Enhance checking of prerequisites in the vsixtest tool.

FossilOrigin-Name: 799d5f09ed058898167e43bd9c8d1bf8c5df23ba

manifest

@@ -1,5 +1,5 @@
-C Improve\sreadability\sand\slogging\sof\sthe\svsixtest\sscript.
-D 2016-02-25T08:02:16.943
+C Enhance\schecking\sof\sprerequisites\sin\sthe\svsixtest\stool.
+D 2016-02-25T23:22:26.535
 F Makefile.in 4e90dc1521879022aa9479268a4cd141d1771142
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 28fc4ee02333996d31b3602b39eeb8e609a89ce4
@@ -1446,11 +1446,11 @@ F vsixtest/Package.appxmanifest 6b6db1eb7df3a315c5d681059754d5f0e0c47a93
 F vsixtest/pch.cpp cb823cfac36f1a39a7eb0acbd7e9a0b0de8f23af
 F vsixtest/pch.h 9cab7980f2ac4baa40807d8b5e52af32a21cf78c
 F vsixtest/vsixtest.sln 77cadbe4e96c1fe1bf51cd77de9e9b0a12ada547
-F vsixtest/vsixtest.tcl 41268d1a0937c517f3c2e3f6538c90da70d155f8
+F vsixtest/vsixtest.tcl 463b7aa846f8f1bdadf2aadb1ac84c34c247437c
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 788f99f47f40be42f30d3f324983f39e84d8cfbb
-R 27bc664c4897fa05fbab9ef38c37f4b7
+P 4fe7c4e90b7adbb1630b4aa15709968a1fcc7d83
+R fa3049ef82e4175b0a6df31159094b76
 U mistachkin
-Z e145e455c738e58b5464d9cf81ba3318
+Z bc452bd15f3f1d06988b3918e97baf68

manifest.uuid

@@ -1 +1 @@
-4fe7c4e90b7adbb1630b4aa15709968a1fcc7d83
+799d5f09ed058898167e43bd9c8d1bf8c5df23ba

vsixtest/vsixtest.tcl

@@ -45,6 +45,44 @@ proc fail { {error ""} {usage false} } {
   exit 1
 }
 
+proc isWindows {} {
+  #
+  # NOTE: Returns non-zero only when running on Windows.
+  #
+  return [expr {[info exists ::tcl_platform(platform)] && \
+      $::tcl_platform(platform) eq "windows"}]
+}
+
+proc isAdministrator {} {
+  #
+  # NOTE: Returns non-zero only when running as "elevated administrator".
+  #
+  if {[isWindows]} then {
+    if {[catch {exec -- whoami /groups} groups] == 0} then {
+      set groups [string map [list \r\n \n] $groups]
+
+      foreach group [split $groups \n] {
+        #
+        # NOTE: Match this group line against the "well-known" SID for
+        #       the "Administrators" group on Windows.
+        #
+        if {[regexp -- {\sS-1-5-32-544\s} $group]} then {
+          #
+          # NOTE: Match this group line against the attributes column
+          #       sub-value that should be present when running with
+          #       elevated administrator credentials.
+          #
+          if {[regexp -- {\sEnabled group(?:,|\s)} $group]} then {
+            return true
+          }
+        }
+      }
+    }
+  }
+
+  return false
+}
+
 proc getEnvironmentVariable { name } {
   #
   # NOTE: Returns the value of the specified environment variable or an empty
@@ -157,6 +195,14 @@ if {[string length $script] == 0} then {
   fail "script file currently being evaluated is unknown" true
 }
 
+if {![isWindows]} then {
+  fail "this tool only works properly on Windows"
+}
+
+if {![isAdministrator]} then {
+  fail "this tool must run with \"elevated administrator\" privileges"
+}
+
 set path [file normalize [file dirname $script]]
 set argc [llength $argv]; if {$argc > 1} then {fail "" true}