[CodingDiego]

Lower CPU use and quicker responses, from a performance audit of the daily-use build, plus most of the #17 backlog and the v1.0 roadmap. Version bumped to 0.1.4; .github/release-notes.md has the release text.

Perf fixes (#9-#16)

• Every change notification reloads the whole folder, also while minimized, and reloads pile up #11 change notifications: shell-change reloads get their own timer: a 150 ms debounce, at most 1 reload/s, one at a time, and none while minimized (one catch-up on restore).
• Sidebar rebuilds everything every 5 seconds while the window is focused #12 sidebar: rebuilt every 30 s while visible instead of every 5 s, plus immediately on WM_DEVICECHANGE.
• Hover preview prefetch fires while the pointer moves, in the background, and for heavy file types #9 hover prefetch: only text and light images (png/jpg/jpeg/gif/bmp/webp/ico); only after the pointer is still for hover_preview_ms; only while the window is in front.
• Preview pane re-hosts the PDF/Office preview handler on every folder refresh #10 preview handler: kept alive when the same file is shown again.
• Home is slow to build and repaints once per arriving icon #13 Home: column maps cached per parent folder, icon repaints coalesced.
• First launch exports about 560 system icon PNGs that no theme uses #14 icon export: the system icon export runs only with icon_theme=default.
• Icons view renders content thumbnails for PDF, Office and video, and preloads them off screen #15 Icons view: icons for heavy types; off-screen lookahead only for pictures.
• Open terminal blocks the window while ShellExecute starts wt.exe #16 terminal: launched on a background thread, by absolute path.

Backlog (#17)

• Sort on the load worker; per-row lazy cell cache; selection restore via a hash set; type-to-select reads cached names.
• Superseded loads stop early; the Home probe moved off the UI thread.
• Background tabs keep their change watch and a dirty flag. Switching tabs reloads only a tab that changed, has no watch on its folder, is virtual, or is on a network path.
• Thumbnail requests limited to the visible window (plus lookahead) and fitted on the worker; the tree is not synced while hidden.
• Search stops at its hit cap; the USN search can be cancelled.
• CMF_OPTIMIZEFORINVOKE for copy/cut/paste/delete/properties; the crumb dropdown skips network crumbs.
• Text preview capped at 64 KB with no redundant SetWindowTextW.
• Second-launch hand-off retries a busy, not hung, first window.

Left in #17: clipboard-change command refresh, sidebar Pin/Unpin enumerating on the UI thread, and a minimum search length.

Fixes found in review

• Sorting carries selection and focus over to the same files. Before, they stayed on row positions, so a Delete right after a sort hit another file.
• Sorting resets the icon views' image slots, so thumbnails no longer stay at their old positions.
• A shell-wide notification no longer restarts an active search tab. Starting a search clears a pending change reload, so typed characters are no longer lost.
• Open terminal also finds wt.exe in PATH's absolute folders.

Roadmap

VERSION-1-X.md lists what a stable 1.0 needs. Each item has an issue (#18-#70, milestone v1.0), tracked in #71.

Verification

All runs used scratch APPDATA profiles, comparing the old and new builds side by side.

• cargo build --release with -D warnings is clean; cargo test --workspace gives 83 + 86 passed.
• Smoke test (guarded copy) vs the official v0.1.3 build: no regression. The 29 checks that ran give identical results. sidebar-shell fails on both builds on this machine; the keyboard checks SKIP on both (no foreground).
• Measured against 0.1.1:
  • idle CPU: 2.2 s to 0.33 s per minute;
  • Details churn: 1.5 s to about 0.5 s per 20 s, at a 1 s pace;
  • minimized churn: about 0;
  • first-launch CPU: 4.5 s to 0.5 s;
  • terminal handler: 65 ms to 0.4 ms;
  • Copy: 350 ms to 80 ms.
• Hover R1-R3 checked with a control build that does prefetch:
  • new build: no read while moving, a read about 2 s after the pointer stops, no read for PDF/TIFF, no read while another window is in front;
  • control: reads in each case.
• Tab switches: 20 switches, 0 reloads (was 20). Changes made in a background tab are listed on return, including when a load lands while the tab is in the background.
• Thumbnails after sort: 0 of 18 wrong tiles (was 18 of 18). Search in a churning folder: 0 restarts in 5 trials (was 5 of 5).

Closes #9
Closes #10
Closes #11
Closes #12
Closes #13
Closes #14
Closes #15
Closes #16

🤖 Generated with Claude Code