From 1599319c7e31b8351e7ce2ed17abaa37d86dd3d6 Mon Sep 17 00:00:00 2001
From: Taowei Luo <uaedante@gmail.com>
Date: Fri, 24 Oct 2014 09:46:43 +0800
Subject: [PATCH] vbox: Make FindMedium support old vbox versions

In old version, function FindMedium in UIVirtualBox doesn't work
for vbox2.2 and 3.0. We assume it will not be used when vbox in
these versions.

But when rewriting vboxStorageVolLookupByPath, we found it was
compatibe to use FindMedium to get a IHardDisk object, even in
vbox old versions. To achieve this, first make FindMedium call
FindHardDisk when VBOX_API_VERSION < 4000000.
Then change the argument type **IMedium to **IHardDisk. (As the
rules in heriachy, we can't transfer a IHardDisk to match
IMedium in output)

In vbox 2.2 and 3.0, the caller must be aware that they will get
a IHardDisk object in return.
---
 src/vbox/vbox_common.c        |  4 ++--
 src/vbox/vbox_tmpl.c          | 29 +++++++++++++++--------------
 src/vbox/vbox_uniformed_api.h |  3 ++-
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/vbox/vbox_common.c b/src/vbox/vbox_common.c
index 22f3198a96..e0836ec0c4 100644
--- a/src/vbox/vbox_common.c
+++ b/src/vbox/vbox_common.c
@@ -1081,8 +1081,8 @@ vboxAttachDrivesNew(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine
                 continue;
             }
 
-            gVBoxAPI.UIVirtualBox.FindMedium(data->vboxObj, mediumFileUtf16,
-                                             deviceType, accessMode, &medium);
+            gVBoxAPI.UIVirtualBox.FindHardDisk(data->vboxObj, mediumFileUtf16,
+                                               deviceType, accessMode, &medium);
 
             if (!medium) {
                 PRUnichar *mediumEmpty = NULL;
diff --git a/src/vbox/vbox_tmpl.c b/src/vbox/vbox_tmpl.c
index e8cfa98b6b..6c4cd734af 100644
--- a/src/vbox/vbox_tmpl.c
+++ b/src/vbox/vbox_tmpl.c
@@ -3553,22 +3553,23 @@ _virtualboxRegisterMachine(IVirtualBox *vboxObj, IMachine *machine)
 }
 
 static nsresult
-_virtualboxFindMedium(IVirtualBox *vboxObj ATTRIBUTE_UNUSED,
-                      PRUnichar *location ATTRIBUTE_UNUSED,
-                      PRUint32 deviceType ATTRIBUTE_UNUSED,
-                      PRUint32 accessMode ATTRIBUTE_UNUSED,
-                      IMedium **medium ATTRIBUTE_UNUSED)
+_virtualboxFindHardDisk(IVirtualBox *vboxObj, PRUnichar *location,
+                        PRUint32 deviceType ATTRIBUTE_UNUSED,
+                        PRUint32 accessMode ATTRIBUTE_UNUSED,
+                        IHardDisk **hardDisk)
 {
-#if VBOX_API_VERSION >= 4000000 && VBOX_API_VERSION < 4002000
+    /* In vbox 2.2 and 3.0, this function will create a IHardDisk object.
+     * In vbox 3.1 and later, this function will create a IMedium object.
+     */
+#if VBOX_API_VERSION < 4000000
+    return vboxObj->vtbl->FindHardDisk(vboxObj, location, hardDisk);
+#elif VBOX_API_VERSION < 4002000
     return vboxObj->vtbl->FindMedium(vboxObj, location,
-                                     deviceType, medium);
-#elif VBOX_API_VERSION >= 4002000
+                                     deviceType, hardDisk);
+#else /* VBOX_API_VERSION >= 4002000 */
     return vboxObj->vtbl->OpenMedium(vboxObj, location,
-                                     deviceType, accessMode, PR_FALSE, medium);
-#else
-    vboxUnsupported();
-    return 0;
-#endif
+                                     deviceType, accessMode, PR_FALSE, hardDisk);
+#endif /* VBOX_API_VERSION >= 4002000 */
 }
 
 static nsresult
@@ -5287,7 +5288,7 @@ static vboxUniformedIVirtualBox _UIVirtualBox = {
     .CreateMachine = _virtualboxCreateMachine,
     .CreateHardDiskMedium = _virtualboxCreateHardDiskMedium,
     .RegisterMachine = _virtualboxRegisterMachine,
-    .FindMedium = _virtualboxFindMedium,
+    .FindHardDisk = _virtualboxFindHardDisk,
     .OpenMedium = _virtualboxOpenMedium,
     .GetHardDiskByIID = _virtualboxGetHardDiskByIID,
     .FindDHCPServerByNetworkName = _virtualboxFindDHCPServerByNetworkName,
diff --git a/src/vbox/vbox_uniformed_api.h b/src/vbox/vbox_uniformed_api.h
index cdc2ebef47..385502f491 100644
--- a/src/vbox/vbox_uniformed_api.h
+++ b/src/vbox/vbox_uniformed_api.h
@@ -196,7 +196,8 @@ typedef struct {
     nsresult (*CreateMachine)(vboxGlobalData *data, virDomainDefPtr def, IMachine **machine, char *uuidstr);
     nsresult (*CreateHardDiskMedium)(IVirtualBox *vboxObj, PRUnichar *format, PRUnichar *location, IMedium **medium);
     nsresult (*RegisterMachine)(IVirtualBox *vboxObj, IMachine *machine);
-    nsresult (*FindMedium)(IVirtualBox *vboxObj, PRUnichar *location, PRUint32 deviceType, PRUint32 accessMode, IMedium **medium);
+    nsresult (*FindHardDisk)(IVirtualBox *vboxObj, PRUnichar *location, PRUint32 deviceType,
+                             PRUint32 accessMode, IHardDisk **hardDisk);
     nsresult (*OpenMedium)(IVirtualBox *vboxObj, PRUnichar *location, PRUint32 deviceType, PRUint32 accessMode, IMedium **medium);
     nsresult (*GetHardDiskByIID)(IVirtualBox *vboxObj, vboxIIDUnion *iidu, IHardDisk **hardDisk);
     nsresult (*FindDHCPServerByNetworkName)(IVirtualBox *vboxObj, PRUnichar *name, IDHCPServer **server);