index: move code operating git index into gitcompat::index

Reviewed By: vilatto

Differential Revision: D93046680

fbshipit-source-id: 9f1eb8643bfcf038e119baffe20b2684c79d8201

Author: taidaii

eden/scm/lib/gitcompat/src/index.rs

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+use std::io;
+use std::process::ExitStatus;
+
+use spawn_ext::CommandExt;
+use types::HgId;
+
+use crate::RepoGit;
+use crate::rungit::GitCmd;
+
+/// Convert `git diff-index --norenames --raw -z <tree-ish>` output
+/// into `git update-index -z --index-info` input.
+///
+/// diff-index entry format:
+///   `:<old_mode> <new_mode> <old_sha> <new_sha> <status>\0<path>\0`
+///
+/// See https://git-scm.com/docs/git-diff-index#_raw_output_format
+///
+/// `git update-index --index-info` format:
+///   `<old_mode> <old_sha> <stage>\t<path>\0`
+///
+/// See https://git-scm.com/docs/git-update-index#_using_index_info
+fn diff_index_to_index_info(raw: &[u8]) -> io::Result<Vec<u8>> {
+    let mut result = Vec::new();
+    let mut pos = 0;
+
+    let parse_err = |msg: &str| io::Error::new(io::ErrorKind::InvalidData, msg.to_owned());
+
+    while pos < raw.len() {
+        // Each entry starts with ':'
+        if raw[pos] != b':' {
+            return Err(parse_err("missing ':' at the beginning"));
+        }
+        pos += 1;
+
+        // Header ends at the first \0: "<old_mode> <new_mode> <old_sha> <new_sha> <status>"
+        let header_end = raw[pos..]
+            .iter()
+            .position(|&b| b == 0)
+            .ok_or_else(|| parse_err("no NUL in the entry"))?
+            + pos;
+
+        let header =
+            std::str::from_utf8(&raw[pos..header_end]).map_err(|e| parse_err(&e.to_string()))?;
+
+        // Split: old_mode, new_mode, old_sha, new_sha, status
+        let mut parts = header.splitn(5, ' ');
+        let old_mode = parts.next().ok_or_else(|| parse_err("missing old_mode"))?;
+        parts.next(); // new_mode
+        let old_sha = parts.next().ok_or_else(|| parse_err("missing old_sha"))?;
+        parts.next(); // new_sha
+        let status = parts.next().ok_or_else(|| parse_err("missing status"))?;
+
+        // Copy (C) and rename (R) should be opted out by the diff-index command.
+        // Copied and renamed files show up as addition (A) and deletion (D) instead.
+        // Unmerged (U) status should not show up as Sapling does not expose merge conflicts to Git.
+        match status {
+            "M" | "A" | "D" | "T" => {}
+            _ => {
+                return Err(parse_err(&format!(
+                    "unexpected diff-index status: {status}"
+                )));
+            }
+        }
+
+        // Remaining: \0<path>\0
+        pos = header_end + 1;
+        let path_end = raw[pos..]
+            .iter()
+            .position(|&b| b == 0)
+            .ok_or_else(|| parse_err("missing NUL after path"))?
+            + pos;
+        let path = &raw[pos..path_end];
+        pos = path_end + 1;
+
+        // <mode>SP<sha1>SP<stage>TAB<path>
+        result.extend_from_slice(old_mode.as_bytes());
+        result.push(b' ');
+        result.extend_from_slice(old_sha.as_bytes());
+        result.extend_from_slice(b" 0\t");
+        result.extend_from_slice(path);
+        result.push(b'\0');
+    }
+
+    Ok(result)
+}
+
+impl RepoGit {
+    /// Update git index for mutated paths compared to given commit.
+    /// Uses `--index-info` to avoid command-line argument length limits.
+    pub fn update_diff_index(&self, treeish: HgId) -> io::Result<ExitStatus> {
+        let hex = treeish.to_hex();
+        let output = self.call(
+            "diff-index",
+            &["--cached", "--no-renames", "--raw", "-z", &hex],
+        )?;
+
+        let index_info = diff_index_to_index_info(&output.stdout)?;
+
+        let mut cmd = self.git_cmd("update-index", &["-z", "--index-info"]);
+        cmd.checked_run_with_stdin(&index_info)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_diff_index_to_index_info() {
+        // Empty input
+        assert_eq!(diff_index_to_index_info(b"").unwrap(), b"");
+
+        let raw = b":100644 100644 aaaa bbbb M\0modifiedfile\0\
+                     :000000 100644 0000 bbbb A\0addedfile\0\
+                     :100755 000000 aaaa 0000 D\0deletedfile\0";
+        let out = diff_index_to_index_info(raw).unwrap();
+        assert_eq!(
+            out,
+            b"100644 aaaa 0\tmodifiedfile\0\
+              000000 0000 0\taddedfile\0\
+              100755 aaaa 0\tdeletedfile\0"
+        );
+    }
+
+    #[test]
+    fn test_diff_index_with_unexpected_status() {
+        let raw = b":000000 000000 0000 0000 U\0unmergedfile\0";
+        let err = diff_index_to_index_info(raw).unwrap_err();
+        assert_eq!(err.kind(), io::ErrorKind::InvalidData);
+        assert!(err.to_string().contains("unexpected diff-index status: U"));
+    }
+}

eden/scm/lib/gitcompat/src/lib.rs

@@ -57,6 +57,9 @@ pub mod rungit;
 /// Work with git references.
 mod refs;
 
+/// Work with the git index.
+mod index;
+
 /// Work with git configs.
 mod config;
 

eden/scm/lib/gitcompat/src/rungit.rs

@@ -19,7 +19,6 @@ use configmodel::Config;
 use configmodel::ConfigExt;
 use identity::dotgit::follow_dotgit_path;
 use spawn_ext::CommandExt;
-use types::HgId;
 
 /// Run `git` outside a repo.
 #[derive(Default, Clone)]
@@ -185,98 +184,6 @@ impl RepoGit {
     pub fn root(&self) -> &Path {
         &self.root
     }
-
-    /// Convert `git diff-index --norenames --raw -z <tree-ish>` output
-    /// into `git update-index -z --index-info` input.
-    ///
-    /// diff-index entry format:
-    ///   `:<old_mode> <new_mode> <old_sha> <new_sha> <status>\0<path>\0`
-    ///
-    /// See https://git-scm.com/docs/git-diff-index#_raw_output_format
-    ///
-    /// `git update-index --index-info` format:
-    ///   `<old_mode> <old_sha> <stage>\t<path>\0`
-    ///
-    /// See https://git-scm.com/docs/git-update-index#_using_index_info
-    fn diff_index_to_index_info(raw: &[u8]) -> io::Result<Vec<u8>> {
-        let mut result = Vec::new();
-        let mut pos = 0;
-
-        let parse_err = |msg: &str| io::Error::new(io::ErrorKind::InvalidData, msg.to_owned());
-
-        while pos < raw.len() {
-            // Each entry starts with ':'
-            if raw[pos] != b':' {
-                return Err(parse_err("missing ':' at the beginning"));
-            }
-            pos += 1;
-
-            // Header ends at the first \0: "<old_mode> <new_mode> <old_sha> <new_sha> <status>"
-            let header_end = raw[pos..]
-                .iter()
-                .position(|&b| b == 0)
-                .ok_or_else(|| parse_err("no NUL in the entry"))?
-                + pos;
-
-            let header = std::str::from_utf8(&raw[pos..header_end])
-                .map_err(|e| parse_err(&e.to_string()))?;
-
-            // Split: old_mode, new_mode, old_sha, new_sha, status
-            let mut parts = header.splitn(5, ' ');
-            let old_mode = parts.next().ok_or_else(|| parse_err("missing old_mode"))?;
-            parts.next(); // new_mode
-            let old_sha = parts.next().ok_or_else(|| parse_err("missing old_sha"))?;
-            parts.next(); // new_sha
-            let status = parts.next().ok_or_else(|| parse_err("missing status"))?;
-
-            // Copy (C) and rename (R) should be opted out by the diff-index command.
-            // Copied and renamed files show up as addition (A) and deletion (D) instead.
-            // Unmerged (U) status should not show up as Sapling does not expose merge conflicts to Git.
-            match status {
-                "M" | "A" | "D" | "T" => {}
-                _ => {
-                    return Err(parse_err(&format!(
-                        "unexpected diff-index status: {status}"
-                    )));
-                }
-            }
-
-            // Remaining: \0<path>\0
-            pos = header_end + 1;
-            let path_end = raw[pos..]
-                .iter()
-                .position(|&b| b == 0)
-                .ok_or_else(|| parse_err("missing NUL after path"))?
-                + pos;
-            let path = &raw[pos..path_end];
-            pos = path_end + 1;
-
-            // <mode>SP<sha1>SP<stage>TAB<path>
-            result.extend_from_slice(old_mode.as_bytes());
-            result.push(b' ');
-            result.extend_from_slice(old_sha.as_bytes());
-            result.extend_from_slice(b" 0\t");
-            result.extend_from_slice(path);
-            result.push(b'\0');
-        }
-
-        Ok(result)
-    }
-
-    /// Update git index for mutated paths compared to given commit.
-    /// Uses `--index-info` to avoid command-line argument length limits.
-    pub fn update_diff_index(&self, treeish: HgId) -> io::Result<ExitStatus> {
-        let hex = treeish.to_hex();
-        let output = self.call(
-            "diff-index",
-            &["--cached", "--no-renames", "--raw", "-z", &hex],
-        )?;
-
-        let index_info = Self::diff_index_to_index_info(&output.stdout)?;
-
-        let mut cmd = self.git_cmd("update-index", &["-z", "--index-info"]);
-        cmd.checked_run_with_stdin(&index_info)
-    }
 }
 
 impl Deref for BareGit {
@@ -417,33 +324,3 @@ fn git_cmd_impl(
 
     cmd
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_diff_index_to_index_info() {
-        // Empty input
-        assert_eq!(RepoGit::diff_index_to_index_info(b"").unwrap(), b"");
-
-        let raw = b":100644 100644 aaaa bbbb M\0modifiedfile\0\
-                     :000000 100644 0000 bbbb A\0addedfile\0\
-                     :100755 000000 aaaa 0000 D\0deletedfile\0";
-        let out = RepoGit::diff_index_to_index_info(raw).unwrap();
-        assert_eq!(
-            out,
-            b"100644 aaaa 0\tmodifiedfile\0\
-              000000 0000 0\taddedfile\0\
-              100755 aaaa 0\tdeletedfile\0"
-        );
-    }
-
-    #[test]
-    fn test_diff_index_with_unexpected_status() {
-        let raw = b":000000 000000 0000 0000 U\0unmergedfile\0";
-        let err = RepoGit::diff_index_to_index_info(raw).unwrap_err();
-        assert_eq!(err.kind(), io::ErrorKind::InvalidData);
-        assert!(err.to_string().contains("unexpected diff-index status: U"));
-    }
-}