrap_or(start);
455 
456     let mut buf = String::new();
457     let append = |buf: &mut String, segment: syn::PathSegment| -> Result<()> {
458         if segment.arguments != syn::PathArguments::None {
459             return Err(Error::new(
460                 span,
461                 "Module path must not contain angles or parens",
462             ));
463         }
464 
465         buf.push_str(&segment.ident.to_string());
466 
467         Ok(())
468     };
469 
470     if path.leading_colon.is_some() {
471         buf.push_str("::");
472     }
473 
474     let mut segments = path.segments.into_iter();
475 
476     if let Some(segment) = segments.next() {
477         append(&mut buf, segment)?;
478     }
479 
480     for segment in segments {
481         buf.push_str("::");
482         append(&mut buf, segment)?;
483     }
484 
485     Ok((interface, buf))
486 }
487 
488 fn parse_function_config(input: ParseStream<'_>) -> Result<FunctionConfig> {
489     let content;
490     syn::braced!(content in input);
491     let mut ret = FunctionConfig::new();
492 
493     let list = Punctuated::<FunctionConfigSyntax, Token![,]>::parse_terminated(&content)?;
494     for item in list.into_iter() {
495         ret.push(item.filter, item.flags);
496     }
497 
498     return Ok(ret);
499 
500     struct FunctionConfigSyntax {
501         filter: FunctionFilter,
502         flags: FunctionFlags,
503     }
504 
505     impl Parse for FunctionConfigSyntax {
506         fn parse(input: ParseStream<'_>) -> Result<Self> {
507             let l = input.lookahead1();
508             let filter = if l.peek(syn::LitStr) {
509                 FunctionFilter::Name(input.parse::<syn::LitStr>()?.value())
510             } else if l.peek(Token![default]) {
511                 input.parse::<Token![default]>()?;
512                 FunctionFilter::Default
513             } else {
514                 return Err(l.error());
515             };
516 
517             input.parse::<Token![:]>()?;
518 
519             let mut flags = FunctionFlags::empty();
520             while !input.is_empty() {
521                 let l = input.lookahead1();
522                 if l.peek(Token![async]) {
523                     input.parse::<Token![async]>()?;
524                     flags |= FunctionFlags::ASYNC;
525                 } else if l.peek(kw::tracing) {
526                     input.parse::<kw::tracing>()?;
527                     flags |= FunctionFlags::TRACING;
528                 } else if l.peek(kw::verbose_tracing) {
529                     input.parse::<kw::verbose_tracing>()?;
530                     flags |= FunctionFlags::VERBOSE_TRACING;
531                 } else if l.peek(kw::store) {
532                     input.parse::<kw::store>()?;
533                     flags |= FunctionFlags::STORE;
534                 } else if l.peek(kw::trappable) {
535                     input.parse::<kw::trappable>()?;
536                     flags |= FunctionFlags::TRAPPABLE;
537                 } else if l.peek(kw::ignore_wit) {
538                     input.parse::<kw::ignore_wit>()?;
539                     flags |= FunctionFlags::IGNORE_WIT;
540                 } else if l.peek(kw::exact) {
541                     input.parse::<kw::exact>()?;
542                     flags |= FunctionFlags::EXACT;
543                 } else if l.peek(kw::task_exit) {
544                     input.parse::<kw::task_exit>()?;
545                     flags |= FunctionFlags::TASK_EXIT;
546                 } else {
547                     return Err(l.error());
548                 }
549 
550                 if input.peek(Token![|]) {
551                     input.parse::<Token![|]>()?;
552                 } else {
553                     break;
554                 }
555             }
556 
557             Ok(FunctionConfigSyntax { filter, flags })
558         }
559     }
560 }
561