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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,108 @@ | ||
| use std::io::Write; | ||
| use std::path::{absolute, Path, PathBuf}; | ||
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| /// Fetch the contents of the given file, and also tell cargo that we looked | ||
| /// in there. | ||
| fn file_contents<P: AsRef<Path>>(path: P) -> String { | ||
| let path = | ||
| absolute(path.as_ref()).expect("Unable to make the path absolute"); | ||
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|
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| let mut stdout = std::io::stdout(); | ||
| stdout | ||
| .write_all(b"cargo::rerun-if-changed=") | ||
| .expect("Unable to write stdout"); | ||
| stdout | ||
| .write_all(path.as_os_str().as_encoded_bytes()) | ||
| .expect("Unable to write path to stdout"); | ||
| stdout | ||
| .write_all(b"\n") | ||
| .expect("Unable to write newline to stdout"); | ||
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| std::fs::read_to_string(path).expect("Unable to read file") | ||
| } | ||
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| /// Emit the current git commit. | ||
| fn emit_git_commit() { | ||
| // Fetch the current commit from the head. We do it this way instead of | ||
| // asking `git rev-parse` to do it for us because we want to reliably | ||
| // tell cargo which files it should monitor for changes. | ||
| let head = file_contents("./.git/HEAD"); | ||
| let rev = if let Some(r) = head.strip_prefix("ref: ") { | ||
| let mut ref_path = PathBuf::from("./.git/"); | ||
| ref_path.push(r.trim()); | ||
| file_contents(ref_path) | ||
| } else { | ||
| head | ||
| }; | ||
|
|
||
| // But *now* we ask git rev-parse to make this into a short hash (a) to | ||
| // make sure we got it right and (b) because git knows how to quickly | ||
| // determine how much of a commit is required to be unique. We don't need | ||
| // to tell cargo anything here, no file that git consults will be | ||
| // mutable. | ||
| let output = std::process::Command::new("git") | ||
| .arg("rev-parse") | ||
| .arg("--short") | ||
| .arg(rev.trim()) | ||
| .output() | ||
| .expect("could not spawn `git` to get the hash"); | ||
| if !output.status.success() { | ||
| let stderr = std::str::from_utf8(&output.stderr) | ||
| .expect("git failed and stderr was not utf8"); | ||
| eprintln!("`git rev-parse --short HEAD` failed, stderr: {stderr}"); | ||
| panic!("`git rev-parse --short HEAD` failed"); | ||
| } | ||
| let rev = | ||
| std::str::from_utf8(&output.stdout).expect("git did not output utf8"); | ||
|
|
||
| println!("cargo::rustc-env=REPO_REV={rev}"); | ||
| } | ||
|
|
||
| fn emit_git_dirty() { | ||
| // Here is the way to see if anything is up with the repository: run `git | ||
| // status --porcelain=v1`. The status output in the v1 porcelain format | ||
| // has one line for every file that's modified in some way: staged, | ||
| // changed but unstaged, untracked, you name it. Files in the working | ||
| // tree that are up to date with the repository are not emitted. This is | ||
| // exactly what we want. | ||
| // | ||
| // (Yes, I want to track untracked files, because they can mess with the | ||
| // build too. The only good build is a clean build!) | ||
| let output = std::process::Command::new("git") | ||
| .arg("status") | ||
| .arg("-z") | ||
| .arg("--porcelain=v1") | ||
| .output() | ||
| .expect("could not spawn `git` to get repository status"); | ||
| if !output.status.success() { | ||
| let stderr = std::str::from_utf8(&output.stderr) | ||
| .expect("git failed and stderr was not utf8"); | ||
| eprintln!("`git status` failed, stderr: {stderr}"); | ||
| panic!("`git status` failed"); | ||
| } | ||
| let output = | ||
| std::str::from_utf8(&output.stdout).expect("git did not output utf8"); | ||
|
|
||
| // If there *was* any output, parse it and tell cargo to re-run if any of | ||
| // these files changed. (Maybe they get reverted! Then the repo status | ||
| // will change.) | ||
| for line in output.lines() { | ||
| let fields: Vec<_> = line.split('\x00').collect(); | ||
| let parts: Vec<_> = fields[0].split(' ').collect(); | ||
| let path = parts[1]; | ||
| println!("cargo::rerun-if-changed={path}"); | ||
| } | ||
|
|
||
| // Emit the repository status. | ||
| let dirty = if output.trim().is_empty() { | ||
| "" | ||
| } else { | ||
| " *dirty*" | ||
| }; | ||
| println!("cargo::rustc-env=REPO_DIRTY={dirty}"); | ||
| } | ||
|
|
||
| fn main() { | ||
| emit_git_commit(); | ||
| emit_git_dirty(); | ||
| } |
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