# dsh-copy-file-button

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)

> A **"copy the whole file"** button in the DSH file preview toolbar — one click puts the complete on-disk content on your clipboard.

> 中文: [README.md](README.md)

## Why this exists

DSH's right sidebar can preview a file, but copying the whole thing means select-all by hand — and the preview may hold only part of the file, or text truncated by a re-render. This button reads through the Host's file authority, so it copies **the real bytes on disk**, not whatever text the preview happens to be showing.

## What it does

Adds a copy button to the `sidebar.right.tab.document.actions` slot — the right end of the file-preview header row, alongside the viewer menu, wrap toggle, reload, and the open-in-VS-Code split button.

- **Copy source**: `remote.workspaceFiles.readBytes(...)` — the same Host read authority the preview itself uses, so the bytes are the on-disk originals.
- **A check mark only after verified success**: the clipboard is **read back and compared** after writing. `execCommand('copy')` can report success while writing nothing, and a document that lost focus makes `clipboard.writeText` reject — either way a naive implementation shows a check mark over an empty clipboard. Only a matching read-back counts as copied.
- **Fallback path**: when `navigator.clipboard` is unavailable or fails, it falls back to a temporary `textarea` plus `execCommand('copy')`, restoring the previous selection afterwards.

## Edge cases

| Case | Behavior |
|---|---|
| Binary file | Probes the first 8 KB for a NUL byte; refuses with "This is not a text file" |
| File too large | Reports "File is too large to copy at once" rather than copying a truncated prefix |
| Empty file | Reports "The file is empty" |
| Read failure | Shows the actual error instead of pretending success |
| Unknown data shape | Reports the real type and size (e.g. `string(1024)`) instead of guessing |

## Two implementation pitfalls

1. **Data crossing the Host bridge is not a `Uint8Array`.**
   The schema declares `Uint8Array`, but after cross-process structured serialization what actually arrives is a **base64 string** (the document preview decodes it with `atob` itself). Calling `new Uint8Array(someString)` **silently yields an empty array** — precisely how "reports copied, clipboard is empty" happens. The code accepts `Uint8Array` / base64 / `ArrayBuffer` / array-like / `{type:'Buffer',data:[...]}` alike.

2. **Strip the UTF-8 BOM.**
   If the first decoded character is `U+FEFF` it is dropped, so the copied text does not start with an invisible character.

## Install

```sh
# from GitHub
dsh plugin --profile desktop add github:<your-user>/dsh-copy-file-button

# or from a local checkout
dsh plugin --profile desktop add link:/path/to/dsh-copy-file-button
```

Then restart DSH. The client half needs one page refresh to load.

## Internationalization

Ships with `locale/en.json`; the button label follows DSH's language setting. Chinese and English strings are built in — adding a language is just another JSON file under `locale/`.

## Uninstall

Remove the entry from your profile's `package.json` (`dependencies` and `dsh.profile.bundles`), delete the `node_modules` link, and restart.

## License

MIT