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::IncludeGeneratedCodeFromFile(i) => include_generated_code_from_file = i,
148                     Opt::Imports(config, span) => {
149                         if imports_configured {
150                             return Err(Error::new(span, "cannot specify imports configuration"));
151                         }
152                         opts.imports = config;
153                         imports_configured = true;
154                     }
155                     Opt::Exports(config, span) => {
156                         if exports_configured {
157                             return Err(Error::new(span, "cannot specify exports configuration"));
158                         }
159                         opts.exports = config;
160                         exports_configured = true;
161                     }
162                 }
163             }
164         } else {
165             world = input.parse::<Option<syn::LitStr>>()?.map(|s| s.value());
166             if input.parse::<Option<syn::token::In>>()?.is_some() {
167                 paths.push(input.parse::<syn::LitStr>()?.value());
168             }
169         }
170         let (resolve, pkgs, files) = parse_source(&paths, &inline)
171             .map_err(|err| Error::new(call_site, format!("{err:?}")))?;
172 
173         let world = resolve
174             .select_world(&pkgs, world.as_deref())
175             .map_err(|e| Error::new(call_site, format!("{e:?}")))?;
176         Ok(Config {
177             opts,
178             resolve,
179             world,
180             files,
181             include_generated_code_from_file,
182         })
183     }
184 }
185 
186 fn parse_source(
187     paths: &Vec<String>,
188     inline: &Option<String>,
189 ) -> anyhow::Result<(Resolve, Vec<PackageId>, Vec<PathBuf>)> {
190     let mut resolve = Resolve::default();
191     resolve.all_features = true;
192     let mut files = Vec::new();
193     let mut pkgs = Vec::new();
194     let root = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
195     let default = root.join("wit");
196 
197     let parse = |resolve: &mut Resolve,
198                  files: &mut Vec<PathBuf>,
199                  pkgs: &mut Vec<PackageId>,
200                  paths: &[PathBuf]|
201      -> anyhow::Result<_> {
202         for path in paths {
203             let p = root.join(path);
204             // Try to normalize the path to make the error message more understandable when
205             // the path is not correct. Fallback to the original path if normalization fails
206             // (probably return an error somewhere else).
207             let normalized_path = match std::fs::canonicalize(&p) {
208                 Ok(p) => p,
209                 Err(_) => p.to_path_buf(),
210             };
211             let (pkg, sources) = resolve.push_path(normalized_path)?;
212             pkgs.push(pkg);
213             files.extend(sources.paths().map(|p| p.to_owned()));
214         }
215         Ok(())
216     };
217 
218     if paths.is_empty() {
219         if default.exists() {
220             parse(&mut resolve, &mut files, &mut pkgs, &[default])?;
221         }
222     } else {
223         parse(
224             &mut resolve,
225             &mut files,
226             &mut pkgs,
227             &paths.iter().map(|s| s.into()).collect::<Vec<_>>(),
228         )?;
229     }
230 
231     if let Some(inline) = inline {
232         pkgs.truncate(0);
233         pkgs.push(resolve.push_group(UnresolvedPackageGroup::parse("macro-input", inline)?)?);
234     }
235 
236     Ok((resolve, pkgs, files))
237 }
238 
239 mod kw {
240     syn::custom_keyword!(inline);
241     syn::custom_keyword!(path);
242     syn::custom_keyword!(tracing);
243     syn::custom_keyword!(verbose_tracing);
244     syn::custom_keyword!(trappable_error_type);
245     syn::custom_keyword!(world);
246     syn::custom_keyword!(ownership);
247     syn::custom_keyword!(interfaces);
248     syn::custom_keyword!(with);
249     syn::custom_keyword!(except_imports);
250     syn::custom_keyword!(only_imports);
251     syn::custom_keyword!(additional_derives);
252     syn::custom_keyword!(stringify);
253     syn::custom_keyword!(skip_mut_forwarding_impls);
254     syn::custom_keyword!(require_store_data_send);
255     syn::custom_keyword!(wasmtime_crate);
256     syn::custom_keyword!(include_generated_code_from_file);
257     syn::custom_keyword!(debug);
258     syn::custom_keyword!(imports);
259     syn::custom_keyword!(exports);
260     syn::custom_keyword!(store);
261     syn::custom_keyword!(trappable);
262     syn::custom_keyword!(ignore_wit);
263     syn::custom_keyword!(exact);
264     syn::custom_keyword!(task_exit);
265 }
266 
267 enum Opt {
268     World(syn::LitStr),
269     Path(Vec<syn::LitStr>),
270     Inline(syn::LitStr),
271     TrappableErrorType(Vec<TrappableError>),
272     Ownership(Ownership),
273     Interfaces(syn::LitStr),
274     With(HashMap<String, String>),
275     AdditionalDerives(Vec<syn::Path>),
276     Stringify(bool),
277     SkipMutForwardingImpls(bool),
278     RequireStoreDataSend(bool),
279     WasmtimeCrate(syn::Path),
280     IncludeGeneratedCodeFromFile(bool),
281     Debug(bool),
282     Imports(FunctionConfig, Span),
283     Exports(FunctionConfig, Span),
284 }
285 
286 impl Parse for Opt {
287     fn parse(input: ParseStream<'_>) -> Result<Self> {
288         let l = input.lookahead1();
289         if l.peek(kw::debug) {
290             input.parse::<kw::debug>()?;
291             input.parse::<Token![:]>()?;
292             Ok(Opt::Debug(input.parse::<syn::LitBool>()?.value))
293         } else if l.peek(kw::path) {
294             input.parse::<kw::path>()?;
295             input.parse::<Token![:]>()?;
296 
297             let mut paths: Vec<syn::LitStr> = vec![];
298 
299             let l = input.lookahead1();
300             if l.peek(syn::LitStr) {
301                 paths.push(input.parse()?);
302             } else if l.peek(syn::token::Bracket) {
303                 let contents;
304                 syn::bracketed!(contents in input);
305                 let list = Punctuated::<_, Token![,]>::parse_terminated(&contents)?;
306 
307                 paths.extend(list);
308             } else {
309                 return Err(l.error());
310             };
311 
312             Ok(Opt::Path(paths))
313         } else if l.peek(kw::inline) {
314             input.parse::<kw::inline>()?;
315             input.parse::<Token![:]>()?;
316             Ok(Opt::Inline(input.parse()?))
317         } else if l.peek(kw::world) {
318             input.parse::<kw::world>()?;
319             input.parse::<Token![:]>()?;
320             Ok(Opt::World(input.parse()?))
321         } else if l.peek(kw::ownership) {
322             input.parse::<kw::ownership>()?;
323             input.parse::<Token![:]>()?;
324             let ownership = input.parse::<syn::Ident>()?;
325             Ok(Opt::Ownership(match ownership.to_string().as_str() {
326                 "Owning" => Ownership::Owning,
327                 "Borrowing" => Ownership::Borrowing {
328                     duplicate_if_necessary: {
329                         let contents;
330                         braced!(contents in input);
331                         let field = contents.parse::<syn::Ident>()?;
332                         match field.to_string().as_str() {
333                             "duplicate_if_necessary" => {
334                                 contents.parse::<Token![:]>()?;
335                                 contents.parse::<syn::LitBool>()?.value
336                             }
337                             name => {
338                                 return Err(Error::new(
339                                     field.span(),
340                                     format!(
341                                         "unrecognized `Ownership::Borrowing` field: `{name}`; \
342                                          expected `duplicate_if_necessary`"
343                                     ),
344                                 ));
345                             }
346                         }
347                     },
348                 },
349                 name => {
350                     return Err(Error::new(
351                         ownership.span(),
352                         format!(
353                             "unrecognized ownership: `{name}`; \
354                              expected `Owning` or `Borrowing`"
355                         ),
356                     ));
357                 }
358             }))
359         } else if l.peek(kw::trappable_error_type) {
360             input.parse::<kw::trappable_error_type>()?;
361             input.parse::<Token![:]>()?;
362             let contents;
363             let _lbrace = braced!(contents in input);
364             let fields: Punctuated<_, Token![,]> =
365                 contents.parse_terminated(trappable_error_field_parse, Token![,])?;
366             Ok(Opt::TrappableErrorType(Vec::from_iter(fields)))
367         } else if l.peek(kw::interfaces) {
368             input.parse::<kw::interfaces>()?;
369             input.parse::<Token![:]>()?;
370             Ok(Opt::Interfaces(input.parse::<syn::LitStr>()?))
371         } else if l.peek(kw::with) {
372             input.parse::<kw::with>()?;
373             input.parse::<Token![:]>()?;
374             let contents;
375             let _lbrace = braced!(contents in input);
376             let fields: Punctuated<(String, String), Token![,]> =
377                 contents.parse_terminated(with_field_parse, Token![,])?;
378             Ok(Opt::With(HashMap::from_iter(fields)))
379         } else if l.peek(kw::additional_derives) {
380             input.parse::<kw::additional_derives>()?;
381             input.parse::<Token![:]>()?;
382             let contents;
383             syn::bracketed!(contents in input);
384             let list = Punctuated::<_, Token![,]>::parse_terminated(&contents)?;
385             Ok(Opt::AdditionalDerives(list.iter().cloned().collect()))
386         } else if l.peek(kw::stringify) {
387             input.parse::<kw::stringify>()?;
388             input.parse::<Token![:]>()?;
389             Ok(Opt::Stringify(input.parse::<syn::LitBool>()?.value))
390         } else if l.peek(kw::skip_mut_forwarding_impls) {
391             input.parse::<kw::skip_mut_forwarding_impls>()?;
392             input.parse::<Token![:]>()?;
393             Ok(Opt::SkipMutForwardingImpls(
394                 input.parse::<syn::LitBool>()?.value,
395             ))
396         } else if l.peek(kw::require_store_data_send) {
397             input.parse::<kw::require_store_data_send>()?;
398             input.parse::<Token![:]>()?;
399             Ok(Opt::RequireStoreDataSend(
400                 input.parse::<syn::LitBool>()?.value,
401             ))
402         } else if l.peek(kw::wasmtime_crate) {
403             input.parse::<kw::wasmtime_crate>()?;
404             input.parse::<Token![:]>()?;
405             Ok(Opt::WasmtimeCrate(input.parse()?))
406         } else if l.peek(kw::include_generated_code_from_file) {
407             input.parse::<kw::include_generated_code_from_file>()?;
408             input.parse::<Token![:]>()?;
409             Ok(Opt::IncludeGeneratedCodeFromFile(
410                 input.parse::<syn::LitBool>()?.value,
411             ))
412         } else if l.peek(kw::imports) {
413             let span = input.parse::<kw::imports>()?.span;
414             input.parse::<Token![:]>()?;
415             Ok(Opt::Imports(parse_function_config(input)?, span))
416         } else if l.peek(kw::exports) {
417             let span = input.parse::<kw::exports>()?.span;
418             input.parse::<Token![:]>()?;
419             Ok(Opt::Exports(parse_function_config(input)?, span))
420         } else {
421             Err(l.error())
422         }
423     }
424 }
425 
426 fn trappable_error_field_parse(input: ParseStream<'_>) -> Result<TrappableError> {
427     let wit_path = input.parse::<syn::LitStr>()?.value();
428     input.parse::<Token![=>]>()?;
429     let rust_type_name = input.parse::<syn::Path>()?.to_token_stream().to_string();
430     Ok(TrappableError {
431         wit_path,
432         rust_type_name,
433     })
434 }
435 
436 fn with_field_parse(input: ParseStream<'_>) -> Result<(String, String)> {
437     let interface = input.parse::<syn::LitStr>()?.value();
438     input.parse::<Token![:]>()?;
439     let start = input.span();
440     let path = input.parse::<syn::Path>()?;
441 
442     // It's not possible for the segments of a path to be empty
443     let span = start
444         .join(path.segments.last().unwrap().ident.span())
445         .unwrap_or(start);
446 
447     let mut buf = String::new();
448     let append = |buf: &mut String, segment: syn::PathSegment| -> Result<()> {
449         if segment.arguments != syn::PathArguments::None {
450             return Err(Error::new(
451                 span,
452                 "Module path must not contain angles or parens",
453             ));
454         }
455 
456         buf.push_str(&segment.ident.to_string());
457 
458         Ok(())
459     };
460 
461     if path.leading_colon.is_some() {
462         buf.push_str("::");
463     }
464 
465     let mut segments = path.segments.into_iter();
466 
467     if let Some(segment) = segments.next() {
468         append(&mut buf, segment)?;
469     }
470 
471     for segment in segments {
472         buf.push_str("::");
473         append(&mut buf, segment)?;
474     }
475 
476     Ok((interface, buf))
477 }
478 
479 fn parse_function_config(input: ParseStream<'_>) -> Result<FunctionConfig> {
480     let content;
481     syn::braced!(content in input);
482     let mut ret = FunctionConfig::new();
483 
484     let list = Punctuated::<FunctionConfigSyntax, Token![,]>::parse_terminated(&content)?;
485     for item in list.into_iter() {
486         ret.push(item.filter, item.flags);
487     }
488 
489     return Ok(ret);
490 
491     struct FunctionConfigSyntax {
492         filter: FunctionFilter,
493         flags: FunctionFlags,
494     }
495 
496     impl Parse for FunctionConfigSyntax {
497         fn parse(input: ParseStream<'_>) -> Result<Self> {
498             let l = input.lookahead1();
499             let filter = if l.peek(syn::LitStr) {
500                 FunctionFilter::Name(input.parse::<syn::LitStr>()?.value())
501             } else if l.peek(Token![default]) {
502                 input.parse::<Token![default]>()?;
503                 FunctionFilter::Default
504             } else {
505                 return Err(l.error());
506             };
507 
508             input.parse::<Token![:]>()?;
509 
510             let mut flags = FunctionFlags::empty();
511             while !input.is_empty() {
512                 let l = input.lookahead1();
513                 if l.peek(Token![async]) {
514                     input.parse::<Token![async]>()?;
515                     flags |= FunctionFlags::ASYNC;
516                 } else if l.peek(kw::tracing) {
517                     input.parse::<kw::tracing>()?;
518                     flags |= FunctionFlags::TRACING;
519                 } else if l.peek(kw::verbose_tracing) {
520                     input.parse::<kw::verbose_tracing>()?;
521                     flags |= FunctionFlags::VERBOSE_TRACING;
522                 } else if l.peek(kw::store) {
523                     input.parse::<kw::store>()?;
524                     flags |= FunctionFlags::STORE;
525                 } else if l.peek(kw::trappable) {
526                     input.parse::<kw::trappable>()?;
527                     flags |= FunctionFlags::TRAPPABLE;
528                 } else if l.peek(kw::ignore_wit) {
529                     input.parse::<kw::ignore_wit>()?;
530                     flags |= FunctionFlags::IGNORE_WIT;
531                 } else if l.peek(kw::exact) {
532                     input.parse::<kw::exact>()?;
533                     flags |= FunctionFlags::EXACT;
534                 } else if l.peek(kw::task_exit) {
535                     input.parse::<kw::task_exit>()?;
536                     flags |= FunctionFlags::TASK_EXIT;
537                 } else {
538                     return Err(l.error());
539                 }
540 
541                 if input.peek(Token![|]) {
542                     input.parse::<Token![|]>()?;
543                 } else {
544                     break;
545                 }
546             }
547 
548             Ok(FunctionConfigSyntax { filter, flags })
549         }
550     }
551 }
552