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