✨ Add custom impl Debug for MmapStats

arthurlm · Sep 18, 2023 · 20efa67 · 20efa67
1 parent a9dd3c2
commit 20efa67
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Showing 2 changed files with 42 additions and 14 deletions.
diff --git a/src/stats.rs b/src/stats.rs
@@ -1,4 +1,7 @@
-use std::sync::atomic::{AtomicU64, Ordering};
+use std::{
+    fmt,
+    sync::atomic::{AtomicU64, Ordering},
+};
 
 pub(crate) static COUNT_ACTIVE_SEGMENT: AtomicU64 = AtomicU64::new(0);
 pub(crate) static COUNT_FTRUNCATE_FAILED: AtomicU64 = AtomicU64::new(0);
@@ -9,9 +12,20 @@ pub(crate) static COUNT_MUNMAP_FAILED: AtomicU64 = AtomicU64::new(0);
 ///
 /// This stats can be useful to debug or to export in various monitoring
 /// systems.
-#[derive(Debug, Default)]
+#[derive(Default)]
 pub struct MmapStats;
 
+impl fmt::Debug for MmapStats {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("MmapStats")
+            .field("active", &self.active_segment())
+            .field("ftruncate_failed", &self.ftruncate_failed())
+            .field("map_failed", &self.map_failed())
+            .field("unmap_failed", &self.unmap_failed())
+            .finish()
+    }
+}
+
 impl MmapStats {
     /// Get number of current segment mounted by this library.
     ///

diff --git a/tests/test_stats.rs b/tests/test_stats.rs
@@ -2,20 +2,34 @@ use mmap_vec::{MmapStats, MmapVec};
 
 #[test]
 fn test_stats() {
-    assert_eq!(MmapStats.active_segment(), 0);
-    assert_eq!(MmapStats.ftruncate_failed(), 0);
-    assert_eq!(MmapStats.map_failed(), 0);
-    assert_eq!(MmapStats.unmap_failed(), 0);
+    let stats = MmapStats::default();
+
+    assert_eq!(stats.active_segment(), 0);
+    assert_eq!(stats.ftruncate_failed(), 0);
+    assert_eq!(stats.map_failed(), 0);
+    assert_eq!(stats.unmap_failed(), 0);
+    assert_eq!(
+        format!("{stats:?}"),
+        "MmapStats { active: 0, ftruncate_failed: 0, map_failed: 0, unmap_failed: 0 }"
+    );
 
     let v = MmapVec::<u8>::with_capacity(500).unwrap();
-    assert_eq!(MmapStats.active_segment(), 1);
-    assert_eq!(MmapStats.ftruncate_failed(), 0);
-    assert_eq!(MmapStats.map_failed(), 0);
-    assert_eq!(MmapStats.unmap_failed(), 0);
+    assert_eq!(stats.active_segment(), 1);
+    assert_eq!(stats.ftruncate_failed(), 0);
+    assert_eq!(stats.map_failed(), 0);
+    assert_eq!(stats.unmap_failed(), 0);
+    assert_eq!(
+        format!("{stats:?}"),
+        "MmapStats { active: 1, ftruncate_failed: 0, map_failed: 0, unmap_failed: 0 }"
+    );
 
     drop(v);
-    assert_eq!(MmapStats.active_segment(), 0);
-    assert_eq!(MmapStats.ftruncate_failed(), 0);
-    assert_eq!(MmapStats.map_failed(), 0);
-    assert_eq!(MmapStats.unmap_failed(), 0);
+    assert_eq!(stats.active_segment(), 0);
+    assert_eq!(stats.ftruncate_failed(), 0);
+    assert_eq!(stats.map_failed(), 0);
+    assert_eq!(stats.unmap_failed(), 0);
+    assert_eq!(
+        format!("{stats:?}"),
+        "MmapStats { active: 0, ftruncate_failed: 0, map_failed: 0, unmap_failed: 0 }"
+    );
 }