add ability to check whether a preview is outdated

2 files changed, 10 insertions, 1 deletions

diff --git a/src/preview/preview_default.rs b/src/preview/preview_default.rs
index 8a216c9..bb5ea64 100644
--- a/src/preview/preview_default.rs
+++ b/src/preview/preview_default.rs
@@ -23,7 +23,12 @@ pub fn load_preview_path(context: &mut AppContext, p: path::PathBuf, metadata: J
         let need_to_load = context
             .preview_context_ref()
             .get_preview_ref(p.as_path())
-            .is_none();
+            .map(|p| {
+                p.as_ref()
+                    .map(|p| p.modified < metadata.modified())
+                    .unwrap_or(true)
+            })
+            .unwrap_or(true);
 
         if need_to_load {
             preview_file::Background::preview_path_with_script(context, p);
diff --git a/src/preview/preview_file.rs b/src/preview/preview_file.rs
index dac3ad2..f929b2e 100644
--- a/src/preview/preview_file.rs
+++ b/src/preview/preview_file.rs
@@ -1,6 +1,7 @@
 use std::path;
 use std::process::{Command, Output};
 use std::thread;
+use std::time;
 
 use crate::context::AppContext;
 use crate::event::AppEvent;
@@ -10,6 +11,7 @@ pub struct FilePreview {
     pub status: std::process::ExitStatus,
     pub output: String,
     pub index: usize,
+    pub modified: time::SystemTime,
 }
 
 impl std::convert::From<Output> for FilePreview {
@@ -17,9 +19,11 @@ impl std::convert::From<Output> for FilePreview {
         let s = String::from_utf8_lossy(&output.stdout).to_string();
         let s2 = s.replace('\t', "        ");
         let status = output.status;
+        let modified = time::SystemTime::now();
         Self {
             status,
             output: s2,
+            modified,
             index: 0,
         }
     }