Merge branch 'checksum' into 'main'

Checksum

See merge request larswirzenius/summain!4

5 files changed, 47 insertions, 8 deletions

diff --git a/Cargo.toml b/Cargo.toml
index c634c79..73924e3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,9 +1,9 @@
 [package]
 name = "summain"
-version = "0.1.0"
+version = "0.2.0"
 description = "File manifests"
 readme = "README.md"
-license = "GPL-3-or-latergbc"
+license = "GPL-3.0-or-later"
 authors = ["Lars Wirzenius <liw@liw.fi>"]
 edition = "2018"
 
@@ -11,7 +11,9 @@ edition = "2018"
 
 [dependencies]
 anyhow = "1"
+digest = "0.9"
 serde = { version = "1", features = ["derive"] }
 serde_yaml = "0.8"
+sha2 = "0.9"
 structopt = "0.3"
 unix_mode = "0.1"
diff --git a/src/bin/summain.rs b/src/bin/summain.rs
index 056bc8b..0abe2f5 100644
--- a/src/bin/summain.rs
+++ b/src/bin/summain.rs
@@ -1,5 +1,4 @@
 use anyhow::Context;
-use std::fs::symlink_metadata;
 use std::path::{Path, PathBuf};
 use structopt::StructOpt;
 use summain::ManifestEntry;
@@ -20,8 +19,7 @@ struct Opt {
 }
 
 fn report(pathname: &Path) -> anyhow::Result<()> {
-    let m = symlink_metadata(pathname)?;
-    let e = ManifestEntry::new(pathname, m);
+    let e = ManifestEntry::new(pathname)?;
     println!("{}", serde_yaml::to_string(&e)?);
     Ok(())
 }
diff --git a/src/lib.rs b/src/lib.rs
index eacce62..9f46f54 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -32,10 +32,15 @@
 //! ~~~
 
 use serde::Serialize;
-use std::fs::Metadata;
+use sha2::{Digest, Sha256};
+use std::fs::symlink_metadata;
+use std::fs::File;
+use std::io::{BufReader, Read};
 use std::os::linux::fs::MetadataExt;
 use std::path::{Path, PathBuf};
 
+const BUF_SIZE: usize = 1024 * 1024;
+
 /// An entry in a file manifest.
 #[derive(Serialize, Debug)]
 pub struct ManifestEntry {
@@ -48,6 +53,7 @@ pub struct ManifestEntry {
     mtime_nsec: i64,
     nlink: u64,
     size: Option<u64>,
+    sha256: Option<String>,
 }
 
 impl ManifestEntry {
@@ -57,8 +63,14 @@ impl ManifestEntry {
     /// caller. This function doesn't query the system for it.
     ///
     /// The structure can be serialized using serde.
-    pub fn new(path: &Path, m: Metadata) -> Self {
-        Self {
+    pub fn new(path: &Path) -> std::io::Result<Self> {
+        let m = symlink_metadata(path)?;
+        let hash = if m.is_file() {
+            Some(file_checksum(path)?)
+        } else {
+            None
+        };
+        Ok(Self {
             path: path.to_path_buf(),
             atime: m.st_atime(),
             atime_nsec: m.st_atime_nsec(),
@@ -67,8 +79,26 @@ impl ManifestEntry {
             mtime_nsec: m.st_mtime_nsec(),
             nlink: m.st_nlink(),
             size: if m.is_dir() { None } else { Some(m.st_size()) },
+            sha256: hash,
+        })
+    }
+}
+
+fn file_checksum(path: &Path) -> std::io::Result<String> {
+    let mut hasher = Sha256::new();
+
+    let file = File::open(path)?;
+    let mut reader = BufReader::new(file);
+    let mut buf = vec![0; BUF_SIZE];
+    loop {
+        let n = reader.read(&mut buf)?;
+        if n == 0 {
+            break;
         }
+        hasher.update(&buf[..n]);
     }
+    let hash = hasher.finalize();
+    Ok(format!("{:x}", hash))
 }
 
 mod mode {
diff --git a/subplot/summain.py b/subplot/summain.py
index 3ea6188..98eecf2 100644
--- a/subplot/summain.py
+++ b/subplot/summain.py
@@ -1,3 +1,4 @@
+import logging
 import os
 
 
@@ -33,4 +34,7 @@ def output_matches_file(ctx, filename=None):
 
     actual = runcmd_get_stdout(ctx)
     expected = get_file(filename).decode("UTF-8")
+    logging.debug("output_matches:")
+    logging.debug(f"  actual: {actual!r}")
+    logging.debug(f"  expect: {expected!r}")
     assert_eq(actual, expected)
diff --git a/summain.md b/summain.md
index 7c2c5fa..e6a4d15 100644
--- a/summain.md
+++ b/summain.md
@@ -87,6 +87,7 @@ mtime: 456
 mtime_nsec: 0
 nlink: 2
 size: ~
+sha256: ~
 ```
 
 ## Writeable file
@@ -112,6 +113,7 @@ mtime: 22
 mtime_nsec: 0
 nlink: 1
 size: 0
+sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 ```
 
 ## Read-only file
@@ -136,6 +138,7 @@ mtime: 44
 mtime_nsec: 0
 nlink: 1
 size: 0
+sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 ```
 
 ## Two files sorted
@@ -163,6 +166,7 @@ mtime: 44
 mtime_nsec: 0
 nlink: 1
 size: 0
+sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 ---
 path: bbb
 atime: 33
@@ -172,6 +176,7 @@ mtime: 44
 mtime_nsec: 0
 nlink: 1
 size: 0
+sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
 ```
 
 ---