Check CEF for consistency after downloading

Revert to old method of computing hash (CertUtil) because escaping batch
scripts is broken

Author: qaisjp

utils/buildactions/install_cef.lua

@@ -105,8 +105,8 @@ newaction {
 			return
 		end
 
+		local downloaded_hash = os.sha256_file(archive_path)
 		if upgrade then
-			local downloaded_hash = os.sha256_file(archive_path)
 			print("New CEF hash is:", downloaded_hash)
 			CEF_HASH = downloaded_hash
 
@@ -117,6 +117,14 @@ newaction {
 			end
 		end
 
+		if downloaded_hash == CEF_HASH then
+			print("CEF consistency checks succeeded")
+		else
+			errormsg("CEF consistency checks failed.", ("Expected %s, got %s"):format(CEF_HASH, downloaded_hash))
+			os.exit(1)
+			return
+		end
+
 		-- Seriously abort now if we're not using Windows
 		if os.host() ~= "windows" then
 			return

utils/buildactions/utils.lua

@@ -84,16 +84,25 @@ function os.expanddir_wildcard(from, to)
 end
 
 function os.sha256_file(path)
+	local windows = os.host() == "windows"
 	local s, errc
-	if os.host() == "windows" then
-		s, errc = os.outputof(string.format("powershell -Command (Get-FileHash \"%s\" -Algorithm SHA256).Hash", path))
+	if windows then
+		s, errc = os.outputof(string.format("CertUtil -hashfile \"%s\" SHA256", path))
 	else
 		s, errc = os.outputof(string.format("sha256sum \"%s\" | awk '{ print $1 }'", path))
 	end
+
+	-- Check for error
 	if errc ~= 0 then
 		print("Error os.sha256_file: ", errc)
 		return ""
 	end
+
+	-- Clean windows output
+	if windows then
+		s = (s:match("\n(.*)\n(.*)") or ""):gsub(" ", "")
+	end
+
 	return s:lower()
 end