1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use hir::map::DefPathData;
12 use hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
13 use ty::{self, Ty, TyCtxt};
15 use syntax::symbol::Symbol;
16 use syntax_pos::DUMMY_SP;
21 static FORCE_ABSOLUTE: Cell<bool> = Cell::new(false);
22 static FORCE_IMPL_FILENAME_LINE: Cell<bool> = Cell::new(false);
25 /// Enforces that item_path_str always returns an absolute path and
26 /// also enables "type-based" impl paths. This is used when building
27 /// symbols that contain types, where we want the crate name to be
28 /// part of the symbol.
29 pub fn with_forced_absolute_paths<F: FnOnce() -> R, R>(f: F) -> R {
30 FORCE_ABSOLUTE.with(|force| {
31 let old = force.get();
39 /// Force us to name impls with just the filename/line number. We
40 /// normally try to use types. But at some points, notably while printing
41 /// cycle errors, this can result in extra or suboptimal error output,
42 /// so this variable disables that check.
43 pub fn with_forced_impl_filename_line<F: FnOnce() -> R, R>(f: F) -> R {
44 FORCE_IMPL_FILENAME_LINE.with(|force| {
45 let old = force.get();
53 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
54 /// Returns a string identifying this def-id. This string is
55 /// suitable for user output. It is relative to the current crate
56 /// root, unless with_forced_absolute_paths was used.
57 pub fn item_path_str(self, def_id: DefId) -> String {
58 let mode = FORCE_ABSOLUTE.with(|force| {
65 let mut buffer = LocalPathBuffer::new(mode);
66 self.push_item_path(&mut buffer, def_id);
70 /// Returns a string identifying this local node-id.
71 pub fn node_path_str(self, id: ast::NodeId) -> String {
72 self.item_path_str(self.hir.local_def_id(id))
75 /// Returns a string identifying this def-id. This string is
76 /// suitable for user output. It always begins with a crate identifier.
77 pub fn absolute_item_path_str(self, def_id: DefId) -> String {
78 let mut buffer = LocalPathBuffer::new(RootMode::Absolute);
79 self.push_item_path(&mut buffer, def_id);
83 /// Returns the "path" to a particular crate. This can proceed in
84 /// various ways, depending on the `root_mode` of the `buffer`.
85 /// (See `RootMode` enum for more details.)
86 pub fn push_krate_path<T>(self, buffer: &mut T, cnum: CrateNum)
87 where T: ItemPathBuffer
89 match *buffer.root_mode() {
91 // In local mode, when we encounter a crate other than
92 // LOCAL_CRATE, execution proceeds in one of two ways:
94 // 1. for a direct dependency, where user added an
95 // `extern crate` manually, we put the `extern
96 // crate` as the parent. So you wind up with
97 // something relative to the current crate.
98 // 2. for an indirect crate, where there is no extern
99 // crate, we just prepend the crate name.
101 // Returns `None` for the local crate.
102 if cnum != LOCAL_CRATE {
103 let opt_extern_crate = self.extern_crate(cnum.as_def_id());
104 let opt_extern_crate = opt_extern_crate.and_then(|extern_crate| {
105 if extern_crate.direct {
106 Some(extern_crate.def_id)
111 if let Some(extern_crate_def_id) = opt_extern_crate {
112 self.push_item_path(buffer, extern_crate_def_id);
114 buffer.push(&self.crate_name(cnum).as_str());
118 RootMode::Absolute => {
119 // In absolute mode, just write the crate name
121 buffer.push(&self.original_crate_name(cnum).as_str());
126 /// If possible, this pushes a global path resolving to `external_def_id` that is visible
127 /// from at least one local module and returns true. If the crate defining `external_def_id` is
128 /// declared with an `extern crate`, the path is guaranteed to use the `extern crate`.
129 pub fn try_push_visible_item_path<T>(self, buffer: &mut T, external_def_id: DefId) -> bool
130 where T: ItemPathBuffer
132 let visible_parent_map = self.sess.cstore.visible_parent_map(self.sess);
134 let (mut cur_def, mut cur_path) = (external_def_id, Vec::<ast::Name>::new());
136 // If `cur_def` is a direct or injected extern crate, push the path to the crate
137 // followed by the path to the item within the crate and return.
138 if cur_def.index == CRATE_DEF_INDEX {
139 match *self.extern_crate(cur_def) {
140 Some(ref extern_crate) if extern_crate.direct => {
141 self.push_item_path(buffer, extern_crate.def_id);
142 cur_path.iter().rev().map(|segment| buffer.push(&segment.as_str())).count();
146 buffer.push(&self.crate_name(cur_def.krate).as_str());
147 cur_path.iter().rev().map(|segment| buffer.push(&segment.as_str())).count();
154 cur_path.push(self.sess.cstore.def_key(cur_def)
155 .disambiguated_data.data.get_opt_name().unwrap_or_else(||
156 Symbol::intern("<unnamed>")));
157 match visible_parent_map.get(&cur_def) {
158 Some(&def) => cur_def = def,
159 None => return false,
164 pub fn push_item_path<T>(self, buffer: &mut T, def_id: DefId)
165 where T: ItemPathBuffer
167 match *buffer.root_mode() {
168 RootMode::Local if !def_id.is_local() =>
169 if self.try_push_visible_item_path(buffer, def_id) { return },
173 let key = self.def_key(def_id);
174 match key.disambiguated_data.data {
175 DefPathData::CrateRoot => {
176 assert!(key.parent.is_none());
177 self.push_krate_path(buffer, def_id.krate);
180 DefPathData::Impl => {
181 self.push_impl_path(buffer, def_id);
184 // Unclear if there is any value in distinguishing these.
185 // Probably eventually (and maybe we would even want
186 // finer-grained distinctions, e.g. between enum/struct).
187 data @ DefPathData::Misc |
188 data @ DefPathData::TypeNs(..) |
189 data @ DefPathData::ValueNs(..) |
190 data @ DefPathData::Module(..) |
191 data @ DefPathData::TypeParam(..) |
192 data @ DefPathData::LifetimeDef(..) |
193 data @ DefPathData::EnumVariant(..) |
194 data @ DefPathData::Field(..) |
195 data @ DefPathData::Initializer |
196 data @ DefPathData::MacroDef(..) |
197 data @ DefPathData::ClosureExpr |
198 data @ DefPathData::Binding(..) |
199 data @ DefPathData::ImplTrait |
200 data @ DefPathData::Typeof |
201 data @ DefPathData::GlobalMetaData(..) => {
202 let parent_def_id = self.parent_def_id(def_id).unwrap();
203 self.push_item_path(buffer, parent_def_id);
204 buffer.push(&data.as_interned_str());
206 DefPathData::StructCtor => { // present `X` instead of `X::{{constructor}}`
207 let parent_def_id = self.parent_def_id(def_id).unwrap();
208 self.push_item_path(buffer, parent_def_id);
213 fn push_impl_path<T>(self,
216 where T: ItemPathBuffer
218 let parent_def_id = self.parent_def_id(impl_def_id).unwrap();
220 // Always use types for non-local impls, where types are always
221 // available, and filename/line-number is mostly uninteresting.
222 let use_types = !self.is_default_impl(impl_def_id) && (!impl_def_id.is_local() || {
223 // Otherwise, use filename/line-number if forced.
224 let force_no_types = FORCE_IMPL_FILENAME_LINE.with(|f| f.get());
226 // Otherwise, use types if we can query them without inducing a cycle.
227 ty::queries::impl_trait_ref::try_get(self, DUMMY_SP, impl_def_id).is_ok() &&
228 ty::queries::type_of::try_get(self, DUMMY_SP, impl_def_id).is_ok()
233 return self.push_impl_path_fallback(buffer, impl_def_id);
236 // Decide whether to print the parent path for the impl.
237 // Logically, since impls are global, it's never needed, but
238 // users may find it useful. Currently, we omit the parent if
239 // the impl is either in the same module as the self-type or
241 let self_ty = self.type_of(impl_def_id);
242 let in_self_mod = match characteristic_def_id_of_type(self_ty) {
244 Some(ty_def_id) => self.parent_def_id(ty_def_id) == Some(parent_def_id),
247 let impl_trait_ref = self.impl_trait_ref(impl_def_id);
248 let in_trait_mod = match impl_trait_ref {
250 Some(trait_ref) => self.parent_def_id(trait_ref.def_id) == Some(parent_def_id),
253 if !in_self_mod && !in_trait_mod {
254 // If the impl is not co-located with either self-type or
255 // trait-type, then fallback to a format that identifies
256 // the module more clearly.
257 self.push_item_path(buffer, parent_def_id);
258 if let Some(trait_ref) = impl_trait_ref {
259 buffer.push(&format!("<impl {} for {}>", trait_ref, self_ty));
261 buffer.push(&format!("<impl {}>", self_ty));
266 // Otherwise, try to give a good form that would be valid language
267 // syntax. Preferably using associated item notation.
269 if let Some(trait_ref) = impl_trait_ref {
271 buffer.push(&format!("<{} as {}>",
277 // Inherent impls. Try to print `Foo::bar` for an inherent
278 // impl on `Foo`, but fallback to `<Foo>::bar` if self-type is
279 // anything other than a simple path.
281 ty::TyAdt(adt_def, substs) => {
282 if substs.types().next().is_none() { // ignore regions
283 self.push_item_path(buffer, adt_def.did);
285 buffer.push(&format!("<{}>", self_ty));
295 buffer.push(&format!("{}", self_ty));
299 buffer.push(&format!("<{}>", self_ty));
304 fn push_impl_path_fallback<T>(self,
307 where T: ItemPathBuffer
309 // If no type info is available, fall back to
310 // pretty printing some span information. This should
311 // only occur very early in the compiler pipeline.
312 let parent_def_id = self.parent_def_id(impl_def_id).unwrap();
313 self.push_item_path(buffer, parent_def_id);
314 let node_id = self.hir.as_local_node_id(impl_def_id).unwrap();
315 let item = self.hir.expect_item(node_id);
316 let span_str = self.sess.codemap().span_to_string(item.span);
317 buffer.push(&format!("<impl at {}>", span_str));
320 /// Returns the def-id of `def_id`'s parent in the def tree. If
321 /// this returns `None`, then `def_id` represents a crate root or
323 pub fn parent_def_id(self, def_id: DefId) -> Option<DefId> {
324 let key = self.def_key(def_id);
325 key.parent.map(|index| DefId { krate: def_id.krate, index: index })
329 /// As a heuristic, when we see an impl, if we see that the
330 /// 'self-type' is a type defined in the same module as the impl,
331 /// we can omit including the path to the impl itself. This
332 /// function tries to find a "characteristic def-id" for a
333 /// type. It's just a heuristic so it makes some questionable
334 /// decisions and we may want to adjust it later.
335 pub fn characteristic_def_id_of_type(ty: Ty) -> Option<DefId> {
337 ty::TyAdt(adt_def, _) => Some(adt_def.did),
339 ty::TyDynamic(data, ..) => data.principal().map(|p| p.def_id()),
341 ty::TyArray(subty, _) |
342 ty::TySlice(subty) => characteristic_def_id_of_type(subty),
345 ty::TyRef(_, mt) => characteristic_def_id_of_type(mt.ty),
347 ty::TyTuple(ref tys, _) => tys.iter()
348 .filter_map(|ty| characteristic_def_id_of_type(ty))
351 ty::TyFnDef(def_id, _) |
352 ty::TyClosure(def_id, _) => Some(def_id),
360 ty::TyProjection(_) |
366 ty::TyFloat(_) => None,
370 /// Unifying Trait for different kinds of item paths we might
371 /// construct. The basic interface is that components get pushed: the
372 /// instance can also customize how we handle the root of a crate.
373 pub trait ItemPathBuffer {
374 fn root_mode(&self) -> &RootMode;
375 fn push(&mut self, text: &str);
380 /// Try to make a path relative to the local crate. In
381 /// particular, local paths have no prefix, and if the path comes
382 /// from an extern crate, start with the path to the `extern
383 /// crate` declaration.
386 /// Always prepend the crate name to the path, forming an absolute
387 /// path from within a given set of crates.
392 struct LocalPathBuffer {
397 impl LocalPathBuffer {
398 fn new(root_mode: RootMode) -> LocalPathBuffer {
405 fn into_string(self) -> String {
410 impl ItemPathBuffer for LocalPathBuffer {
411 fn root_mode(&self) -> &RootMode {
415 fn push(&mut self, text: &str) {
416 if !self.str.is_empty() {
417 self.str.push_str("::");
419 self.str.push_str(text);