Add support for OSC 52 clipboard copy in conhost #18949
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| // The clipboard can only be updated from the main GUI thread, so we | ||
| // need to post a message to trigger the actual copy operation. But if | ||
| // the pending clipboard content is already set, a message would have | ||
| // already been posted, so there's no need to post another one. | ||
| const auto clipboardMessageSent = _pendingClipboardText.has_value(); | ||
| _pendingClipboardText = text; | ||
| if (!clipboardMessageSent) | ||
| { | ||
| PostMessageW(window->GetWindowHandle(), CM_UPDATE_CLIPBOARD, 0, 0); | ||
| } |
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I don't know if I've just misunderstood how you're supposed to use the windows clipboard, but I couldn't get it working from a background thread, and this technique worked for me. I don't know if maybe there's a better way to do this.
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Yep, reading doesn't require a HWND but writing does, to my knowledge.
| void Clipboard::CopyText(const std::wstring& text) | ||
| { | ||
| const auto clipboard = _openClipboard(ServiceLocator::LocateConsoleWindow()->GetWindowHandle()); | ||
| if (!clipboard) | ||
| { | ||
| LOG_LAST_ERROR(); | ||
| return; | ||
| } | ||
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| EmptyClipboard(); | ||
| // As per: https://learn.microsoft.com/en-us/windows/win32/dataxchg/standard-clipboard-formats | ||
| // CF_UNICODETEXT: [...] A null character signals the end of the data. | ||
| // --> We add +1 to the length. This works because .c_str() is null-terminated. | ||
| _copyToClipboard(CF_UNICODETEXT, text.c_str(), (text.size() + 1) * sizeof(wchar_t)); | ||
| } |
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The content of this method is copied directly from StoreSelectionToClipboard, but there's really not much to it, so I didn't think there was any point in trying to share the code somehow.
src/host/consoleInformation.cpp
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| const auto clipboardText = _pendingClipboardText; | ||
| _pendingClipboardText.reset(); | ||
| return clipboardText; |
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We can avoid a copy here by doing this:
return std::exchange(_pendingClipboardText, {});I've tested OSC 52 with Windows Terminal with up to 100MiB and it was relatively snappy. So I think avoiding a copy may be useful to reduce the peak memory usage.
...now that I mention this, I realize that immediately copying the clipboard contents into an HGLOBAL would have another benefit... Well, that's a minor issue though.
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Thanks for the exchange suggestion. I was hoping there was way to avoid that copy. That's definitely made a difference.
Summary of the Pull Request
This adds support for copying to the clipboard in conhost using the OSC
52 escape sequence, extending the original implementation which was for
Windows Terminal only.
References and Relevant Issues
The Windows Terminal implementation was added in PR #5823.
Detailed Description of the Pull Request / Additional comments
Because the clipboard can't be accessed from a background thread, this
works by saving the content in a global variable, and then posting a
custom message to the main GUI thread, which takes care of the actual
copy operation.
Validation Steps Performed
I've manually confirmed that tmux copy mode is now able to copy to the
system clipboard.
PR Checklist