[commitgraph] Stub out commit-graph-verify plumbing command.

Commit graphs are optional, so commit-graph plumbing is guarded by a
`commitgraph` feature that is enabled by default.

gitoxide-core/Cargo.toml

@@ -28,3 +28,4 @@ anyhow = "1.0.31"
 quick-error = "2.0.0"
 bytesize = "1.0.1"
 serde_json = { version = "1.0.56", optional = true }
+git-commitgraph = { version = "^0.1.2", path = "../git-commitgraph" }

gitoxide-core/src/commitgraph/mod.rs

@@ -0,0 +1 @@
+pub mod verify;

gitoxide-core/src/commitgraph/verify.rs

@@ -0,0 +1,36 @@
+use anyhow::{Context as AnyhowContext, Result};
+use std::{io, path::Path};
+
+/// A general purpose context for many operations provided here
+pub struct Context<W1: io::Write, W2: io::Write> {
+    /// A stream to which to output operation results
+    pub out: W1,
+    /// A stream to which to errors
+    pub err: W2,
+}
+
+impl Default for Context<Vec<u8>, Vec<u8>> {
+    fn default() -> Self {
+        Context {
+            out: Vec::new(),
+            err: Vec::new(),
+        }
+    }
+}
+
+pub fn graph_or_file<W1, W2>(
+    path: impl AsRef<Path>,
+    Context {
+        out: mut _out,
+        err: mut _err,
+    }: Context<W1, W2>,
+) -> Result<()>
+where
+    W1: io::Write,
+    W2: io::Write,
+{
+    // TODO: Handle `path` being objects/info, objects/info/commit-graph,
+    //   or objects/info/commit-graphs/graph-xyz.graph.
+    let _g = git_commitgraph::Graph::from_info_dir(path).with_context(|| "Could not open commit graph")?;
+    Err(anyhow::Error::msg("not implemented"))
+}

gitoxide-core/src/lib.rs

@@ -37,6 +37,7 @@ impl FromStr for OutputFormat {
 mod protocol;
 pub use protocol::Protocol;
 
+pub mod commitgraph;
 pub mod pack;
 pub mod remote;
 pub mod repository;

src/plumbing/lean/main.rs

@@ -140,5 +140,17 @@ pub fn main() -> Result<()> {
             )
             .map(|_| ())
         }
+        SubCommands::CommitGraphVerify(CommitGraphVerify { path }) => {
+            use self::core::commitgraph::verify;
+
+            verify::graph_or_file(
+                path,
+                verify::Context {
+                    out: stdout(),
+                    err: stderr(),
+                },
+            )
+            .map(|_| ())
+        }
     }
 }

src/plumbing/lean/options.rs

@@ -32,6 +32,7 @@ pub enum SubCommands {
     IndexFromPack(IndexFromPack),
     RemoteRefList(RemoteRefList),
     PackReceive(PackReceive),
+    CommitGraphVerify(CommitGraphVerify),
 }
 
 /// Create an index from a packfile.
@@ -188,3 +189,11 @@ pub struct PackVerify {
     #[argh(positional)]
     pub path: PathBuf,
 }
+
+/// Verify a commit graph
+#[derive(FromArgs, PartialEq, Debug)]
+#[argh(subcommand, name = "commit-graph-verify")]
+pub struct CommitGraphVerify {
+    #[argh(positional)]
+    pub path: PathBuf,
+}

src/plumbing/pretty/main.rs

@@ -256,6 +256,17 @@ pub fn main() -> Result<()> {
             },
         )
         .map(|_| ()),
+        Subcommands::CommitGraphVerify { path } => prepare_and_run(
+            "commit-graph-verify",
+            verbose,
+            progress,
+            progress_keep_open,
+            None,
+            move |_progress, out, err| {
+                core::commitgraph::verify::graph_or_file(path, core::commitgraph::verify::Context { out, err })
+            },
+        )
+        .map(|_| ()),
     }?;
     Ok(())
 }

src/plumbing/pretty/options.rs

@@ -186,4 +186,12 @@ pub enum Subcommands {
         #[clap(parse(from_os_str))]
         path: PathBuf,
     },
+    /// Verify the integrity of a commit graph
+    #[clap(setting = AppSettings::ColoredHelp)]
+    #[clap(setting = AppSettings::DisableVersion)]
+    CommitGraphVerify {
+        /// The 'objects/info/' dir, 'objects/info/commit-graphs' dir, or 'objects/info/commit-graph' file to validate.
+        #[clap(parse(from_os_str))]
+        path: PathBuf,
+    },
 }