Fix bidirectional RF-001A coordination

tools/capture_process_runner.ps1

@@ -0,0 +1,104 @@
+param(
+    [Parameter(Mandatory = $true)][string]$Executable,
+    [Parameter(Mandatory = $true)][string]$ArgumentsJsonPath,
+    [Parameter(Mandatory = $true)][string]$CapturePath,
+    [Parameter(Mandatory = $true)][string]$StdoutPath,
+    [Parameter(Mandatory = $true)][string]$StderrPath,
+    [Parameter(Mandatory = $true)][string]$StartedStatusPath,
+    [Parameter(Mandatory = $true)][string]$ResultStatusPath
+)
+
+$ErrorActionPreference = 'Stop'
+
+function Write-JsonAtomically {
+    param(
+        [Parameter(Mandatory = $true)][object]$Value,
+        [Parameter(Mandatory = $true)][string]$Path
+    )
+
+    $temporaryPath = "$Path.tmp"
+    $json = $Value | ConvertTo-Json -Depth 8
+    $encoding = New-Object System.Text.UTF8Encoding($false)
+    [System.IO.File]::WriteAllText($temporaryPath, $json + [Environment]::NewLine, $encoding)
+    Move-Item -LiteralPath $temporaryPath -Destination $Path -Force
+}
+
+$decodedArguments = Get-Content -Raw -LiteralPath $ArgumentsJsonPath |
+    ConvertFrom-Json
+if ($decodedArguments -isnot [System.Array]) {
+    throw 'ArgumentsJsonPath must contain a JSON array.'
+}
+$childArguments = @(
+    foreach ($argument in $decodedArguments) {
+        [string]$argument
+    }
+)
+$startedAt = [DateTimeOffset]::UtcNow
+$finishedAt = $null
+$childProcess = $null
+$exitCode = $null
+$runnerError = $null
+$captureSize = 0
+$sha256 = $null
+
+try {
+    $startParameters = @{
+        FilePath = $Executable
+        ArgumentList = $childArguments
+        RedirectStandardOutput = $StdoutPath
+        RedirectStandardError = $StderrPath
+        PassThru = $true
+        WindowStyle = 'Hidden'
+    }
+    $childProcess = Start-Process @startParameters
+    # PowerShell 5 can lose ExitCode for redirected processes unless the
+    # underlying process handle is opened before WaitForExit().
+    $null = $childProcess.Handle
+
+    Write-JsonAtomically -Path $StartedStatusPath -Value ([ordered]@{
+        state = 'RUNNING'
+        pid = $childProcess.Id
+        started_at = $startedAt.ToString('o')
+        capture_path = $CapturePath
+    })
+
+    $childProcess.WaitForExit()
+    $childProcess.Refresh()
+    $exitCode = [int]$childProcess.ExitCode
+} catch {
+    $runnerError = $_.Exception.ToString()
+} finally {
+    $finishedAt = [DateTimeOffset]::UtcNow
+    if (Test-Path -LiteralPath $CapturePath) {
+        try {
+            $captureSize = [int64](Get-Item -LiteralPath $CapturePath).Length
+            $sha256 = (
+                Get-FileHash -LiteralPath $CapturePath -Algorithm SHA256
+            ).Hash.ToLowerInvariant()
+        } catch {
+            $additionalError = $_.Exception.ToString()
+            if ([string]::IsNullOrWhiteSpace($runnerError)) {
+                $runnerError = $additionalError
+            } else {
+                $runnerError = $runnerError + [Environment]::NewLine + $additionalError
+            }
+        }
+    }
+
+    Write-JsonAtomically -Path $ResultStatusPath -Value ([ordered]@{
+        pid = if ($null -ne $childProcess) { $childProcess.Id } else { $null }
+        started_at = $startedAt.ToString('o')
+        finished_at = $finishedAt.ToString('o')
+        duration = ($finishedAt - $startedAt).TotalSeconds
+        exit_code = $exitCode
+        capture_path = $CapturePath
+        capture_size = $captureSize
+        sha256 = $sha256
+        runner_error = $runnerError
+    })
+}
+
+if ($null -eq $exitCode) {
+    exit 255
+}
+exit $exitCode