rustbuild: Implement DESTDIR support

This commit primarily starts supporting the `DESTDIR` environment variable like
the old build system. Along the way this brings `config.toml` up to date with
support in `config.mk` with install options supported.

Closes rust-lang#38441

Author: alexcrichton

src/bootstrap/compile.rs

@@ -187,7 +187,7 @@ pub fn rustc<'a>(build: &'a Build, target: &str, compiler: &Compiler<'a>) {
     cargo.env("CFG_RELEASE", &build.release)
          .env("CFG_RELEASE_CHANNEL", &build.config.channel)
          .env("CFG_VERSION", &build.version)
-         .env("CFG_PREFIX", build.config.prefix.clone().unwrap_or(String::new()))
+         .env("CFG_PREFIX", build.config.prefix.clone().unwrap_or(PathBuf::new()))
          .env("CFG_LIBDIR_RELATIVE", "lib");
 
     if let Some(ref ver_date) = build.ver_date {

src/bootstrap/config.rs

@@ -84,10 +84,10 @@ pub struct Config {
     pub quiet_tests: bool,
     // Fallback musl-root for all targets
     pub musl_root: Option<PathBuf>,
-    pub prefix: Option<String>,
-    pub docdir: Option<String>,
-    pub libdir: Option<String>,
-    pub mandir: Option<String>,
+    pub prefix: Option<PathBuf>,
+    pub docdir: Option<PathBuf>,
+    pub libdir: Option<PathBuf>,
+    pub mandir: Option<PathBuf>,
     pub codegen_tests: bool,
     pub nodejs: Option<PathBuf>,
     pub gdb: Option<PathBuf>,
@@ -140,6 +140,9 @@ struct Build {
 #[derive(RustcDecodable, Default, Clone)]
 struct Install {
     prefix: Option<String>,
+    mandir: Option<String>,
+    docdir: Option<String>,
+    libdir: Option<String>,
 }
 
 /// TOML representation of how the LLVM build is configured.
@@ -266,7 +269,10 @@ impl Config {
         set(&mut config.vendor, build.vendor);
 
         if let Some(ref install) = toml.install {
-            config.prefix = install.prefix.clone();
+            config.prefix = install.prefix.clone().map(PathBuf::from);
+            config.mandir = install.mandir.clone().map(PathBuf::from);
+            config.docdir = install.docdir.clone().map(PathBuf::from);
+            config.libdir = install.libdir.clone().map(PathBuf::from);
         }
 
         if let Some(ref llvm) = toml.llvm {
@@ -451,16 +457,16 @@ impl Config {
                     self.channel = value.to_string();
                 }
                 "CFG_PREFIX" => {
-                    self.prefix = Some(value.to_string());
+                    self.prefix = Some(PathBuf::from(value));
                 }
                 "CFG_DOCDIR" => {
-                    self.docdir = Some(value.to_string());
+                    self.docdir = Some(PathBuf::from(value));
                 }
                 "CFG_LIBDIR" => {
-                    self.libdir = Some(value.to_string());
+                    self.libdir = Some(PathBuf::from(value));
                 }
                 "CFG_MANDIR" => {
-                    self.mandir = Some(value.to_string());
+                    self.mandir = Some(PathBuf::from(value));
                 }
                 "CFG_LLVM_ROOT" if value.len() > 0 => {
                     let target = self.target_config.entry(self.build.clone())

src/bootstrap/config.toml.example

@@ -106,7 +106,16 @@
 [install]
 
 # Instead of installing to /usr/local, install to this path instead.
-#prefix = "/path/to/install"
+#prefix = "/usr/local"
+
+# Where to install libraries in `prefix` above
+#libdir = "lib"
+
+# Where to install man pages in `prefix` above
+#mandir = "share/man"
+
+# Where to install documentation in `prefix` above
+#docdir = "share/doc/rust"
 
 # =============================================================================
 # Options for compiling Rust code itself

src/bootstrap/install.rs

@@ -13,33 +13,45 @@
 //! This module is responsible for installing the standard library,
 //! compiler, and documentation.
 
+use std::env;
 use std::fs;
-use std::borrow::Cow;
-use std::path::Path;
+use std::path::{Path, PathBuf, Component};
 use std::process::Command;
 
 use Build;
 use dist::{package_vers, sanitize_sh, tmpdir};
 
 /// Installs everything.
 pub fn install(build: &Build, stage: u32, host: &str) {
-    let prefix = build.config.prefix.as_ref().clone().map(|x| Path::new(x))
-        .unwrap_or(Path::new("/usr/local"));
-    let docdir = build.config.docdir.as_ref().clone().map(|x| Cow::Borrowed(Path::new(x)))
-        .unwrap_or(Cow::Owned(prefix.join("share/doc/rust")));
-    let libdir = build.config.libdir.as_ref().clone().map(|x| Cow::Borrowed(Path::new(x)))
-        .unwrap_or(Cow::Owned(prefix.join("lib")));
-    let mandir = build.config.mandir.as_ref().clone().map(|x| Cow::Borrowed(Path::new(x)))
-        .unwrap_or(Cow::Owned(prefix.join("share/man")));
+    let prefix_default = PathBuf::from("/usr/local");
+    let docdir_default = PathBuf::from("share/doc/rust");
+    let mandir_default = PathBuf::from("share/man");
+    let libdir_default = PathBuf::from("lib");
+    let prefix = build.config.prefix.as_ref().unwrap_or(&prefix_default);
+    let docdir = build.config.docdir.as_ref().unwrap_or(&docdir_default);
+    let libdir = build.config.libdir.as_ref().unwrap_or(&libdir_default);
+    let mandir = build.config.mandir.as_ref().unwrap_or(&mandir_default);
+
+    let docdir = prefix.join(docdir);
+    let libdir = prefix.join(libdir);
+    let mandir = prefix.join(mandir);
+
+    let destdir = env::var_os("DESTDIR").map(PathBuf::from);
+
+    let prefix = add_destdir(&prefix, &destdir);
+    let docdir = add_destdir(&docdir, &destdir);
+    let libdir = add_destdir(&libdir, &destdir);
+    let mandir = add_destdir(&mandir, &destdir);
+
     let empty_dir = build.out.join("tmp/empty_dir");
     t!(fs::create_dir_all(&empty_dir));
     if build.config.docs {
-        install_sh(&build, "docs", "rust-docs", stage, host, prefix,
+        install_sh(&build, "docs", "rust-docs", stage, host, &prefix,
                    &docdir, &libdir, &mandir, &empty_dir);
     }
-    install_sh(&build, "std", "rust-std", stage, host, prefix,
+    install_sh(&build, "std", "rust-std", stage, host, &prefix,
                &docdir, &libdir, &mandir, &empty_dir);
-    install_sh(&build, "rustc", "rustc", stage, host, prefix,
+    install_sh(&build, "rustc", "rustc", stage, host, &prefix,
                &docdir, &libdir, &mandir, &empty_dir);
     t!(fs::remove_dir_all(&empty_dir));
 }
@@ -59,3 +71,17 @@ fn install_sh(build: &Build, package: &str, name: &str, stage: u32, host: &str,
        .arg("--disable-ldconfig");
     build.run(&mut cmd);
 }
+
+fn add_destdir(path: &Path, destdir: &Option<PathBuf>) -> PathBuf {
+    let mut ret = match *destdir {
+        Some(ref dest) => dest.clone(),
+        None => return path.to_path_buf(),
+    };
+    for part in path.components() {
+        match part {
+            Component::Normal(s) => ret.push(s),
+            _ => {}
+        }
+    }
+    return ret
+}