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 //! Finds crate binaries and loads their metadata
13 //! Might I be the first to welcome you to a world of platform differences,
14 //! version requirements, dependency graphs, conflicting desires, and fun! This
15 //! is the major guts (along with metadata::creader) of the compiler for loading
16 //! crates and resolving dependencies. Let's take a tour!
20 //! Each invocation of the compiler is immediately concerned with one primary
21 //! problem, to connect a set of crates to resolved crates on the filesystem.
22 //! Concretely speaking, the compiler follows roughly these steps to get here:
24 //! 1. Discover a set of `extern crate` statements.
25 //! 2. Transform these directives into crate names. If the directive does not
26 //! have an explicit name, then the identifier is the name.
27 //! 3. For each of these crate names, find a corresponding crate on the
30 //! Sounds easy, right? Let's walk into some of the nuances.
32 //! ## Transitive Dependencies
34 //! Let's say we've got three crates: A, B, and C. A depends on B, and B depends
35 //! on C. When we're compiling A, we primarily need to find and locate B, but we
36 //! also end up needing to find and locate C as well.
38 //! The reason for this is that any of B's types could be composed of C's types,
39 //! any function in B could return a type from C, etc. To be able to guarantee
40 //! that we can always typecheck/translate any function, we have to have
41 //! complete knowledge of the whole ecosystem, not just our immediate
44 //! So now as part of the "find a corresponding crate on the filesystem" step
45 //! above, this involves also finding all crates for *all upstream
46 //! dependencies*. This includes all dependencies transitively.
48 //! ## Rlibs and Dylibs
50 //! The compiler has two forms of intermediate dependencies. These are dubbed
51 //! rlibs and dylibs for the static and dynamic variants, respectively. An rlib
52 //! is a rustc-defined file format (currently just an ar archive) while a dylib
53 //! is a platform-defined dynamic library. Each library has a metadata somewhere
56 //! A third kind of dependency is an rmeta file. These are metadata files and do
57 //! not contain any code, etc. To a first approximation, these are treated in the
58 //! same way as rlibs. Where there is both an rlib and an rmeta file, the rlib
59 //! gets priority (even if the rmeta file is newer). An rmeta file is only
60 //! useful for checking a downstream crate, attempting to link one will cause an
63 //! When translating a crate name to a crate on the filesystem, we all of a
64 //! sudden need to take into account both rlibs and dylibs! Linkage later on may
65 //! use either one of these files, as each has their pros/cons. The job of crate
66 //! loading is to discover what's possible by finding all candidates.
68 //! Most parts of this loading systems keep the dylib/rlib as just separate
73 //! We can't exactly scan your whole hard drive when looking for dependencies,
74 //! so we need to places to look. Currently the compiler will implicitly add the
75 //! target lib search path ($prefix/lib/rustlib/$target/lib) to any compilation,
76 //! and otherwise all -L flags are added to the search paths.
78 //! ## What criterion to select on?
80 //! This a pretty tricky area of loading crates. Given a file, how do we know
81 //! whether it's the right crate? Currently, the rules look along these lines:
83 //! 1. Does the filename match an rlib/dylib pattern? That is to say, does the
84 //! filename have the right prefix/suffix?
85 //! 2. Does the filename have the right prefix for the crate name being queried?
86 //! This is filtering for files like `libfoo*.rlib` and such.
87 //! 3. Is the file an actual rust library? This is done by loading the metadata
88 //! from the library and making sure it's actually there.
89 //! 4. Does the name in the metadata agree with the name of the library?
90 //! 5. Does the target in the metadata agree with the current target?
91 //! 6. Does the SVH match? (more on this later)
93 //! If the file answers `yes` to all these questions, then the file is
94 //! considered as being *candidate* for being accepted. It is illegal to have
95 //! more than two candidates as the compiler has no method by which to resolve
96 //! this conflict. Additionally, rlib/dylib candidates are considered
99 //! After all this has happened, we have 1 or two files as candidates. These
100 //! represent the rlib/dylib file found for a library, and they're returned as
103 //! ### What about versions?
105 //! A lot of effort has been put forth to remove versioning from the compiler.
106 //! There have been forays in the past to have versioning baked in, but it was
107 //! largely always deemed insufficient to the point that it was recognized that
108 //! it's probably something the compiler shouldn't do anyway due to its
109 //! complicated nature and the state of the half-baked solutions.
111 //! With a departure from versioning, the primary criterion for loading crates
112 //! is just the name of a crate. If we stopped here, it would imply that you
113 //! could never link two crates of the same name from different sources
114 //! together, which is clearly a bad state to be in.
116 //! To resolve this problem, we come to the next section!
120 //! A number of flags have been added to the compiler to solve the "version
121 //! problem" in the previous section, as well as generally enabling more
122 //! powerful usage of the crate loading system of the compiler. The goal of
123 //! these flags and options are to enable third-party tools to drive the
124 //! compiler with prior knowledge about how the world should look.
126 //! ## The `--extern` flag
128 //! The compiler accepts a flag of this form a number of times:
131 //! --extern crate-name=path/to/the/crate.rlib
134 //! This flag is basically the following letter to the compiler:
138 //! > When you are attempting to load the immediate dependency `crate-name`, I
139 //! > would like you to assume that the library is located at
140 //! > `path/to/the/crate.rlib`, and look nowhere else. Also, please do not
141 //! > assume that the path I specified has the name `crate-name`.
143 //! This flag basically overrides most matching logic except for validating that
144 //! the file is indeed a rust library. The same `crate-name` can be specified
145 //! twice to specify the rlib/dylib pair.
147 //! ## Enabling "multiple versions"
149 //! This basically boils down to the ability to specify arbitrary packages to
150 //! the compiler. For example, if crate A wanted to use Bv1 and Bv2, then it
151 //! would look something like:
160 //! and the compiler would be invoked as:
163 //! rustc a.rs --extern b1=path/to/libb1.rlib --extern b2=path/to/libb2.rlib
166 //! In this scenario there are two crates named `b` and the compiler must be
167 //! manually driven to be informed where each crate is.
169 //! ## Frobbing symbols
171 //! One of the immediate problems with linking the same library together twice
172 //! in the same problem is dealing with duplicate symbols. The primary way to
173 //! deal with this in rustc is to add hashes to the end of each symbol.
175 //! In order to force hashes to change between versions of a library, if
176 //! desired, the compiler exposes an option `-C metadata=foo`, which is used to
177 //! initially seed each symbol hash. The string `foo` is prepended to each
178 //! string-to-hash to ensure that symbols change over time.
180 //! ## Loading transitive dependencies
182 //! Dealing with same-named-but-distinct crates is not just a local problem, but
183 //! one that also needs to be dealt with for transitive dependencies. Note that
184 //! in the letter above `--extern` flags only apply to the *local* set of
185 //! dependencies, not the upstream transitive dependencies. Consider this
186 //! dependency graph:
198 //! In this scenario, when we compile `D`, we need to be able to distinctly
199 //! resolve `A.1` and `A.2`, but an `--extern` flag cannot apply to these
200 //! transitive dependencies.
202 //! Note that the key idea here is that `B` and `C` are both *already compiled*.
203 //! That is, they have already resolved their dependencies. Due to unrelated
204 //! technical reasons, when a library is compiled, it is only compatible with
205 //! the *exact same* version of the upstream libraries it was compiled against.
206 //! We use the "Strict Version Hash" to identify the exact copy of an upstream
209 //! With this knowledge, we know that `B` and `C` will depend on `A` with
210 //! different SVH values, so we crawl the normal `-L` paths looking for
211 //! `liba*.rlib` and filter based on the contained SVH.
213 //! In the end, this ends up not needing `--extern` to specify upstream
214 //! transitive dependencies.
218 //! That's the general overview of loading crates in the compiler, but it's by
219 //! no means all of the necessary details. Take a look at the rest of
220 //! metadata::locator or metadata::creader for all the juicy details!
222 use cstore::MetadataBlob;
223 use creader::Library;
224 use schema::{METADATA_HEADER, rustc_version};
226 use rustc::hir::svh::Svh;
227 use rustc::middle::cstore::MetadataLoader;
228 use rustc::session::{config, Session};
229 use rustc::session::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
230 use rustc::session::search_paths::PathKind;
231 use rustc::util::nodemap::FxHashMap;
233 use errors::DiagnosticBuilder;
234 use syntax::symbol::Symbol;
235 use syntax_pos::Span;
236 use rustc_back::target::Target;
240 use std::fs::{self, File};
241 use std::io::{self, Read};
242 use std::path::{Path, PathBuf};
243 use std::time::Instant;
246 use owning_ref::{ErasedBoxRef, OwningRef};
248 pub struct CrateMismatch {
253 pub struct Context<'a> {
254 pub sess: &'a Session,
257 pub crate_name: Symbol,
258 pub hash: Option<&'a Svh>,
259 // points to either self.sess.target.target or self.sess.host, must match triple
260 pub target: &'a Target,
262 pub filesearch: FileSearch<'a>,
263 pub root: &'a Option<CratePaths>,
264 pub rejected_via_hash: Vec<CrateMismatch>,
265 pub rejected_via_triple: Vec<CrateMismatch>,
266 pub rejected_via_kind: Vec<CrateMismatch>,
267 pub rejected_via_version: Vec<CrateMismatch>,
268 pub rejected_via_filename: Vec<CrateMismatch>,
269 pub should_match_name: bool,
270 pub is_proc_macro: Option<bool>,
271 pub metadata_loader: &'a MetadataLoader,
274 pub struct CratePaths {
276 pub dylib: Option<PathBuf>,
277 pub rlib: Option<PathBuf>,
278 pub rmeta: Option<PathBuf>,
281 #[derive(Copy, Clone, PartialEq)]
288 impl fmt::Display for CrateFlavor {
289 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
290 f.write_str(match *self {
291 CrateFlavor::Rlib => "rlib",
292 CrateFlavor::Rmeta => "rmeta",
293 CrateFlavor::Dylib => "dylib",
299 fn paths(&self) -> Vec<PathBuf> {
300 self.dylib.iter().chain(self.rlib.iter()).chain(self.rmeta.iter()).cloned().collect()
304 impl<'a> Context<'a> {
305 pub fn maybe_load_library_crate(&mut self) -> Option<Library> {
306 self.find_library_crate()
309 pub fn load_library_crate(&mut self) -> Library {
310 self.find_library_crate().unwrap_or_else(|| self.report_errs())
313 pub fn report_errs(&mut self) -> ! {
314 let add = match self.root {
315 &None => String::new(),
316 &Some(ref r) => format!(" which `{}` depends on", r.ident),
318 let mut err = if !self.rejected_via_hash.is_empty() {
319 struct_span_err!(self.sess,
322 "found possibly newer version of crate `{}`{}",
325 } else if !self.rejected_via_triple.is_empty() {
326 struct_span_err!(self.sess,
329 "couldn't find crate `{}` with expected target triple {}{}",
333 } else if !self.rejected_via_kind.is_empty() {
334 struct_span_err!(self.sess,
337 "found staticlib `{}` instead of rlib or dylib{}",
340 } else if !self.rejected_via_version.is_empty() {
341 struct_span_err!(self.sess,
344 "found crate `{}` compiled by an incompatible version of rustc{}",
348 let mut err = struct_span_err!(self.sess,
351 "can't find crate for `{}`{}",
355 if (self.ident == "std" || self.ident == "core")
356 && self.triple != config::host_triple() {
357 err.note(&format!("the `{}` target may not be installed", self.triple));
359 err.span_label(self.span, "can't find crate");
363 if !self.rejected_via_triple.is_empty() {
364 let mismatches = self.rejected_via_triple.iter();
365 for (i, &CrateMismatch { ref path, ref got }) in mismatches.enumerate() {
366 err.note(&format!("crate `{}`, path #{}, triple {}: {}",
373 if !self.rejected_via_hash.is_empty() {
374 err.note("perhaps that crate needs to be recompiled?");
375 let mismatches = self.rejected_via_hash.iter();
376 for (i, &CrateMismatch { ref path, .. }) in mismatches.enumerate() {
377 err.note(&format!("crate `{}` path #{}: {}", self.ident, i + 1, path.display()));
382 for (i, path) in r.paths().iter().enumerate() {
383 err.note(&format!("crate `{}` path #{}: {}",
391 if !self.rejected_via_kind.is_empty() {
392 err.help("please recompile that crate using --crate-type lib");
393 let mismatches = self.rejected_via_kind.iter();
394 for (i, &CrateMismatch { ref path, .. }) in mismatches.enumerate() {
395 err.note(&format!("crate `{}` path #{}: {}", self.ident, i + 1, path.display()));
398 if !self.rejected_via_version.is_empty() {
399 err.help(&format!("please recompile that crate using this compiler ({})",
401 let mismatches = self.rejected_via_version.iter();
402 for (i, &CrateMismatch { ref path, ref got }) in mismatches.enumerate() {
403 err.note(&format!("crate `{}` path #{}: {} compiled by {:?}",
410 if !self.rejected_via_filename.is_empty() {
411 let dylibname = self.dylibname();
412 let mismatches = self.rejected_via_filename.iter();
413 for &CrateMismatch { ref path, .. } in mismatches {
414 err.note(&format!("extern location for {} is of an unknown type: {}",
417 .help(&format!("file name should be lib*.rlib or {}*.{}",
424 self.sess.abort_if_errors();
428 fn find_library_crate(&mut self) -> Option<Library> {
429 // If an SVH is specified, then this is a transitive dependency that
430 // must be loaded via -L plus some filtering.
431 if self.hash.is_none() {
432 self.should_match_name = false;
433 if let Some(s) = self.sess.opts.externs.get(&self.crate_name.as_str()) {
434 return self.find_commandline_library(s.iter());
436 self.should_match_name = true;
439 let dypair = self.dylibname();
440 let staticpair = self.staticlibname();
442 // want: crate_name.dir_part() + prefix + crate_name.file_part + "-"
443 let dylib_prefix = format!("{}{}", dypair.0, self.crate_name);
444 let rlib_prefix = format!("lib{}", self.crate_name);
445 let staticlib_prefix = format!("{}{}", staticpair.0, self.crate_name);
447 let mut candidates = FxHashMap();
448 let mut staticlibs = vec![];
450 // First, find all possible candidate rlibs and dylibs purely based on
451 // the name of the files themselves. We're trying to match against an
452 // exact crate name and a possibly an exact hash.
454 // During this step, we can filter all found libraries based on the
455 // name and id found in the crate id (we ignore the path portion for
456 // filename matching), as well as the exact hash (if specified). If we
457 // end up having many candidates, we must look at the metadata to
458 // perform exact matches against hashes/crate ids. Note that opening up
459 // the metadata is where we do an exact match against the full contents
460 // of the crate id (path/name/id).
462 // The goal of this step is to look at as little metadata as possible.
463 self.filesearch.search(|path, kind| {
464 let file = match path.file_name().and_then(|s| s.to_str()) {
465 None => return FileDoesntMatch,
468 let (hash, found_kind) =
469 if file.starts_with(&rlib_prefix) && file.ends_with(".rlib") {
470 (&file[(rlib_prefix.len())..(file.len() - ".rlib".len())], CrateFlavor::Rlib)
471 } else if file.starts_with(&rlib_prefix) && file.ends_with(".rmeta") {
472 (&file[(rlib_prefix.len())..(file.len() - ".rmeta".len())], CrateFlavor::Rmeta)
473 } else if file.starts_with(&dylib_prefix) &&
474 file.ends_with(&dypair.1) {
475 (&file[(dylib_prefix.len())..(file.len() - dypair.1.len())], CrateFlavor::Dylib)
477 if file.starts_with(&staticlib_prefix) && file.ends_with(&staticpair.1) {
478 staticlibs.push(CrateMismatch {
479 path: path.to_path_buf(),
480 got: "static".to_string(),
483 return FileDoesntMatch;
485 info!("lib candidate: {}", path.display());
487 let hash_str = hash.to_string();
488 let slot = candidates.entry(hash_str)
489 .or_insert_with(|| (FxHashMap(), FxHashMap(), FxHashMap()));
490 let (ref mut rlibs, ref mut rmetas, ref mut dylibs) = *slot;
491 fs::canonicalize(path)
494 CrateFlavor::Rlib => { rlibs.insert(p, kind); }
495 CrateFlavor::Rmeta => { rmetas.insert(p, kind); }
496 CrateFlavor::Dylib => { dylibs.insert(p, kind); }
500 .unwrap_or(FileDoesntMatch)
502 self.rejected_via_kind.extend(staticlibs);
504 // We have now collected all known libraries into a set of candidates
505 // keyed of the filename hash listed. For each filename, we also have a
506 // list of rlibs/dylibs that apply. Here, we map each of these lists
507 // (per hash), to a Library candidate for returning.
509 // A Library candidate is created if the metadata for the set of
510 // libraries corresponds to the crate id and hash criteria that this
511 // search is being performed for.
512 let mut libraries = FxHashMap();
513 for (_hash, (rlibs, rmetas, dylibs)) in candidates {
515 let rlib = self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot);
516 let rmeta = self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot);
517 let dylib = self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot);
518 if let Some((h, m)) = slot {
529 // Having now translated all relevant found hashes into libraries, see
530 // what we've got and figure out if we found multiple candidates for
532 match libraries.len() {
534 1 => Some(libraries.into_iter().next().unwrap().1),
536 let mut err = struct_span_err!(self.sess,
539 "multiple matching crates for `{}`",
541 err.note("candidates:");
542 for (_, lib) in libraries {
543 if let Some((ref p, _)) = lib.dylib {
544 err.note(&format!("path: {}", p.display()));
546 if let Some((ref p, _)) = lib.rlib {
547 err.note(&format!("path: {}", p.display()));
549 note_crate_name(&mut err, &lib.metadata.get_root().name.as_str());
557 // Attempts to extract *one* library from the set `m`. If the set has no
558 // elements, `None` is returned. If the set has more than one element, then
559 // the errors and notes are emitted about the set of libraries.
561 // With only one library in the set, this function will extract it, and then
562 // read the metadata from it if `*slot` is `None`. If the metadata couldn't
563 // be read, it is assumed that the file isn't a valid rust library (no
564 // errors are emitted).
565 fn extract_one(&mut self,
566 m: FxHashMap<PathBuf, PathKind>,
568 slot: &mut Option<(Svh, MetadataBlob)>)
569 -> Option<(PathBuf, PathKind)> {
570 let mut ret: Option<(PathBuf, PathKind)> = None;
574 // FIXME(#10786): for an optimization, we only read one of the
575 // libraries' metadata sections. In theory we should
576 // read both, but reading dylib metadata is quite
580 } else if m.len() == 1 {
581 return Some(m.into_iter().next().unwrap());
585 let mut err: Option<DiagnosticBuilder> = None;
586 for (lib, kind) in m {
587 info!("{} reading metadata from: {}", flavor, lib.display());
588 let (hash, metadata) =
589 match get_metadata_section(self.target, flavor, &lib, self.metadata_loader) {
591 if let Some(h) = self.crate_matches(&blob, &lib) {
594 info!("metadata mismatch");
599 info!("no metadata found: {}", err);
603 // If we see multiple hashes, emit an error about duplicate candidates.
604 if slot.as_ref().map_or(false, |s| s.0 != hash) {
605 let mut e = struct_span_err!(self.sess,
608 "multiple {} candidates for `{}` found",
611 e.span_note(self.span,
612 &format!(r"candidate #1: {}",
617 if let Some(ref mut e) = err {
626 err.as_mut().unwrap().span_note(self.span,
627 &format!(r"candidate #{}: {}",
633 // Ok so at this point we've determined that `(lib, kind)` above is
634 // a candidate crate to load, and that `slot` is either none (this
635 // is the first crate of its kind) or if some the previous path has
636 // the exact same hash (e.g. it's the exact same crate).
638 // In principle these two candidate crates are exactly the same so
639 // we can choose either of them to link. As a stupidly gross hack,
640 // however, we favor crate in the sysroot.
642 // You can find more info in rust-lang/rust#39518 and various linked
643 // issues, but the general gist is that during testing libstd the
644 // compilers has two candidates to choose from: one in the sysroot
645 // and one in the deps folder. These two crates are the exact same
646 // crate but if the compiler chooses the one in the deps folder
647 // it'll cause spurious errors on Windows.
649 // As a result, we favor the sysroot crate here. Note that the
650 // candidates are all canonicalized, so we canonicalize the sysroot
652 if let Some((ref prev, _)) = ret {
653 let sysroot = self.sess.sysroot();
654 let sysroot = sysroot.canonicalize()
655 .unwrap_or(sysroot.to_path_buf());
656 if prev.starts_with(&sysroot) {
660 *slot = Some((hash, metadata));
661 ret = Some((lib, kind));
672 fn crate_matches(&mut self, metadata: &MetadataBlob, libpath: &Path) -> Option<Svh> {
673 let rustc_version = rustc_version();
674 let found_version = metadata.get_rustc_version();
675 if found_version != rustc_version {
676 info!("Rejecting via version: expected {} got {}",
679 self.rejected_via_version.push(CrateMismatch {
680 path: libpath.to_path_buf(),
686 let root = metadata.get_root();
687 if let Some(is_proc_macro) = self.is_proc_macro {
688 if root.macro_derive_registrar.is_some() != is_proc_macro {
693 if self.should_match_name {
694 if self.crate_name != root.name {
695 info!("Rejecting via crate name");
700 if root.triple != self.triple {
701 info!("Rejecting via crate triple: expected {} got {}",
704 self.rejected_via_triple.push(CrateMismatch {
705 path: libpath.to_path_buf(),
711 if let Some(myhash) = self.hash {
712 if *myhash != root.hash {
713 info!("Rejecting via hash: expected {} got {}", *myhash, root.hash);
714 self.rejected_via_hash.push(CrateMismatch {
715 path: libpath.to_path_buf(),
716 got: myhash.to_string(),
726 // Returns the corresponding (prefix, suffix) that files need to have for
728 fn dylibname(&self) -> (String, String) {
729 let t = &self.target;
730 (t.options.dll_prefix.clone(), t.options.dll_suffix.clone())
733 // Returns the corresponding (prefix, suffix) that files need to have for
735 fn staticlibname(&self) -> (String, String) {
736 let t = &self.target;
737 (t.options.staticlib_prefix.clone(), t.options.staticlib_suffix.clone())
740 fn find_commandline_library<'b, LOCS>(&mut self, locs: LOCS) -> Option<Library>
741 where LOCS: Iterator<Item = &'b String>
743 // First, filter out all libraries that look suspicious. We only accept
744 // files which actually exist that have the correct naming scheme for
746 let sess = self.sess;
747 let dylibname = self.dylibname();
748 let mut rlibs = FxHashMap();
749 let mut rmetas = FxHashMap();
750 let mut dylibs = FxHashMap();
752 let locs = locs.map(|l| PathBuf::from(l)).filter(|loc| {
754 sess.err(&format!("extern location for {} does not exist: {}",
759 let file = match loc.file_name().and_then(|s| s.to_str()) {
762 sess.err(&format!("extern location for {} is not a file: {}",
768 if file.starts_with("lib") &&
769 (file.ends_with(".rlib") || file.ends_with(".rmeta")) {
772 let (ref prefix, ref suffix) = dylibname;
773 if file.starts_with(&prefix[..]) && file.ends_with(&suffix[..]) {
778 self.rejected_via_filename.push(CrateMismatch {
786 // Now that we have an iterator of good candidates, make sure
787 // there's at most one rlib and at most one dylib.
789 if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
790 rlibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
791 } else if loc.file_name().unwrap().to_str().unwrap().ends_with(".rmeta") {
792 rmetas.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
794 dylibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
799 // Extract the rlib/dylib pair.
801 let rlib = self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot);
802 let rmeta = self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot);
803 let dylib = self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot);
805 if rlib.is_none() && rmeta.is_none() && dylib.is_none() {
809 Some((_, metadata)) => {
822 pub fn note_crate_name(err: &mut DiagnosticBuilder, name: &str) {
823 err.note(&format!("crate name: {}", name));
826 // Just a small wrapper to time how long reading metadata takes.
827 fn get_metadata_section(target: &Target,
830 loader: &MetadataLoader)
831 -> Result<MetadataBlob, String> {
832 let start = Instant::now();
833 let ret = get_metadata_section_imp(target, flavor, filename, loader);
834 info!("reading {:?} => {:?}",
835 filename.file_name().unwrap(),
840 fn get_metadata_section_imp(target: &Target,
843 loader: &MetadataLoader)
844 -> Result<MetadataBlob, String> {
845 if !filename.exists() {
846 return Err(format!("no such file: '{}'", filename.display()));
848 let raw_bytes: ErasedBoxRef<[u8]> = match flavor {
849 CrateFlavor::Rlib => loader.get_rlib_metadata(target, filename)?,
850 CrateFlavor::Dylib => {
851 let buf = loader.get_dylib_metadata(target, filename)?;
852 // The header is uncompressed
853 let header_len = METADATA_HEADER.len();
854 debug!("checking {} bytes of metadata-version stamp", header_len);
855 let header = &buf[..cmp::min(header_len, buf.len())];
856 if header != METADATA_HEADER {
857 return Err(format!("incompatible metadata version found: '{}'",
858 filename.display()));
861 // Header is okay -> inflate the actual metadata
862 let compressed_bytes = &buf[header_len..];
863 debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
864 match flate::inflate_bytes(compressed_bytes) {
866 let buf = unsafe { OwningRef::new_assert_stable_address(inflated) };
867 buf.map_owner_box().erase_owner()
870 return Err(format!("failed to decompress metadata: {}", filename.display()));
874 CrateFlavor::Rmeta => {
875 let mut file = File::open(filename).map_err(|_|
876 format!("could not open file: '{}'", filename.display()))?;
877 let mut buf = vec![];
878 file.read_to_end(&mut buf).map_err(|_|
879 format!("failed to read rmeta metadata: '{}'", filename.display()))?;
880 OwningRef::new(buf).map_owner_box().erase_owner()
883 let blob = MetadataBlob(raw_bytes);
884 if blob.is_compatible() {
887 Err(format!("incompatible metadata version found: '{}'", filename.display()))
891 // A diagnostic function for dumping crate metadata to an output stream
892 pub fn list_file_metadata(target: &Target,
894 loader: &MetadataLoader,
897 let filename = path.file_name().unwrap().to_str().unwrap();
898 let flavor = if filename.ends_with(".rlib") {
900 } else if filename.ends_with(".rmeta") {
905 match get_metadata_section(target, flavor, path, loader) {
906 Ok(metadata) => metadata.list_crate_metadata(out),
907 Err(msg) => write!(out, "{}\n", msg),