JSON output for index entries (#293)

Mainly intended for seeing all the values, at the cost of readability.

git-repository/Cargo.toml

@@ -15,7 +15,7 @@ test = true
 [features]
 default = ["max-performance", "one-stop-shop"]
 unstable = ["git-index"]
-serde1 = ["git-pack/serde1", "git-object/serde1", "git-protocol/serde1", "git-transport/serde1", "git-ref/serde1", "git-odb/serde1"]
+serde1 = ["git-pack/serde1", "git-object/serde1", "git-protocol/serde1", "git-transport/serde1", "git-ref/serde1", "git-odb/serde1", "git-index/serde1"]
 # enable when https://github.com/RustCrypto/asm-hashes/issues/17 is fixed
 # max-performance = ["git-features/parallel", "git-features/zlib-ng-compat", "git-features/fast-sha1"]
 max-performance = ["git-features/parallel", "git-features/zlib-ng-compat", "git-pack/pack-cache-lru-static", "git-pack/pack-cache-lru-dynamic"]

gitoxide-core/src/index.rs

@@ -1,38 +1,105 @@
 use git_repository as git;
+use git_repository::bstr::ByteSlice;
+use std::io::Write;
 use std::path::Path;
 
+pub mod entries {
+    use git_repository as git;
+
+    pub struct Options {
+        pub object_hash: git::hash::Kind,
+        pub format: crate::OutputFormat,
+    }
+}
+
 #[allow(unused)]
 pub fn entries(
     index_path: impl AsRef<Path>,
     mut out: impl std::io::Write,
-    object_hash: git::hash::Kind,
+    entries::Options { object_hash, format }: entries::Options,
 ) -> anyhow::Result<()> {
+    use crate::OutputFormat::*;
     let file = git::index::File::at(
         index_path.as_ref(),
         git::index::decode::Options {
             object_hash,
             ..Default::default()
         },
     )?;
-    for entry in file.entries() {
-        writeln!(
-            out,
-            "{} {}{:?} {} {}",
-            match entry.flags.stage() {
-                0 => "BASE   ",
-                1 => "OURS   ",
-                2 => "THEIRS ",
-                _ => "UNKNOWN",
-            },
-            if entry.flags.is_empty() {
-                "".to_string()
-            } else {
-                format!("{:?} ", entry.flags)
-            },
-            entry.mode,
-            entry.id,
-            entry.path(&file.state)
-        )?;
+
+    #[cfg(feature = "serde1")]
+    if let Json = format {
+        out.write_all(b"[\n")?;
+    }
+
+    let mut entries = file.entries().iter().peekable();
+    while let Some(entry) = entries.next() {
+        match format {
+            Human => human_entry(&mut out, &file, entry)?,
+            #[cfg(feature = "serde1")]
+            Json => json_entry_oneline(&mut out, &file, entry, entries.peek().is_none())?,
+        }
+    }
+
+    #[cfg(feature = "serde1")]
+    if let Json = format {
+        out.write_all(b"]\n")?;
     }
     Ok(())
 }
+
+#[cfg(feature = "serde1")]
+fn json_entry_oneline(
+    mut out: &mut impl Write,
+    file: &git::index::File,
+    entry: &git::index::Entry,
+    is_last: bool,
+) -> anyhow::Result<()> {
+    #[cfg_attr(feature = "serde1", derive(serde::Serialize))]
+    struct Entry<'a> {
+        stat: &'a git::index::entry::Stat,
+        hex_id: String,
+        flags: u32,
+        mode: u32,
+        path: std::borrow::Cow<'a, str>,
+    }
+
+    serde_json::to_writer(
+        &mut out,
+        &Entry {
+            stat: &entry.stat,
+            hex_id: entry.id.to_hex().to_string(),
+            flags: entry.flags.bits(),
+            mode: entry.mode.bits(),
+            path: entry.path(&file.state).to_str_lossy(),
+        },
+    )?;
+
+    if is_last {
+        out.write_all(b"\n")?;
+    } else {
+        out.write_all(b",\n")?;
+    }
+    Ok(())
+}
+
+fn human_entry(out: &mut impl Write, file: &git::index::File, entry: &git::index::Entry) -> std::io::Result<()> {
+    writeln!(
+        out,
+        "{} {}{:?} {} {}",
+        match entry.flags.stage() {
+            0 => "BASE   ",
+            1 => "OURS   ",
+            2 => "THEIRS ",
+            _ => "UNKNOWN",
+        },
+        if entry.flags.is_empty() {
+            "".to_string()
+        } else {
+            format!("{:?} ", entry.flags)
+        },
+        entry.mode,
+        entry.id,
+        entry.path(&file.state)
+    )
+}

src/plumbing/main.rs

@@ -84,7 +84,9 @@ pub fn main() -> Result<()> {
                 progress,
                 progress_keep_open,
                 None,
-                move |_progress, out, _err| core::index::entries(index_path, out, object_hash),
+                move |_progress, out, _err| {
+                    core::index::entries(index_path, out, core::index::entries::Options { object_hash, format })
+                },
             ),
         },
         Subcommands::Repository(subcommands) => match subcommands {