Suggestion.diff_command: Return the right side version blob

Don't run the `git diff` command in this function, instead return the
new blob created for the right hand side of the comparison.

This will facilitate showing the diffs of multiple suggestions at once.
Maybe. I haven't tried the command yet.

Actually, looking at the man page, it doesn't say we can include more
than one blob pair, so I might need to put all of the suggestion changes
into a single blob and compare the original commit with that.

2 files changed, 19 insertions, 15 deletions

diff --git a/github-suggestion/src/suggestion.rs b/github-suggestion/src/suggestion.rs
index 3f124ce..21591b1 100644
--- a/github-suggestion/src/suggestion.rs
+++ b/github-suggestion/src/suggestion.rs
@@ -16,7 +16,6 @@
 
 use std::io::{BufRead, BufReader, BufWriter, Write};
 use std::path::Path;
-use std::process::Command;
 
 use git2::{Patch, Repository};
 use regex::Regex;
@@ -81,6 +80,14 @@ pub struct Suggestion {
 }
 
 impl Suggestion {
+    pub fn commit(&self) -> &str {
+        &self.commit
+    }
+
+    pub fn path(&self) -> &str {
+        &self.path
+    }
+
     /// Get the suggestion diff for the current repository.
     pub fn diff(&self) -> Result<String, Error> {
         let repo = Repository::open(".")?;
@@ -127,7 +134,7 @@ impl Suggestion {
         )
     }
 
-    pub fn diff_command(&self) -> Result<(), Error> {
+    pub fn diff_command(&self) -> Result<git2::Oid, Error> {
         let repo = Repository::open(".")?;
         let commit = repo.find_commit(self.commit.parse()?)?;
 
@@ -150,18 +157,7 @@ impl Suggestion {
                 message: "unable to read right side of patch".to_owned(),
             })?;
 
-        let patched_blob = repo.blob(&new_buffer)?;
-
-        Command::new("git")
-            .arg("diff")
-            .arg(format!("{}:{}", commit.id(), self.path))
-            .arg(patched_blob.to_string())
-            .spawn()
-            .unwrap();
-
-        // Maybe: Return blob
-
-        Ok(())
+        Ok(repo.blob(&new_buffer)?)
     }
 
     /// Extract suggestion code from a comment body.
diff --git a/src/bin/git-sugdiff.rs b/src/bin/git-sugdiff.rs
index c8ecf40..9c7ff1f 100644
--- a/src/bin/git-sugdiff.rs
+++ b/src/bin/git-sugdiff.rs
@@ -16,6 +16,7 @@
 
 use std::env;
 use std::process;
+use std::process::Command;
 
 use exitcode;
 
@@ -42,7 +43,14 @@ fn main() {
         &config,
         |suggestion| {
             // TODO: Needs to work for multiple suggestions at once
-            suggestion.diff_command().unwrap();
+            let blob = suggestion.diff_command().unwrap();
+
+            Command::new("git")
+                .arg("diff")
+                .arg(format!("{}:{}", suggestion.commit(), suggestion.path()))
+                .arg(blob.to_string())
+                .spawn()
+                .unwrap();
         },
     );
 }