Add typed native WEC runtime observations (#424)

* Observe typed native WEC subscription runtime status

* Link typed WEC runtime changelog to PR 424

* Pass a native null source for subscription runtime queries

* Ignore unused count storage for native null WEC variants

* Keep unavailable WEC source inventories unknown and diagnose native XML reads

* Read native WEC subscription XML with bounded explicit Unicode pipes

* Use bounded Unicode subscription reads in runtime observations and cleanup

* Decode native WEC XML BOMs without unsupported Unicode switch

* Describe strict native WEC XML byte decoding

* Reference System.Xml explicitly when compiling under Windows PowerShell

* Regenerate website changelog snapshots with their proper headers

modules/WecSubscriptionXml.cs

@@ -0,0 +1,58 @@
+// Bounded native XML bytes, decoded independently of the PowerShell console code page.
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using System.Xml;
+namespace Wela.WecXml {
+ public static class Reader {
+  static async Task<byte[]> ReadBounded(Stream stream,int maximum) {
+   using(MemoryStream output=new MemoryStream()) {
+    byte[] buffer=new byte[8192];int count;
+    while((count=await stream.ReadAsync(buffer,0,buffer.Length).ConfigureAwait(false))!=0) {
+     if(output.Length+count>maximum)throw new IOException("Native WEC output exceeds its byte limit.");
+     output.Write(buffer,0,count);
+    }
+    return output.ToArray();
+   }
+  }
+  public static string DecodeXml(byte[] bytes) {
+   if(bytes==null||bytes.Length==0||bytes.Length>10485760)throw new InvalidDataException("Expected bounded native WEC XML bytes.");
+   int skip=0;Encoding encoding=new UTF8Encoding(false,true);
+   if(bytes.Length>=3&&bytes[0]==239&&bytes[1]==187&&bytes[2]==191){skip=3;}
+   else if(bytes.Length>=2&&bytes[0]==255&&bytes[1]==254){skip=2;encoding=new UnicodeEncoding(false,false,true);}
+   else if(bytes.Length>=2&&bytes[0]==254&&bytes[1]==255){skip=2;encoding=new UnicodeEncoding(true,false,true);}
+   else if(bytes.Length>=4&&bytes[0]==60&&bytes[1]==0){encoding=new UnicodeEncoding(false,false,true);}
+   else if(bytes.Length>=4&&bytes[0]==0&&bytes[1]==60){encoding=new UnicodeEncoding(true,false,true);}
+   string text=encoding.GetString(bytes,skip,bytes.Length-skip);
+   XmlReaderSettings settings=new XmlReaderSettings();settings.DtdProcessing=DtdProcessing.Prohibit;settings.XmlResolver=null;settings.MaxCharactersInDocument=10485760;
+   using(XmlReader reader=XmlReader.Create(new StringReader(text),settings)){while(reader.Read()){};}
+   return text;
+  }
+  public static string ReadXml(string id) {
+   if(id==null||!Regex.IsMatch(id,@"\A[A-Za-z0-9][A-Za-z0-9 ._-]{0,127}\z"))throw new ArgumentException("Select one exact supported subscription ID.");
+   ProcessStartInfo start=new ProcessStartInfo();start.FileName=Path.Combine(Environment.SystemDirectory,"wecutil.exe");
+   start.Arguments="gs \""+id+"\" /f:xml";start.UseShellExecute=false;start.CreateNoWindow=true;start.RedirectStandardOutput=true;start.RedirectStandardError=true;
+   using(Process process=new Process()) {
+    process.StartInfo=start;bool started=false;
+    try {
+     started=process.Start();if(!started)throw new IOException("Native WEC process did not start.");
+     Stopwatch timer=Stopwatch.StartNew();Task<byte[]> output=ReadBounded(process.StandardOutput.BaseStream,10485760);Task<byte[]> error=ReadBounded(process.StandardError.BaseStream,65536);
+     while(!process.WaitForExit(100)) {
+      if(output.IsFaulted||error.IsFaulted)throw new IOException("Native WEC output could not be read within its bounds.");
+      if(timer.ElapsedMilliseconds>=30000)throw new TimeoutException("Native WEC definition read exceeded thirty seconds.");
+     }
+     int remaining=Math.Max(1,30000-(int)timer.ElapsedMilliseconds);
+     if(!Task.WaitAll(new Task[]{output,error},remaining))throw new TimeoutException("Native WEC output did not complete within thirty seconds.");
+     if(process.ExitCode!=0)throw new IOException("Native WEC definition read failed with exit code "+process.ExitCode+"; no definition was accepted.");
+     if(error.Result.Length!=0)throw new IOException("Native WEC returned unexpected diagnostic bytes; no definition was accepted.");
+     return DecodeXml(output.Result);
+    } finally {
+     if(started){try{if(!process.HasExited){process.Kill();process.WaitForExit(1000);}}catch(InvalidOperationException){}}
+    }
+   }
+  }
+ }
+}

modules/WefSubscriptions.psm1

@@ -159,4 +159,17 @@ function Import-WelaWefConfig {
     [pscustomobject]@{ Config=$config; Path=$full; Subscriptions=$subscriptions }
 }
 
-Export-ModuleMember -Function Read-WelaWefXml, Get-WelaWefXmlKey, ConvertFrom-WelaWefQuery, Get-WelaWefAuthorization, ConvertFrom-WelaWefSubscription, Import-WelaWefConfig
+function Read-WelaWecSubscriptionXml {
+    param([Parameter(Mandatory)][string]$Id)
+    if([Environment]::OSVersion.Platform -ne [PlatformID]::Win32NT -or -not [Environment]::Is64BitProcess){throw 'Native WEC XML reads require 64-bit Windows.'}
+    $path=Join-Path $PSScriptRoot 'WecSubscriptionXml.cs';$hash=(Get-FileHash -LiteralPath $path -Algorithm SHA256 -ErrorAction Stop).Hash
+    if(-not ('Wela.WecXml.Reader' -as [type])){
+        $compile=@{Path=$path;ErrorAction='Stop'}
+        if($PSVersionTable.PSEdition -eq 'Desktop'){$compile.ReferencedAssemblies=@('System.dll','System.Core.dll','System.Xml.dll')}
+        Add-Type @compile;$script:WelaWecXmlSourceHash=$hash
+    }
+    if($script:WelaWecXmlSourceHash -cne $hash){throw 'Loaded native WEC XML reader differs from its source; start a fresh session.'}
+    [Wela.WecXml.Reader]::ReadXml($Id)
+}
+
+Export-ModuleMember -Function Read-WelaWecSubscriptionXml, Read-WelaWefXml, Get-WelaWefXmlKey, ConvertFrom-WelaWefQuery, Get-WelaWefAuthorization, ConvertFrom-WelaWefSubscription, Import-WelaWefConfig