save number of visible files instead of recalculating it every time

src/files.rs

@@ -103,6 +103,7 @@ pub fn tags_loaded() -> HResult<()> {
 pub struct RefreshPackage {
     pub new_files: Option<Vec<File>>,
     pub new_buffer: Option<Vec<String>>,
+    pub new_len: usize,
 }
 
 
@@ -187,6 +188,9 @@ impl RefreshPackage {
         // Finally add all new files
         files.files.extend(new_files);
 
+        // Files added, removed, renamed to hidden, etc...
+        files.recalculate_len();
+        let new_len = files.len();
         // Need to unpack this to prevent issue with recursive Files type
         // Also, if no files remain add placeholder
         let files = if files.len() > 0 {
@@ -222,6 +226,7 @@ impl RefreshPackage {
         RefreshPackage {
             new_files: Some(files),
             new_buffer: Some(new_buffer),
+            new_len: new_len
         }
     }
 }
@@ -232,6 +237,7 @@ impl RefreshPackage {
 pub struct Files {
     pub directory: File,
     pub files: Vec<File>,
+    pub len: usize,
     #[derivative(Debug="ignore")]
     #[derivative(PartialEq="ignore")]
     #[derivative(Hash="ignore")]
@@ -273,11 +279,33 @@ impl Dirtyable for Files {
     }
 }
 
+use std::default::Default;
+
+impl Default for Files {
+    fn default() -> Files {
+        Files {
+            directory: File::new_placeholder(Path::new("")).unwrap(),
+            files: vec![],
+            len: 0,
+            pending_events: Arc::new(RwLock::new(vec![])),
+            refresh: None,
+            meta_upto: None,
+            sort: SortBy::Name,
+            dirs_first: true,
+            reverse: false,
+            show_hidden: true,
+            filter: None,
+            filter_selected: false,
+            dirty: DirtyBit::new(),
+            dirty_meta: AsyncDirtyBit::new(),
+        }
+    }
+}
+
 
 impl Files {
     pub fn new_from_path(path: &Path) -> Result<Files, Error> {
         let direntries: Result<Vec<_>, _> = std::fs::read_dir(&path)?.collect();
-        let dirty = DirtyBit::new();
         let dirty_meta = AsyncDirtyBit::new();
 
         let files: Vec<_> = direntries?
@@ -292,30 +320,14 @@ impl Files {
             })
             .collect();
 
-        let mut files = Files {
-            directory: File::new_from_path(&path, None)?,
-            files: files,
-            pending_events: Arc::new(RwLock::new(vec![])),
-            refresh: None,
-            meta_upto: None,
-            sort: SortBy::Name,
-            dirs_first: true,
-            reverse: false,
-            show_hidden: true,
-            filter: None,
-            filter_selected: false,
-            dirty: dirty,
-            dirty_meta: dirty_meta,
-        };
+        let len = files.len();
 
-        files.sort();
+        let mut files = Files::default();
+        files.directory = File::new_from_path(&path, None)?;
+        files.len = len;
+        files.dirty_meta = dirty_meta;
 
 
-
-        if files.files.len() == 0 {
-            files.files = vec![File::new_placeholder(&path)?];
-        }
-
         Ok(files)
     }
 
@@ -351,9 +363,12 @@ impl Files {
             })?;
         }
 
-        let mut files = Files {
+        let len = files.len();
+
+        let files = Files {
             directory: File::new_from_path(&path, None)?,
             files: files,
+            len: len,
             pending_events: Arc::new(RwLock::new(vec![])),
             refresh: None,
             meta_upto: None,
@@ -367,15 +382,13 @@ impl Files {
             dirty_meta: dirty_meta,
         };
 
-        files.sort();
-
-        if files.files.len() == 0 {
-            files.files = vec![File::new_placeholder(&path)?];
-        }
-
         Ok(files)
     }
 
+    pub fn recalculate_len(&mut self) {
+        self.len = self.iter_files().count();
+    }
+
     pub fn get_file_mut(&mut self, index: usize) -> Option<&mut File> {
         self.iter_files_mut()
             .nth(index)
@@ -511,13 +524,19 @@ impl Files {
 
         if self.show_hidden == true && self.len() > 1 {
             self.remove_placeholder();
+        } else {
+            // avoid doing this twice, since remove_placeholder() does it too
+            self.recalculate_len();
         }
     }
 
     fn remove_placeholder(&mut self) {
         let dirpath = self.directory.path.clone();
         self.find_file_with_path(&dirpath).cloned()
-            .map(|placeholder| self.files.remove_item(&placeholder));
+            .map(|placeholder| {
+                self.files.remove_item(&placeholder);
+                self.recalculate_len();
+            });
     }
 
     pub fn ready_to_refresh(&self) -> HResult<bool> {
@@ -532,6 +551,9 @@ impl Files {
                 refresh.pull_async()?;
                 let mut refresh = refresh.value?;
                 self.files = refresh.new_files.take()?;
+                if refresh.new_len != self.len() {
+                    self.len = refresh.new_len;
+                }
                 return Ok(Some(refresh));
             } else {
                 self.refresh.replace(refresh);
@@ -658,6 +680,7 @@ impl Files {
         if self.len() == 0 {
             let placeholder = File::new_placeholder(&self.directory.path).unwrap();
             self.files.push(placeholder);
+            self.len = 1;
         }
 
         self.set_dirty();
@@ -672,7 +695,7 @@ impl Files {
     }
 
     pub fn len(&self) -> usize {
-        self.iter_files().count()
+        self.len
     }
 
     pub fn get_selected(&self) -> impl Iterator<Item=&File> {

src/fscache.rs

@@ -176,6 +176,7 @@ impl FsCache {
                 cache.fs_event_dispatcher.add_target(&dir,
                                                      &files.pending_events).log();
                 FsCache::apply_settingss(&cache, &mut files).ok();
+                files.sort();
                 Ok(files)
             });
             Ok((selection, files))
@@ -184,8 +185,7 @@ impl FsCache {
 
     pub fn get_files_sync(&self, dir: &File) -> HResult<Files> {
         let files = self.get_files(&dir, Stale::new())?.1;
-        let mut files = files.run_sync()?;
-        FsCache::apply_settingss(&self, &mut files).ok();
+        let files = files.run_sync()?;
         let files = FsCache::ensure_not_empty(files)?;
         Ok(files)
     }
@@ -268,7 +268,6 @@ impl FsCache {
                 }
             }
 
-            files.sort();
             let files = FsCache::ensure_not_empty(files)?;
             Ok(files)
         });
@@ -285,6 +284,12 @@ impl FsCache {
         if tab_settings.is_none() { return Ok(()) }
         let tab_settings = tab_settings?;
 
+        if files.show_hidden != tab_settings.dir_settings.show_hidden ||
+            files.filter != tab_settings.dir_settings.filter ||
+            files.filter_selected != tab_settings.dir_settings.filter_selected {
+                files.recalculate_len();
+            }
+
         files.sort = tab_settings.dir_settings.sort;
         files.dirs_first = tab_settings.dir_settings.dirs_first;
         files.reverse = tab_settings.dir_settings.reverse;
@@ -292,6 +297,8 @@ impl FsCache {
         files.filter = tab_settings.dir_settings.filter.clone();
         files.filter_selected = tab_settings.dir_settings.filter_selected;
 
+
+
         if tab_settings.multi_selections.len() > 0 {
             for file in &mut files.files {
                 for selected_files in &tab_settings.multi_selections {
@@ -302,7 +309,6 @@ impl FsCache {
             }
         }
 
-        files.sort();
         Ok(())
     }
 
@@ -311,6 +317,7 @@ impl FsCache {
             let path = &files.directory.path;
             let placeholder = File::new_placeholder(&path)?;
             files.files.push(placeholder);
+            files.len = 1;
         }
         Ok(files)
     }

src/listview.rs

@@ -707,7 +707,7 @@ impl<T> Widget for ListView<T> where ListView<T>: Listable {
             self.selection = self.buffer.len() - 1;
         }
 
-        if self.core.is_dirty() || buffer_len != self.len() {
+        if self.core.is_dirty() {
             self.buffer = self.render();
             self.core.set_clean();
         }