1 use internals::symbol::*;
2 use internals::{ungroup, Ctxt};
3 use proc_macro2::{Group, Span, TokenStream, TokenTree};
4 use quote::ToTokens;
5 use std::borrow::Cow;
6 use std::collections::BTreeSet;
7 use std::str::FromStr;
8 use syn;
9 use syn::parse::{self, Parse, ParseStream};
10 use syn::punctuated::Punctuated;
11 use syn::Ident;
12 use syn::Meta::{List, NameValue, Path};
13 use syn::NestedMeta::{Lit, Meta};
14
15 // This module handles parsing of `#[serde(...)]` attributes. The entrypoints
16 // are `attr::Container::from_ast`, `attr::Variant::from_ast`, and
17 // `attr::Field::from_ast`. Each returns an instance of the corresponding
18 // struct. Note that none of them return a Result. Unrecognized, malformed, or
19 // duplicated attributes result in a span_err but otherwise are ignored. The
20 // user will see errors simultaneously for all bad attributes in the crate
21 // rather than just the first.
22
23 pub use internals::case::RenameRule;
24
25 struct Attr<'c, T> {
26 cx: &'c Ctxt,
27 name: Symbol,
28 tokens: TokenStream,
29 value: Option<T>,
30 }
31
32 impl<'c, T> Attr<'c, T> {
none(cx: &'c Ctxt, name: Symbol) -> Self33 fn none(cx: &'c Ctxt, name: Symbol) -> Self {
34 Attr {
35 cx,
36 name,
37 tokens: TokenStream::new(),
38 value: None,
39 }
40 }
41
set<A: ToTokens>(&mut self, obj: A, value: T)42 fn set<A: ToTokens>(&mut self, obj: A, value: T) {
43 let tokens = obj.into_token_stream();
44
45 if self.value.is_some() {
46 self.cx
47 .error_spanned_by(tokens, format!("duplicate serde attribute `{}`", self.name));
48 } else {
49 self.tokens = tokens;
50 self.value = Some(value);
51 }
52 }
53
set_opt<A: ToTokens>(&mut self, obj: A, value: Option<T>)54 fn set_opt<A: ToTokens>(&mut self, obj: A, value: Option<T>) {
55 if let Some(value) = value {
56 self.set(obj, value);
57 }
58 }
59
set_if_none(&mut self, value: T)60 fn set_if_none(&mut self, value: T) {
61 if self.value.is_none() {
62 self.value = Some(value);
63 }
64 }
65
get(self) -> Option<T>66 fn get(self) -> Option<T> {
67 self.value
68 }
69
get_with_tokens(self) -> Option<(TokenStream, T)>70 fn get_with_tokens(self) -> Option<(TokenStream, T)> {
71 match self.value {
72 Some(v) => Some((self.tokens, v)),
73 None => None,
74 }
75 }
76 }
77
78 struct BoolAttr<'c>(Attr<'c, ()>);
79
80 impl<'c> BoolAttr<'c> {
none(cx: &'c Ctxt, name: Symbol) -> Self81 fn none(cx: &'c Ctxt, name: Symbol) -> Self {
82 BoolAttr(Attr::none(cx, name))
83 }
84
set_true<A: ToTokens>(&mut self, obj: A)85 fn set_true<A: ToTokens>(&mut self, obj: A) {
86 self.0.set(obj, ());
87 }
88
get(&self) -> bool89 fn get(&self) -> bool {
90 self.0.value.is_some()
91 }
92 }
93
94 struct VecAttr<'c, T> {
95 cx: &'c Ctxt,
96 name: Symbol,
97 first_dup_tokens: TokenStream,
98 values: Vec<T>,
99 }
100
101 impl<'c, T> VecAttr<'c, T> {
none(cx: &'c Ctxt, name: Symbol) -> Self102 fn none(cx: &'c Ctxt, name: Symbol) -> Self {
103 VecAttr {
104 cx,
105 name,
106 first_dup_tokens: TokenStream::new(),
107 values: Vec::new(),
108 }
109 }
110
insert<A: ToTokens>(&mut self, obj: A, value: T)111 fn insert<A: ToTokens>(&mut self, obj: A, value: T) {
112 if self.values.len() == 1 {
113 self.first_dup_tokens = obj.into_token_stream();
114 }
115 self.values.push(value);
116 }
117
at_most_one(mut self) -> Result<Option<T>, ()>118 fn at_most_one(mut self) -> Result<Option<T>, ()> {
119 if self.values.len() > 1 {
120 let dup_token = self.first_dup_tokens;
121 self.cx.error_spanned_by(
122 dup_token,
123 format!("duplicate serde attribute `{}`", self.name),
124 );
125 Err(())
126 } else {
127 Ok(self.values.pop())
128 }
129 }
130
get(self) -> Vec<T>131 fn get(self) -> Vec<T> {
132 self.values
133 }
134 }
135
136 pub struct Name {
137 serialize: String,
138 serialize_renamed: bool,
139 deserialize: String,
140 deserialize_renamed: bool,
141 deserialize_aliases: Vec<String>,
142 }
143
144 #[allow(deprecated)]
unraw(ident: &Ident) -> String145 fn unraw(ident: &Ident) -> String {
146 // str::trim_start_matches was added in 1.30, trim_left_matches deprecated
147 // in 1.33. We currently support rustc back to 1.15 so we need to continue
148 // to use the deprecated one.
149 ident.to_string().trim_left_matches("r#").to_owned()
150 }
151
152 impl Name {
from_attrs( source_name: String, ser_name: Attr<String>, de_name: Attr<String>, de_aliases: Option<VecAttr<String>>, ) -> Name153 fn from_attrs(
154 source_name: String,
155 ser_name: Attr<String>,
156 de_name: Attr<String>,
157 de_aliases: Option<VecAttr<String>>,
158 ) -> Name {
159 let deserialize_aliases = match de_aliases {
160 Some(de_aliases) => {
161 let mut alias_list = BTreeSet::new();
162 for alias_name in de_aliases.get() {
163 alias_list.insert(alias_name);
164 }
165 alias_list.into_iter().collect()
166 }
167 None => Vec::new(),
168 };
169
170 let ser_name = ser_name.get();
171 let ser_renamed = ser_name.is_some();
172 let de_name = de_name.get();
173 let de_renamed = de_name.is_some();
174 Name {
175 serialize: ser_name.unwrap_or_else(|| source_name.clone()),
176 serialize_renamed: ser_renamed,
177 deserialize: de_name.unwrap_or(source_name),
178 deserialize_renamed: de_renamed,
179 deserialize_aliases,
180 }
181 }
182
183 /// Return the container name for the container when serializing.
serialize_name(&self) -> String184 pub fn serialize_name(&self) -> String {
185 self.serialize.clone()
186 }
187
188 /// Return the container name for the container when deserializing.
deserialize_name(&self) -> String189 pub fn deserialize_name(&self) -> String {
190 self.deserialize.clone()
191 }
192
deserialize_aliases(&self) -> Vec<String>193 fn deserialize_aliases(&self) -> Vec<String> {
194 let mut aliases = self.deserialize_aliases.clone();
195 let main_name = self.deserialize_name();
196 if !aliases.contains(&main_name) {
197 aliases.push(main_name);
198 }
199 aliases
200 }
201 }
202
203 pub struct RenameAllRules {
204 serialize: RenameRule,
205 deserialize: RenameRule,
206 }
207
208 /// Represents struct or enum attribute information.
209 pub struct Container {
210 name: Name,
211 transparent: bool,
212 deny_unknown_fields: bool,
213 default: Default,
214 rename_all_rules: RenameAllRules,
215 ser_bound: Option<Vec<syn::WherePredicate>>,
216 de_bound: Option<Vec<syn::WherePredicate>>,
217 tag: TagType,
218 type_from: Option<syn::Type>,
219 type_try_from: Option<syn::Type>,
220 type_into: Option<syn::Type>,
221 remote: Option<syn::Path>,
222 identifier: Identifier,
223 has_flatten: bool,
224 serde_path: Option<syn::Path>,
225 is_packed: bool,
226 }
227
228 /// Styles of representing an enum.
229 pub enum TagType {
230 /// The default.
231 ///
232 /// ```json
233 /// {"variant1": {"key1": "value1", "key2": "value2"}}
234 /// ```
235 External,
236
237 /// `#[serde(tag = "type")]`
238 ///
239 /// ```json
240 /// {"type": "variant1", "key1": "value1", "key2": "value2"}
241 /// ```
242 Internal { tag: String },
243
244 /// `#[serde(tag = "t", content = "c")]`
245 ///
246 /// ```json
247 /// {"t": "variant1", "c": {"key1": "value1", "key2": "value2"}}
248 /// ```
249 Adjacent { tag: String, content: String },
250
251 /// `#[serde(untagged)]`
252 ///
253 /// ```json
254 /// {"key1": "value1", "key2": "value2"}
255 /// ```
256 None,
257 }
258
259 /// Whether this enum represents the fields of a struct or the variants of an
260 /// enum.
261 #[derive(Copy, Clone)]
262 pub enum Identifier {
263 /// It does not.
264 No,
265
266 /// This enum represents the fields of a struct. All of the variants must be
267 /// unit variants, except possibly one which is annotated with
268 /// `#[serde(other)]` and is a newtype variant.
269 Field,
270
271 /// This enum represents the variants of an enum. All of the variants must
272 /// be unit variants.
273 Variant,
274 }
275
276 impl Identifier {
277 #[cfg(feature = "deserialize_in_place")]
is_some(self) -> bool278 pub fn is_some(self) -> bool {
279 match self {
280 Identifier::No => false,
281 Identifier::Field | Identifier::Variant => true,
282 }
283 }
284 }
285
286 impl Container {
287 /// Extract out the `#[serde(...)]` attributes from an item.
from_ast(cx: &Ctxt, item: &syn::DeriveInput) -> Self288 pub fn from_ast(cx: &Ctxt, item: &syn::DeriveInput) -> Self {
289 let mut ser_name = Attr::none(cx, RENAME);
290 let mut de_name = Attr::none(cx, RENAME);
291 let mut transparent = BoolAttr::none(cx, TRANSPARENT);
292 let mut deny_unknown_fields = BoolAttr::none(cx, DENY_UNKNOWN_FIELDS);
293 let mut default = Attr::none(cx, DEFAULT);
294 let mut rename_all_ser_rule = Attr::none(cx, RENAME_ALL);
295 let mut rename_all_de_rule = Attr::none(cx, RENAME_ALL);
296 let mut ser_bound = Attr::none(cx, BOUND);
297 let mut de_bound = Attr::none(cx, BOUND);
298 let mut untagged = BoolAttr::none(cx, UNTAGGED);
299 let mut internal_tag = Attr::none(cx, TAG);
300 let mut content = Attr::none(cx, CONTENT);
301 let mut type_from = Attr::none(cx, FROM);
302 let mut type_try_from = Attr::none(cx, TRY_FROM);
303 let mut type_into = Attr::none(cx, INTO);
304 let mut remote = Attr::none(cx, REMOTE);
305 let mut field_identifier = BoolAttr::none(cx, FIELD_IDENTIFIER);
306 let mut variant_identifier = BoolAttr::none(cx, VARIANT_IDENTIFIER);
307 let mut serde_path = Attr::none(cx, CRATE);
308
309 for meta_item in item
310 .attrs
311 .iter()
312 .flat_map(|attr| get_serde_meta_items(cx, attr))
313 .flatten()
314 {
315 match &meta_item {
316 // Parse `#[serde(rename = "foo")]`
317 Meta(NameValue(m)) if m.path == RENAME => {
318 if let Ok(s) = get_lit_str(cx, RENAME, &m.lit) {
319 ser_name.set(&m.path, s.value());
320 de_name.set(&m.path, s.value());
321 }
322 }
323
324 // Parse `#[serde(rename(serialize = "foo", deserialize = "bar"))]`
325 Meta(List(m)) if m.path == RENAME => {
326 if let Ok((ser, de)) = get_renames(cx, &m.nested) {
327 ser_name.set_opt(&m.path, ser.map(syn::LitStr::value));
328 de_name.set_opt(&m.path, de.map(syn::LitStr::value));
329 }
330 }
331
332 // Parse `#[serde(rename_all = "foo")]`
333 Meta(NameValue(m)) if m.path == RENAME_ALL => {
334 if let Ok(s) = get_lit_str(cx, RENAME_ALL, &m.lit) {
335 match RenameRule::from_str(&s.value()) {
336 Ok(rename_rule) => {
337 rename_all_ser_rule.set(&m.path, rename_rule);
338 rename_all_de_rule.set(&m.path, rename_rule);
339 }
340 Err(()) => cx.error_spanned_by(
341 s,
342 format!(
343 "unknown rename rule for #[serde(rename_all = {:?})]",
344 s.value(),
345 ),
346 ),
347 }
348 }
349 }
350
351 // Parse `#[serde(rename_all(serialize = "foo", deserialize = "bar"))]`
352 Meta(List(m)) if m.path == RENAME_ALL => {
353 if let Ok((ser, de)) = get_renames(cx, &m.nested) {
354 if let Some(ser) = ser {
355 match RenameRule::from_str(&ser.value()) {
356 Ok(rename_rule) => rename_all_ser_rule.set(&m.path, rename_rule),
357 Err(()) => cx.error_spanned_by(
358 ser,
359 format!(
360 "unknown rename rule for #[serde(rename_all = {:?})]",
361 ser.value(),
362 ),
363 ),
364 }
365 }
366 if let Some(de) = de {
367 match RenameRule::from_str(&de.value()) {
368 Ok(rename_rule) => rename_all_de_rule.set(&m.path, rename_rule),
369 Err(()) => cx.error_spanned_by(
370 de,
371 format!(
372 "unknown rename rule for #[serde(rename_all = {:?})]",
373 de.value(),
374 ),
375 ),
376 }
377 }
378 }
379 }
380
381 // Parse `#[serde(transparent)]`
382 Meta(Path(word)) if word == TRANSPARENT => {
383 transparent.set_true(word);
384 }
385
386 // Parse `#[serde(deny_unknown_fields)]`
387 Meta(Path(word)) if word == DENY_UNKNOWN_FIELDS => {
388 deny_unknown_fields.set_true(word);
389 }
390
391 // Parse `#[serde(default)]`
392 Meta(Path(word)) if word == DEFAULT => match &item.data {
393 syn::Data::Struct(syn::DataStruct { fields, .. }) => match fields {
394 syn::Fields::Named(_) => {
395 default.set(word, Default::Default);
396 }
397 syn::Fields::Unnamed(_) | syn::Fields::Unit => cx.error_spanned_by(
398 fields,
399 "#[serde(default)] can only be used on structs with named fields",
400 ),
401 },
402 syn::Data::Enum(syn::DataEnum { enum_token, .. }) => cx.error_spanned_by(
403 enum_token,
404 "#[serde(default)] can only be used on structs with named fields",
405 ),
406 syn::Data::Union(syn::DataUnion { union_token, .. }) => cx.error_spanned_by(
407 union_token,
408 "#[serde(default)] can only be used on structs with named fields",
409 ),
410 },
411
412 // Parse `#[serde(default = "...")]`
413 Meta(NameValue(m)) if m.path == DEFAULT => {
414 if let Ok(path) = parse_lit_into_expr_path(cx, DEFAULT, &m.lit) {
415 match &item.data {
416 syn::Data::Struct(syn::DataStruct { fields, .. }) => {
417 match fields {
418 syn::Fields::Named(_) => {
419 default.set(&m.path, Default::Path(path));
420 }
421 syn::Fields::Unnamed(_) | syn::Fields::Unit => cx
422 .error_spanned_by(
423 fields,
424 "#[serde(default = \"...\")] can only be used on structs with named fields",
425 ),
426 }
427 }
428 syn::Data::Enum(syn::DataEnum { enum_token, .. }) => cx
429 .error_spanned_by(
430 enum_token,
431 "#[serde(default = \"...\")] can only be used on structs with named fields",
432 ),
433 syn::Data::Union(syn::DataUnion {
434 union_token, ..
435 }) => cx.error_spanned_by(
436 union_token,
437 "#[serde(default = \"...\")] can only be used on structs with named fields",
438 ),
439 }
440 }
441 }
442
443 // Parse `#[serde(bound = "T: SomeBound")]`
444 Meta(NameValue(m)) if m.path == BOUND => {
445 if let Ok(where_predicates) = parse_lit_into_where(cx, BOUND, BOUND, &m.lit) {
446 ser_bound.set(&m.path, where_predicates.clone());
447 de_bound.set(&m.path, where_predicates);
448 }
449 }
450
451 // Parse `#[serde(bound(serialize = "...", deserialize = "..."))]`
452 Meta(List(m)) if m.path == BOUND => {
453 if let Ok((ser, de)) = get_where_predicates(cx, &m.nested) {
454 ser_bound.set_opt(&m.path, ser);
455 de_bound.set_opt(&m.path, de);
456 }
457 }
458
459 // Parse `#[serde(untagged)]`
460 Meta(Path(word)) if word == UNTAGGED => match item.data {
461 syn::Data::Enum(_) => {
462 untagged.set_true(word);
463 }
464 syn::Data::Struct(syn::DataStruct { struct_token, .. }) => {
465 cx.error_spanned_by(
466 struct_token,
467 "#[serde(untagged)] can only be used on enums",
468 );
469 }
470 syn::Data::Union(syn::DataUnion { union_token, .. }) => {
471 cx.error_spanned_by(
472 union_token,
473 "#[serde(untagged)] can only be used on enums",
474 );
475 }
476 },
477
478 // Parse `#[serde(tag = "type")]`
479 Meta(NameValue(m)) if m.path == TAG => {
480 if let Ok(s) = get_lit_str(cx, TAG, &m.lit) {
481 match &item.data {
482 syn::Data::Enum(_) => {
483 internal_tag.set(&m.path, s.value());
484 }
485 syn::Data::Struct(syn::DataStruct { fields, .. }) => match fields {
486 syn::Fields::Named(_) => {
487 internal_tag.set(&m.path, s.value());
488 }
489 syn::Fields::Unnamed(_) | syn::Fields::Unit => {
490 cx.error_spanned_by(
491 fields,
492 "#[serde(tag = \"...\")] can only be used on enums and structs with named fields",
493 );
494 }
495 },
496 syn::Data::Union(syn::DataUnion { union_token, .. }) => {
497 cx.error_spanned_by(
498 union_token,
499 "#[serde(tag = \"...\")] can only be used on enums and structs with named fields",
500 );
501 }
502 }
503 }
504 }
505
506 // Parse `#[serde(content = "c")]`
507 Meta(NameValue(m)) if m.path == CONTENT => {
508 if let Ok(s) = get_lit_str(cx, CONTENT, &m.lit) {
509 match &item.data {
510 syn::Data::Enum(_) => {
511 content.set(&m.path, s.value());
512 }
513 syn::Data::Struct(syn::DataStruct { struct_token, .. }) => {
514 cx.error_spanned_by(
515 struct_token,
516 "#[serde(content = \"...\")] can only be used on enums",
517 );
518 }
519 syn::Data::Union(syn::DataUnion { union_token, .. }) => {
520 cx.error_spanned_by(
521 union_token,
522 "#[serde(content = \"...\")] can only be used on enums",
523 );
524 }
525 }
526 }
527 }
528
529 // Parse `#[serde(from = "Type")]
530 Meta(NameValue(m)) if m.path == FROM => {
531 if let Ok(from_ty) = parse_lit_into_ty(cx, FROM, &m.lit) {
532 type_from.set_opt(&m.path, Some(from_ty));
533 }
534 }
535
536 // Parse `#[serde(try_from = "Type")]
537 Meta(NameValue(m)) if m.path == TRY_FROM => {
538 if let Ok(try_from_ty) = parse_lit_into_ty(cx, TRY_FROM, &m.lit) {
539 type_try_from.set_opt(&m.path, Some(try_from_ty));
540 }
541 }
542
543 // Parse `#[serde(into = "Type")]
544 Meta(NameValue(m)) if m.path == INTO => {
545 if let Ok(into_ty) = parse_lit_into_ty(cx, INTO, &m.lit) {
546 type_into.set_opt(&m.path, Some(into_ty));
547 }
548 }
549
550 // Parse `#[serde(remote = "...")]`
551 Meta(NameValue(m)) if m.path == REMOTE => {
552 if let Ok(path) = parse_lit_into_path(cx, REMOTE, &m.lit) {
553 if is_primitive_path(&path, "Self") {
554 remote.set(&m.path, item.ident.clone().into());
555 } else {
556 remote.set(&m.path, path);
557 }
558 }
559 }
560
561 // Parse `#[serde(field_identifier)]`
562 Meta(Path(word)) if word == FIELD_IDENTIFIER => {
563 field_identifier.set_true(word);
564 }
565
566 // Parse `#[serde(variant_identifier)]`
567 Meta(Path(word)) if word == VARIANT_IDENTIFIER => {
568 variant_identifier.set_true(word);
569 }
570
571 // Parse `#[serde(crate = "foo")]`
572 Meta(NameValue(m)) if m.path == CRATE => {
573 if let Ok(path) = parse_lit_into_path(cx, CRATE, &m.lit) {
574 serde_path.set(&m.path, path)
575 }
576 }
577
578 Meta(meta_item) => {
579 let path = meta_item
580 .path()
581 .into_token_stream()
582 .to_string()
583 .replace(' ', "");
584 cx.error_spanned_by(
585 meta_item.path(),
586 format!("unknown serde container attribute `{}`", path),
587 );
588 }
589
590 Lit(lit) => {
591 cx.error_spanned_by(lit, "unexpected literal in serde container attribute");
592 }
593 }
594 }
595
596 let mut is_packed = false;
597 for attr in &item.attrs {
598 if attr.path.is_ident("repr") {
599 let _ = attr.parse_args_with(|input: ParseStream| {
600 is_packed |= input.parse::<Ident>()? == "packed";
601 Ok(())
602 });
603 }
604 }
605
606 Container {
607 name: Name::from_attrs(unraw(&item.ident), ser_name, de_name, None),
608 transparent: transparent.get(),
609 deny_unknown_fields: deny_unknown_fields.get(),
610 default: default.get().unwrap_or(Default::None),
611 rename_all_rules: RenameAllRules {
612 serialize: rename_all_ser_rule.get().unwrap_or(RenameRule::None),
613 deserialize: rename_all_de_rule.get().unwrap_or(RenameRule::None),
614 },
615 ser_bound: ser_bound.get(),
616 de_bound: de_bound.get(),
617 tag: decide_tag(cx, item, untagged, internal_tag, content),
618 type_from: type_from.get(),
619 type_try_from: type_try_from.get(),
620 type_into: type_into.get(),
621 remote: remote.get(),
622 identifier: decide_identifier(cx, item, field_identifier, variant_identifier),
623 has_flatten: false,
624 serde_path: serde_path.get(),
625 is_packed,
626 }
627 }
628
name(&self) -> &Name629 pub fn name(&self) -> &Name {
630 &self.name
631 }
632
rename_all_rules(&self) -> &RenameAllRules633 pub fn rename_all_rules(&self) -> &RenameAllRules {
634 &self.rename_all_rules
635 }
636
transparent(&self) -> bool637 pub fn transparent(&self) -> bool {
638 self.transparent
639 }
640
deny_unknown_fields(&self) -> bool641 pub fn deny_unknown_fields(&self) -> bool {
642 self.deny_unknown_fields
643 }
644
default(&self) -> &Default645 pub fn default(&self) -> &Default {
646 &self.default
647 }
648
ser_bound(&self) -> Option<&[syn::WherePredicate]>649 pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> {
650 self.ser_bound.as_ref().map(|vec| &vec[..])
651 }
652
de_bound(&self) -> Option<&[syn::WherePredicate]>653 pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> {
654 self.de_bound.as_ref().map(|vec| &vec[..])
655 }
656
tag(&self) -> &TagType657 pub fn tag(&self) -> &TagType {
658 &self.tag
659 }
660
type_from(&self) -> Option<&syn::Type>661 pub fn type_from(&self) -> Option<&syn::Type> {
662 self.type_from.as_ref()
663 }
664
type_try_from(&self) -> Option<&syn::Type>665 pub fn type_try_from(&self) -> Option<&syn::Type> {
666 self.type_try_from.as_ref()
667 }
668
type_into(&self) -> Option<&syn::Type>669 pub fn type_into(&self) -> Option<&syn::Type> {
670 self.type_into.as_ref()
671 }
672
remote(&self) -> Option<&syn::Path>673 pub fn remote(&self) -> Option<&syn::Path> {
674 self.remote.as_ref()
675 }
676
is_packed(&self) -> bool677 pub fn is_packed(&self) -> bool {
678 self.is_packed
679 }
680
identifier(&self) -> Identifier681 pub fn identifier(&self) -> Identifier {
682 self.identifier
683 }
684
has_flatten(&self) -> bool685 pub fn has_flatten(&self) -> bool {
686 self.has_flatten
687 }
688
mark_has_flatten(&mut self)689 pub fn mark_has_flatten(&mut self) {
690 self.has_flatten = true;
691 }
692
custom_serde_path(&self) -> Option<&syn::Path>693 pub fn custom_serde_path(&self) -> Option<&syn::Path> {
694 self.serde_path.as_ref()
695 }
696
serde_path(&self) -> Cow<syn::Path>697 pub fn serde_path(&self) -> Cow<syn::Path> {
698 self.custom_serde_path()
699 .map_or_else(|| Cow::Owned(parse_quote!(_serde)), Cow::Borrowed)
700 }
701 }
702
decide_tag( cx: &Ctxt, item: &syn::DeriveInput, untagged: BoolAttr, internal_tag: Attr<String>, content: Attr<String>, ) -> TagType703 fn decide_tag(
704 cx: &Ctxt,
705 item: &syn::DeriveInput,
706 untagged: BoolAttr,
707 internal_tag: Attr<String>,
708 content: Attr<String>,
709 ) -> TagType {
710 match (
711 untagged.0.get_with_tokens(),
712 internal_tag.get_with_tokens(),
713 content.get_with_tokens(),
714 ) {
715 (None, None, None) => TagType::External,
716 (Some(_), None, None) => TagType::None,
717 (None, Some((_, tag)), None) => {
718 // Check that there are no tuple variants.
719 if let syn::Data::Enum(data) = &item.data {
720 for variant in &data.variants {
721 match &variant.fields {
722 syn::Fields::Named(_) | syn::Fields::Unit => {}
723 syn::Fields::Unnamed(fields) => {
724 if fields.unnamed.len() != 1 {
725 cx.error_spanned_by(
726 variant,
727 "#[serde(tag = \"...\")] cannot be used with tuple variants",
728 );
729 break;
730 }
731 }
732 }
733 }
734 }
735 TagType::Internal { tag }
736 }
737 (Some((untagged_tokens, _)), Some((tag_tokens, _)), None) => {
738 cx.error_spanned_by(
739 untagged_tokens,
740 "enum cannot be both untagged and internally tagged",
741 );
742 cx.error_spanned_by(
743 tag_tokens,
744 "enum cannot be both untagged and internally tagged",
745 );
746 TagType::External // doesn't matter, will error
747 }
748 (None, None, Some((content_tokens, _))) => {
749 cx.error_spanned_by(
750 content_tokens,
751 "#[serde(tag = \"...\", content = \"...\")] must be used together",
752 );
753 TagType::External
754 }
755 (Some((untagged_tokens, _)), None, Some((content_tokens, _))) => {
756 cx.error_spanned_by(
757 untagged_tokens,
758 "untagged enum cannot have #[serde(content = \"...\")]",
759 );
760 cx.error_spanned_by(
761 content_tokens,
762 "untagged enum cannot have #[serde(content = \"...\")]",
763 );
764 TagType::External
765 }
766 (None, Some((_, tag)), Some((_, content))) => TagType::Adjacent { tag, content },
767 (Some((untagged_tokens, _)), Some((tag_tokens, _)), Some((content_tokens, _))) => {
768 cx.error_spanned_by(
769 untagged_tokens,
770 "untagged enum cannot have #[serde(tag = \"...\", content = \"...\")]",
771 );
772 cx.error_spanned_by(
773 tag_tokens,
774 "untagged enum cannot have #[serde(tag = \"...\", content = \"...\")]",
775 );
776 cx.error_spanned_by(
777 content_tokens,
778 "untagged enum cannot have #[serde(tag = \"...\", content = \"...\")]",
779 );
780 TagType::External
781 }
782 }
783 }
784
decide_identifier( cx: &Ctxt, item: &syn::DeriveInput, field_identifier: BoolAttr, variant_identifier: BoolAttr, ) -> Identifier785 fn decide_identifier(
786 cx: &Ctxt,
787 item: &syn::DeriveInput,
788 field_identifier: BoolAttr,
789 variant_identifier: BoolAttr,
790 ) -> Identifier {
791 match (
792 &item.data,
793 field_identifier.0.get_with_tokens(),
794 variant_identifier.0.get_with_tokens(),
795 ) {
796 (_, None, None) => Identifier::No,
797 (_, Some((field_identifier_tokens, _)), Some((variant_identifier_tokens, _))) => {
798 cx.error_spanned_by(
799 field_identifier_tokens,
800 "#[serde(field_identifier)] and #[serde(variant_identifier)] cannot both be set",
801 );
802 cx.error_spanned_by(
803 variant_identifier_tokens,
804 "#[serde(field_identifier)] and #[serde(variant_identifier)] cannot both be set",
805 );
806 Identifier::No
807 }
808 (syn::Data::Enum(_), Some(_), None) => Identifier::Field,
809 (syn::Data::Enum(_), None, Some(_)) => Identifier::Variant,
810 (syn::Data::Struct(syn::DataStruct { struct_token, .. }), Some(_), None) => {
811 cx.error_spanned_by(
812 struct_token,
813 "#[serde(field_identifier)] can only be used on an enum",
814 );
815 Identifier::No
816 }
817 (syn::Data::Union(syn::DataUnion { union_token, .. }), Some(_), None) => {
818 cx.error_spanned_by(
819 union_token,
820 "#[serde(field_identifier)] can only be used on an enum",
821 );
822 Identifier::No
823 }
824 (syn::Data::Struct(syn::DataStruct { struct_token, .. }), None, Some(_)) => {
825 cx.error_spanned_by(
826 struct_token,
827 "#[serde(variant_identifier)] can only be used on an enum",
828 );
829 Identifier::No
830 }
831 (syn::Data::Union(syn::DataUnion { union_token, .. }), None, Some(_)) => {
832 cx.error_spanned_by(
833 union_token,
834 "#[serde(variant_identifier)] can only be used on an enum",
835 );
836 Identifier::No
837 }
838 }
839 }
840
841 /// Represents variant attribute information
842 pub struct Variant {
843 name: Name,
844 rename_all_rules: RenameAllRules,
845 ser_bound: Option<Vec<syn::WherePredicate>>,
846 de_bound: Option<Vec<syn::WherePredicate>>,
847 skip_deserializing: bool,
848 skip_serializing: bool,
849 other: bool,
850 serialize_with: Option<syn::ExprPath>,
851 deserialize_with: Option<syn::ExprPath>,
852 borrow: Option<syn::Meta>,
853 }
854
855 impl Variant {
from_ast(cx: &Ctxt, variant: &syn::Variant) -> Self856 pub fn from_ast(cx: &Ctxt, variant: &syn::Variant) -> Self {
857 let mut ser_name = Attr::none(cx, RENAME);
858 let mut de_name = Attr::none(cx, RENAME);
859 let mut de_aliases = VecAttr::none(cx, RENAME);
860 let mut skip_deserializing = BoolAttr::none(cx, SKIP_DESERIALIZING);
861 let mut skip_serializing = BoolAttr::none(cx, SKIP_SERIALIZING);
862 let mut rename_all_ser_rule = Attr::none(cx, RENAME_ALL);
863 let mut rename_all_de_rule = Attr::none(cx, RENAME_ALL);
864 let mut ser_bound = Attr::none(cx, BOUND);
865 let mut de_bound = Attr::none(cx, BOUND);
866 let mut other = BoolAttr::none(cx, OTHER);
867 let mut serialize_with = Attr::none(cx, SERIALIZE_WITH);
868 let mut deserialize_with = Attr::none(cx, DESERIALIZE_WITH);
869 let mut borrow = Attr::none(cx, BORROW);
870
871 for meta_item in variant
872 .attrs
873 .iter()
874 .flat_map(|attr| get_serde_meta_items(cx, attr))
875 .flatten()
876 {
877 match &meta_item {
878 // Parse `#[serde(rename = "foo")]`
879 Meta(NameValue(m)) if m.path == RENAME => {
880 if let Ok(s) = get_lit_str(cx, RENAME, &m.lit) {
881 ser_name.set(&m.path, s.value());
882 de_name.set_if_none(s.value());
883 de_aliases.insert(&m.path, s.value());
884 }
885 }
886
887 // Parse `#[serde(rename(serialize = "foo", deserialize = "bar"))]`
888 Meta(List(m)) if m.path == RENAME => {
889 if let Ok((ser, de)) = get_multiple_renames(cx, &m.nested) {
890 ser_name.set_opt(&m.path, ser.map(syn::LitStr::value));
891 for de_value in de {
892 de_name.set_if_none(de_value.value());
893 de_aliases.insert(&m.path, de_value.value());
894 }
895 }
896 }
897
898 // Parse `#[serde(alias = "foo")]`
899 Meta(NameValue(m)) if m.path == ALIAS => {
900 if let Ok(s) = get_lit_str(cx, ALIAS, &m.lit) {
901 de_aliases.insert(&m.path, s.value());
902 }
903 }
904
905 // Parse `#[serde(rename_all = "foo")]`
906 Meta(NameValue(m)) if m.path == RENAME_ALL => {
907 if let Ok(s) = get_lit_str(cx, RENAME_ALL, &m.lit) {
908 match RenameRule::from_str(&s.value()) {
909 Ok(rename_rule) => {
910 rename_all_ser_rule.set(&m.path, rename_rule);
911 rename_all_de_rule.set(&m.path, rename_rule);
912 }
913 Err(()) => cx.error_spanned_by(
914 s,
915 format!(
916 "unknown rename rule for #[serde(rename_all = {:?})]",
917 s.value()
918 ),
919 ),
920 }
921 }
922 }
923
924 // Parse `#[serde(rename_all(serialize = "foo", deserialize = "bar"))]`
925 Meta(List(m)) if m.path == RENAME_ALL => {
926 if let Ok((ser, de)) = get_renames(cx, &m.nested) {
927 if let Some(ser) = ser {
928 match RenameRule::from_str(&ser.value()) {
929 Ok(rename_rule) => rename_all_ser_rule.set(&m.path, rename_rule),
930 Err(()) => cx.error_spanned_by(
931 ser,
932 format!(
933 "unknown rename rule for #[serde(rename_all = {:?})]",
934 ser.value(),
935 ),
936 ),
937 }
938 }
939 if let Some(de) = de {
940 match RenameRule::from_str(&de.value()) {
941 Ok(rename_rule) => rename_all_de_rule.set(&m.path, rename_rule),
942 Err(()) => cx.error_spanned_by(
943 de,
944 format!(
945 "unknown rename rule for #[serde(rename_all = {:?})]",
946 de.value(),
947 ),
948 ),
949 }
950 }
951 }
952 }
953
954 // Parse `#[serde(skip)]`
955 Meta(Path(word)) if word == SKIP => {
956 skip_serializing.set_true(word);
957 skip_deserializing.set_true(word);
958 }
959
960 // Parse `#[serde(skip_deserializing)]`
961 Meta(Path(word)) if word == SKIP_DESERIALIZING => {
962 skip_deserializing.set_true(word);
963 }
964
965 // Parse `#[serde(skip_serializing)]`
966 Meta(Path(word)) if word == SKIP_SERIALIZING => {
967 skip_serializing.set_true(word);
968 }
969
970 // Parse `#[serde(other)]`
971 Meta(Path(word)) if word == OTHER => {
972 other.set_true(word);
973 }
974
975 // Parse `#[serde(bound = "T: SomeBound")]`
976 Meta(NameValue(m)) if m.path == BOUND => {
977 if let Ok(where_predicates) = parse_lit_into_where(cx, BOUND, BOUND, &m.lit) {
978 ser_bound.set(&m.path, where_predicates.clone());
979 de_bound.set(&m.path, where_predicates);
980 }
981 }
982
983 // Parse `#[serde(bound(serialize = "...", deserialize = "..."))]`
984 Meta(List(m)) if m.path == BOUND => {
985 if let Ok((ser, de)) = get_where_predicates(cx, &m.nested) {
986 ser_bound.set_opt(&m.path, ser);
987 de_bound.set_opt(&m.path, de);
988 }
989 }
990
991 // Parse `#[serde(with = "...")]`
992 Meta(NameValue(m)) if m.path == WITH => {
993 if let Ok(path) = parse_lit_into_expr_path(cx, WITH, &m.lit) {
994 let mut ser_path = path.clone();
995 ser_path
996 .path
997 .segments
998 .push(Ident::new("serialize", Span::call_site()).into());
999 serialize_with.set(&m.path, ser_path);
1000 let mut de_path = path;
1001 de_path
1002 .path
1003 .segments
1004 .push(Ident::new("deserialize", Span::call_site()).into());
1005 deserialize_with.set(&m.path, de_path);
1006 }
1007 }
1008
1009 // Parse `#[serde(serialize_with = "...")]`
1010 Meta(NameValue(m)) if m.path == SERIALIZE_WITH => {
1011 if let Ok(path) = parse_lit_into_expr_path(cx, SERIALIZE_WITH, &m.lit) {
1012 serialize_with.set(&m.path, path);
1013 }
1014 }
1015
1016 // Parse `#[serde(deserialize_with = "...")]`
1017 Meta(NameValue(m)) if m.path == DESERIALIZE_WITH => {
1018 if let Ok(path) = parse_lit_into_expr_path(cx, DESERIALIZE_WITH, &m.lit) {
1019 deserialize_with.set(&m.path, path);
1020 }
1021 }
1022
1023 // Defer `#[serde(borrow)]` and `#[serde(borrow = "'a + 'b")]`
1024 Meta(m) if m.path() == BORROW => match &variant.fields {
1025 syn::Fields::Unnamed(fields) if fields.unnamed.len() == 1 => {
1026 borrow.set(m.path(), m.clone());
1027 }
1028 _ => {
1029 cx.error_spanned_by(
1030 variant,
1031 "#[serde(borrow)] may only be used on newtype variants",
1032 );
1033 }
1034 },
1035
1036 Meta(meta_item) => {
1037 let path = meta_item
1038 .path()
1039 .into_token_stream()
1040 .to_string()
1041 .replace(' ', "");
1042 cx.error_spanned_by(
1043 meta_item.path(),
1044 format!("unknown serde variant attribute `{}`", path),
1045 );
1046 }
1047
1048 Lit(lit) => {
1049 cx.error_spanned_by(lit, "unexpected literal in serde variant attribute");
1050 }
1051 }
1052 }
1053
1054 Variant {
1055 name: Name::from_attrs(unraw(&variant.ident), ser_name, de_name, Some(de_aliases)),
1056 rename_all_rules: RenameAllRules {
1057 serialize: rename_all_ser_rule.get().unwrap_or(RenameRule::None),
1058 deserialize: rename_all_de_rule.get().unwrap_or(RenameRule::None),
1059 },
1060 ser_bound: ser_bound.get(),
1061 de_bound: de_bound.get(),
1062 skip_deserializing: skip_deserializing.get(),
1063 skip_serializing: skip_serializing.get(),
1064 other: other.get(),
1065 serialize_with: serialize_with.get(),
1066 deserialize_with: deserialize_with.get(),
1067 borrow: borrow.get(),
1068 }
1069 }
1070
name(&self) -> &Name1071 pub fn name(&self) -> &Name {
1072 &self.name
1073 }
1074
aliases(&self) -> Vec<String>1075 pub fn aliases(&self) -> Vec<String> {
1076 self.name.deserialize_aliases()
1077 }
1078
rename_by_rules(&mut self, rules: &RenameAllRules)1079 pub fn rename_by_rules(&mut self, rules: &RenameAllRules) {
1080 if !self.name.serialize_renamed {
1081 self.name.serialize = rules.serialize.apply_to_variant(&self.name.serialize);
1082 }
1083 if !self.name.deserialize_renamed {
1084 self.name.deserialize = rules.deserialize.apply_to_variant(&self.name.deserialize);
1085 }
1086 }
1087
rename_all_rules(&self) -> &RenameAllRules1088 pub fn rename_all_rules(&self) -> &RenameAllRules {
1089 &self.rename_all_rules
1090 }
1091
ser_bound(&self) -> Option<&[syn::WherePredicate]>1092 pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> {
1093 self.ser_bound.as_ref().map(|vec| &vec[..])
1094 }
1095
de_bound(&self) -> Option<&[syn::WherePredicate]>1096 pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> {
1097 self.de_bound.as_ref().map(|vec| &vec[..])
1098 }
1099
skip_deserializing(&self) -> bool1100 pub fn skip_deserializing(&self) -> bool {
1101 self.skip_deserializing
1102 }
1103
skip_serializing(&self) -> bool1104 pub fn skip_serializing(&self) -> bool {
1105 self.skip_serializing
1106 }
1107
other(&self) -> bool1108 pub fn other(&self) -> bool {
1109 self.other
1110 }
1111
serialize_with(&self) -> Option<&syn::ExprPath>1112 pub fn serialize_with(&self) -> Option<&syn::ExprPath> {
1113 self.serialize_with.as_ref()
1114 }
1115
deserialize_with(&self) -> Option<&syn::ExprPath>1116 pub fn deserialize_with(&self) -> Option<&syn::ExprPath> {
1117 self.deserialize_with.as_ref()
1118 }
1119 }
1120
1121 /// Represents field attribute information
1122 pub struct Field {
1123 name: Name,
1124 skip_serializing: bool,
1125 skip_deserializing: bool,
1126 skip_serializing_if: Option<syn::ExprPath>,
1127 default: Default,
1128 serialize_with: Option<syn::ExprPath>,
1129 deserialize_with: Option<syn::ExprPath>,
1130 ser_bound: Option<Vec<syn::WherePredicate>>,
1131 de_bound: Option<Vec<syn::WherePredicate>>,
1132 borrowed_lifetimes: BTreeSet<syn::Lifetime>,
1133 getter: Option<syn::ExprPath>,
1134 flatten: bool,
1135 transparent: bool,
1136 }
1137
1138 /// Represents the default to use for a field when deserializing.
1139 pub enum Default {
1140 /// Field must always be specified because it does not have a default.
1141 None,
1142 /// The default is given by `std::default::Default::default()`.
1143 Default,
1144 /// The default is given by this function.
1145 Path(syn::ExprPath),
1146 }
1147
1148 impl Default {
is_none(&self) -> bool1149 pub fn is_none(&self) -> bool {
1150 match self {
1151 Default::None => true,
1152 Default::Default | Default::Path(_) => false,
1153 }
1154 }
1155 }
1156
1157 impl Field {
1158 /// Extract out the `#[serde(...)]` attributes from a struct field.
from_ast( cx: &Ctxt, index: usize, field: &syn::Field, attrs: Option<&Variant>, container_default: &Default, ) -> Self1159 pub fn from_ast(
1160 cx: &Ctxt,
1161 index: usize,
1162 field: &syn::Field,
1163 attrs: Option<&Variant>,
1164 container_default: &Default,
1165 ) -> Self {
1166 let mut ser_name = Attr::none(cx, RENAME);
1167 let mut de_name = Attr::none(cx, RENAME);
1168 let mut de_aliases = VecAttr::none(cx, RENAME);
1169 let mut skip_serializing = BoolAttr::none(cx, SKIP_SERIALIZING);
1170 let mut skip_deserializing = BoolAttr::none(cx, SKIP_DESERIALIZING);
1171 let mut skip_serializing_if = Attr::none(cx, SKIP_SERIALIZING_IF);
1172 let mut default = Attr::none(cx, DEFAULT);
1173 let mut serialize_with = Attr::none(cx, SERIALIZE_WITH);
1174 let mut deserialize_with = Attr::none(cx, DESERIALIZE_WITH);
1175 let mut ser_bound = Attr::none(cx, BOUND);
1176 let mut de_bound = Attr::none(cx, BOUND);
1177 let mut borrowed_lifetimes = Attr::none(cx, BORROW);
1178 let mut getter = Attr::none(cx, GETTER);
1179 let mut flatten = BoolAttr::none(cx, FLATTEN);
1180
1181 let ident = match &field.ident {
1182 Some(ident) => unraw(ident),
1183 None => index.to_string(),
1184 };
1185
1186 let variant_borrow = attrs
1187 .and_then(|variant| variant.borrow.as_ref())
1188 .map(|borrow| Meta(borrow.clone()));
1189
1190 for meta_item in field
1191 .attrs
1192 .iter()
1193 .flat_map(|attr| get_serde_meta_items(cx, attr))
1194 .flatten()
1195 .chain(variant_borrow)
1196 {
1197 match &meta_item {
1198 // Parse `#[serde(rename = "foo")]`
1199 Meta(NameValue(m)) if m.path == RENAME => {
1200 if let Ok(s) = get_lit_str(cx, RENAME, &m.lit) {
1201 ser_name.set(&m.path, s.value());
1202 de_name.set_if_none(s.value());
1203 de_aliases.insert(&m.path, s.value());
1204 }
1205 }
1206
1207 // Parse `#[serde(rename(serialize = "foo", deserialize = "bar"))]`
1208 Meta(List(m)) if m.path == RENAME => {
1209 if let Ok((ser, de)) = get_multiple_renames(cx, &m.nested) {
1210 ser_name.set_opt(&m.path, ser.map(syn::LitStr::value));
1211 for de_value in de {
1212 de_name.set_if_none(de_value.value());
1213 de_aliases.insert(&m.path, de_value.value());
1214 }
1215 }
1216 }
1217
1218 // Parse `#[serde(alias = "foo")]`
1219 Meta(NameValue(m)) if m.path == ALIAS => {
1220 if let Ok(s) = get_lit_str(cx, ALIAS, &m.lit) {
1221 de_aliases.insert(&m.path, s.value());
1222 }
1223 }
1224
1225 // Parse `#[serde(default)]`
1226 Meta(Path(word)) if word == DEFAULT => {
1227 default.set(word, Default::Default);
1228 }
1229
1230 // Parse `#[serde(default = "...")]`
1231 Meta(NameValue(m)) if m.path == DEFAULT => {
1232 if let Ok(path) = parse_lit_into_expr_path(cx, DEFAULT, &m.lit) {
1233 default.set(&m.path, Default::Path(path));
1234 }
1235 }
1236
1237 // Parse `#[serde(skip_serializing)]`
1238 Meta(Path(word)) if word == SKIP_SERIALIZING => {
1239 skip_serializing.set_true(word);
1240 }
1241
1242 // Parse `#[serde(skip_deserializing)]`
1243 Meta(Path(word)) if word == SKIP_DESERIALIZING => {
1244 skip_deserializing.set_true(word);
1245 }
1246
1247 // Parse `#[serde(skip)]`
1248 Meta(Path(word)) if word == SKIP => {
1249 skip_serializing.set_true(word);
1250 skip_deserializing.set_true(word);
1251 }
1252
1253 // Parse `#[serde(skip_serializing_if = "...")]`
1254 Meta(NameValue(m)) if m.path == SKIP_SERIALIZING_IF => {
1255 if let Ok(path) = parse_lit_into_expr_path(cx, SKIP_SERIALIZING_IF, &m.lit) {
1256 skip_serializing_if.set(&m.path, path);
1257 }
1258 }
1259
1260 // Parse `#[serde(serialize_with = "...")]`
1261 Meta(NameValue(m)) if m.path == SERIALIZE_WITH => {
1262 if let Ok(path) = parse_lit_into_expr_path(cx, SERIALIZE_WITH, &m.lit) {
1263 serialize_with.set(&m.path, path);
1264 }
1265 }
1266
1267 // Parse `#[serde(deserialize_with = "...")]`
1268 Meta(NameValue(m)) if m.path == DESERIALIZE_WITH => {
1269 if let Ok(path) = parse_lit_into_expr_path(cx, DESERIALIZE_WITH, &m.lit) {
1270 deserialize_with.set(&m.path, path);
1271 }
1272 }
1273
1274 // Parse `#[serde(with = "...")]`
1275 Meta(NameValue(m)) if m.path == WITH => {
1276 if let Ok(path) = parse_lit_into_expr_path(cx, WITH, &m.lit) {
1277 let mut ser_path = path.clone();
1278 ser_path
1279 .path
1280 .segments
1281 .push(Ident::new("serialize", Span::call_site()).into());
1282 serialize_with.set(&m.path, ser_path);
1283 let mut de_path = path;
1284 de_path
1285 .path
1286 .segments
1287 .push(Ident::new("deserialize", Span::call_site()).into());
1288 deserialize_with.set(&m.path, de_path);
1289 }
1290 }
1291
1292 // Parse `#[serde(bound = "T: SomeBound")]`
1293 Meta(NameValue(m)) if m.path == BOUND => {
1294 if let Ok(where_predicates) = parse_lit_into_where(cx, BOUND, BOUND, &m.lit) {
1295 ser_bound.set(&m.path, where_predicates.clone());
1296 de_bound.set(&m.path, where_predicates);
1297 }
1298 }
1299
1300 // Parse `#[serde(bound(serialize = "...", deserialize = "..."))]`
1301 Meta(List(m)) if m.path == BOUND => {
1302 if let Ok((ser, de)) = get_where_predicates(cx, &m.nested) {
1303 ser_bound.set_opt(&m.path, ser);
1304 de_bound.set_opt(&m.path, de);
1305 }
1306 }
1307
1308 // Parse `#[serde(borrow)]`
1309 Meta(Path(word)) if word == BORROW => {
1310 if let Ok(borrowable) = borrowable_lifetimes(cx, &ident, field) {
1311 borrowed_lifetimes.set(word, borrowable);
1312 }
1313 }
1314
1315 // Parse `#[serde(borrow = "'a + 'b")]`
1316 Meta(NameValue(m)) if m.path == BORROW => {
1317 if let Ok(lifetimes) = parse_lit_into_lifetimes(cx, BORROW, &m.lit) {
1318 if let Ok(borrowable) = borrowable_lifetimes(cx, &ident, field) {
1319 for lifetime in &lifetimes {
1320 if !borrowable.contains(lifetime) {
1321 cx.error_spanned_by(
1322 field,
1323 format!(
1324 "field `{}` does not have lifetime {}",
1325 ident, lifetime
1326 ),
1327 );
1328 }
1329 }
1330 borrowed_lifetimes.set(&m.path, lifetimes);
1331 }
1332 }
1333 }
1334
1335 // Parse `#[serde(getter = "...")]`
1336 Meta(NameValue(m)) if m.path == GETTER => {
1337 if let Ok(path) = parse_lit_into_expr_path(cx, GETTER, &m.lit) {
1338 getter.set(&m.path, path);
1339 }
1340 }
1341
1342 // Parse `#[serde(flatten)]`
1343 Meta(Path(word)) if word == FLATTEN => {
1344 flatten.set_true(word);
1345 }
1346
1347 Meta(meta_item) => {
1348 let path = meta_item
1349 .path()
1350 .into_token_stream()
1351 .to_string()
1352 .replace(' ', "");
1353 cx.error_spanned_by(
1354 meta_item.path(),
1355 format!("unknown serde field attribute `{}`", path),
1356 );
1357 }
1358
1359 Lit(lit) => {
1360 cx.error_spanned_by(lit, "unexpected literal in serde field attribute");
1361 }
1362 }
1363 }
1364
1365 // Is skip_deserializing, initialize the field to Default::default() unless a
1366 // different default is specified by `#[serde(default = "...")]` on
1367 // ourselves or our container (e.g. the struct we are in).
1368 if let Default::None = *container_default {
1369 if skip_deserializing.0.value.is_some() {
1370 default.set_if_none(Default::Default);
1371 }
1372 }
1373
1374 let mut borrowed_lifetimes = borrowed_lifetimes.get().unwrap_or_default();
1375 if !borrowed_lifetimes.is_empty() {
1376 // Cow<str> and Cow<[u8]> never borrow by default:
1377 //
1378 // impl<'de, 'a, T: ?Sized> Deserialize<'de> for Cow<'a, T>
1379 //
1380 // A #[serde(borrow)] attribute enables borrowing that corresponds
1381 // roughly to these impls:
1382 //
1383 // impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, str>
1384 // impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, [u8]>
1385 if is_cow(&field.ty, is_str) {
1386 let mut path = syn::Path {
1387 leading_colon: None,
1388 segments: Punctuated::new(),
1389 };
1390 let span = Span::call_site();
1391 path.segments.push(Ident::new("_serde", span).into());
1392 path.segments.push(Ident::new("private", span).into());
1393 path.segments.push(Ident::new("de", span).into());
1394 path.segments
1395 .push(Ident::new("borrow_cow_str", span).into());
1396 let expr = syn::ExprPath {
1397 attrs: Vec::new(),
1398 qself: None,
1399 path,
1400 };
1401 deserialize_with.set_if_none(expr);
1402 } else if is_cow(&field.ty, is_slice_u8) {
1403 let mut path = syn::Path {
1404 leading_colon: None,
1405 segments: Punctuated::new(),
1406 };
1407 let span = Span::call_site();
1408 path.segments.push(Ident::new("_serde", span).into());
1409 path.segments.push(Ident::new("private", span).into());
1410 path.segments.push(Ident::new("de", span).into());
1411 path.segments
1412 .push(Ident::new("borrow_cow_bytes", span).into());
1413 let expr = syn::ExprPath {
1414 attrs: Vec::new(),
1415 qself: None,
1416 path,
1417 };
1418 deserialize_with.set_if_none(expr);
1419 }
1420 } else if is_implicitly_borrowed(&field.ty) {
1421 // Types &str and &[u8] are always implicitly borrowed. No need for
1422 // a #[serde(borrow)].
1423 collect_lifetimes(&field.ty, &mut borrowed_lifetimes);
1424 }
1425
1426 Field {
1427 name: Name::from_attrs(ident, ser_name, de_name, Some(de_aliases)),
1428 skip_serializing: skip_serializing.get(),
1429 skip_deserializing: skip_deserializing.get(),
1430 skip_serializing_if: skip_serializing_if.get(),
1431 default: default.get().unwrap_or(Default::None),
1432 serialize_with: serialize_with.get(),
1433 deserialize_with: deserialize_with.get(),
1434 ser_bound: ser_bound.get(),
1435 de_bound: de_bound.get(),
1436 borrowed_lifetimes,
1437 getter: getter.get(),
1438 flatten: flatten.get(),
1439 transparent: false,
1440 }
1441 }
1442
name(&self) -> &Name1443 pub fn name(&self) -> &Name {
1444 &self.name
1445 }
1446
aliases(&self) -> Vec<String>1447 pub fn aliases(&self) -> Vec<String> {
1448 self.name.deserialize_aliases()
1449 }
1450
rename_by_rules(&mut self, rules: &RenameAllRules)1451 pub fn rename_by_rules(&mut self, rules: &RenameAllRules) {
1452 if !self.name.serialize_renamed {
1453 self.name.serialize = rules.serialize.apply_to_field(&self.name.serialize);
1454 }
1455 if !self.name.deserialize_renamed {
1456 self.name.deserialize = rules.deserialize.apply_to_field(&self.name.deserialize);
1457 }
1458 }
1459
skip_serializing(&self) -> bool1460 pub fn skip_serializing(&self) -> bool {
1461 self.skip_serializing
1462 }
1463
skip_deserializing(&self) -> bool1464 pub fn skip_deserializing(&self) -> bool {
1465 self.skip_deserializing
1466 }
1467
skip_serializing_if(&self) -> Option<&syn::ExprPath>1468 pub fn skip_serializing_if(&self) -> Option<&syn::ExprPath> {
1469 self.skip_serializing_if.as_ref()
1470 }
1471
default(&self) -> &Default1472 pub fn default(&self) -> &Default {
1473 &self.default
1474 }
1475
serialize_with(&self) -> Option<&syn::ExprPath>1476 pub fn serialize_with(&self) -> Option<&syn::ExprPath> {
1477 self.serialize_with.as_ref()
1478 }
1479
deserialize_with(&self) -> Option<&syn::ExprPath>1480 pub fn deserialize_with(&self) -> Option<&syn::ExprPath> {
1481 self.deserialize_with.as_ref()
1482 }
1483
ser_bound(&self) -> Option<&[syn::WherePredicate]>1484 pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> {
1485 self.ser_bound.as_ref().map(|vec| &vec[..])
1486 }
1487
de_bound(&self) -> Option<&[syn::WherePredicate]>1488 pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> {
1489 self.de_bound.as_ref().map(|vec| &vec[..])
1490 }
1491
borrowed_lifetimes(&self) -> &BTreeSet<syn::Lifetime>1492 pub fn borrowed_lifetimes(&self) -> &BTreeSet<syn::Lifetime> {
1493 &self.borrowed_lifetimes
1494 }
1495
getter(&self) -> Option<&syn::ExprPath>1496 pub fn getter(&self) -> Option<&syn::ExprPath> {
1497 self.getter.as_ref()
1498 }
1499
flatten(&self) -> bool1500 pub fn flatten(&self) -> bool {
1501 self.flatten
1502 }
1503
transparent(&self) -> bool1504 pub fn transparent(&self) -> bool {
1505 self.transparent
1506 }
1507
mark_transparent(&mut self)1508 pub fn mark_transparent(&mut self) {
1509 self.transparent = true;
1510 }
1511 }
1512
1513 type SerAndDe<T> = (Option<T>, Option<T>);
1514
get_ser_and_de<'a, 'b, T, F>( cx: &'b Ctxt, attr_name: Symbol, metas: &'a Punctuated<syn::NestedMeta, Token![,]>, f: F, ) -> Result<(VecAttr<'b, T>, VecAttr<'b, T>), ()> where T: 'a, F: Fn(&Ctxt, Symbol, Symbol, &'a syn::Lit) -> Result<T, ()>,1515 fn get_ser_and_de<'a, 'b, T, F>(
1516 cx: &'b Ctxt,
1517 attr_name: Symbol,
1518 metas: &'a Punctuated<syn::NestedMeta, Token![,]>,
1519 f: F,
1520 ) -> Result<(VecAttr<'b, T>, VecAttr<'b, T>), ()>
1521 where
1522 T: 'a,
1523 F: Fn(&Ctxt, Symbol, Symbol, &'a syn::Lit) -> Result<T, ()>,
1524 {
1525 let mut ser_meta = VecAttr::none(cx, attr_name);
1526 let mut de_meta = VecAttr::none(cx, attr_name);
1527
1528 for meta in metas {
1529 match meta {
1530 Meta(NameValue(meta)) if meta.path == SERIALIZE => {
1531 if let Ok(v) = f(cx, attr_name, SERIALIZE, &meta.lit) {
1532 ser_meta.insert(&meta.path, v);
1533 }
1534 }
1535
1536 Meta(NameValue(meta)) if meta.path == DESERIALIZE => {
1537 if let Ok(v) = f(cx, attr_name, DESERIALIZE, &meta.lit) {
1538 de_meta.insert(&meta.path, v);
1539 }
1540 }
1541
1542 _ => {
1543 cx.error_spanned_by(
1544 meta,
1545 format!(
1546 "malformed {0} attribute, expected `{0}(serialize = ..., deserialize = ...)`",
1547 attr_name
1548 ),
1549 );
1550 return Err(());
1551 }
1552 }
1553 }
1554
1555 Ok((ser_meta, de_meta))
1556 }
1557
get_renames<'a>( cx: &Ctxt, items: &'a Punctuated<syn::NestedMeta, Token![,]>, ) -> Result<SerAndDe<&'a syn::LitStr>, ()>1558 fn get_renames<'a>(
1559 cx: &Ctxt,
1560 items: &'a Punctuated<syn::NestedMeta, Token![,]>,
1561 ) -> Result<SerAndDe<&'a syn::LitStr>, ()> {
1562 let (ser, de) = get_ser_and_de(cx, RENAME, items, get_lit_str2)?;
1563 Ok((ser.at_most_one()?, de.at_most_one()?))
1564 }
1565
get_multiple_renames<'a>( cx: &Ctxt, items: &'a Punctuated<syn::NestedMeta, Token![,]>, ) -> Result<(Option<&'a syn::LitStr>, Vec<&'a syn::LitStr>), ()>1566 fn get_multiple_renames<'a>(
1567 cx: &Ctxt,
1568 items: &'a Punctuated<syn::NestedMeta, Token![,]>,
1569 ) -> Result<(Option<&'a syn::LitStr>, Vec<&'a syn::LitStr>), ()> {
1570 let (ser, de) = get_ser_and_de(cx, RENAME, items, get_lit_str2)?;
1571 Ok((ser.at_most_one()?, de.get()))
1572 }
1573
get_where_predicates( cx: &Ctxt, items: &Punctuated<syn::NestedMeta, Token![,]>, ) -> Result<SerAndDe<Vec<syn::WherePredicate>>, ()>1574 fn get_where_predicates(
1575 cx: &Ctxt,
1576 items: &Punctuated<syn::NestedMeta, Token![,]>,
1577 ) -> Result<SerAndDe<Vec<syn::WherePredicate>>, ()> {
1578 let (ser, de) = get_ser_and_de(cx, BOUND, items, parse_lit_into_where)?;
1579 Ok((ser.at_most_one()?, de.at_most_one()?))
1580 }
1581
get_serde_meta_items(cx: &Ctxt, attr: &syn::Attribute) -> Result<Vec<syn::NestedMeta>, ()>1582 pub fn get_serde_meta_items(cx: &Ctxt, attr: &syn::Attribute) -> Result<Vec<syn::NestedMeta>, ()> {
1583 if attr.path != SERDE {
1584 return Ok(Vec::new());
1585 }
1586
1587 match attr.parse_meta() {
1588 Ok(List(meta)) => Ok(meta.nested.into_iter().collect()),
1589 Ok(other) => {
1590 cx.error_spanned_by(other, "expected #[serde(...)]");
1591 Err(())
1592 }
1593 Err(err) => {
1594 cx.syn_error(err);
1595 Err(())
1596 }
1597 }
1598 }
1599
get_lit_str<'a>(cx: &Ctxt, attr_name: Symbol, lit: &'a syn::Lit) -> Result<&'a syn::LitStr, ()>1600 fn get_lit_str<'a>(cx: &Ctxt, attr_name: Symbol, lit: &'a syn::Lit) -> Result<&'a syn::LitStr, ()> {
1601 get_lit_str2(cx, attr_name, attr_name, lit)
1602 }
1603
get_lit_str2<'a>( cx: &Ctxt, attr_name: Symbol, meta_item_name: Symbol, lit: &'a syn::Lit, ) -> Result<&'a syn::LitStr, ()>1604 fn get_lit_str2<'a>(
1605 cx: &Ctxt,
1606 attr_name: Symbol,
1607 meta_item_name: Symbol,
1608 lit: &'a syn::Lit,
1609 ) -> Result<&'a syn::LitStr, ()> {
1610 if let syn::Lit::Str(lit) = lit {
1611 Ok(lit)
1612 } else {
1613 cx.error_spanned_by(
1614 lit,
1615 format!(
1616 "expected serde {} attribute to be a string: `{} = \"...\"`",
1617 attr_name, meta_item_name
1618 ),
1619 );
1620 Err(())
1621 }
1622 }
1623
parse_lit_into_path(cx: &Ctxt, attr_name: Symbol, lit: &syn::Lit) -> Result<syn::Path, ()>1624 fn parse_lit_into_path(cx: &Ctxt, attr_name: Symbol, lit: &syn::Lit) -> Result<syn::Path, ()> {
1625 let string = get_lit_str(cx, attr_name, lit)?;
1626 parse_lit_str(string).map_err(|_| {
1627 cx.error_spanned_by(lit, format!("failed to parse path: {:?}", string.value()))
1628 })
1629 }
1630
parse_lit_into_expr_path( cx: &Ctxt, attr_name: Symbol, lit: &syn::Lit, ) -> Result<syn::ExprPath, ()>1631 fn parse_lit_into_expr_path(
1632 cx: &Ctxt,
1633 attr_name: Symbol,
1634 lit: &syn::Lit,
1635 ) -> Result<syn::ExprPath, ()> {
1636 let string = get_lit_str(cx, attr_name, lit)?;
1637 parse_lit_str(string).map_err(|_| {
1638 cx.error_spanned_by(lit, format!("failed to parse path: {:?}", string.value()))
1639 })
1640 }
1641
parse_lit_into_where( cx: &Ctxt, attr_name: Symbol, meta_item_name: Symbol, lit: &syn::Lit, ) -> Result<Vec<syn::WherePredicate>, ()>1642 fn parse_lit_into_where(
1643 cx: &Ctxt,
1644 attr_name: Symbol,
1645 meta_item_name: Symbol,
1646 lit: &syn::Lit,
1647 ) -> Result<Vec<syn::WherePredicate>, ()> {
1648 let string = get_lit_str2(cx, attr_name, meta_item_name, lit)?;
1649 if string.value().is_empty() {
1650 return Ok(Vec::new());
1651 }
1652
1653 let where_string = syn::LitStr::new(&format!("where {}", string.value()), string.span());
1654
1655 parse_lit_str::<syn::WhereClause>(&where_string)
1656 .map(|wh| wh.predicates.into_iter().collect())
1657 .map_err(|err| cx.error_spanned_by(lit, err))
1658 }
1659
parse_lit_into_ty(cx: &Ctxt, attr_name: Symbol, lit: &syn::Lit) -> Result<syn::Type, ()>1660 fn parse_lit_into_ty(cx: &Ctxt, attr_name: Symbol, lit: &syn::Lit) -> Result<syn::Type, ()> {
1661 let string = get_lit_str(cx, attr_name, lit)?;
1662
1663 parse_lit_str(string).map_err(|_| {
1664 cx.error_spanned_by(
1665 lit,
1666 format!("failed to parse type: {} = {:?}", attr_name, string.value()),
1667 )
1668 })
1669 }
1670
1671 // Parses a string literal like "'a + 'b + 'c" containing a nonempty list of
1672 // lifetimes separated by `+`.
parse_lit_into_lifetimes( cx: &Ctxt, attr_name: Symbol, lit: &syn::Lit, ) -> Result<BTreeSet<syn::Lifetime>, ()>1673 fn parse_lit_into_lifetimes(
1674 cx: &Ctxt,
1675 attr_name: Symbol,
1676 lit: &syn::Lit,
1677 ) -> Result<BTreeSet<syn::Lifetime>, ()> {
1678 let string = get_lit_str(cx, attr_name, lit)?;
1679 if string.value().is_empty() {
1680 cx.error_spanned_by(lit, "at least one lifetime must be borrowed");
1681 return Err(());
1682 }
1683
1684 struct BorrowedLifetimes(Punctuated<syn::Lifetime, Token![+]>);
1685
1686 impl Parse for BorrowedLifetimes {
1687 fn parse(input: ParseStream) -> parse::Result<Self> {
1688 Punctuated::parse_separated_nonempty(input).map(BorrowedLifetimes)
1689 }
1690 }
1691
1692 if let Ok(BorrowedLifetimes(lifetimes)) = parse_lit_str(string) {
1693 let mut set = BTreeSet::new();
1694 for lifetime in lifetimes {
1695 if !set.insert(lifetime.clone()) {
1696 cx.error_spanned_by(lit, format!("duplicate borrowed lifetime `{}`", lifetime));
1697 }
1698 }
1699 return Ok(set);
1700 }
1701
1702 cx.error_spanned_by(
1703 lit,
1704 format!("failed to parse borrowed lifetimes: {:?}", string.value()),
1705 );
1706 Err(())
1707 }
1708
is_implicitly_borrowed(ty: &syn::Type) -> bool1709 fn is_implicitly_borrowed(ty: &syn::Type) -> bool {
1710 is_implicitly_borrowed_reference(ty) || is_option(ty, is_implicitly_borrowed_reference)
1711 }
1712
is_implicitly_borrowed_reference(ty: &syn::Type) -> bool1713 fn is_implicitly_borrowed_reference(ty: &syn::Type) -> bool {
1714 is_reference(ty, is_str) || is_reference(ty, is_slice_u8)
1715 }
1716
1717 // Whether the type looks like it might be `std::borrow::Cow<T>` where elem="T".
1718 // This can have false negatives and false positives.
1719 //
1720 // False negative:
1721 //
1722 // use std::borrow::Cow as Pig;
1723 //
1724 // #[derive(Deserialize)]
1725 // struct S<'a> {
1726 // #[serde(borrow)]
1727 // pig: Pig<'a, str>,
1728 // }
1729 //
1730 // False positive:
1731 //
1732 // type str = [i16];
1733 //
1734 // #[derive(Deserialize)]
1735 // struct S<'a> {
1736 // #[serde(borrow)]
1737 // cow: Cow<'a, str>,
1738 // }
is_cow(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool1739 fn is_cow(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
1740 let path = match ungroup(ty) {
1741 syn::Type::Path(ty) => &ty.path,
1742 _ => {
1743 return false;
1744 }
1745 };
1746 let seg = match path.segments.last() {
1747 Some(seg) => seg,
1748 None => {
1749 return false;
1750 }
1751 };
1752 let args = match &seg.arguments {
1753 syn::PathArguments::AngleBracketed(bracketed) => &bracketed.args,
1754 _ => {
1755 return false;
1756 }
1757 };
1758 seg.ident == "Cow"
1759 && args.len() == 2
1760 && match (&args[0], &args[1]) {
1761 (syn::GenericArgument::Lifetime(_), syn::GenericArgument::Type(arg)) => elem(arg),
1762 _ => false,
1763 }
1764 }
1765
is_option(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool1766 fn is_option(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
1767 let path = match ungroup(ty) {
1768 syn::Type::Path(ty) => &ty.path,
1769 _ => {
1770 return false;
1771 }
1772 };
1773 let seg = match path.segments.last() {
1774 Some(seg) => seg,
1775 None => {
1776 return false;
1777 }
1778 };
1779 let args = match &seg.arguments {
1780 syn::PathArguments::AngleBracketed(bracketed) => &bracketed.args,
1781 _ => {
1782 return false;
1783 }
1784 };
1785 seg.ident == "Option"
1786 && args.len() == 1
1787 && match &args[0] {
1788 syn::GenericArgument::Type(arg) => elem(arg),
1789 _ => false,
1790 }
1791 }
1792
1793 // Whether the type looks like it might be `&T` where elem="T". This can have
1794 // false negatives and false positives.
1795 //
1796 // False negative:
1797 //
1798 // type Yarn = str;
1799 //
1800 // #[derive(Deserialize)]
1801 // struct S<'a> {
1802 // r: &'a Yarn,
1803 // }
1804 //
1805 // False positive:
1806 //
1807 // type str = [i16];
1808 //
1809 // #[derive(Deserialize)]
1810 // struct S<'a> {
1811 // r: &'a str,
1812 // }
is_reference(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool1813 fn is_reference(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
1814 match ungroup(ty) {
1815 syn::Type::Reference(ty) => ty.mutability.is_none() && elem(&ty.elem),
1816 _ => false,
1817 }
1818 }
1819
is_str(ty: &syn::Type) -> bool1820 fn is_str(ty: &syn::Type) -> bool {
1821 is_primitive_type(ty, "str")
1822 }
1823
is_slice_u8(ty: &syn::Type) -> bool1824 fn is_slice_u8(ty: &syn::Type) -> bool {
1825 match ungroup(ty) {
1826 syn::Type::Slice(ty) => is_primitive_type(&ty.elem, "u8"),
1827 _ => false,
1828 }
1829 }
1830
is_primitive_type(ty: &syn::Type, primitive: &str) -> bool1831 fn is_primitive_type(ty: &syn::Type, primitive: &str) -> bool {
1832 match ungroup(ty) {
1833 syn::Type::Path(ty) => ty.qself.is_none() && is_primitive_path(&ty.path, primitive),
1834 _ => false,
1835 }
1836 }
1837
is_primitive_path(path: &syn::Path, primitive: &str) -> bool1838 fn is_primitive_path(path: &syn::Path, primitive: &str) -> bool {
1839 path.leading_colon.is_none()
1840 && path.segments.len() == 1
1841 && path.segments[0].ident == primitive
1842 && path.segments[0].arguments.is_empty()
1843 }
1844
1845 // All lifetimes that this type could borrow from a Deserializer.
1846 //
1847 // For example a type `S<'a, 'b>` could borrow `'a` and `'b`. On the other hand
1848 // a type `for<'a> fn(&'a str)` could not borrow `'a` from the Deserializer.
1849 //
1850 // This is used when there is an explicit or implicit `#[serde(borrow)]`
1851 // attribute on the field so there must be at least one borrowable lifetime.
borrowable_lifetimes( cx: &Ctxt, name: &str, field: &syn::Field, ) -> Result<BTreeSet<syn::Lifetime>, ()>1852 fn borrowable_lifetimes(
1853 cx: &Ctxt,
1854 name: &str,
1855 field: &syn::Field,
1856 ) -> Result<BTreeSet<syn::Lifetime>, ()> {
1857 let mut lifetimes = BTreeSet::new();
1858 collect_lifetimes(&field.ty, &mut lifetimes);
1859 if lifetimes.is_empty() {
1860 cx.error_spanned_by(
1861 field,
1862 format!("field `{}` has no lifetimes to borrow", name),
1863 );
1864 Err(())
1865 } else {
1866 Ok(lifetimes)
1867 }
1868 }
1869
collect_lifetimes(ty: &syn::Type, out: &mut BTreeSet<syn::Lifetime>)1870 fn collect_lifetimes(ty: &syn::Type, out: &mut BTreeSet<syn::Lifetime>) {
1871 match ty {
1872 syn::Type::Slice(ty) => {
1873 collect_lifetimes(&ty.elem, out);
1874 }
1875 syn::Type::Array(ty) => {
1876 collect_lifetimes(&ty.elem, out);
1877 }
1878 syn::Type::Ptr(ty) => {
1879 collect_lifetimes(&ty.elem, out);
1880 }
1881 syn::Type::Reference(ty) => {
1882 out.extend(ty.lifetime.iter().cloned());
1883 collect_lifetimes(&ty.elem, out);
1884 }
1885 syn::Type::Tuple(ty) => {
1886 for elem in &ty.elems {
1887 collect_lifetimes(elem, out);
1888 }
1889 }
1890 syn::Type::Path(ty) => {
1891 if let Some(qself) = &ty.qself {
1892 collect_lifetimes(&qself.ty, out);
1893 }
1894 for seg in &ty.path.segments {
1895 if let syn::PathArguments::AngleBracketed(bracketed) = &seg.arguments {
1896 for arg in &bracketed.args {
1897 match arg {
1898 syn::GenericArgument::Lifetime(lifetime) => {
1899 out.insert(lifetime.clone());
1900 }
1901 syn::GenericArgument::Type(ty) => {
1902 collect_lifetimes(ty, out);
1903 }
1904 syn::GenericArgument::Binding(binding) => {
1905 collect_lifetimes(&binding.ty, out);
1906 }
1907 syn::GenericArgument::Constraint(_)
1908 | syn::GenericArgument::Const(_) => {}
1909 }
1910 }
1911 }
1912 }
1913 }
1914 syn::Type::Paren(ty) => {
1915 collect_lifetimes(&ty.elem, out);
1916 }
1917 syn::Type::Group(ty) => {
1918 collect_lifetimes(&ty.elem, out);
1919 }
1920 syn::Type::BareFn(_)
1921 | syn::Type::Never(_)
1922 | syn::Type::TraitObject(_)
1923 | syn::Type::ImplTrait(_)
1924 | syn::Type::Infer(_)
1925 | syn::Type::Macro(_)
1926 | syn::Type::Verbatim(_)
1927 | _ => {}
1928 }
1929 }
1930
parse_lit_str<T>(s: &syn::LitStr) -> parse::Result<T> where T: Parse,1931 fn parse_lit_str<T>(s: &syn::LitStr) -> parse::Result<T>
1932 where
1933 T: Parse,
1934 {
1935 let tokens = spanned_tokens(s)?;
1936 syn::parse2(tokens)
1937 }
1938
spanned_tokens(s: &syn::LitStr) -> parse::Result<TokenStream>1939 fn spanned_tokens(s: &syn::LitStr) -> parse::Result<TokenStream> {
1940 let stream = syn::parse_str(&s.value())?;
1941 Ok(respan_token_stream(stream, s.span()))
1942 }
1943
respan_token_stream(stream: TokenStream, span: Span) -> TokenStream1944 fn respan_token_stream(stream: TokenStream, span: Span) -> TokenStream {
1945 stream
1946 .into_iter()
1947 .map(|token| respan_token_tree(token, span))
1948 .collect()
1949 }
1950
respan_token_tree(mut token: TokenTree, span: Span) -> TokenTree1951 fn respan_token_tree(mut token: TokenTree, span: Span) -> TokenTree {
1952 if let TokenTree::Group(g) = &mut token {
1953 *g = Group::new(g.delimiter(), respan_token_stream(g.stream(), span));
1954 }
1955 token.set_span(span);
1956 token
1957 }
1958