Fix OpenConsole.psm1 to use vswhere (#1113)

* Fix OpenConsole.psm1 to use vswhere

I'm not sure this is good, since I don't write a lot of powershell, and
I don't know the project very well, but hopefully it's good!

* Do as @DHowett-MSFT says and use VSSetup

whee!

* try to do what @heaths is recommending

* fix `Import-LocalModule`

* fix openconsole.psm1 for hopefully the last time

.gitignore

@@ -263,6 +263,9 @@ build*.metadata
 
 # .razzlerc.cmd file - used by dev environment
 tools/.razzlerc.*
+# .PowershellModules - if one needs a powershell module dependency, one
+# can save it here. used by tools/OpenConsole.psm1
+.PowershellModules
 # message compiler output
 MSG*.bin
 /*.exe

tools/OpenConsole.psm1

@@ -2,21 +2,87 @@
 # The project's root directory.
 Set-Item -force -path "env:OpenConsoleRoot" -value "$PSScriptRoot\.."
 
+#.SYNOPSIS
+# Finds and imports a module that should be local to the project
+#.PARAMETER ModuleName
+# The name of the module to import
+function Import-LocalModule
+{
+    [CmdletBinding()]
+    param(
+        [parameter(Mandatory=$true, Position=0)]
+        [string]$Name
+    )
+
+    $ErrorActionPreference = 'Stop'
+
+    $modules_root = "$env:OpenConsoleRoot\.PowershellModules"
+
+    $local = $null -eq (Get-Module -Name $Name)
+
+    if (-not $local)
+    {
+        return
+    }
+
+    if (-not (Test-Path $modules_root)) {
+        New-Item $modules_root -ItemType 'directory' | Out-Null
+    }
+
+    if (-not (Test-Path "$modules_root\$Name")) {
+        Write-Verbose "$Name not downloaded -- downloading now"
+        $module = Find-Module "$Name"
+        $version = $module.Version
+
+        Write-Verbose "Saving $Name to $modules_root"
+        Save-Module -InputObject $module -Path $modules_root
+        Import-Module "$modules_root\$Name\$version\$Name.psd1"
+    } else {
+        Write-Verbose "$Name already downloaded"
+        $versions = Get-ChildItem "$modules_root\$Name" | Sort-Object
+
+        Get-ChildItem -Path $versions[0] "$Name.psd1" | Import-Module
+    }
+}
+
 #.SYNOPSIS
 # Grabs all environment variable set after vcvarsall.bat is called and pulls
 # them into the Powershell environment.
-function Set-MsbuildDevEnvironment()
+function Set-MsbuildDevEnvironment
 {
-    $path = "$env:VS140COMNTOOLS\..\.."
-    pushd $path
-    cmd /c "vcvarsall.bat&set" | foreach {
-        if ($_ -match "=")
+    [CmdletBinding()]
+    param()
+
+    $ErrorActionPreference = 'Stop'
+
+    Import-LocalModule -Name 'VSSetup'
+
+    Write-Verbose 'Searching for VC++ instances'
+    $vsinfo = `
+        Get-VSSetupInstance  -All `
+        | Select-VSSetupInstance `
+            -Latest -Product * `
+            -Require 'Microsoft.VisualStudio.Component.VC.Tools.x86.x64'
+
+    $vspath = $vsinfo.InstallationPath
+
+    switch ($env:PROCESSOR_ARCHITECTURE) {
+        "amd64" { $arch = "x64" }
+        "x86" { $arch = "x86" }
+        default { throw "Unknown architecture: $switch" }
+    }
+
+    $vcvarsall = "$vspath\VC\Auxiliary\Build\vcvarsall.bat"
+
+    Write-Verbose 'Setting up environment variables'
+    cmd /c ("`"$vcvarsall`" $arch & set") | ForEach-Object {
+        if ($_ -match '=')
         {
             $s = $_.Split("=");
             Set-Item -force -path "env:\$($s[0])" -value "$($s[1])"
         }
     }
-    popd
+
     Write-Host "Dev environment variables set" -ForegroundColor Green
 }