From 0ec05d0a9961955d8d01fa8b2ef31f6ec30153ee Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Tue, 28 Jul 2020 11:15:58 +0200
Subject: [PATCH] fix for changed rustc directory layout

---
 src/rustc.rs   | 29 ++++++-----------------------
 src/sysroot.rs | 25 +++++++++++++++++--------
 2 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/src/rustc.rs b/src/rustc.rs
index f614f50..9074129 100644
--- a/src/rustc.rs
+++ b/src/rustc.rs
@@ -1,5 +1,4 @@
 use std::env;
-use std::ffi::OsStr;
 use std::hash::{Hash, Hasher};
 use std::path::{Path, PathBuf};
 use std::process::Command;
@@ -8,7 +7,6 @@ pub use rustc_version::version_meta as version;
 
 use serde_json::Value;
 use serde_json;
-use walkdir::WalkDir;
 
 use CurrentDirectory;
 use errors::*;
@@ -69,8 +67,8 @@ impl Sysroot {
         &self.path
     }
 
-    /// Returns the path to Rust source, `$SRC`, where `$SRC/libstd/Carg.toml`
-    /// exists
+    /// Returns the path to Rust source, `$SRC`, where `$SRC/libstd/Cargo.toml`
+    /// or `$SRC/std/Cargo.toml` exists.
     pub fn src(&self) -> Result<Src> {
         let src = self.path().join("lib").join("rustlib").join("src");
 
@@ -80,25 +78,10 @@ impl Sysroot {
             });
         }
 
-        if src.exists() {
-            for e in WalkDir::new(src) {
-                let e = e.chain_err(|| "couldn't walk the sysroot")?;
-
-                // Looking for $SRC/libstd/Cargo.toml
-                if e.file_type().is_file() && e.file_name() == "Cargo.toml" {
-                    let toml = e.path();
-
-                    if let Some(std) = toml.parent() {
-                        if let Some(src) = std.parent() {
-                            if std.file_name() == Some(OsStr::new("libstd")) {
-                                return Ok(Src {
-                                    path: src.to_owned(),
-                                });
-                            }
-                        }
-                    }
-                }
-            }
+        if src.join("rust").join("library").join("std").join("Cargo.toml").is_file() {
+            return Ok(Src {
+                path: src.join("rust").join("library"),
+            });
         }
 
         Err(
diff --git a/src/sysroot.rs b/src/sysroot.rs
index 9d9f2f7..4987dd4 100644
--- a/src/sysroot.rs
+++ b/src/sysroot.rs
@@ -412,9 +412,13 @@ impl Blueprint {
     }
 
     /// Add $CRATE to `patch` section, as needed to build libstd.
-    fn add_patch(patch: &mut Table, mut path: PathBuf, crate_: &str) -> Result<()> {
-        path.push(crate_);
-        if path.exists() {
+    fn add_patch(patch: &mut Table, src_path: &Path, crate_: &str) -> Result<()> {
+        // Old sysroots have this in `src/tools/$CRATE`, new sysroots in `library/$CRATE`.
+        let paths = [
+            src_path.join(crate_),
+            src_path.join("tools").join(crate_),
+        ];
+        if let Some(path) = paths.iter().find(|p| p.exists()) {
             // add crate to patch section (if not specified)
             fn table_entry<'a>(table: &'a mut Table, key: &str) -> Result<&'a mut Table> {
                 table
@@ -479,9 +483,9 @@ impl Blueprint {
             }
         }
 
-        Blueprint::add_patch(&mut patch, src.path().join("tools"), "rustc-std-workspace-core")?;
-        Blueprint::add_patch(&mut patch, src.path().join("tools"), "rustc-std-workspace-alloc")?;
-        Blueprint::add_patch(&mut patch, src.path().join("tools"), "rustc-std-workspace-std")?;
+        Blueprint::add_patch(&mut patch, src.path(), "rustc-std-workspace-core")?;
+        Blueprint::add_patch(&mut patch, src.path(), "rustc-std-workspace-alloc")?;
+        Blueprint::add_patch(&mut patch, src.path(), "rustc-std-workspace-std")?;
 
         // Compose dependency sections
         let deps = match (
@@ -559,8 +563,13 @@ impl Blueprint {
 
                 if !map.contains_key("path") && !map.contains_key("git") {
                     // No path and no git given.  This might be in the sysroot, but if we don't find it there we assume it comes from crates.io.
-                    let path = src.path().join(format!("lib{}", k));
-                    if path.exists() {
+                    // Current sysroots call it just "std" (etc), but older sysroots use "libstd" (etc),
+                    // so we check both.
+                    let paths = [
+                        src.path().join(&k),
+                        src.path().join(format!("lib{}", k)),
+                    ];
+                    if let Some(path) = paths.iter().find(|p| p.exists()) {
                         map.insert("path".to_owned(), Value::String(path.display().to_string()));
                     }
                 }