src/librustc_incremental/persist/util.rs

   1 // Copyright 2014 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.
   4 //
   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.
  10
  11 use rustc::middle::cstore::LOCAL_CRATE;
  12 use rustc::session::Session;
  13 use rustc::ty::TyCtxt;
  14
  15 use std::fs;
  16 use std::io;
  17 use std::path::{Path, PathBuf};
  18 use syntax::ast;
  19
  20 pub fn dep_graph_path(tcx: TyCtxt) -> Option<PathBuf> {
  21     tcx_path(tcx, LOCAL_CRATE, "local")
  22 }
  23
  24 pub fn metadata_hash_path(tcx: TyCtxt, cnum: ast::CrateNum) -> Option<PathBuf> {
  25     tcx_path(tcx, cnum, "metadata")
  26 }
  27
  28 pub fn tcx_work_products_path(tcx: TyCtxt) -> Option<PathBuf> {
  29     let crate_name = tcx.crate_name(LOCAL_CRATE);
  30     sess_work_products_path(tcx.sess, &crate_name)
  31 }
  32
  33 pub fn sess_work_products_path(sess: &Session,
  34                                local_crate_name: &str)
  35                                -> Option<PathBuf> {
  36     let crate_disambiguator = sess.local_crate_disambiguator();
  37     path(sess, local_crate_name, &crate_disambiguator, "work-products")
  38 }
  39
  40 pub fn in_incr_comp_dir(sess: &Session, file_name: &str) -> Option<PathBuf> {
  41     sess.opts.incremental.as_ref().map(|incr_dir| incr_dir.join(file_name))
  42 }
  43
  44 fn tcx_path(tcx: TyCtxt,
  45             cnum: ast::CrateNum,
  46             middle: &str)
  47             -> Option<PathBuf> {
  48     path(tcx.sess, &tcx.crate_name(cnum), &tcx.crate_disambiguator(cnum), middle)
  49 }
  50
  51 fn path(sess: &Session,
  52         crate_name: &str,
  53         crate_disambiguator: &str,
  54         middle: &str)
  55         -> Option<PathBuf> {
  56     // For now, just save/load dep-graph from
  57     // directory/dep_graph.rbml
  58     sess.opts.incremental.as_ref().and_then(|incr_dir| {
  59         match create_dir_racy(&incr_dir) {
  60             Ok(()) => {}
  61             Err(err) => {
  62                 sess.err(
  63                     &format!("could not create the directory `{}`: {}",
  64                              incr_dir.display(), err));
  65                 return None;
  66             }
  67         }
  68
  69         let file_name = format!("{}-{}.{}.bin", crate_name, crate_disambiguator, middle);
  70
  71         Some(incr_dir.join(file_name))
  72     })
  73 }
  74
  75 // Like std::fs::create_dir_all, except handles concurrent calls among multiple
  76 // threads or processes.
  77 fn create_dir_racy(path: &Path) -> io::Result<()> {
  78     match fs::create_dir(path) {
  79         Ok(()) => return Ok(()),
  80         Err(ref e) if e.kind() == io::ErrorKind::AlreadyExists => return Ok(()),
  81         Err(ref e) if e.kind() == io::ErrorKind::NotFound => {}
  82         Err(e) => return Err(e),
  83     }
  84     match path.parent() {
  85         Some(p) => try!(create_dir_racy(p)),
  86         None => return Err(io::Error::new(io::ErrorKind::Other,
  87                                           "failed to create whole tree")),
  88     }
  89     match fs::create_dir(path) {
  90         Ok(()) => Ok(()),
  91         Err(ref e) if e.kind() == io::ErrorKind::AlreadyExists => Ok(()),
  92         Err(e) => Err(e),
  93     }
  94 }
  95