Implement the rest of the FTCS marks

[zadjii-msft]

As noted in #11000.

This adds support for FTCS_COMMAND_START, FTCS_COMMAND_EXECUTED and FTCS_COMMAND_FINISHED, which allow a shell to more clearly markup parts of the buffer.

As a trick, I'm also making the experimental.autoMarkPrompts setting act like a FTCS_COMMAND_EXECUTED if it comes after a FTCS_COMMAND_START. This lets the whole sequence work for cmd.exe (which wouldn't otherwise be possible).

• My cmd prompt

  PROMPT $e]133;D$e\$e]133;A$e\$e]9;9;$P$e\[$T]$e[97;46m%_seperator%$P$e[36;49m%_seperator%$e[0m$_$e[0m%_GITPROMPT%$e[94m%username%$e[0m@$e[32m%computername%$e[0m$G$e]133;B$e\

• pwsh profile, heavily cribbed from vscode

    $Global:__LastHistoryId = -1
    
    function Global:__Terminal-Get-LastExitCode {
      if ($? -eq $True) {
        return 0
      }
      # TODO: Should we just return a string instead?
      # return -1
      if ("$LastExitCode" -ne "") { return $LastExitCode }
      return -1
    }
    
    function prompt {
      # $gle = $LastExitCode
    
    
      $gle = $(__Terminal-Get-LastExitCode);
      $LastHistoryEntry = $(Get-History -Count 1)
      # Skip finishing the command if the first command has not yet started
      if ($Global:__LastHistoryId -ne -1) {
        if ($LastHistoryEntry.Id -eq $Global:__LastHistoryId) {
          # Don't provide a command line or exit code if there was no history entry (eg. ctrl+c, enter on no command)
          $out += "`e]133;D`a"
        } else {
          # Command finished exit code
          # OSC 633 ; D [; <ExitCode>] ST
          $out += "`e]133;D;$gle`a"
        }
      }
    
    
      $loc = $($executionContext.SessionState.Path.CurrentLocation);
      # IMPORTANT: Make sure there's a printable charater _last_ in the prompt.
      # Otherwise, PSReadline is gonna use the terminating `\` here and colorize
      # that if it detects a syntax error
      $out += "`e]133;A$([char]07)";
      $out += "`e]9;9;`"$loc`"$([char]07)";
      $out += "PWSH $loc$('>' * ($nestedPromptLevel + 1)) ";
      $out += "`e]133;B$([char]07)";
    
      $Global:__LastHistoryId = $LastHistoryEntry.Id
    
      return $out
    }

• Doesn't close any issues, because this was always just an element in megathread: Scrollbar Marks #11000

• I work here

• From FHL code

[lhecker]

nit: Both branches end up calling OutputStart at the end.

[carlos-zamora]

I've only got nits. Definitely want resolution on Leonard's comment before approving though (the dangling pointer thing): #14341 (comment)

[lhecker]

I believe that using indices would be better than using .back() and adding .insert().
Rust exposes this problem much more obviously, as you can't "borrow" foreign data easily there without introducing lifetime issues. A common solution is to instead save a numeric index (or similar) of where the data is stored at. In this case you could store a size_t _currentPromptMarkIndex which stores the index of the mark inside _scrollMarks, so that you can safely retrieve it from _scrollMarks at a later time.
It's basically exactly like the _currentPrompt pointer since it's still sort of a (relative) memory location, but unlike it, it's much easier to prove that it doesn't reference invalid data (by checking that _currentPromptMarkIndex < .size()). This way you don't need to insert() user marks at the beginning either, allowing you to remove this boolean parameter. Such a numeric index doesn't fix any "stateful" bugs of course, but it does prevent memory lifetime issues, as was the case with the raw pointer.

[DHowett]

(I just realized that the two positions were for a selection!)

[DHowett]

I am moderately horrified about this actually -- why is this better than UINT_MAX or whatever? Do we really want to use -1 to indicate.. uh, something? But, if we really want -1 shouldn't it be signed?

[ghost]

Hello @zadjii-msft!

Because this pull request has the AutoMerge label, I will be glad to assist with helping to merge this pull request once all check-in policies pass.

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[ghost]

🎉Windows Terminal Preview v1.17.1023 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Store Download

[JanDeDobbeleer]

@zadjii-msft how can I play around with this? I'm adding support to oh-my-posh for this, so I would love to validate. I'm already on the correct version (v1.17.1023).

[zadjii-msft]

@JanDeDobbeleer I absolutely need to write a better guide, but in leiu of that,

• https://gist.github.com/zadjii-msft/eddb07cd490f5ee78193fea21a74e6f8 has notes on how I set up the A, B, D marks for a powershell prompt. (it also has a lot of other noise on things that didn't end up shipping)
• megathread: Scrollbar Marks #11000 is my giant tracking thread for all things marks
• Spec for shell integration marks #14792 also has more notes