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August 25, 2024 18:31
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Git-like Diff Tool in PowerShell
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| # Git-like Diff Tool in PowerShell | |
| function Compare-Files { | |
| param ( | |
| [string]$OldFilePath, | |
| [string]$NewFilePath, | |
| [int]$ContextLines = 3 | |
| ) | |
| $oldFile = Get-Content -Path $OldFilePath | |
| $newFile = Get-Content -Path $NewFilePath | |
| $diffs = [System.Collections.Generic.List[PSObject]]::new() | |
| $oldIndex = 0 | |
| $newIndex = 0 | |
| while ($oldIndex -lt $oldFile.Count -or $newIndex -lt $newFile.Count) { | |
| $oldLine = if ($oldIndex -lt $oldFile.Count) { $oldFile[$oldIndex] } else { $null } | |
| $newLine = if ($newIndex -lt $newFile.Count) { $newFile[$newIndex] } else { $null } | |
| if ($oldLine -eq $newLine) { | |
| $oldIndex++ | |
| $newIndex++ | |
| } | |
| else { | |
| $diffs.Add([pscustomobject]@{ | |
| ChangeType = if ($null -eq $oldLine) { 'Added' } elseif ($newLine -eq $null) { 'Deleted' } else { 'Modified' } | |
| OldLineNumber = if ($null -ne $oldLine) { $oldIndex + 1 } else { $null } | |
| NewLineNumber = if ($null -ne $newLine) { $newIndex + 1 } else { $null } | |
| OldLine = $oldLine | |
| NewLine = $newLine | |
| }) | |
| if ($null -ne $oldLine) { $oldIndex++ } | |
| if ($null -ne $newLine) { $newIndex++ } | |
| } | |
| } | |
| return $diffs | |
| } | |
| function Write-Diff { | |
| param ( | |
| [psobject[]]$Diffs, | |
| [string[]]$OldFile, | |
| [string[]]$NewFile, | |
| [int]$ContextLines = 3 | |
| ) | |
| foreach ($diff in $Diffs) { | |
| if ($diff.ChangeType -eq 'Modified') { | |
| Write-Host "Line $($diff.OldLineNumber),$($diff.NewLineNumber) Modified:" -ForegroundColor Yellow | |
| for ($i = [Math]::Max(0, $diff.OldLineNumber - $ContextLines - 1); $i -lt [Math]::Min($OldFile.Count, $diff.OldLineNumber + $ContextLines); $i++) { | |
| Write-Host " $($OldFile[$i])" | |
| } | |
| Write-Host "- $($diff.OldLine)" -ForegroundColor Red | |
| Write-Host "+ $($diff.NewLine)" -ForegroundColor Green | |
| } | |
| elseif ($diff.ChangeType -eq 'Added') { | |
| Write-Host "Line $($diff.NewLineNumber) Added:" -ForegroundColor Green | |
| Write-Host "+ $($diff.NewLine)" -ForegroundColor Green | |
| } | |
| elseif ($diff.ChangeType -eq 'Deleted') { | |
| Write-Host "Line $($diff.OldLineNumber) Deleted:" -ForegroundColor Red | |
| Write-Host "- $($diff.OldLine)" -ForegroundColor Red | |
| } | |
| } | |
| } | |
| function Show-GitLikeDiff { | |
| param ( | |
| [string]$OldFilePath, | |
| [string]$NewFilePath, | |
| [int]$ContextLines = 3 | |
| ) | |
| $oldFile = Get-Content -Path $OldFilePath | |
| $newFile = Get-Content -Path $NewFilePath | |
| $diffs = Compare-Files -OldFilePath $OldFilePath -NewFilePath $NewFilePath -ContextLines $ContextLines | |
| Write-Diff -Diffs $diffs -OldFile $oldFile -NewFile $newFile -ContextLines $ContextLines | |
| } | |
| # Example usage: | |
| Show-GitLikeDiff -OldFilePath './old.ps1' -NewFilePath './new.ps1' |
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