fix the default mtime when timestamps are not present

Author: maminrayej

lib/virtual-fs/src/webc_volume_fs.rs

@@ -4,7 +4,9 @@ use std::{
     path::{Path, PathBuf},
     pin::Pin,
     result::Result,
+    sync::OnceLock,
     task::Poll,
+    time::UNIX_EPOCH,
 };
 
 use futures::future::BoxFuture;
@@ -206,13 +208,9 @@ impl VirtualFile for File {
     }
 
     fn last_modified(&self) -> u64 {
-        self.timestamps.map(|t| t.modified()).unwrap_or_else(|| {
-            // HACK: timestamps are not present in webc v2, so we have to return
-            // a stub modified time. previously we used to just return 0, but that
-            // proved to cause problems with programs that interpret the value 0.
-            // to circumvent this problem, we decided to return a non-zero value.
-            std::time::UNIX_EPOCH.elapsed().unwrap().as_secs()
-        })
+        self.timestamps
+            .map(|t| t.modified())
+            .unwrap_or_else(|| get_modified(None))
     }
 
     fn created_time(&self) -> u64 {
@@ -295,17 +293,19 @@ impl AsyncWrite for File {
     }
 }
 
-fn compat_meta(meta: webc::compat::Metadata) -> Metadata {
-    // HACK: timestamps are not present in webc v2, so we have to return
-    // a stub modified time. previously we used to just return 0, but that
-    // proved to cause problems with programs that interpret the value 0.
-    // to circumvent this problem, we decided to return a non-zero value.
-    fn get_modified(timestamps: Option<webc::Timestamps>) -> u64 {
-        timestamps
-            .map(|t| t.modified())
-            .unwrap_or(std::time::UNIX_EPOCH.elapsed().unwrap().as_secs())
-    }
+// HACK: timestamps are not present in webc v2, so we have to return
+// a stub modified time. previously we used to just return 0, but that
+// proved to cause problems with programs that interpret the value 0.
+// to circumvent this problem, we decided to return a non-zero value.
+fn get_modified(timestamps: Option<webc::Timestamps>) -> u64 {
+    static DEFAULT: OnceLock<u64> = OnceLock::new();
 
+    timestamps
+        .map(|t| t.modified())
+        .unwrap_or(*DEFAULT.get_or_init(|| UNIX_EPOCH.elapsed().unwrap().as_secs()))
+}
+
+fn compat_meta(meta: webc::compat::Metadata) -> Metadata {
     match meta {
         webc::compat::Metadata::Dir { timestamps } => Metadata {
             ft: FileType {
@@ -437,6 +437,8 @@ mod tests {
             .unwrap()
             .map(|r| r.unwrap())
             .collect();
+
+        let modified = get_modified(None);
         let expected = vec![
             DirEntry {
                 path: "/lib/.DS_Store".into(),
@@ -447,7 +449,7 @@ mod tests {
                     },
                     accessed: 0,
                     created: 0,
-                    modified: 0,
+                    modified,
                     len: 6148,
                 }),
             },
@@ -460,7 +462,7 @@ mod tests {
                     },
                     accessed: 0,
                     created: 0,
-                    modified: 0,
+                    modified,
                     len: 0,
                 }),
             },
@@ -473,7 +475,7 @@ mod tests {
                     },
                     accessed: 0,
                     created: 0,
-                    modified: 0,
+                    modified,
                     len: 4694941,
                 }),
             },
@@ -486,7 +488,7 @@ mod tests {
                     },
                     accessed: 0,
                     created: 0,
-                    modified: 0,
+                    modified,
                     len: 0,
                 }),
             },
@@ -502,14 +504,15 @@ mod tests {
 
         let fs = WebcVolumeFileSystem::new(volume);
 
+        let modified = get_modified(None);
         let python_wasm = crate::Metadata {
             ft: crate::FileType {
                 file: true,
                 ..Default::default()
             },
             accessed: 0,
             created: 0,
-            modified: 0,
+            modified,
             len: 4694941,
         };
         assert_eq!(
@@ -535,7 +538,7 @@ mod tests {
                 },
                 accessed: 0,
                 created: 0,
-                modified: 0,
+                modified,
                 len: 0,
             },
         );