file_sum small optimizations

(still a temporary implementation)

2 files changed, 39 insertions, 22 deletions

diff --git a/src/file_sum/mod.rs b/src/file_sum/mod.rs
index fa6eaf5..894f457 100644
--- a/src/file_sum/mod.rs
+++ b/src/file_sum/mod.rs
@@ -11,15 +11,13 @@ use {
     crate::task_sync::Dam,
     std::{
         collections::HashMap,
-        fs::Metadata,
         ops::AddAssign,
         path::{Path, PathBuf},
         sync::Mutex,
-        time::UNIX_EPOCH,
     },
 };
 
-const SUM_NAMES: &[&str] = &["", "K", "M", "G", "T", "P", "E", "Z", "Y"];
+const SIZE_NAMES: &[&str] = &["", "K", "M", "G", "T", "P", "E", "Z", "Y"];
 
 lazy_static! {
     static ref SUM_CACHE_MUTEX: Mutex<HashMap<PathBuf, FileSum>> = Mutex::new(HashMap::new());
@@ -30,19 +28,13 @@ pub fn clear_cache() {
     sum_cache.clear();
 }
 
-pub fn extract_seconds(md: &Metadata) -> u64 {
-    md.modified().map_or(
-        0,
-        |st| st.duration_since(UNIX_EPOCH).map_or(0, |d| d.as_secs())
-    )
-}
-
+/// Reduction of counts, dates and sizes on a file or directory
 #[derive(Debug, Copy, Clone)]
 pub struct FileSum {
-    real_size: u64,   // bytes, the space it takes on disk
-    sparse: bool, // only for non directories: tells whether the file is sparse
+    real_size: u64, // bytes, the space it takes on disk
     count: usize, // number of files
-    modified: u64, // seconds from Epoch to last modification, or 0 if there was an error
+    modified: u32, // seconds from Epoch to last modification, or 0 if there was an error
+    sparse: bool, // only for non directories: tells whether the file is sparse
 }
 
 impl FileSum {
@@ -50,7 +42,7 @@ impl FileSum {
         real_size: u64,
         sparse: bool,
         count: usize,
-        modified: u64,
+        modified: u32,
     ) -> Self {
         Self { real_size, sparse, count, modified }
     }
@@ -102,11 +94,11 @@ impl FileSum {
     pub fn to_size_string(self) -> String {
         let mut v = self.real_size;
         let mut i = 0;
-        while v >= 5000 && i < SUM_NAMES.len() - 1 {
+        while v >= 5000 && i < SIZE_NAMES.len() - 1 {
             v /= 1000;
             i += 1;
         }
-        format!("{}{}", v, &SUM_NAMES[i])
+        format!("{}{}", v, &SIZE_NAMES[i])
     }
     /// return the number of files (normally at least 1)
     pub fn to_count(self) -> usize {
@@ -114,7 +106,7 @@ impl FileSum {
     }
     /// return the number of seconds from Epoch to last modification,
     /// or 0 if the computation failed
-    pub fn to_seconds(self) -> u64 {
+    pub fn to_seconds(self) -> u32 {
         self.modified
     }
     /// return the size in bytes
diff --git a/src/file_sum/sum_computation.rs b/src/file_sum/sum_computation.rs
index 6e7a099..7e46ad2 100644
--- a/src/file_sum/sum_computation.rs
+++ b/src/file_sum/sum_computation.rs
@@ -1,23 +1,30 @@
 use {
-    super::{extract_seconds, FileSum},
+    super::FileSum,
     crate::task_sync::Dam,
     crossbeam::channel,
     std::{
-        collections::HashSet,
+        convert::TryInto,
         fs,
         path::{Path, PathBuf},
         sync::{
             atomic::{AtomicIsize, Ordering},
-            Arc, Mutex,
+            Arc,
         },
         thread,
+
     },
 };
 
 #[cfg(unix)]
-use std::os::unix::fs::MetadataExt;
+use {
+    std::{
+        collections::HashSet,
+        os::unix::fs::MetadataExt,
+        sync::Mutex,
+    },
+};
 
-const THREADS_COUNT: usize = 8;
+const THREADS_COUNT: usize = 4;
 
 /// compute the consolidated numbers for a directory, with implementation
 /// varying depending on the OS:
@@ -150,3 +157,21 @@ pub fn compute_file_sum(path: &Path) -> FileSum {
         Err(_) => FileSum::new(0, false, 1, 0),
     }
 }
+
+#[cfg(unix)]
+fn extract_seconds(md: &fs::Metadata) -> u32 {
+    md.mtime().try_into().unwrap_or(0)
+}
+
+#[cfg(not(unix))]
+fn extract_seconds(md: &fs::Metadata) -> u32 {
+    if let Ok(st) = md.modified() {
+        if let Ok(d) = st.duration_since(std::time::UNIX_EPOCH) {
+            if let Ok(secs) = d.as_secs().try_into() {
+                return secs
+            }
+        }
+    }
+    0
+}
+