Private/Tools/Lock-AvmToolCache.ps1
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function Lock-AvmToolCache { <# .SYNOPSIS Acquire a cross-process exclusive lock for a tool's cache directory. .DESCRIPTION Returns the open FileStream once the lock is held. The caller MUST Dispose the stream (typically in a finally block) to release the lock. If another process holds the lock this function retries up to TimeoutSec; on timeout it throws TimeoutException. The lock file lives at '<Data>/tools/<tool>/.lock'. The .lock file is left on disk after release; that is intentional and matches the spec. .PARAMETER LockFile Absolute path to the .lock file. Parent directory is created if it does not exist. .PARAMETER TimeoutSec Maximum time to wait for the lock. Default 60 seconds. #> [CmdletBinding()] [OutputType([System.IO.FileStream])] param( [Parameter(Mandatory)] [string] $LockFile, [int] $TimeoutSec = 60 ) Set-StrictMode -Version 3.0 $ErrorActionPreference = 'Stop' $dir = Split-Path -Parent $LockFile if ($dir -and -not (Test-Path -LiteralPath $dir)) { New-Item -ItemType Directory -Path $dir -Force | Out-Null } $deadline = (Get-Date).AddSeconds($TimeoutSec) while ($true) { try { return [System.IO.File]::Open( $LockFile, [System.IO.FileMode]::OpenOrCreate, [System.IO.FileAccess]::Write, [System.IO.FileShare]::None) } catch [System.IO.IOException] { if ((Get-Date) -ge $deadline) { throw [System.TimeoutException]::new( "Could not acquire lock '$LockFile' within $TimeoutSec seconds.") } Start-Sleep -Milliseconds 250 } } } |