asynchronous git prompt updates

GitPrompt.ps1

@@ -128,6 +128,6 @@ function Global:Write-VcsStatus { $Global:VcsPromptStatuses | foreach { & $_ } }
 
 # Add scriptblock that will execute for Write-VcsStatus
 $Global:VcsPromptStatuses += {
-    $Global:GitStatus = Get-GitStatus
+    $Global:GitStatus = Get-GitPromptStatus
     Write-GitStatus $GitStatus
-}
+}

GitPromptAsync.ps1

@@ -0,0 +1,131 @@
+function Start-GitPrompt([switch] $Asynchronous) {
+    if (-not $GitPromptState) {
+        if ($Asynchronous) {
+            $timer = New-Object Timers.Timer -Property @{
+                Interval = 250
+                AutoReset = $true
+                Enabled = $true
+            }
+            Set-Variable GitPromptState -Scope Global -Value (New-Object PSObject -Property @{
+                Asynchronous = $true
+                Repositories = @{ }
+                Timer = $timer
+                Elapsed = Register-ObjectEvent $timer Elapsed -Action { Update-GitPromptRepositories }
+            })
+        }
+        else {
+            Set-Variable GitPromptState -Scope Global -Value (New-Object PSObject -Property @{
+                Asynchronous = $false
+                Repositories = @{ }
+            })
+        }
+    }
+}
+
+function Update-GitPromptRepositories {
+    if ($GitPromptState) {
+        $repositories = $GitPromptState.Repositories
+        foreach($key in $repositories.Keys) {
+            $repository = $repositories[$key]
+            if ($repository.LastStatusUpdate -lt $repository.LastUpdate) {
+                if ($repository.LastStatusUpdate.AddMilliseconds($repository.StatusUpdateIntervalBuffer) -lt [DateTime]::Now) {
+                    Push-Location $repository.Path
+                    try { $repository.Status = Get-GitStatus $repository.Path }
+                    finally { Pop-Location }
+                }
+                $repository.LastStatusUpdate = [DateTime]::Now
+            }
+        }
+    }
+}
+
+function Stop-GitPrompt {
+    if ($GitPromptState) {
+        if ($GitPromptState.Asynchronous) {
+            $GitPromptState.Timer.Enabled = $false
+            Unregister-Event $GitPromptState.Elapsed.Id
+        }
+        $GitPromptState.Repositories.Keys | ForEach-Object { Stop-GitPromptRepository $_ }
+        Remove-Variable GitPromptState -Scope Global
+    }
+}
+
+function Start-GitPromptRepository($Path) {
+    if ($GitPromptState -and (-not $GitPromptState.Repositories.ContainsKey($Path))) {
+        $repositories = $GitPromptState.Repositories.Clone()
+        $watcher = New-Object IO.FileSystemWatcher $Path, '*.*' -Property @{
+            IncludeSubdirectories = $true
+            EnableRaisingEvents = $true
+        }
+        $watcherAction = [scriptblock]::Create( { Publish-GitPromptRepositoryUpdated $Path $eventArgs.Name }.ToString().Replace('$Path', $Path) )
+
+        $repositories[$Path] = New-Object PSObject -Property @{
+            Path = $Path
+            Status = (Get-GitStatus $Path)
+            StatusUpdateIntervalBuffer = 500
+            LastStatusUpdate = ([DateTime]::Now)
+            LastUpdate = ([DateTime]::Now)
+            Watcher = $watcher
+            Changed = Register-ObjectEvent $watcher Changed -Action $watcherAction
+            Created = Register-ObjectEvent $watcher Created -Action $watcherAction
+            Deleted = Register-ObjectEvent $watcher Deleted -Action $watcherAction
+            Renamed = Register-ObjectEvent $watcher Renamed -Action $watcherAction
+            Ignore = @('^\.git$', '^\.git\\index\.lock$', '^\.git\\objects\\')
+        }
+        $GitPromptState.Repositories = $repositories
+    }
+}
+
+function Publish-GitPromptRepositoryUpdated($Path, $File) {
+    if ($GitPromptState -and $GitPromptState.Repositories.ContainsKey($Path)) {
+        $repository = $GitPromptState.Repositories.Get_Item($Path)
+        if ($repository.Ignore | Where-Object { $File -match $_ }) { return }
+        $repository.LastUpdate = [DateTime]::Now
+    }
+}
+
+function Stop-GitPromptRepository($Path) {
+    if ($GitPromptState -and $GitPromptState.Repositories.ContainsKey($Path)) {
+        $repository = $GitPromptState.Repositories[$Path]
+        $repository.Watcher.EnableRaisingEvents = $false
+        Unregister-Event $repository.Changed.Id
+        Unregister-Event $repository.Created.Id
+        Unregister-Event $repository.Deleted.Id
+        Unregister-Event $repository.Renamed.Id
+
+        $repositories = $GitPromptState.Repositories.Clone()
+        $repositories.Remove($Path)
+        $GitPromptState.Repositories = $repositories
+    }
+}
+
+function Update-GitPromptRepository($Path) {
+    if ($GitPromptState -and $GitPromptState.Repositories.ContainsKey($Path) -and (-not $GitPromptState.Asynchronous)) {
+        $repository = $GitPromptState.Repositories[$Path]
+        if ($repository.LastStatusUpdate -lt $repository.LastUpdate) {
+            Push-Location $repository.Path
+            try { $repository.Status = Get-GitStatus $repository.Path }
+            finally { Pop-Location }
+            $repository.LastStatusUpdate = [DateTime]::Now
+        }
+    }
+}
+
+function Get-GitPromptStatus {
+    $Path = Get-GitDirectory
+    if ($Path) {
+        $repositoryPath = Split-Path -parent $Path
+        if ($GitPromptState) {
+            if ($GitPromptState.Repositories.ContainsKey($repositoryPath)) {
+                Update-GitPromptRepository $repositoryPath
+            }
+            else {
+                Start-GitPromptRepository $repositoryPath
+            }
+            $GitPromptState.Repositories[$repositoryPath].Status
+        }
+        else {
+            Get-GitStatus $Path
+        }
+    }
+}

posh-git.psm1

@@ -6,6 +6,7 @@ Push-Location $psScriptRoot
 . ./Utils.ps1
 . ./GitUtils.ps1
 . ./GitPrompt.ps1
+. ./GitPromptAsync.ps1
 . ./GitTabExpansion.ps1
 . ./TortoiseGit.ps1
 Pop-Location
@@ -15,7 +16,12 @@ if (!$Env:HOME) { $Env:HOME = "$Env:USERPROFILE" }
 
 Export-ModuleMember -Function @(
         'Write-GitStatus',
-        'Get-GitStatus', 
+        'Get-GitStatus',
+        'Start-GitPrompt',
+        'Update-GitPromptRepositories',
+        'Publish-GitPromptRepositoryUpdated',
+        'Stop-GitPrompt',
+        'Get-GitPromptStatus',
         'Enable-GitColors', 
         'Get-GitDirectory',
         'TabExpansion',
@@ -24,4 +30,3 @@ Export-ModuleMember -Function @(
         'Stop-SshAgent',
         'Add-SshKey',
         'tgit')
-