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1 | // Copyright 2017 Serde Developers |
2 | // | |
3 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
4 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
5 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
6 | // option. This file may not be copied, modified, or distributed | |
7 | // except according to those terms. | |
8 | ||
9 | use Ctxt; | |
10 | use syn; | |
11 | use syn::MetaItem::{List, NameValue, Word}; | |
12 | use syn::NestedMetaItem::{Literal, MetaItem}; | |
13 | use synom::IResult; | |
14 | use std::collections::BTreeSet; | |
15 | use std::str::FromStr; | |
16 | ||
17 | // This module handles parsing of `#[serde(...)]` attributes. The entrypoints | |
18 | // are `attr::Container::from_ast`, `attr::Variant::from_ast`, and | |
19 | // `attr::Field::from_ast`. Each returns an instance of the corresponding | |
20 | // struct. Note that none of them return a Result. Unrecognized, malformed, or | |
21 | // duplicated attributes result in a span_err but otherwise are ignored. The | |
22 | // user will see errors simultaneously for all bad attributes in the crate | |
23 | // rather than just the first. | |
24 | ||
25 | pub use case::RenameRule; | |
26 | ||
27 | struct Attr<'c, T> { | |
28 | cx: &'c Ctxt, | |
29 | name: &'static str, | |
30 | value: Option<T>, | |
31 | } | |
32 | ||
33 | impl<'c, T> Attr<'c, T> { | |
34 | fn none(cx: &'c Ctxt, name: &'static str) -> Self { | |
35 | Attr { | |
36 | cx: cx, | |
37 | name: name, | |
38 | value: None, | |
39 | } | |
40 | } | |
41 | ||
42 | fn set(&mut self, value: T) { | |
43 | if self.value.is_some() { | |
44 | self.cx | |
45 | .error(format!("duplicate serde attribute `{}`", self.name)); | |
46 | } else { | |
47 | self.value = Some(value); | |
48 | } | |
49 | } | |
50 | ||
51 | fn set_opt(&mut self, value: Option<T>) { | |
52 | if let Some(value) = value { | |
53 | self.set(value); | |
54 | } | |
55 | } | |
56 | ||
57 | fn set_if_none(&mut self, value: T) { | |
58 | if self.value.is_none() { | |
59 | self.value = Some(value); | |
60 | } | |
61 | } | |
62 | ||
63 | fn get(self) -> Option<T> { | |
64 | self.value | |
65 | } | |
66 | } | |
67 | ||
68 | struct BoolAttr<'c>(Attr<'c, ()>); | |
69 | ||
70 | impl<'c> BoolAttr<'c> { | |
71 | fn none(cx: &'c Ctxt, name: &'static str) -> Self { | |
72 | BoolAttr(Attr::none(cx, name)) | |
73 | } | |
74 | ||
75 | fn set_true(&mut self) { | |
76 | self.0.set(()); | |
77 | } | |
78 | ||
79 | fn get(&self) -> bool { | |
80 | self.0.value.is_some() | |
81 | } | |
82 | } | |
83 | ||
84 | #[derive(Debug)] | |
85 | pub struct Name { | |
86 | serialize: String, | |
87 | deserialize: String, | |
88 | } | |
89 | ||
90 | impl Name { | |
91 | /// Return the container name for the container when serializing. | |
92 | pub fn serialize_name(&self) -> String { | |
93 | self.serialize.clone() | |
94 | } | |
95 | ||
96 | /// Return the container name for the container when deserializing. | |
97 | pub fn deserialize_name(&self) -> String { | |
98 | self.deserialize.clone() | |
99 | } | |
100 | } | |
101 | ||
102 | /// Represents container (e.g. struct) attribute information | |
103 | #[derive(Debug)] | |
104 | pub struct Container { | |
105 | name: Name, | |
106 | deny_unknown_fields: bool, | |
107 | default: Default, | |
108 | rename_all: RenameRule, | |
109 | ser_bound: Option<Vec<syn::WherePredicate>>, | |
110 | de_bound: Option<Vec<syn::WherePredicate>>, | |
111 | tag: EnumTag, | |
112 | from_type: Option<syn::Ty>, | |
113 | into_type: Option<syn::Ty>, | |
114 | remote: Option<syn::Path>, | |
115 | identifier: Identifier, | |
116 | } | |
117 | ||
118 | /// Styles of representing an enum. | |
119 | #[derive(Debug)] | |
120 | pub enum EnumTag { | |
121 | /// The default. | |
122 | /// | |
123 | /// ```json | |
124 | /// {"variant1": {"key1": "value1", "key2": "value2"}} | |
125 | /// ``` | |
126 | External, | |
127 | ||
128 | /// `#[serde(tag = "type")]` | |
129 | /// | |
130 | /// ```json | |
131 | /// {"type": "variant1", "key1": "value1", "key2": "value2"} | |
132 | /// ``` | |
133 | Internal { tag: String }, | |
134 | ||
135 | /// `#[serde(tag = "t", content = "c")]` | |
136 | /// | |
137 | /// ```json | |
138 | /// {"t": "variant1", "c": {"key1": "value1", "key2": "value2"}} | |
139 | /// ``` | |
140 | Adjacent { tag: String, content: String }, | |
141 | ||
142 | /// `#[serde(untagged)]` | |
143 | /// | |
144 | /// ```json | |
145 | /// {"key1": "value1", "key2": "value2"} | |
146 | /// ``` | |
147 | None, | |
148 | } | |
149 | ||
150 | /// Whether this enum represents the fields of a struct or the variants of an | |
151 | /// enum. | |
152 | #[derive(Copy, Clone, Debug)] | |
153 | pub enum Identifier { | |
154 | /// It does not. | |
155 | No, | |
156 | ||
157 | /// This enum represents the fields of a struct. All of the variants must be | |
158 | /// unit variants, except possibly one which is annotated with | |
159 | /// `#[serde(other)]` and is a newtype variant. | |
160 | Field, | |
161 | ||
162 | /// This enum represents the variants of an enum. All of the variants must | |
163 | /// be unit variants. | |
164 | Variant, | |
165 | } | |
166 | ||
167 | impl Container { | |
168 | /// Extract out the `#[serde(...)]` attributes from an item. | |
169 | pub fn from_ast(cx: &Ctxt, item: &syn::DeriveInput) -> Self { | |
170 | let mut ser_name = Attr::none(cx, "rename"); | |
171 | let mut de_name = Attr::none(cx, "rename"); | |
172 | let mut deny_unknown_fields = BoolAttr::none(cx, "deny_unknown_fields"); | |
173 | let mut default = Attr::none(cx, "default"); | |
174 | let mut rename_all = Attr::none(cx, "rename_all"); | |
175 | let mut ser_bound = Attr::none(cx, "bound"); | |
176 | let mut de_bound = Attr::none(cx, "bound"); | |
177 | let mut untagged = BoolAttr::none(cx, "untagged"); | |
178 | let mut internal_tag = Attr::none(cx, "tag"); | |
179 | let mut content = Attr::none(cx, "content"); | |
180 | let mut from_type = Attr::none(cx, "from"); | |
181 | let mut into_type = Attr::none(cx, "into"); | |
182 | let mut remote = Attr::none(cx, "remote"); | |
183 | let mut field_identifier = BoolAttr::none(cx, "field_identifier"); | |
184 | let mut variant_identifier = BoolAttr::none(cx, "variant_identifier"); | |
185 | ||
186 | for meta_items in item.attrs.iter().filter_map(get_serde_meta_items) { | |
187 | for meta_item in meta_items { | |
188 | match meta_item { | |
189 | // Parse `#[serde(rename = "foo")]` | |
190 | MetaItem(NameValue(ref name, ref lit)) if name == "rename" => { | |
191 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
192 | ser_name.set(s.clone()); | |
193 | de_name.set(s); | |
194 | } | |
195 | } | |
196 | ||
197 | // Parse `#[serde(rename(serialize = "foo", deserialize = "bar"))]` | |
198 | MetaItem(List(ref name, ref meta_items)) if name == "rename" => { | |
199 | if let Ok((ser, de)) = get_renames(cx, meta_items) { | |
200 | ser_name.set_opt(ser); | |
201 | de_name.set_opt(de); | |
202 | } | |
203 | } | |
204 | ||
205 | // Parse `#[serde(rename_all = "foo")]` | |
206 | MetaItem(NameValue(ref name, ref lit)) if name == "rename_all" => { | |
207 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
208 | match RenameRule::from_str(&s) { | |
209 | Ok(rename_rule) => rename_all.set(rename_rule), | |
210 | Err(()) => { | |
211 | cx.error(format!("unknown rename rule for #[serde(rename_all \ | |
212 | = {:?})]", | |
213 | s)) | |
214 | } | |
215 | } | |
216 | } | |
217 | } | |
218 | ||
219 | // Parse `#[serde(deny_unknown_fields)]` | |
220 | MetaItem(Word(ref name)) if name == "deny_unknown_fields" => { | |
221 | deny_unknown_fields.set_true(); | |
222 | } | |
223 | ||
224 | // Parse `#[serde(default)]` | |
225 | MetaItem(Word(ref name)) if name == "default" => { | |
226 | match item.body { | |
227 | syn::Body::Struct(syn::VariantData::Struct(_)) => { | |
228 | default.set(Default::Default); | |
229 | } | |
230 | _ => { | |
231 | cx.error( | |
232 | "#[serde(default)] can only be used on structs \ | |
233 | with named fields", | |
234 | ) | |
235 | } | |
236 | } | |
237 | } | |
238 | ||
239 | // Parse `#[serde(default = "...")]` | |
240 | MetaItem(NameValue(ref name, ref lit)) if name == "default" => { | |
241 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
242 | match item.body { | |
243 | syn::Body::Struct(syn::VariantData::Struct(_)) => { | |
244 | default.set(Default::Path(path)); | |
245 | } | |
246 | _ => { | |
247 | cx.error( | |
248 | "#[serde(default = \"...\")] can only be used \ | |
249 | on structs with named fields", | |
250 | ) | |
251 | } | |
252 | } | |
253 | } | |
254 | } | |
255 | ||
256 | // Parse `#[serde(bound = "D: Serialize")]` | |
257 | MetaItem(NameValue(ref name, ref lit)) if name == "bound" => { | |
258 | if let Ok(where_predicates) = | |
259 | parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) { | |
260 | ser_bound.set(where_predicates.clone()); | |
261 | de_bound.set(where_predicates); | |
262 | } | |
263 | } | |
264 | ||
265 | // Parse `#[serde(bound(serialize = "D: Serialize", deserialize = "D: Deserialize"))]` | |
266 | MetaItem(List(ref name, ref meta_items)) if name == "bound" => { | |
267 | if let Ok((ser, de)) = get_where_predicates(cx, meta_items) { | |
268 | ser_bound.set_opt(ser); | |
269 | de_bound.set_opt(de); | |
270 | } | |
271 | } | |
272 | ||
273 | // Parse `#[serde(untagged)]` | |
274 | MetaItem(Word(ref name)) if name == "untagged" => { | |
275 | match item.body { | |
276 | syn::Body::Enum(_) => { | |
277 | untagged.set_true(); | |
278 | } | |
279 | syn::Body::Struct(_) => { | |
280 | cx.error("#[serde(untagged)] can only be used on enums") | |
281 | } | |
282 | } | |
283 | } | |
284 | ||
285 | // Parse `#[serde(tag = "type")]` | |
286 | MetaItem(NameValue(ref name, ref lit)) if name == "tag" => { | |
287 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
288 | match item.body { | |
289 | syn::Body::Enum(_) => { | |
290 | internal_tag.set(s); | |
291 | } | |
292 | syn::Body::Struct(_) => { | |
293 | cx.error("#[serde(tag = \"...\")] can only be used on enums") | |
294 | } | |
295 | } | |
296 | } | |
297 | } | |
298 | ||
299 | // Parse `#[serde(content = "c")]` | |
300 | MetaItem(NameValue(ref name, ref lit)) if name == "content" => { | |
301 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
302 | match item.body { | |
303 | syn::Body::Enum(_) => { | |
304 | content.set(s); | |
305 | } | |
306 | syn::Body::Struct(_) => { | |
307 | cx.error( | |
308 | "#[serde(content = \"...\")] can only be used on \ | |
309 | enums", | |
310 | ) | |
311 | } | |
312 | } | |
313 | } | |
314 | } | |
315 | ||
316 | // Parse `#[serde(from = "Type")] | |
317 | MetaItem(NameValue(ref name, ref lit)) if name == "from" => { | |
318 | if let Ok(from_ty) = parse_lit_into_ty(cx, name.as_ref(), lit) { | |
319 | from_type.set_opt(Some(from_ty)); | |
320 | } | |
321 | } | |
322 | ||
323 | // Parse `#[serde(into = "Type")] | |
324 | MetaItem(NameValue(ref name, ref lit)) if name == "into" => { | |
325 | if let Ok(into_ty) = parse_lit_into_ty(cx, name.as_ref(), lit) { | |
326 | into_type.set_opt(Some(into_ty)); | |
327 | } | |
328 | } | |
329 | ||
330 | // Parse `#[serde(remote = "...")]` | |
331 | MetaItem(NameValue(ref name, ref lit)) if name == "remote" => { | |
332 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
333 | remote.set(path); | |
334 | } | |
335 | } | |
336 | ||
337 | // Parse `#[serde(field_identifier)]` | |
338 | MetaItem(Word(ref name)) if name == "field_identifier" => { | |
339 | field_identifier.set_true(); | |
340 | } | |
341 | ||
342 | // Parse `#[serde(variant_identifier)]` | |
343 | MetaItem(Word(ref name)) if name == "variant_identifier" => { | |
344 | variant_identifier.set_true(); | |
345 | } | |
346 | ||
347 | MetaItem(ref meta_item) => { | |
348 | cx.error(format!("unknown serde container attribute `{}`", | |
349 | meta_item.name())); | |
350 | } | |
351 | ||
352 | Literal(_) => { | |
353 | cx.error("unexpected literal in serde container attribute"); | |
354 | } | |
355 | } | |
356 | } | |
357 | } | |
358 | ||
359 | Container { | |
360 | name: Name { | |
361 | serialize: ser_name.get().unwrap_or_else(|| item.ident.to_string()), | |
362 | deserialize: de_name.get().unwrap_or_else(|| item.ident.to_string()), | |
363 | }, | |
364 | deny_unknown_fields: deny_unknown_fields.get(), | |
365 | default: default.get().unwrap_or(Default::None), | |
366 | rename_all: rename_all.get().unwrap_or(RenameRule::None), | |
367 | ser_bound: ser_bound.get(), | |
368 | de_bound: de_bound.get(), | |
369 | tag: decide_tag(cx, item, untagged, internal_tag, content), | |
370 | from_type: from_type.get(), | |
371 | into_type: into_type.get(), | |
372 | remote: remote.get(), | |
373 | identifier: decide_identifier(cx, item, field_identifier, variant_identifier), | |
374 | } | |
375 | } | |
376 | ||
377 | pub fn name(&self) -> &Name { | |
378 | &self.name | |
379 | } | |
380 | ||
381 | pub fn rename_all(&self) -> &RenameRule { | |
382 | &self.rename_all | |
383 | } | |
384 | ||
385 | pub fn deny_unknown_fields(&self) -> bool { | |
386 | self.deny_unknown_fields | |
387 | } | |
388 | ||
389 | pub fn default(&self) -> &Default { | |
390 | &self.default | |
391 | } | |
392 | ||
393 | pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> { | |
394 | self.ser_bound.as_ref().map(|vec| &vec[..]) | |
395 | } | |
396 | ||
397 | pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> { | |
398 | self.de_bound.as_ref().map(|vec| &vec[..]) | |
399 | } | |
400 | ||
401 | pub fn tag(&self) -> &EnumTag { | |
402 | &self.tag | |
403 | } | |
404 | ||
405 | pub fn from_type(&self) -> Option<&syn::Ty> { | |
406 | self.from_type.as_ref() | |
407 | } | |
408 | ||
409 | pub fn into_type(&self) -> Option<&syn::Ty> { | |
410 | self.into_type.as_ref() | |
411 | } | |
412 | ||
413 | pub fn remote(&self) -> Option<&syn::Path> { | |
414 | self.remote.as_ref() | |
415 | } | |
416 | ||
417 | pub fn identifier(&self) -> Identifier { | |
418 | self.identifier | |
419 | } | |
420 | } | |
421 | ||
422 | fn decide_tag( | |
423 | cx: &Ctxt, | |
424 | item: &syn::DeriveInput, | |
425 | untagged: BoolAttr, | |
426 | internal_tag: Attr<String>, | |
427 | content: Attr<String>, | |
428 | ) -> EnumTag { | |
429 | match (untagged.get(), internal_tag.get(), content.get()) { | |
430 | (false, None, None) => EnumTag::External, | |
431 | (true, None, None) => EnumTag::None, | |
432 | (false, Some(tag), None) => { | |
433 | // Check that there are no tuple variants. | |
434 | if let syn::Body::Enum(ref variants) = item.body { | |
435 | for variant in variants { | |
436 | match variant.data { | |
437 | syn::VariantData::Struct(_) | | |
438 | syn::VariantData::Unit => {} | |
439 | syn::VariantData::Tuple(ref fields) => { | |
440 | if fields.len() != 1 { | |
441 | cx.error( | |
442 | "#[serde(tag = \"...\")] cannot be used with tuple \ | |
443 | variants", | |
444 | ); | |
445 | break; | |
446 | } | |
447 | } | |
448 | } | |
449 | } | |
450 | } | |
451 | EnumTag::Internal { tag: tag } | |
452 | } | |
453 | (true, Some(_), None) => { | |
454 | cx.error("enum cannot be both untagged and internally tagged"); | |
455 | EnumTag::External // doesn't matter, will error | |
456 | } | |
457 | (false, None, Some(_)) => { | |
458 | cx.error("#[serde(tag = \"...\", content = \"...\")] must be used together",); | |
459 | EnumTag::External | |
460 | } | |
461 | (true, None, Some(_)) => { | |
462 | cx.error("untagged enum cannot have #[serde(content = \"...\")]"); | |
463 | EnumTag::External | |
464 | } | |
465 | (false, Some(tag), Some(content)) => { | |
466 | EnumTag::Adjacent { | |
467 | tag: tag, | |
468 | content: content, | |
469 | } | |
470 | } | |
471 | (true, Some(_), Some(_)) => { | |
472 | cx.error("untagged enum cannot have #[serde(tag = \"...\", content = \"...\")]",); | |
473 | EnumTag::External | |
474 | } | |
475 | } | |
476 | } | |
477 | ||
478 | fn decide_identifier( | |
479 | cx: &Ctxt, | |
480 | item: &syn::DeriveInput, | |
481 | field_identifier: BoolAttr, | |
482 | variant_identifier: BoolAttr, | |
483 | ) -> Identifier { | |
484 | match (&item.body, field_identifier.get(), variant_identifier.get()) { | |
485 | (_, false, false) => Identifier::No, | |
486 | (_, true, true) => { | |
487 | cx.error("`field_identifier` and `variant_identifier` cannot both be set",); | |
488 | Identifier::No | |
489 | } | |
490 | (&syn::Body::Struct(_), true, false) => { | |
491 | cx.error("`field_identifier` can only be used on an enum"); | |
492 | Identifier::No | |
493 | } | |
494 | (&syn::Body::Struct(_), false, true) => { | |
495 | cx.error("`variant_identifier` can only be used on an enum"); | |
496 | Identifier::No | |
497 | } | |
498 | (&syn::Body::Enum(_), true, false) => Identifier::Field, | |
499 | (&syn::Body::Enum(_), false, true) => Identifier::Variant, | |
500 | } | |
501 | } | |
502 | ||
503 | /// Represents variant attribute information | |
504 | #[derive(Debug)] | |
505 | pub struct Variant { | |
506 | name: Name, | |
507 | ser_renamed: bool, | |
508 | de_renamed: bool, | |
509 | rename_all: RenameRule, | |
510 | skip_deserializing: bool, | |
511 | skip_serializing: bool, | |
512 | other: bool, | |
ea8adc8c XL |
513 | serialize_with: Option<syn::Path>, |
514 | deserialize_with: Option<syn::Path>, | |
abe05a73 | 515 | borrow: Option<syn::MetaItem>, |
3b2f2976 XL |
516 | } |
517 | ||
518 | impl Variant { | |
519 | pub fn from_ast(cx: &Ctxt, variant: &syn::Variant) -> Self { | |
520 | let mut ser_name = Attr::none(cx, "rename"); | |
521 | let mut de_name = Attr::none(cx, "rename"); | |
522 | let mut skip_deserializing = BoolAttr::none(cx, "skip_deserializing"); | |
523 | let mut skip_serializing = BoolAttr::none(cx, "skip_serializing"); | |
524 | let mut rename_all = Attr::none(cx, "rename_all"); | |
525 | let mut other = BoolAttr::none(cx, "other"); | |
ea8adc8c XL |
526 | let mut serialize_with = Attr::none(cx, "serialize_with"); |
527 | let mut deserialize_with = Attr::none(cx, "deserialize_with"); | |
abe05a73 | 528 | let mut borrow = Attr::none(cx, "borrow"); |
3b2f2976 XL |
529 | |
530 | for meta_items in variant.attrs.iter().filter_map(get_serde_meta_items) { | |
531 | for meta_item in meta_items { | |
532 | match meta_item { | |
533 | // Parse `#[serde(rename = "foo")]` | |
534 | MetaItem(NameValue(ref name, ref lit)) if name == "rename" => { | |
535 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
536 | ser_name.set(s.clone()); | |
537 | de_name.set(s); | |
538 | } | |
539 | } | |
540 | ||
541 | // Parse `#[serde(rename(serialize = "foo", deserialize = "bar"))]` | |
542 | MetaItem(List(ref name, ref meta_items)) if name == "rename" => { | |
543 | if let Ok((ser, de)) = get_renames(cx, meta_items) { | |
544 | ser_name.set_opt(ser); | |
545 | de_name.set_opt(de); | |
546 | } | |
547 | } | |
548 | ||
549 | // Parse `#[serde(rename_all = "foo")]` | |
550 | MetaItem(NameValue(ref name, ref lit)) if name == "rename_all" => { | |
551 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
552 | match RenameRule::from_str(&s) { | |
553 | Ok(rename_rule) => rename_all.set(rename_rule), | |
554 | Err(()) => { | |
555 | cx.error(format!("unknown rename rule for #[serde(rename_all \ | |
556 | = {:?})]", | |
557 | s)) | |
558 | } | |
559 | } | |
560 | } | |
561 | } | |
562 | ||
563 | // Parse `#[serde(skip_deserializing)]` | |
564 | MetaItem(Word(ref name)) if name == "skip_deserializing" => { | |
565 | skip_deserializing.set_true(); | |
566 | } | |
567 | ||
568 | // Parse `#[serde(skip_serializing)]` | |
569 | MetaItem(Word(ref name)) if name == "skip_serializing" => { | |
570 | skip_serializing.set_true(); | |
571 | } | |
572 | ||
573 | // Parse `#[serde(other)]` | |
574 | MetaItem(Word(ref name)) if name == "other" => { | |
575 | other.set_true(); | |
576 | } | |
577 | ||
ea8adc8c XL |
578 | // Parse `#[serde(with = "...")]` |
579 | MetaItem(NameValue(ref name, ref lit)) if name == "with" => { | |
580 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
581 | let mut ser_path = path.clone(); | |
582 | ser_path.segments.push("serialize".into()); | |
583 | serialize_with.set(ser_path); | |
584 | let mut de_path = path; | |
585 | de_path.segments.push("deserialize".into()); | |
586 | deserialize_with.set(de_path); | |
587 | } | |
588 | } | |
589 | ||
590 | // Parse `#[serde(serialize_with = "...")]` | |
591 | MetaItem(NameValue(ref name, ref lit)) if name == "serialize_with" => { | |
592 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
593 | serialize_with.set(path); | |
594 | } | |
595 | } | |
596 | ||
597 | // Parse `#[serde(deserialize_with = "...")]` | |
598 | MetaItem(NameValue(ref name, ref lit)) if name == "deserialize_with" => { | |
599 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
600 | deserialize_with.set(path); | |
601 | } | |
602 | } | |
603 | ||
abe05a73 XL |
604 | // Defer `#[serde(borrow)]` and `#[serde(borrow = "'a + 'b")]` |
605 | MetaItem(ref mi) if mi.name() == "borrow" => { | |
606 | match variant.data { | |
607 | syn::VariantData::Tuple(ref fields) if fields.len() == 1 => { | |
608 | borrow.set(mi.clone()); | |
609 | } | |
610 | _ => { | |
611 | cx.error("#[serde(borrow)] may only be used on newtype variants"); | |
612 | } | |
613 | } | |
614 | } | |
615 | ||
3b2f2976 XL |
616 | MetaItem(ref meta_item) => { |
617 | cx.error(format!("unknown serde variant attribute `{}`", meta_item.name())); | |
618 | } | |
619 | ||
620 | Literal(_) => { | |
621 | cx.error("unexpected literal in serde variant attribute"); | |
622 | } | |
623 | } | |
624 | } | |
625 | } | |
626 | ||
627 | let ser_name = ser_name.get(); | |
628 | let ser_renamed = ser_name.is_some(); | |
629 | let de_name = de_name.get(); | |
630 | let de_renamed = de_name.is_some(); | |
631 | Variant { | |
632 | name: Name { | |
633 | serialize: ser_name.unwrap_or_else(|| variant.ident.to_string()), | |
634 | deserialize: de_name.unwrap_or_else(|| variant.ident.to_string()), | |
635 | }, | |
636 | ser_renamed: ser_renamed, | |
637 | de_renamed: de_renamed, | |
638 | rename_all: rename_all.get().unwrap_or(RenameRule::None), | |
639 | skip_deserializing: skip_deserializing.get(), | |
640 | skip_serializing: skip_serializing.get(), | |
641 | other: other.get(), | |
ea8adc8c XL |
642 | serialize_with: serialize_with.get(), |
643 | deserialize_with: deserialize_with.get(), | |
abe05a73 | 644 | borrow: borrow.get(), |
3b2f2976 XL |
645 | } |
646 | } | |
647 | ||
648 | pub fn name(&self) -> &Name { | |
649 | &self.name | |
650 | } | |
651 | ||
652 | pub fn rename_by_rule(&mut self, rule: &RenameRule) { | |
653 | if !self.ser_renamed { | |
654 | self.name.serialize = rule.apply_to_variant(&self.name.serialize); | |
655 | } | |
656 | if !self.de_renamed { | |
657 | self.name.deserialize = rule.apply_to_variant(&self.name.deserialize); | |
658 | } | |
659 | } | |
660 | ||
661 | pub fn rename_all(&self) -> &RenameRule { | |
662 | &self.rename_all | |
663 | } | |
664 | ||
665 | pub fn skip_deserializing(&self) -> bool { | |
666 | self.skip_deserializing | |
667 | } | |
668 | ||
669 | pub fn skip_serializing(&self) -> bool { | |
670 | self.skip_serializing | |
671 | } | |
672 | ||
673 | pub fn other(&self) -> bool { | |
674 | self.other | |
675 | } | |
ea8adc8c XL |
676 | |
677 | pub fn serialize_with(&self) -> Option<&syn::Path> { | |
678 | self.serialize_with.as_ref() | |
679 | } | |
680 | ||
681 | pub fn deserialize_with(&self) -> Option<&syn::Path> { | |
682 | self.deserialize_with.as_ref() | |
683 | } | |
3b2f2976 XL |
684 | } |
685 | ||
686 | /// Represents field attribute information | |
687 | #[derive(Debug)] | |
688 | pub struct Field { | |
689 | name: Name, | |
690 | ser_renamed: bool, | |
691 | de_renamed: bool, | |
692 | skip_serializing: bool, | |
693 | skip_deserializing: bool, | |
694 | skip_serializing_if: Option<syn::Path>, | |
695 | default: Default, | |
696 | serialize_with: Option<syn::Path>, | |
697 | deserialize_with: Option<syn::Path>, | |
698 | ser_bound: Option<Vec<syn::WherePredicate>>, | |
699 | de_bound: Option<Vec<syn::WherePredicate>>, | |
700 | borrowed_lifetimes: BTreeSet<syn::Lifetime>, | |
701 | getter: Option<syn::Path>, | |
702 | } | |
703 | ||
704 | /// Represents the default to use for a field when deserializing. | |
705 | #[derive(Debug, PartialEq)] | |
706 | pub enum Default { | |
707 | /// Field must always be specified because it does not have a default. | |
708 | None, | |
709 | /// The default is given by `std::default::Default::default()`. | |
710 | Default, | |
711 | /// The default is given by this function. | |
712 | Path(syn::Path), | |
713 | } | |
714 | ||
715 | impl Field { | |
716 | /// Extract out the `#[serde(...)]` attributes from a struct field. | |
abe05a73 | 717 | pub fn from_ast(cx: &Ctxt, index: usize, field: &syn::Field, attrs: Option<&Variant>) -> Self { |
3b2f2976 XL |
718 | let mut ser_name = Attr::none(cx, "rename"); |
719 | let mut de_name = Attr::none(cx, "rename"); | |
720 | let mut skip_serializing = BoolAttr::none(cx, "skip_serializing"); | |
721 | let mut skip_deserializing = BoolAttr::none(cx, "skip_deserializing"); | |
722 | let mut skip_serializing_if = Attr::none(cx, "skip_serializing_if"); | |
723 | let mut default = Attr::none(cx, "default"); | |
724 | let mut serialize_with = Attr::none(cx, "serialize_with"); | |
725 | let mut deserialize_with = Attr::none(cx, "deserialize_with"); | |
726 | let mut ser_bound = Attr::none(cx, "bound"); | |
727 | let mut de_bound = Attr::none(cx, "bound"); | |
728 | let mut borrowed_lifetimes = Attr::none(cx, "borrow"); | |
729 | let mut getter = Attr::none(cx, "getter"); | |
730 | ||
731 | let ident = match field.ident { | |
732 | Some(ref ident) => ident.to_string(), | |
733 | None => index.to_string(), | |
734 | }; | |
735 | ||
abe05a73 XL |
736 | let variant_borrow = attrs |
737 | .map(|variant| &variant.borrow) | |
738 | .unwrap_or(&None) | |
739 | .as_ref() | |
740 | .map(|borrow| vec![MetaItem(borrow.clone())]); | |
741 | ||
742 | for meta_items in field.attrs.iter().filter_map(get_serde_meta_items).chain(variant_borrow) { | |
3b2f2976 XL |
743 | for meta_item in meta_items { |
744 | match meta_item { | |
745 | // Parse `#[serde(rename = "foo")]` | |
746 | MetaItem(NameValue(ref name, ref lit)) if name == "rename" => { | |
747 | if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) { | |
748 | ser_name.set(s.clone()); | |
749 | de_name.set(s); | |
750 | } | |
751 | } | |
752 | ||
753 | // Parse `#[serde(rename(serialize = "foo", deserialize = "bar"))]` | |
754 | MetaItem(List(ref name, ref meta_items)) if name == "rename" => { | |
755 | if let Ok((ser, de)) = get_renames(cx, meta_items) { | |
756 | ser_name.set_opt(ser); | |
757 | de_name.set_opt(de); | |
758 | } | |
759 | } | |
760 | ||
761 | // Parse `#[serde(default)]` | |
762 | MetaItem(Word(ref name)) if name == "default" => { | |
763 | default.set(Default::Default); | |
764 | } | |
765 | ||
766 | // Parse `#[serde(default = "...")]` | |
767 | MetaItem(NameValue(ref name, ref lit)) if name == "default" => { | |
768 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
769 | default.set(Default::Path(path)); | |
770 | } | |
771 | } | |
772 | ||
773 | // Parse `#[serde(skip_serializing)]` | |
774 | MetaItem(Word(ref name)) if name == "skip_serializing" => { | |
775 | skip_serializing.set_true(); | |
776 | } | |
777 | ||
778 | // Parse `#[serde(skip_deserializing)]` | |
779 | MetaItem(Word(ref name)) if name == "skip_deserializing" => { | |
780 | skip_deserializing.set_true(); | |
781 | } | |
782 | ||
783 | // Parse `#[serde(skip)]` | |
784 | MetaItem(Word(ref name)) if name == "skip" => { | |
785 | skip_serializing.set_true(); | |
786 | skip_deserializing.set_true(); | |
787 | }, | |
788 | ||
789 | // Parse `#[serde(skip_serializing_if = "...")]` | |
790 | MetaItem(NameValue(ref name, ref lit)) if name == "skip_serializing_if" => { | |
791 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
792 | skip_serializing_if.set(path); | |
793 | } | |
794 | } | |
795 | ||
796 | // Parse `#[serde(serialize_with = "...")]` | |
797 | MetaItem(NameValue(ref name, ref lit)) if name == "serialize_with" => { | |
798 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
799 | serialize_with.set(path); | |
800 | } | |
801 | } | |
802 | ||
803 | // Parse `#[serde(deserialize_with = "...")]` | |
804 | MetaItem(NameValue(ref name, ref lit)) if name == "deserialize_with" => { | |
805 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
806 | deserialize_with.set(path); | |
807 | } | |
808 | } | |
809 | ||
810 | // Parse `#[serde(with = "...")]` | |
811 | MetaItem(NameValue(ref name, ref lit)) if name == "with" => { | |
812 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
813 | let mut ser_path = path.clone(); | |
814 | ser_path.segments.push("serialize".into()); | |
815 | serialize_with.set(ser_path); | |
816 | let mut de_path = path; | |
817 | de_path.segments.push("deserialize".into()); | |
818 | deserialize_with.set(de_path); | |
819 | } | |
820 | } | |
821 | ||
822 | // Parse `#[serde(bound = "D: Serialize")]` | |
823 | MetaItem(NameValue(ref name, ref lit)) if name == "bound" => { | |
824 | if let Ok(where_predicates) = | |
825 | parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) { | |
826 | ser_bound.set(where_predicates.clone()); | |
827 | de_bound.set(where_predicates); | |
828 | } | |
829 | } | |
830 | ||
831 | // Parse `#[serde(bound(serialize = "D: Serialize", deserialize = "D: Deserialize"))]` | |
832 | MetaItem(List(ref name, ref meta_items)) if name == "bound" => { | |
833 | if let Ok((ser, de)) = get_where_predicates(cx, meta_items) { | |
834 | ser_bound.set_opt(ser); | |
835 | de_bound.set_opt(de); | |
836 | } | |
837 | } | |
838 | ||
839 | // Parse `#[serde(borrow)]` | |
840 | MetaItem(Word(ref name)) if name == "borrow" => { | |
841 | if let Ok(borrowable) = borrowable_lifetimes(cx, &ident, &field.ty) { | |
842 | borrowed_lifetimes.set(borrowable); | |
843 | } | |
844 | } | |
845 | ||
846 | // Parse `#[serde(borrow = "'a + 'b")]` | |
847 | MetaItem(NameValue(ref name, ref lit)) if name == "borrow" => { | |
848 | if let Ok(lifetimes) = parse_lit_into_lifetimes(cx, name.as_ref(), lit) { | |
849 | if let Ok(borrowable) = borrowable_lifetimes(cx, &ident, &field.ty) { | |
850 | for lifetime in &lifetimes { | |
851 | if !borrowable.contains(lifetime) { | |
852 | cx.error( | |
853 | format!( | |
854 | "field `{}` does not have lifetime {}", | |
855 | ident, | |
856 | lifetime.ident | |
857 | ), | |
858 | ); | |
859 | } | |
860 | } | |
861 | borrowed_lifetimes.set(lifetimes); | |
862 | } | |
863 | } | |
864 | } | |
865 | ||
866 | // Parse `#[serde(getter = "...")]` | |
867 | MetaItem(NameValue(ref name, ref lit)) if name == "getter" => { | |
868 | if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) { | |
869 | getter.set(path); | |
870 | } | |
871 | } | |
872 | ||
873 | MetaItem(ref meta_item) => { | |
874 | cx.error(format!("unknown serde field attribute `{}`", meta_item.name()),); | |
875 | } | |
876 | ||
877 | Literal(_) => { | |
878 | cx.error("unexpected literal in serde field attribute"); | |
879 | } | |
880 | } | |
881 | } | |
882 | } | |
883 | ||
884 | // Is skip_deserializing, initialize the field to Default::default() | |
885 | // unless a different default is specified by `#[serde(default = "...")]` | |
886 | if skip_deserializing.0.value.is_some() { | |
887 | default.set_if_none(Default::Default); | |
888 | } | |
889 | ||
890 | let mut borrowed_lifetimes = borrowed_lifetimes.get().unwrap_or_default(); | |
891 | if !borrowed_lifetimes.is_empty() { | |
892 | // Cow<str> and Cow<[u8]> never borrow by default: | |
893 | // | |
894 | // impl<'de, 'a, T: ?Sized> Deserialize<'de> for Cow<'a, T> | |
895 | // | |
896 | // A #[serde(borrow)] attribute enables borrowing that corresponds | |
897 | // roughly to these impls: | |
898 | // | |
899 | // impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, str> | |
900 | // impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, [u8]> | |
901 | if is_cow(&field.ty, "str") { | |
902 | let path = syn::parse_path("_serde::private::de::borrow_cow_str").unwrap(); | |
903 | deserialize_with.set_if_none(path); | |
904 | } else if is_cow(&field.ty, "[u8]") { | |
905 | let path = syn::parse_path("_serde::private::de::borrow_cow_bytes").unwrap(); | |
906 | deserialize_with.set_if_none(path); | |
907 | } | |
908 | } else if is_rptr(&field.ty, "str") || is_rptr(&field.ty, "[u8]") { | |
909 | // Types &str and &[u8] are always implicitly borrowed. No need for | |
910 | // a #[serde(borrow)]. | |
911 | borrowed_lifetimes = borrowable_lifetimes(cx, &ident, &field.ty).unwrap(); | |
912 | } | |
913 | ||
914 | let ser_name = ser_name.get(); | |
915 | let ser_renamed = ser_name.is_some(); | |
916 | let de_name = de_name.get(); | |
917 | let de_renamed = de_name.is_some(); | |
918 | Field { | |
919 | name: Name { | |
920 | serialize: ser_name.unwrap_or_else(|| ident.clone()), | |
921 | deserialize: de_name.unwrap_or(ident), | |
922 | }, | |
923 | ser_renamed: ser_renamed, | |
924 | de_renamed: de_renamed, | |
925 | skip_serializing: skip_serializing.get(), | |
926 | skip_deserializing: skip_deserializing.get(), | |
927 | skip_serializing_if: skip_serializing_if.get(), | |
928 | default: default.get().unwrap_or(Default::None), | |
929 | serialize_with: serialize_with.get(), | |
930 | deserialize_with: deserialize_with.get(), | |
931 | ser_bound: ser_bound.get(), | |
932 | de_bound: de_bound.get(), | |
933 | borrowed_lifetimes: borrowed_lifetimes, | |
934 | getter: getter.get(), | |
935 | } | |
936 | } | |
937 | ||
938 | pub fn name(&self) -> &Name { | |
939 | &self.name | |
940 | } | |
941 | ||
942 | pub fn rename_by_rule(&mut self, rule: &RenameRule) { | |
943 | if !self.ser_renamed { | |
944 | self.name.serialize = rule.apply_to_field(&self.name.serialize); | |
945 | } | |
946 | if !self.de_renamed { | |
947 | self.name.deserialize = rule.apply_to_field(&self.name.deserialize); | |
948 | } | |
949 | } | |
950 | ||
951 | pub fn skip_serializing(&self) -> bool { | |
952 | self.skip_serializing | |
953 | } | |
954 | ||
955 | pub fn skip_deserializing(&self) -> bool { | |
956 | self.skip_deserializing | |
957 | } | |
958 | ||
959 | pub fn skip_serializing_if(&self) -> Option<&syn::Path> { | |
960 | self.skip_serializing_if.as_ref() | |
961 | } | |
962 | ||
963 | pub fn default(&self) -> &Default { | |
964 | &self.default | |
965 | } | |
966 | ||
967 | pub fn serialize_with(&self) -> Option<&syn::Path> { | |
968 | self.serialize_with.as_ref() | |
969 | } | |
970 | ||
971 | pub fn deserialize_with(&self) -> Option<&syn::Path> { | |
972 | self.deserialize_with.as_ref() | |
973 | } | |
974 | ||
975 | pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> { | |
976 | self.ser_bound.as_ref().map(|vec| &vec[..]) | |
977 | } | |
978 | ||
979 | pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> { | |
980 | self.de_bound.as_ref().map(|vec| &vec[..]) | |
981 | } | |
982 | ||
983 | pub fn borrowed_lifetimes(&self) -> &BTreeSet<syn::Lifetime> { | |
984 | &self.borrowed_lifetimes | |
985 | } | |
986 | ||
987 | pub fn getter(&self) -> Option<&syn::Path> { | |
988 | self.getter.as_ref() | |
989 | } | |
990 | } | |
991 | ||
992 | type SerAndDe<T> = (Option<T>, Option<T>); | |
993 | ||
994 | fn get_ser_and_de<T, F>( | |
995 | cx: &Ctxt, | |
996 | attr_name: &'static str, | |
997 | items: &[syn::NestedMetaItem], | |
998 | f: F, | |
999 | ) -> Result<SerAndDe<T>, ()> | |
1000 | where | |
1001 | F: Fn(&Ctxt, &str, &str, &syn::Lit) -> Result<T, ()>, | |
1002 | { | |
1003 | let mut ser_item = Attr::none(cx, attr_name); | |
1004 | let mut de_item = Attr::none(cx, attr_name); | |
1005 | ||
1006 | for item in items { | |
1007 | match *item { | |
1008 | MetaItem(NameValue(ref name, ref lit)) if name == "serialize" => { | |
1009 | if let Ok(v) = f(cx, attr_name, name.as_ref(), lit) { | |
1010 | ser_item.set(v); | |
1011 | } | |
1012 | } | |
1013 | ||
1014 | MetaItem(NameValue(ref name, ref lit)) if name == "deserialize" => { | |
1015 | if let Ok(v) = f(cx, attr_name, name.as_ref(), lit) { | |
1016 | de_item.set(v); | |
1017 | } | |
1018 | } | |
1019 | ||
1020 | _ => { | |
1021 | cx.error( | |
1022 | format!( | |
1023 | "malformed {0} attribute, expected `{0}(serialize = ..., \ | |
1024 | deserialize = ...)`", | |
1025 | attr_name | |
1026 | ), | |
1027 | ); | |
1028 | return Err(()); | |
1029 | } | |
1030 | } | |
1031 | } | |
1032 | ||
1033 | Ok((ser_item.get(), de_item.get())) | |
1034 | } | |
1035 | ||
1036 | fn get_renames(cx: &Ctxt, items: &[syn::NestedMetaItem]) -> Result<SerAndDe<String>, ()> { | |
1037 | get_ser_and_de(cx, "rename", items, get_string_from_lit) | |
1038 | } | |
1039 | ||
1040 | fn get_where_predicates( | |
1041 | cx: &Ctxt, | |
1042 | items: &[syn::NestedMetaItem], | |
1043 | ) -> Result<SerAndDe<Vec<syn::WherePredicate>>, ()> { | |
1044 | get_ser_and_de(cx, "bound", items, parse_lit_into_where) | |
1045 | } | |
1046 | ||
1047 | pub fn get_serde_meta_items(attr: &syn::Attribute) -> Option<Vec<syn::NestedMetaItem>> { | |
1048 | match attr.value { | |
1049 | List(ref name, ref items) if name == "serde" => Some(items.iter().cloned().collect()), | |
1050 | _ => None, | |
1051 | } | |
1052 | } | |
1053 | ||
1054 | fn get_string_from_lit( | |
1055 | cx: &Ctxt, | |
1056 | attr_name: &str, | |
1057 | meta_item_name: &str, | |
1058 | lit: &syn::Lit, | |
1059 | ) -> Result<String, ()> { | |
1060 | if let syn::Lit::Str(ref s, _) = *lit { | |
1061 | Ok(s.clone()) | |
1062 | } else { | |
1063 | cx.error( | |
1064 | format!( | |
1065 | "expected serde {} attribute to be a string: `{} = \"...\"`", | |
1066 | attr_name, | |
1067 | meta_item_name | |
1068 | ), | |
1069 | ); | |
1070 | Err(()) | |
1071 | } | |
1072 | } | |
1073 | ||
1074 | fn parse_lit_into_path(cx: &Ctxt, attr_name: &str, lit: &syn::Lit) -> Result<syn::Path, ()> { | |
1075 | let string = try!(get_string_from_lit(cx, attr_name, attr_name, lit)); | |
1076 | syn::parse_path(&string).map_err(|err| cx.error(err)) | |
1077 | } | |
1078 | ||
1079 | fn parse_lit_into_where( | |
1080 | cx: &Ctxt, | |
1081 | attr_name: &str, | |
1082 | meta_item_name: &str, | |
1083 | lit: &syn::Lit, | |
1084 | ) -> Result<Vec<syn::WherePredicate>, ()> { | |
1085 | let string = try!(get_string_from_lit(cx, attr_name, meta_item_name, lit)); | |
1086 | if string.is_empty() { | |
1087 | return Ok(Vec::new()); | |
1088 | } | |
1089 | ||
1090 | let where_string = format!("where {}", string); | |
1091 | ||
1092 | syn::parse_where_clause(&where_string) | |
1093 | .map(|wh| wh.predicates) | |
1094 | .map_err(|err| cx.error(err)) | |
1095 | } | |
1096 | ||
1097 | fn parse_lit_into_ty(cx: &Ctxt, attr_name: &str, lit: &syn::Lit) -> Result<syn::Ty, ()> { | |
1098 | let string = try!(get_string_from_lit(cx, attr_name, attr_name, lit)); | |
1099 | ||
1100 | syn::parse_type(&string).map_err( | |
1101 | |_| { | |
1102 | cx.error(format!("failed to parse type: {} = {:?}", attr_name, string),) | |
1103 | }, | |
1104 | ) | |
1105 | } | |
1106 | ||
1107 | // Parses a string literal like "'a + 'b + 'c" containing a nonempty list of | |
1108 | // lifetimes separated by `+`. | |
1109 | fn parse_lit_into_lifetimes( | |
1110 | cx: &Ctxt, | |
1111 | attr_name: &str, | |
1112 | lit: &syn::Lit, | |
1113 | ) -> Result<BTreeSet<syn::Lifetime>, ()> { | |
1114 | let string = try!(get_string_from_lit(cx, attr_name, attr_name, lit)); | |
1115 | if string.is_empty() { | |
1116 | cx.error("at least one lifetime must be borrowed"); | |
1117 | return Err(()); | |
1118 | } | |
1119 | ||
1120 | named!(lifetimes -> Vec<syn::Lifetime>, | |
1121 | separated_nonempty_list!(punct!("+"), syn::parse::lifetime) | |
1122 | ); | |
1123 | ||
1124 | if let IResult::Done(rest, o) = lifetimes(&string) { | |
1125 | if rest.trim().is_empty() { | |
1126 | let mut set = BTreeSet::new(); | |
1127 | for lifetime in o { | |
1128 | if !set.insert(lifetime.clone()) { | |
1129 | cx.error(format!("duplicate borrowed lifetime `{}`", lifetime.ident)); | |
1130 | } | |
1131 | } | |
1132 | return Ok(set); | |
1133 | } | |
1134 | } | |
1135 | Err(cx.error(format!("failed to parse borrowed lifetimes: {:?}", string)),) | |
1136 | } | |
1137 | ||
1138 | // Whether the type looks like it might be `std::borrow::Cow<T>` where elem="T". | |
1139 | // This can have false negatives and false positives. | |
1140 | // | |
1141 | // False negative: | |
1142 | // | |
1143 | // use std::borrow::Cow as Pig; | |
1144 | // | |
1145 | // #[derive(Deserialize)] | |
1146 | // struct S<'a> { | |
1147 | // #[serde(borrow)] | |
1148 | // pig: Pig<'a, str>, | |
1149 | // } | |
1150 | // | |
1151 | // False positive: | |
1152 | // | |
1153 | // type str = [i16]; | |
1154 | // | |
1155 | // #[derive(Deserialize)] | |
1156 | // struct S<'a> { | |
1157 | // #[serde(borrow)] | |
1158 | // cow: Cow<'a, str>, | |
1159 | // } | |
1160 | fn is_cow(ty: &syn::Ty, elem: &str) -> bool { | |
1161 | let path = match *ty { | |
1162 | syn::Ty::Path(None, ref path) => path, | |
1163 | _ => { | |
1164 | return false; | |
1165 | } | |
1166 | }; | |
1167 | let seg = match path.segments.last() { | |
1168 | Some(seg) => seg, | |
1169 | None => { | |
1170 | return false; | |
1171 | } | |
1172 | }; | |
1173 | let params = match seg.parameters { | |
1174 | syn::PathParameters::AngleBracketed(ref params) => params, | |
1175 | _ => { | |
1176 | return false; | |
1177 | } | |
1178 | }; | |
1179 | seg.ident == "Cow" && params.lifetimes.len() == 1 && | |
1180 | params.types == vec![syn::parse_type(elem).unwrap()] && params.bindings.is_empty() | |
1181 | } | |
1182 | ||
1183 | // Whether the type looks like it might be `&T` where elem="T". This can have | |
1184 | // false negatives and false positives. | |
1185 | // | |
1186 | // False negative: | |
1187 | // | |
1188 | // type Yarn = str; | |
1189 | // | |
1190 | // #[derive(Deserialize)] | |
1191 | // struct S<'a> { | |
1192 | // r: &'a Yarn, | |
1193 | // } | |
1194 | // | |
1195 | // False positive: | |
1196 | // | |
1197 | // type str = [i16]; | |
1198 | // | |
1199 | // #[derive(Deserialize)] | |
1200 | // struct S<'a> { | |
1201 | // r: &'a str, | |
1202 | // } | |
1203 | fn is_rptr(ty: &syn::Ty, elem: &str) -> bool { | |
1204 | match *ty { | |
1205 | syn::Ty::Rptr(Some(_), ref mut_ty) => { | |
1206 | mut_ty.mutability == syn::Mutability::Immutable && | |
1207 | mut_ty.ty == syn::parse_type(elem).unwrap() | |
1208 | } | |
1209 | _ => false, | |
1210 | } | |
1211 | } | |
1212 | ||
1213 | // All lifetimes that this type could borrow from a Deserializer. | |
1214 | // | |
1215 | // For example a type `S<'a, 'b>` could borrow `'a` and `'b`. On the other hand | |
1216 | // a type `for<'a> fn(&'a str)` could not borrow `'a` from the Deserializer. | |
1217 | // | |
1218 | // This is used when there is an explicit or implicit `#[serde(borrow)]` | |
1219 | // attribute on the field so there must be at least one borrowable lifetime. | |
1220 | fn borrowable_lifetimes( | |
1221 | cx: &Ctxt, | |
1222 | name: &str, | |
1223 | ty: &syn::Ty, | |
1224 | ) -> Result<BTreeSet<syn::Lifetime>, ()> { | |
1225 | let mut lifetimes = BTreeSet::new(); | |
1226 | collect_lifetimes(ty, &mut lifetimes); | |
1227 | if lifetimes.is_empty() { | |
1228 | Err(cx.error(format!("field `{}` has no lifetimes to borrow", name)),) | |
1229 | } else { | |
1230 | Ok(lifetimes) | |
1231 | } | |
1232 | } | |
1233 | ||
1234 | fn collect_lifetimes(ty: &syn::Ty, out: &mut BTreeSet<syn::Lifetime>) { | |
1235 | match *ty { | |
1236 | syn::Ty::Slice(ref elem) | | |
1237 | syn::Ty::Array(ref elem, _) | | |
1238 | syn::Ty::Paren(ref elem) => { | |
1239 | collect_lifetimes(elem, out); | |
1240 | } | |
1241 | syn::Ty::Ptr(ref elem) => { | |
1242 | collect_lifetimes(&elem.ty, out); | |
1243 | } | |
1244 | syn::Ty::Rptr(ref lifetime, ref elem) => { | |
1245 | out.extend(lifetime.iter().cloned()); | |
1246 | collect_lifetimes(&elem.ty, out); | |
1247 | } | |
1248 | syn::Ty::Tup(ref elems) => { | |
1249 | for elem in elems { | |
1250 | collect_lifetimes(elem, out); | |
1251 | } | |
1252 | } | |
1253 | syn::Ty::Path(ref qself, ref path) => { | |
1254 | if let Some(ref qself) = *qself { | |
1255 | collect_lifetimes(&qself.ty, out); | |
1256 | } | |
1257 | for seg in &path.segments { | |
1258 | if let syn::PathParameters::AngleBracketed(ref params) = seg.parameters { | |
1259 | out.extend(params.lifetimes.iter().cloned()); | |
1260 | for ty in ¶ms.types { | |
1261 | collect_lifetimes(ty, out); | |
1262 | } | |
1263 | for binding in ¶ms.bindings { | |
1264 | collect_lifetimes(&binding.ty, out); | |
1265 | } | |
1266 | } | |
1267 | } | |
1268 | } | |
1269 | syn::Ty::BareFn(_) | | |
1270 | syn::Ty::Never | | |
1271 | syn::Ty::TraitObject(_) | | |
1272 | syn::Ty::ImplTrait(_) | | |
1273 | syn::Ty::Infer | | |
1274 | syn::Ty::Mac(_) => {} | |
1275 | } | |
1276 | } |