src/build_helper/lib.rs - third_party/rust - Git at Google

 use std::fs::File;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 use std::time::{SystemTime, UNIX_EPOCH};
 use std::{env, fs};
 use std::thread;

 /// A helper macro to `unwrap` a result except also print out details like:
 ///
 /// * The file/line of the panic
 /// * The expression that failed
 /// * The error itself
 ///
 /// This is currently used judiciously throughout the build system rather than
 /// using a `Result` with `try!`, but this may change one day...
 #[macro_export]
 macro_rules! t {
     ($e:expr) => {
         match $e {
             Ok(e) => e,
             Err(e) => panic!("{} failed with {}", stringify!($e), e),
         }
     };
 }

 pub fn run(cmd: &mut Command) {
     println!("running: {:?}", cmd);
     run_silent(cmd);
 }

 pub fn run_silent(cmd: &mut Command) {
     if !try_run_silent(cmd) {
         std::process::exit(1);
     }
 }

 pub fn try_run_silent(cmd: &mut Command) -> bool {
     let status = match cmd.status() {
         Ok(status) => status,
         Err(e) => fail(&format!(
             "failed to execute command: {:?}\nerror: {}",
             cmd, e
         )),
     };
     if !status.success() {
         println!(
             "\n\ncommand did not execute successfully: {:?}\n\
              expected success, got: {}\n\n",
             cmd, status
         );
     }
     status.success()
 }

 pub fn run_suppressed(cmd: &mut Command) {
     if !try_run_suppressed(cmd) {
         std::process::exit(1);
     }
 }

 pub fn try_run_suppressed(cmd: &mut Command) -> bool {
     let output = match cmd.output() {
         Ok(status) => status,
         Err(e) => fail(&format!(
             "failed to execute command: {:?}\nerror: {}",
             cmd, e
         )),
     };
     if !output.status.success() {
         println!(
             "\n\ncommand did not execute successfully: {:?}\n\
              expected success, got: {}\n\n\
              stdout ----\n{}\n\
              stderr ----\n{}\n\n",
             cmd,
             output.status,
             String::from_utf8_lossy(&output.stdout),
             String::from_utf8_lossy(&output.stderr)
         );
     }
     output.status.success()
 }

 pub fn gnu_target(target: &str) -> &str {
     match target {
         "i686-pc-windows-msvc" => "i686-pc-win32",
         "x86_64-pc-windows-msvc" => "x86_64-pc-win32",
         "i686-pc-windows-gnu" => "i686-w64-mingw32",
         "x86_64-pc-windows-gnu" => "x86_64-w64-mingw32",
         s => s,
     }
 }

 pub fn make(host: &str) -> PathBuf {
     if host.contains("bitrig") || host.contains("dragonfly") || host.contains("freebsd")
         || host.contains("netbsd") || host.contains("openbsd")
     {
         PathBuf::from("gmake")
     } else {
         PathBuf::from("make")
     }
 }

 pub fn output(cmd: &mut Command) -> String {
     let output = match cmd.stderr(Stdio::inherit()).output() {
         Ok(status) => status,
         Err(e) => fail(&format!(
             "failed to execute command: {:?}\nerror: {}",
             cmd, e
         )),
     };
     if !output.status.success() {
         panic!(
             "command did not execute successfully: {:?}\n\
              expected success, got: {}",
             cmd, output.status
         );
     }
     String::from_utf8(output.stdout).unwrap()
 }

 pub fn rerun_if_changed_anything_in_dir(dir: &Path) {
     let mut stack = dir.read_dir()
         .unwrap()
         .map(|e| e.unwrap())
         .filter(|e| &*e.file_name() != ".git")
         .collect::<Vec<_>>();
     while let Some(entry) = stack.pop() {
         let path = entry.path();
         if entry.file_type().unwrap().is_dir() {
             stack.extend(path.read_dir().unwrap().map(|e| e.unwrap()));
         } else {
             println!("cargo:rerun-if-changed={}", path.display());
         }
     }
 }

 /// Returns the last-modified time for `path`, or zero if it doesn't exist.
 pub fn mtime(path: &Path) -> SystemTime {
     fs::metadata(path)
         .and_then(|f| f.modified())
         .unwrap_or(UNIX_EPOCH)
 }

 /// Returns whether `dst` is up to date given that the file or files in `src`
 /// are used to generate it.
 ///
 /// Uses last-modified time checks to verify this.
 pub fn up_to_date(src: &Path, dst: &Path) -> bool {
     if !dst.exists() {
         return false;
     }
     let threshold = mtime(dst);
     let meta = match fs::metadata(src) {
         Ok(meta) => meta,
         Err(e) => panic!("source {:?} failed to get metadata: {}", src, e),
     };
     if meta.is_dir() {
         dir_up_to_date(src, threshold)
     } else {
         meta.modified().unwrap_or(UNIX_EPOCH) <= threshold
     }
 }

 #[must_use]
 pub struct NativeLibBoilerplate {
     pub src_dir: PathBuf,
     pub out_dir: PathBuf,
 }

 impl NativeLibBoilerplate {
     /// On OSX we don't want to ship the exact filename that compiler-rt builds.
     /// This conflicts with the system and ours is likely a wildly different
     /// version, so they can't be substituted.
     ///
     /// As a result, we rename it here but we need to also use
     /// `install_name_tool` on OSX to rename the commands listed inside of it to
     /// ensure it's linked against correctly.
     pub fn fixup_sanitizer_lib_name(&self, sanitizer_name: &str) {
         if env::var("TARGET").unwrap() != "x86_64-apple-darwin" {
             return
         }

         let dir = self.out_dir.join("build/lib/darwin");
         let name = format!("clang_rt.{}_osx_dynamic", sanitizer_name);
         let src = dir.join(&format!("lib{}.dylib", name));
         let new_name = format!("lib__rustc__{}.dylib", name);
         let dst = dir.join(&new_name);

         println!("{} => {}", src.display(), dst.display());
         fs::rename(&src, &dst).unwrap();
         let status = Command::new("install_name_tool")
             .arg("-id")
             .arg(format!("@rpath/{}", new_name))
             .arg(&dst)
             .status()
             .expect("failed to execute `install_name_tool`");
         assert!(status.success());
     }
 }

 impl Drop for NativeLibBoilerplate {
     fn drop(&mut self) {
         if !thread::panicking() {
             t!(File::create(self.out_dir.join("rustbuild.timestamp")));
         }
     }
 }

 // Perform standard preparations for native libraries that are build only once for all stages.
 // Emit rerun-if-changed and linking attributes for Cargo, check if any source files are
 // updated, calculate paths used later in actual build with CMake/make or C/C++ compiler.
 // If Err is returned, then everything is up-to-date and further build actions can be skipped.
 // Timestamps are created automatically when the result of `native_lib_boilerplate` goes out
 // of scope, so all the build actions should be completed until then.
 pub fn native_lib_boilerplate(
     src_dir: &Path,
     out_name: &str,
     link_name: &str,
     search_subdir: &str,
 ) -> Result<NativeLibBoilerplate, ()> {
     rerun_if_changed_anything_in_dir(src_dir);

     let out_dir = env::var_os("RUSTBUILD_NATIVE_DIR").unwrap_or_else(||
         env::var_os("OUT_DIR").unwrap());
     let out_dir = PathBuf::from(out_dir).join(out_name);
     t!(fs::create_dir_all(&out_dir));
     if link_name.contains('=') {
         println!("cargo:rustc-link-lib={}", link_name);
     } else {
         println!("cargo:rustc-link-lib=static={}", link_name);
     }
     println!(
         "cargo:rustc-link-search=native={}",
         out_dir.join(search_subdir).display()
     );

     let timestamp = out_dir.join("rustbuild.timestamp");
     if !up_to_date(Path::new("build.rs"), &timestamp) || !up_to_date(src_dir, &timestamp) {
         Ok(NativeLibBoilerplate {
             src_dir: src_dir.to_path_buf(),
             out_dir: out_dir,
         })
     } else {
         Err(())
     }
 }

 pub fn sanitizer_lib_boilerplate(sanitizer_name: &str)
     -> Result<(NativeLibBoilerplate, String), ()>
 {
     let (link_name, search_path, apple) = match &*env::var("TARGET").unwrap() {
         "x86_64-unknown-linux-gnu" => (
             format!("clang_rt.{}-x86_64", sanitizer_name),
             "build/lib/linux",
             false,
         ),
         "x86_64-apple-darwin" => (
             format!("clang_rt.{}_osx_dynamic", sanitizer_name),
             "build/lib/darwin",
             true,
         ),
         _ => return Err(()),
     };
     let to_link = if apple {
         format!("dylib=__rustc__{}", link_name)
     } else {
         format!("static={}", link_name)
     };
     // The source for `compiler-rt` comes from the `compiler-builtins` crate, so
     // load our env var set by cargo to find the source code.
     let dir = env::var_os("DEP_COMPILER_RT_COMPILER_RT").unwrap();
     let lib = native_lib_boilerplate(
         dir.as_ref(),
         sanitizer_name,
         &to_link,
         search_path,
     )?;
     Ok((lib, link_name))
 }

 fn dir_up_to_date(src: &Path, threshold: SystemTime) -> bool {
     t!(fs::read_dir(src)).map(|e| t!(e)).all(|e| {
         let meta = t!(e.metadata());
         if meta.is_dir() {
             dir_up_to_date(&e.path(), threshold)
         } else {
             meta.modified().unwrap_or(UNIX_EPOCH) < threshold
         }
     })
 }

 fn fail(s: &str) -> ! {
     println!("\n\n{}\n\n", s);
     std::process::exit(1);
 }
	use std::fs::File;
	use std::path::{Path, PathBuf};
	use std::process::{Command, Stdio};
	use std::time::{SystemTime, UNIX_EPOCH};
	use std::{env, fs};
	use std::thread;

	/// A helper macro to `unwrap` a result except also print out details like:
	///
	/// * The file/line of the panic
	/// * The expression that failed
	/// * The error itself
	///
	/// This is currently used judiciously throughout the build system rather than
	/// using a `Result` with `try!`, but this may change one day...
	#[macro_export]
	macro_rules! t {
	($e:expr) => {
	match $e {
	Ok(e) => e,
	Err(e) => panic!("{} failed with {}", stringify!($e), e),
	}
	};
	}

	pub fn run(cmd: &mut Command) {
	println!("running: {:?}", cmd);
	run_silent(cmd);
	}

	pub fn run_silent(cmd: &mut Command) {
	if !try_run_silent(cmd) {
	std::process::exit(1);
	}
	}

	pub fn try_run_silent(cmd: &mut Command) -> bool {
	let status = match cmd.status() {
	Ok(status) => status,
	Err(e) => fail(&format!(
	"failed to execute command: {:?}\nerror: {}",
	cmd, e
	)),
	};
	if !status.success() {
	println!(
	"\n\ncommand did not execute successfully: {:?}\n\
	expected success, got: {}\n\n",
	cmd, status
	);
	}
	status.success()
	}

	pub fn run_suppressed(cmd: &mut Command) {
	if !try_run_suppressed(cmd) {
	std::process::exit(1);
	}
	}

	pub fn try_run_suppressed(cmd: &mut Command) -> bool {
	let output = match cmd.output() {
	Ok(status) => status,
	Err(e) => fail(&format!(
	"failed to execute command: {:?}\nerror: {}",
	cmd, e
	)),
	};
	if !output.status.success() {
	println!(
	"\n\ncommand did not execute successfully: {:?}\n\
	expected success, got: {}\n\n\
	stdout ----\n{}\n\
	stderr ----\n{}\n\n",
	cmd,
	output.status,
	String::from_utf8_lossy(&output.stdout),
	String::from_utf8_lossy(&output.stderr)
	);
	}
	output.status.success()
	}

	pub fn gnu_target(target: &str) -> &str {
	match target {
	"i686-pc-windows-msvc" => "i686-pc-win32",
	"x86_64-pc-windows-msvc" => "x86_64-pc-win32",
	"i686-pc-windows-gnu" => "i686-w64-mingw32",
	"x86_64-pc-windows-gnu" => "x86_64-w64-mingw32",
	s => s,
	}
	}

	pub fn make(host: &str) -> PathBuf {
	if host.contains("bitrig") \|\| host.contains("dragonfly") \|\| host.contains("freebsd")
	\|\| host.contains("netbsd") \|\| host.contains("openbsd")
	{
	PathBuf::from("gmake")
	} else {
	PathBuf::from("make")
	}
	}

	pub fn output(cmd: &mut Command) -> String {
	let output = match cmd.stderr(Stdio::inherit()).output() {
	Ok(status) => status,
	Err(e) => fail(&format!(
	"failed to execute command: {:?}\nerror: {}",
	cmd, e
	)),
	};
	if !output.status.success() {
	panic!(
	"command did not execute successfully: {:?}\n\
	expected success, got: {}",
	cmd, output.status
	);
	}
	String::from_utf8(output.stdout).unwrap()
	}

	pub fn rerun_if_changed_anything_in_dir(dir: &Path) {
	let mut stack = dir.read_dir()
	.unwrap()
	.map(\|e\| e.unwrap())
	.filter(\|e\| &*e.file_name() != ".git")
	.collect::<Vec<_>>();
	while let Some(entry) = stack.pop() {
	let path = entry.path();
	if entry.file_type().unwrap().is_dir() {
	stack.extend(path.read_dir().unwrap().map(\|e\| e.unwrap()));
	} else {
	println!("cargo:rerun-if-changed={}", path.display());
	}
	}
	}

	/// Returns the last-modified time for `path`, or zero if it doesn't exist.
	pub fn mtime(path: &Path) -> SystemTime {
	fs::metadata(path)
	.and_then(\|f\| f.modified())
	.unwrap_or(UNIX_EPOCH)
	}

	/// Returns whether `dst` is up to date given that the file or files in `src`
	/// are used to generate it.
	///
	/// Uses last-modified time checks to verify this.
	pub fn up_to_date(src: &Path, dst: &Path) -> bool {
	if !dst.exists() {
	return false;
	}
	let threshold = mtime(dst);
	let meta = match fs::metadata(src) {
	Ok(meta) => meta,
	Err(e) => panic!("source {:?} failed to get metadata: {}", src, e),
	};
	if meta.is_dir() {
	dir_up_to_date(src, threshold)
	} else {
	meta.modified().unwrap_or(UNIX_EPOCH) <= threshold
	}
	}

	#[must_use]
	pub struct NativeLibBoilerplate {
	pub src_dir: PathBuf,
	pub out_dir: PathBuf,
	}

	impl NativeLibBoilerplate {
	/// On OSX we don't want to ship the exact filename that compiler-rt builds.
	/// This conflicts with the system and ours is likely a wildly different
	/// version, so they can't be substituted.
	///
	/// As a result, we rename it here but we need to also use
	/// `install_name_tool` on OSX to rename the commands listed inside of it to
	/// ensure it's linked against correctly.
	pub fn fixup_sanitizer_lib_name(&self, sanitizer_name: &str) {
	if env::var("TARGET").unwrap() != "x86_64-apple-darwin" {
	return
	}

	let dir = self.out_dir.join("build/lib/darwin");
	let name = format!("clang_rt.{}_osx_dynamic", sanitizer_name);
	let src = dir.join(&format!("lib{}.dylib", name));
	let new_name = format!("lib__rustc__{}.dylib", name);
	let dst = dir.join(&new_name);

	println!("{} => {}", src.display(), dst.display());
	fs::rename(&src, &dst).unwrap();
	let status = Command::new("install_name_tool")
	.arg("-id")
	.arg(format!("@rpath/{}", new_name))
	.arg(&dst)
	.status()
	.expect("failed to execute `install_name_tool`");
	assert!(status.success());
	}
	}

	impl Drop for NativeLibBoilerplate {
	fn drop(&mut self) {
	if !thread::panicking() {
	t!(File::create(self.out_dir.join("rustbuild.timestamp")));
	}
	}
	}

	// Perform standard preparations for native libraries that are build only once for all stages.
	// Emit rerun-if-changed and linking attributes for Cargo, check if any source files are
	// updated, calculate paths used later in actual build with CMake/make or C/C++ compiler.
	// If Err is returned, then everything is up-to-date and further build actions can be skipped.
	// Timestamps are created automatically when the result of `native_lib_boilerplate` goes out
	// of scope, so all the build actions should be completed until then.
	pub fn native_lib_boilerplate(
	src_dir: &Path,
	out_name: &str,
	link_name: &str,
	search_subdir: &str,
	) -> Result<NativeLibBoilerplate, ()> {
	rerun_if_changed_anything_in_dir(src_dir);

	let out_dir = env::var_os("RUSTBUILD_NATIVE_DIR").unwrap_or_else(\|\|
	env::var_os("OUT_DIR").unwrap());
	let out_dir = PathBuf::from(out_dir).join(out_name);
	t!(fs::create_dir_all(&out_dir));
	if link_name.contains('=') {
	println!("cargo:rustc-link-lib={}", link_name);
	} else {
	println!("cargo:rustc-link-lib=static={}", link_name);
	}
	println!(
	"cargo:rustc-link-search=native={}",
	out_dir.join(search_subdir).display()
	);

	let timestamp = out_dir.join("rustbuild.timestamp");
	if !up_to_date(Path::new("build.rs"), &timestamp) \|\| !up_to_date(src_dir, &timestamp) {
	Ok(NativeLibBoilerplate {
	src_dir: src_dir.to_path_buf(),
	out_dir: out_dir,
	})
	} else {
	Err(())
	}
	}

	pub fn sanitizer_lib_boilerplate(sanitizer_name: &str)
	-> Result<(NativeLibBoilerplate, String), ()>
	{
	let (link_name, search_path, apple) = match &*env::var("TARGET").unwrap() {
	"x86_64-unknown-linux-gnu" => (
	format!("clang_rt.{}-x86_64", sanitizer_name),
	"build/lib/linux",
	false,
	),
	"x86_64-apple-darwin" => (
	format!("clang_rt.{}_osx_dynamic", sanitizer_name),
	"build/lib/darwin",
	true,
	),
	_ => return Err(()),
	};
	let to_link = if apple {
	format!("dylib=__rustc__{}", link_name)
	} else {
	format!("static={}", link_name)
	};
	// The source for `compiler-rt` comes from the `compiler-builtins` crate, so
	// load our env var set by cargo to find the source code.
	let dir = env::var_os("DEP_COMPILER_RT_COMPILER_RT").unwrap();
	let lib = native_lib_boilerplate(
	dir.as_ref(),
	sanitizer_name,
	&to_link,
	search_path,
	)?;
	Ok((lib, link_name))
	}

	fn dir_up_to_date(src: &Path, threshold: SystemTime) -> bool {
	t!(fs::read_dir(src)).map(\|e\| t!(e)).all(\|e\| {
	let meta = t!(e.metadata());
	if meta.is_dir() {
	dir_up_to_date(&e.path(), threshold)
	} else {
	meta.modified().unwrap_or(UNIX_EPOCH) < threshold
	}
	})
	}

	fn fail(s: &str) -> ! {
	println!("\n\n{}\n\n", s);
	std::process::exit(1);
	}