[commitgraph] Implement commit-graph-verify plumbing command.

git-commitgraph/Cargo.toml

@@ -12,15 +12,18 @@ include = ["src/**/*"]
 [lib]
 doctest = false
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[features]
+serde1 = ["serde", "git-object/serde1"]
 
 [dependencies]
+git-features = { version = "^0.6.0", path = "../git-features" }
 git-object = { version = "^0.4.0", path = "../git-object" }
 
 bstr = { version = "0.2.13", default-features = false, features = ["std"] }
 byteorder = "1.2.3"
 filebuffer = "0.4.0"
-quick-error = "2.0.0"
+serde = { version = "1.0.114", optional = true, default-features = false, features = ["derive"] }
+thiserror = "1.0.20"
 
 [dev-dependencies]
 tempfile = "3.1.0"

git-commitgraph/src/file/access.rs

@@ -8,6 +8,10 @@ use std::{
 
 /// Access
 impl File {
+    pub fn base_graph_count(&self) -> u8 {
+        self.base_graph_count
+    }
+
     /// Returns the commit data for the commit located at the given lexigraphical position.
     ///
     /// `pos` must range from 0 to self.num_commits().
@@ -42,12 +46,10 @@ impl File {
     }
 
     pub fn iter_base_graph_ids(&self) -> impl Iterator<Item = borrowed::Id<'_>> {
-        let base_graphs_list = match self.base_graphs_list_offset {
-            Some(v) => &self.data[v..v + (SHA1_SIZE * self.base_graph_count as usize)],
-            None => &[],
-        };
+        let start = self.base_graphs_list_offset.unwrap_or(0);
+        let base_graphs_list = &self.data[start..start + (SHA1_SIZE * usize::from(self.base_graph_count))];
         base_graphs_list
-            .chunks_exact(SHA1_SIZE)
+            .chunks(SHA1_SIZE)
             .map(|bytes| borrowed::Id::try_from(bytes).expect("20 bytes SHA1 to be alright"))
     }
 
@@ -61,7 +63,7 @@ impl File {
 
     // copied from git-odb/src/pack/index/access.rs
     pub fn lookup(&self, id: borrowed::Id<'_>) -> Option<file::Position> {
-        let first_byte = id.first_byte() as usize;
+        let first_byte = usize::from(id.first_byte());
         let mut upper_bound = self.fan[first_byte];
         let mut lower_bound = if first_byte != 0 { self.fan[first_byte - 1] } else { 0 };
 

git-commitgraph/src/file/commit.rs

@@ -4,38 +4,22 @@ use crate::{
 };
 use byteorder::{BigEndian, ByteOrder};
 use git_object::{borrowed, owned, SHA1_SIZE};
-use quick_error::quick_error;
 use std::{
     convert::{TryFrom, TryInto},
     fmt::{Debug, Formatter},
     slice::Chunks,
 };
 
-quick_error! {
-    #[derive(Debug)]
-    pub enum Error {
-        ExtraEdgesListOverflow(commit: owned::Id) {
-            display(
-                "commit {}'s extra edges overflows the commit-graph file's extra edges list",
-                commit,
-            )
-        }
-        FirstParentIsExtraEdgeIndex(commit: owned::Id) {
-            display(
-                "commit {}'s first parent is an extra edge index, which is invalid",
-                commit,
-            )
-        }
-        MissingExtraEdgesList(commit: owned::Id) {
-            display(
-                "commit {} has extra edges, but commit-graph file has no extra edges list",
-                commit,
-            )
-        }
-        SecondParentWithoutFirstParent(commit: owned::Id) {
-            display("commit {} has a second parent but not a first parent", commit)
-        }
-    }
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+    #[error("commit {0}'s extra edges overflows the commit-graph file's extra edges list")]
+    ExtraEdgesListOverflow(owned::Id),
+    #[error("commit {0}'s first parent is an extra edge index, which is invalid")]
+    FirstParentIsExtraEdgeIndex(owned::Id),
+    #[error("commit {0} has extra edges, but commit-graph file has no extra edges list")]
+    MissingExtraEdgesList(owned::Id),
+    #[error("commit {0} has a second parent but not a first parent")]
+    SecondParentWithoutFirstParent(owned::Id),
 }
 
 // Note that git's commit-graph-format.txt as of v2.28.0 gives an incorrect value 0x0700_0000 for
@@ -93,15 +77,29 @@ impl<'a> Commit<'a> {
         }
     }
 
-    pub fn id(&self) -> borrowed::Id<'_> {
+    // Allow the return value to outlive this Commit object, as it only needs to be bound by the
+    // lifetime of the parent file.
+    pub fn id<'b>(&'b self) -> borrowed::Id<'a>
+    where
+        'a: 'b,
+    {
         self.file.id_at(self.pos)
     }
 
     pub fn parent1(&self) -> Result<Option<graph::Position>, Error> {
         self.iter_parents().next().transpose()
     }
 
-    pub fn root_tree_id(&self) -> borrowed::Id<'_> {
+    pub fn position(&self) -> file::Position {
+        self.pos
+    }
+
+    // Allow the return value to outlive this Commit object, as it only needs to be bound by the
+    // lifetime of the parent file.
+    pub fn root_tree_id<'b>(&'b self) -> borrowed::Id<'a>
+    where
+        'a: 'b,
+    {
         self.root_tree_id
     }
 }