From a8f1e11ed24329ab0c30da71e37d00b75cc60fe6 Mon Sep 17 00:00:00 2001
From: "Stefan J. Wernli" <swernli@microsoft.com>
Date: Tue, 21 Jul 2015 12:46:42 -0700
Subject: [PATCH] Adding methods for calling into hcsshim to do string to guid
 hashing.

Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>
---
 hcsshim.go    |  1 +
 nametoguid.go | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 nametoguid.go

diff --git a/hcsshim.go b/hcsshim.go
index c17c96b3a7..6ef12489bb 100644
--- a/hcsshim.go
+++ b/hcsshim.go
@@ -39,6 +39,7 @@ const (
 	procExportLayer         = "ExportLayer"
 	procImportLayer         = "ImportLayer"
 	procGetSharedBaseImages = "GetBaseImages"
+	procNameToGuid          = "NameToGuid"
 
 	// Name of the standard OLE dll
 	oleDLLName = "Ole32.dll"
diff --git a/nametoguid.go b/nametoguid.go
new file mode 100644
index 0000000000..a371e49ca0
--- /dev/null
+++ b/nametoguid.go
@@ -0,0 +1,46 @@
+package hcsshim
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"github.com/Sirupsen/logrus"
+)
+
+func NameToGuid(name string) (id GUID, err error) {
+	title := "hcsshim::NameToGuid "
+	logrus.Debugf(title+"Name %s", name)
+
+	// Load the DLL and get a handle to the procedure we need
+	dll, proc, err := loadAndFind(procNameToGuid)
+	if dll != nil {
+		defer dll.Release()
+	}
+	if err != nil {
+		return
+	}
+
+	// Convert name to uint16 pointer for calling the procedure
+	namep, err := syscall.UTF16PtrFromString(name)
+	if err != nil {
+		err = fmt.Errorf(title+" - Failed conversion of name %s to pointer %s", name, err)
+		logrus.Error(err)
+		return
+	}
+
+	// Call the procedure itself.
+	logrus.Debugf("Calling proc (1)")
+	r1, _, _ := proc.Call(
+		uintptr(unsafe.Pointer(namep)),
+		uintptr(unsafe.Pointer(&id)))
+
+	if r1 != 0 {
+		err = fmt.Errorf(title+" - Win32 API call returned error r1=%d err=%s name=%s",
+			r1, syscall.Errno(r1), name)
+		logrus.Error(err)
+		return
+	}
+
+	return
+}