Out-Git.ps1
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function Out-Git { <# .Synopsis Outputs Git to PowerShell .Description Outputs Git as PowerShell Objects. Git Output can be provided by any number of extensions to Out-Git. Extensions use two attributes to indicate if they should be run: ~~~PowerShell [Management.Automation.Cmdlet("Out","Git")] # This signals that this is an extension for Out-Git [ValidatePattern("RegularExpression")] # This is run on $GitCommand to determine if the extension should run. ~~~ .LINK Invoke-Git .Example # Log entries are returned as objects, with properties and methods. git log -n 1 | Get-Member .Example # Status entries are converted into objects. git status .Example # Display untracked files. git status | Select-Object -ExpandProperty Untracked .Example # Display the list of branches, as objects. git branch #> [CmdletBinding(PositionalBinding=$false)] param( # One or more output lines from Git. [Parameter(ValueFromPipeline)] [string[]] $OutputObject, # The arguments that were passed to git. [string[]] $GitArgument, # The root of the current git repository. [string] $GitRoot ) begin { # First, we need to determine what the combined git command was. # Luckily, this is easy: just combine "git" with the list of git argument $gitCommand = @('git') + $GitArgument[0..$GitArgument.Length] -join ' ' # Now that we have that, let's initialize an empty variable to keep any extension validation errors. $extensionValidationErrors = $null # Then we create a hashtable containing the parameters to Get-UGitExtension: $uGitExtensionParams = @{ CommandName = $MyInvocation.MyCommand # We want extensions for this command ValidateInput = $gitCommand # that are valid, given $GitCommand. ErrorAction = 'SilentlyContinue' # We do not want to display errors ErrorVariable = 'extensionValidationErrors' # we want to redirect them into $extensionValidationErrros. } # Now we get a list of git output extensions $gitOutputExtensions = @(Get-UGitExtension @uGitExtensionParams) # If any of them had errors, and we want to see the -Verbose channel if ($extensionValidationErrors -and $VerbosePreference -ne 'silentlyContinue') { foreach ($validationError in $extensionValidationErrors) { Write-Verbose "$validationError" # write the validation errors to verbose. # It should be noted that there will almost always be validation errors, # since most extensions will not apply to a given $GitCommand } } # Next we want to create a collection of SteppablePipelines. # These allow us to run the begin/process/end blocks of each Extension. $steppablePipelines = [Collections.ArrayList]::new(@(if ($gitOutputExtensions) { foreach ($ext in $gitOutputExtensions) { $scriptCmd = {& $ext} $scriptCmd.GetSteppablePipeline() } })) # Next we need to start any steppable pipelines. # Each extension can break, continue in it's begin block to indicate it should not be processed. $spi = 0 $spiToRemove = @() $beginIsRunning = $false # Walk over each steppable pipeline. :NextExtension foreach ($steppable in $steppablePipelines) { if ($beginIsRunning) { # If beginIsRunning is set, then the last steppable pipeline continued $spiToRemove+=$steppablePipelines[$spi] # so mark it to be removed. } $beginIsRunning = $true # Note that beginIsRunning=$false, try { $steppable.Begin($false) # then try to run begin } catch { $PSCmdlet.WriteError($_) # Write any exceptions as errors } $beginIsRunning = $false # Note that beginIsRunning=$false $spi++ # and increment the index. } # If this is still true, an extenion used 'break', which signals to stop processing of it any subsequent pipelines. if ($beginIsRunning) { $spiToRemove += @(for (; $spi -lt $steppablePipelines.Count; $spi++) { $steppablePipelines[$spi] }) } # Remove all of the steppable pipelines that signaled they no longer wish to run. foreach ($tr in $spiToRemove) { $steppablePipelines.Remove($tr) } } process { # Walk over each output. foreach ($out in $OutputObject) { # If the out was a literal string of 'System.Management.Automation.RemoteException', if ("$out" -eq "System.Management.Automation.RemoteException") { # ignore it and continue (these things happen with some exes from time to time). continue } # Wrap the output in a PSObject $gitOut = [PSObject]::new($out) # Next, clear it's typenames and determine an automatic typename. # The first typename is the complete set of arguments ( separated by periods ) # Followed by each smaller set of arguments, separated by periods # Followed by a PSTypeName of 'git' # Thus, for example, git clone $repo # Would have the typenames of :"git.clone.$repo.output", "git.clone.output","git.output" $gitOut.pstypenames.clear() for ($n = $GitArgument.Length - 1 ; $n -ge 0; $n--) { $gitOut.pstypenames.add(@('git') + $GitArgument[0..$n] + @('output') -join '.') } $gitOut.pstypenames.add('git.output') # All gitOutput should attach the original output line, as well as the command that produced that line. $gitOut.psobject.properties.add([PSNoteProperty]::new('GitOutput',"$out")) $gitOut.psobject.properties.add([PSNoteProperty]::new('GitCommand', $(@('git') + $GitArgument) -join ' ') ) # If the output started with "error" or "fatal" if ("$out" -match "^(?:error|fatal):") { $exception = [Exception]::new($("$out" -replace '^(?:error|fatal):')) # Create an exception $PSCmdlet.WriteError( # and write an error using $psCmdlet (this simplifies the displayed callstack). [Management.Automation.ErrorRecord]::new($exception,"$GitCommand", 'NotSpecified',$gitOut) ) # If there was an error, cancel all steppable pipelines (thus stopping any extensions) $steppablePipelines = @() continue # then move onto the next output. } else { Write-Verbose "$out" } if (-not $steppablePipelines) { # If we do not have steppable pipelines, output directly $gitOut } else { # If we have steppable pipelines, then we have to do a similar operation as we did for begin. $spi = 0 $spiToRemove = @() $processIsRunning = $false # We have to walk thru each steppable pipeline, :NextExtension foreach ($steppable in $steppablePipelines) { if ($processIsRunning) { # if $ProcessIsRunning, the pipeline was skipped with continue. $spiToRemove+=$steppablePipelines[$spi] # and we should add it to the list of pipelines to remove } $processIsRunning = $true # Set $processIsRunning, try { $steppable.Process($gitOut) # attempt to run process, using the $gitOut object. } catch { $PSCmdlet.WriteError($_) # (catch any exceptions and write them as errors). } $processIsRunning = $false # Set $processIsRunning to $false for the next step. } if ($processIsRunning) { # If $ProcessIsRunning was true, the extension used break # which should signal cancellation of all subsequent extensions. $spiToRemove += @(for (; $spi -lt $steppablePipelines.Count; $spi++) { $steppablePipelines[$spi] }) $gitOut # We will also output the gitOut object in this case. } # Remove any steppable pipelines we need to remove. foreach ($tr in $spiToRemove) { $steppablePipelines.Remove($tr) } } } } end { # End remaining steppable pipelines need to end. # Ending does not support the cancellation of other extensions. foreach ($steppable in $steppablePipelines) { try { $steppable.End() } catch { Write-Error -ErrorRecord $_ } } } } |