Compute git statuses using the bundled git executable, not libgit2 (#12444)

I realized that somehow, the `git` executable is able to compute `git
status` much more quickly than libgit2, so I've switched our git status
logic to use `git`. Follow-up to
https://github.com/zed-industries/zed/pull/12266.

Release Notes:

- Improved the performance of git status updated when working in large
git repositories.

crates/git/src/status.rs

@@ -0,0 +1,99 @@
+use crate::repository::{GitFileStatus, RepoPath};
+use anyhow::{anyhow, Result};
+use std::{
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+    sync::Arc,
+};
+
+#[derive(Clone)]
+pub struct GitStatus {
+    pub entries: Arc<[(RepoPath, GitFileStatus)]>,
+}
+
+impl GitStatus {
+    pub(crate) fn new(
+        git_binary: &Path,
+        working_directory: &Path,
+        mut path_prefix: &Path,
+    ) -> Result<Self> {
+        let mut child = Command::new(git_binary);
+
+        if path_prefix == Path::new("") {
+            path_prefix = Path::new(".");
+        }
+
+        child
+            .current_dir(working_directory)
+            .args([
+                "--no-optional-locks",
+                "status",
+                "--porcelain=v1",
+                "--untracked-files=all",
+                "-z",
+            ])
+            .arg(path_prefix)
+            .stdin(Stdio::null())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped());
+
+        #[cfg(windows)]
+        {
+            use std::os::windows::process::CommandExt;
+            child.creation_flags(windows::Win32::System::Threading::CREATE_NO_WINDOW.0);
+        }
+
+        let child = child
+            .spawn()
+            .map_err(|e| anyhow!("Failed to start git status process: {}", e))?;
+
+        let output = child
+            .wait_with_output()
+            .map_err(|e| anyhow!("Failed to read git blame output: {}", e))?;
+
+        if !output.status.success() {
+            let stderr = String::from_utf8_lossy(&output.stderr);
+            return Err(anyhow!("git status process failed: {}", stderr));
+        }
+
+        let stdout = String::from_utf8_lossy(&output.stdout);
+        let mut entries = stdout
+            .split('\0')
+            .filter_map(|entry| {
+                if entry.is_char_boundary(3) {
+                    let (status, path) = entry.split_at(3);
+                    let status = status.trim();
+                    Some((
+                        RepoPath(PathBuf::from(path)),
+                        match status {
+                            "A" | "??" => GitFileStatus::Added,
+                            "M" => GitFileStatus::Modified,
+                            _ => return None,
+                        },
+                    ))
+                } else {
+                    None
+                }
+            })
+            .collect::<Vec<_>>();
+        entries.sort_unstable_by(|a, b| a.0.cmp(&b.0));
+        Ok(Self {
+            entries: entries.into(),
+        })
+    }
+
+    pub fn get(&self, path: &Path) -> Option<GitFileStatus> {
+        self.entries
+            .binary_search_by(|(repo_path, _)| repo_path.0.as_path().cmp(path))
+            .ok()
+            .map(|index| self.entries[index].1)
+    }
+}
+
+impl Default for GitStatus {
+    fn default() -> Self {
+        Self {
+            entries: Arc::new([]),
+        }
+    }
+}