From 4d76163e6e7e25acadc320e77b2226a7c42ea5df Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sun, 7 Oct 2018 13:21:50 +0300
Subject: Refactor: how sha256 of a file is computed (simpler code)

---
 src/format.rs | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/src/format.rs b/src/format.rs
index 3ba85b9..a45eea9 100644
--- a/src/format.rs
+++ b/src/format.rs
@@ -5,6 +5,7 @@ use std::io;
 use std::fs;
 use std::os::unix::fs::PermissionsExt;
 use std::os::linux::fs::MetadataExt;
+use std::path::Path;
 use std::io::prelude::*;
 
 use walkdir::DirEntry;
@@ -101,30 +102,29 @@ pub fn group(e: &DirEntry) -> serde_yaml::Value {
 
 
 pub fn sha256(e: &DirEntry) -> serde_yaml::Value {
-    let mut ok = true;
-    let mut hasher = Hasher::new(Algorithm::SHA256);
-    if let Ok(file) = fs::File::open(e.path()) {
-        let mut reader = io::BufReader::new(file);
-        let mut buf = [0; 1024 * 1024];
-        let mut done = false;
-        while ok && !done{
-            if let Ok(n) = reader.read(&mut buf) {
-                if n == 0 {
-                    done = true;
-                } else if let Err(_) = hasher.write(&buf[0..n]) {
-                    ok = false;
-                }
-            } else {
-                ok = false;
-            }
-        }
+    if let Ok(digest) = sha256_file(e.path()) {
+        str_value(&digest)
     } else {
-        ok = false;
+        str_value("error reading file")
     }
-    if ok {
-        let digest = hasher.finish();
-        str_value(&hex::encode(digest))
-    } else {
-        str_value("can't read file")
+}
+
+
+fn sha256_file(filename: &Path) -> io::Result<String> {
+    let file = fs::File::open(filename)?;
+    let mut reader = io::BufReader::new(file);
+    let mut hasher = Hasher::new(Algorithm::SHA256);
+    let mut buf = [0; 1024 * 1024];
+    let mut done = false;
+    while !done {
+        let n = reader.read(&mut buf)?;
+        if n == 0 {
+            done = true;
+        } else {
+            hasher.write(&buf[0..n])?;
+        }
     }
+
+    let digest = hasher.finish();
+    Ok(hex::encode(digest))
 }
-- 
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