PSCodeDemo.psm1
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function git { Write-Verbose "git $args" git.exe $args if ($LASTEXITCODE) { throw "git $args failed with exit code $LASTEXITCODE" } } class DemoCompleter : System.Management.Automation.IArgumentCompleter { [System.Collections.Generic.IEnumerable[System.Management.Automation.CompletionResult]] CompleteArgument( [System.String] $commandName, [System.String] $parameterName, [System.String] $wordToComplete, [System.Management.Automation.Language.CommandAst] $commandAst, [System.Collections.IDictionary] $fakeBoundParameters ) { switch ("${CommandName}:$ParameterName") { "Start-CodeDemo:FromCommit" { $repoPath = $fakeBoundParameters['RepositoryPath'] return $this.CompleteCommit($repoPath, $wordToComplete, 1, 0) } "Start-CodeDemo:ToCommit" { $repoPath = $fakeBoundParameters['RepositoryPath'] return $this.CompleteCommit($repoPath, $wordToComplete, 1, 0) } } return [System.Management.Automation.CompletionResult[]] @() } [System.Collections.Generic.IEnumerable[System.Management.Automation.CompletionResult]] CompleteCommit([string] $repositoryPath, [string] $wordToComplete, [int] $skipFirst, [int] $skipLast) { $entries = [GitLogEntry]::GetLogEntries($repositoryPath) [System.Management.Automation.CompletionResult[]]$completions = @( $entries | Select-Object -Skip:$skipFirst -SkipLast:$skipLast | Where-Object { $_.Commit.StartsWith($wordToComplete) } | ForEach-Object { [System.Management.Automation.CompletionResult]::new($_.Commit, $_.Title, 'ParameterValue', "{0}`n{1}`n{2}" -f $_.Title, $_.Author, $_.Commit ) } ) return $completions } } class GitLogEntry { [string] $Commit [string] $Title [string] $Author [string] $AuthorEmail [string] $Date [string] $FullMessage [string] ToString() { return "$($this.Commit.Substring(0, 7)) - `"$($this.Title)`"" } static [GitLogEntry[]] GetLogEntries([string] $Path) { $entries = @( foreach ($line in git -C $path log --format='%h%x00%s%x00%f%x00%an%x00%ae%x00%aI') { $local:commit, $local:title, $local:fullMessage, $local:author, $local:authorEmail, $local:date = $line -split '\x00' [GitLogEntry] @{ Title = $title Commit = $commit Author = $author AuthorEmail = $authorEmail Date = $date FullMessage = $fullMessage } } ) return $entries } static [int] IndexOf([GitLogEntry[]] $Entries, [string] $Commit) { for ($i = 0; $i -lt $Entries.Count; $i++) { if ($Entries[$i].Commit -eq $Commit) { return $i } } return -1 } } class GitTagEntry { [string] $Commit [string] $Name static [GitTagEntry[]] GetTagEntries([string] $Path) { $entries = @( foreach ($line in git -C $path tag --format='%(objectname)%00%(refname:lstrip=2)') { $local:commit, $local:name = $line -split '\0' [GitTagEntry] @{ Commit = $commit Name = $name } } ) return $entries } } class PSCodeDemo { [string] $RepositoryPath [string] $WorkTree [GitLogEntry[]] $DemoCommits [int] $CurrentCommitIndex [string] $OriginalBranch PSCodeDemo([string] $RepositoryPath, [string] $WorkTree, [string] $FromCommit, [string] $ToCommit) { $this.RepositoryPath = $RepositoryPath $this.WorkTree = $WorkTree $tags = [GitTagEntry]::GetTagEntries($RepositoryPath) $log = [GitLogEntry]::GetLogEntries($RepositoryPath) $currentBranch = $this.GetCurrentBranch() if ($log.Count -lt 2) { Write-Error "The repository must have at least two commits to start a demo." return } if (!$FromCommit) { $fromTag = $tags | Where-Object { $_.Name -eq 'demo-start' } $FromCommit = ${fromTag}?.Commit ?? $log[-1].Commit } if (!$ToCommit) { $toTag = $tags | Where-Object { $_.Name -eq 'demo-end' } $ToCommit = ${toTag}?.Commit ?? $log[0].Commit } $fromIndex = [GitLogEntry]::IndexOf($log, $FromCommit) $toIndex = [GitLogEntry]::IndexOf($log, $ToCommit) $demoLog = $log[$fromIndex..$toIndex] $this.DemoCommits = $demoLog $this.CurrentCommitIndex = 0 $this.OriginalBranch = $currentBranch } [void] CreateDemoBranch() { git -C $this.RepositoryPath switch -C demo } [GitLogEntry] GetCurrentCommit() { return $this.DemoCommits[$this.CurrentCommitIndex] } [void] SwitchToDemoBranch() { git -C $this.RepositoryPath --work-tree=$($this.WorkTree) switch -C demo } [GitLogEntry] CheckoutCurrentCommit() { $currentObject = $this.GetCurrentCommit() $output = git --work-tree=$($this.WorkTree) -C $this.RepositoryPath checkout -f $currentObject.Commit return $currentObject } [GitLogEntry] Next() { if ($this.CurrentCommitIndex -lt ($this.DemoCommits.Count - 1)) { $this.CurrentCommitIndex++ $this.CheckoutCurrentCommit() } return $this.GetCurrentCommit() } [GitLogEntry] Previous() { if ($this.CurrentCommitIndex -gt 0) { $this.CurrentCommitIndex-- $this.CheckoutCurrentCommit() } return $this.GetCurrentCommit() } [string] ToString() { $current = $this.GetCurrentCommit() return "Demo on $($current.ToString())" } [string] GetCurrentBranch() { $output = git -C $this.RepositoryPath status --branch --porcelain switch -regex ($output) { '^\#\# HEAD \(no branch\)$' { throw 'Cannot start a demo when not on a branch.' } '^\#\# (.\S+)$' { return $Matches[1] } default { throw "Unexpected git status output: $output" } } return "" } } [PSCodeDemo] $script:DemoState <# .SYNOPSIS Start a code demo in a git repository .DESCRIPTION Starts a demo in a git repository by remembering the current state of the repository and checking out the specified commit. .PARAMETER Path The path to the git repository to start the demo in. .PARAMETER FromCommit An optional commit to start the demo from. If not specified, the first commit in the history will be used, unless a tag 'demo-start' exists, in which case the commit the tag points to will be used. .PARAMETER ToCommit An optional commit to end the demo at. If not specified, the current commit will be used, unless a tag 'demo-end' exists, in which case the commit the tag points to will be used. .PARAMETER Force If a demo is already in progress, this switch will force a reset of the demo state and start a new demo. #> function Start-CodeDemo { [CmdletBinding()] param ( [Parameter()] [string] $RepositoryPath, [string] $WorkTree = $PWD, [ArgumentCompleter([DemoCompleter])] [string] $FromCommit, [ArgumentCompleter([DemoCompleter])] [string] $ToCommit, [switch] $Force ) $workTree = $PSCmdlet.GetUnresolvedProviderPathFromPSPath($WorkTree) $RepositoryPath = $PSCmdlet.GetUnresolvedProviderPathFromPSPath($RepositoryPath) if (-not (Test-Path -PathType:Container -LiteralPath:$workTree)) { Write-Error "The specified work tree path '$workTree' does not exist." return } if ($null -ne $script:DemoState) { if ($Force) { Write-Warning "A demo is already in progress. Forcing a new demo will reset the demo state." $script:DemoState = $null } else { Write-Error "A demo is already in progress. Use -Force to reset the demo state." return } } $demoState = [PSCodeDemo]::new($RepositoryPath, $WorkTree, $FromCommit, $ToCommit) $demoState.SwitchToDemoBranch() $demoState.CheckoutCurrentCommit() $script:DemoState = $demoState } function Update-CodeDemo { param( [switch] $PreviousCommit ) $local:state = $script:DemoState if ($state) { if ($PreviousCommit) { $state.Previous() } else { $state.Next() } } } function Stop-CodeDemo { $state = $script:DemoState git -C $state.RepositoryPath switch -f $state.OriginalBranch $script:DemoState = $null } function Install-CodeDemoKeyHandler { Set-PSReadLineKeyHandler -Chord Ctrl-UpArrow { Update-CodeDemo } Set-PSReadLineKeyHandler -Chord Ctrl-DownArrow { Update-CodeDemo -PreviousCommit } } function Uninstall-CodeDemoKeyHandler { Remove-PSREadLineKeyHandler -Chord Ctrl-UpArrow Remove-PSREadLineKeyHandler -Chord Ctrl-DownArrow } |