substrate_build_script_utils/
git.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// 	http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
17
18use std::{
19	env, fs,
20	fs::File,
21	io,
22	io::Read,
23	path::{Path, PathBuf},
24};
25
26/// Make sure the calling `build.rs` script is rerun when `.git/HEAD` or the ref of `.git/HEAD`
27/// changed.
28///
29/// The file is searched from the `CARGO_MANIFEST_DIR` upwards. If the file can not be found,
30/// a warning is generated.
31pub fn rerun_if_git_head_changed() {
32	let mut manifest_dir = PathBuf::from(
33		env::var("CARGO_MANIFEST_DIR").expect("`CARGO_MANIFEST_DIR` is always set by cargo."),
34	);
35	let manifest_dir_copy = manifest_dir.clone();
36
37	while manifest_dir.parent().is_some() {
38		match get_git_paths(&manifest_dir) {
39			Err(err) => {
40				eprintln!("cargo:warning=Unable to read the Git repository: {}", err);
41
42				return
43			},
44			Ok(None) => {},
45			Ok(Some(paths)) => {
46				for p in paths {
47					println!("cargo:rerun-if-changed={}", p.display());
48				}
49
50				return
51			},
52		}
53
54		manifest_dir.pop();
55	}
56
57	println!(
58		"cargo:warning=Could not find `.git/HEAD` searching from `{}` upwards!",
59		manifest_dir_copy.display(),
60	);
61}
62
63// Code taken from https://github.com/rustyhorde/vergen/blob/8d522db8c8e16e26c0fc9ea8e6b0247cbf5cca84/src/output/envvar.rs
64fn get_git_paths(path: &Path) -> Result<Option<Vec<PathBuf>>, io::Error> {
65	let git_dir_or_file = path.join(".git");
66
67	if let Ok(metadata) = fs::metadata(&git_dir_or_file) {
68		if metadata.is_dir() {
69			// Echo the HEAD path
70			let git_head_path = git_dir_or_file.join("HEAD");
71
72			// Determine where HEAD points and echo that path also.
73			let mut f = File::open(&git_head_path)?;
74			let mut git_head_contents = String::new();
75			let _ = f.read_to_string(&mut git_head_contents)?;
76			let ref_vec: Vec<&str> = git_head_contents.split(": ").collect();
77
78			if ref_vec.len() == 2 {
79				let current_head_file = ref_vec[1];
80				let git_refs_path = git_dir_or_file.join(current_head_file);
81
82				Ok(Some(vec![git_head_path, git_refs_path]))
83			} else {
84				Err(io::Error::new(
85					io::ErrorKind::Other,
86					"You are most likely in a detached HEAD state",
87				))
88			}
89		} else if metadata.is_file() {
90			// We are in a worktree, so find out where the actual worktrees/<name>/HEAD file is.
91			let mut git_file = File::open(&git_dir_or_file)?;
92			let mut git_contents = String::new();
93			let _ = git_file.read_to_string(&mut git_contents)?;
94			let dir_vec: Vec<&str> = git_contents.split(": ").collect();
95			let git_path = dir_vec[1].trim();
96
97			// Echo the HEAD psth
98			let git_head_path = PathBuf::from(git_path).join("HEAD");
99
100			// Find out what the full path to the .git dir is.
101			let mut actual_git_dir = PathBuf::from(git_path);
102			actual_git_dir.pop();
103			actual_git_dir.pop();
104
105			// Determine where HEAD points and echo that path also.
106			let mut f = File::open(&git_head_path)?;
107			let mut git_head_contents = String::new();
108			let _ = f.read_to_string(&mut git_head_contents)?;
109			let ref_vec: Vec<&str> = git_head_contents.split(": ").collect();
110
111			if ref_vec.len() == 2 {
112				let current_head_file = ref_vec[1];
113				let git_refs_path = actual_git_dir.join(current_head_file);
114
115				Ok(Some(vec![git_head_path, git_refs_path]))
116			} else {
117				Err(io::Error::new(
118					io::ErrorKind::Other,
119					"You are most likely in a detached HEAD state",
120				))
121			}
122		} else {
123			Err(io::Error::new(
124				io::ErrorKind::Other,
125				"Invalid .git format (Not a directory or a file)",
126			))
127		}
128	} else {
129		Ok(None)
130	}
131}
substrate_build_script_utils/git.rs

substrate_build_script_utils/
git.rs
