Prepare for introducing a bunch of new public APIs related to
backup checkpoints by first introducing a new internal type
and errors associated with that type.  Checkpoints are modeled
heavily after virDomainSnapshotPtr (both represent a point in
time of the guest), although a snapshot exists with the intent
of rolling back to that state, while a checkpoint exists to
make it possible to create an incremental backup at a later
time.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 include/libvirt/libvirt-domain-snapshot.h |  8 ++--
 include/libvirt/libvirt.h                 |  2 +
 include/libvirt/virterror.h               |  5 ++-
 src/datatypes.c                           | 62 ++++++++++++++++++++++++++++++-
 src/datatypes.h                           | 31 +++++++++++++++-
 src/libvirt_private.syms                  |  2 +
 src/util/virerror.c                       | 15 +++++++-
 7 files changed, 118 insertions(+), 7 deletions(-)

diff --git a/include/libvirt/libvirt-domain-snapshot.h b/include/libvirt/libvirt-domain-snapshot.h
index e5a893a767..ff1e890cfc 100644
--- a/include/libvirt/libvirt-domain-snapshot.h
+++ b/include/libvirt/libvirt-domain-snapshot.h
@@ -31,15 +31,17 @@
 /**
  * virDomainSnapshot:
  *
- * a virDomainSnapshot is a private structure representing a snapshot of
- * a domain.
+ * A virDomainSnapshot is a private structure representing a snapshot of
+ * a domain.  A snapshot captures the state of the domain at a point in
+ * time, with the intent that the guest can be reverted back to that
+ * state at a later time.

  */
 typedef struct _virDomainSnapshot virDomainSnapshot;

 /**
  * virDomainSnapshotPtr:
  *
- * a virDomainSnapshotPtr is pointer to a virDomainSnapshot private structure,
+ * A virDomainSnapshotPtr is pointer to a virDomainSnapshot private structure,
  * and is the type used to reference a domain snapshot in the API.
  */

 typedef virDomainSnapshot *virDomainSnapshotPtr;
diff --git a/include/libvirt/libvirt.h b/include/libvirt/libvirt.h
index 36f6d60775..26887a40e7 100644
--- a/include/libvirt/libvirt.h
+++ b/include/libvirt/libvirt.h
@@ -36,6 +36,8 @@ extern "C" {
 # include <libvirt/libvirt-common.h>
 # include <libvirt/libvirt-host.h>
 # include <libvirt/libvirt-domain.h>
+typedef struct _virDomainCheckpoint virDomainCheckpoint;
+typedef virDomainCheckpoint *virDomainCheckpointPtr;
 # include <libvirt/libvirt-domain-snapshot.h>
 # include <libvirt/libvirt-event.h>
 # include <libvirt/libvirt-interface.h>
diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h
index 5e58b6a3f9..87ac16be0b 100644
--- a/include/libvirt/virterror.h
+++ b/include/libvirt/virterror.h
@@ -4,7 +4,7 @@
  * Description: Provides the interfaces of the libvirt library to handle
  *              errors raised while using the library.
  *
- * Copyright (C) 2006-2016 Red Hat, Inc.
+ * Copyright (C) 2006-2018 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -133,6 +133,7 @@ typedef enum {
     VIR_FROM_PERF = 65,         /* Error from perf */
     VIR_FROM_LIBSSH = 66,       /* Error from libssh connection transport */
     VIR_FROM_RESCTRL = 67,      /* Error from resource control */
+    VIR_FROM_DOMAIN_CHECKPOINT = 68,/* Error from domain checkpoint */

 # ifdef VIR_ENUM_SENTINELS
     VIR_ERR_DOMAIN_LAST
@@ -321,6 +322,8 @@ typedef enum {
                                            to guest-sync command (DEPRECATED)*/
     VIR_ERR_LIBSSH = 98,                /* error in libssh transport driver */
     VIR_ERR_DEVICE_MISSING = 99,        /* fail to find the desired device */
+    VIR_ERR_INVALID_DOMAIN_CHECKPOINT = 100,/* invalid domain checkpoint */

+    VIR_ERR_NO_DOMAIN_CHECKPOINT = 101, /* domain checkpoint not found */ 

 } virErrorNumber;

 /**
diff --git a/src/datatypes.c b/src/datatypes.c
index 09b8eea5a2..3c9069c938 100644
--- a/src/datatypes.c
+++ b/src/datatypes.c
@@ -1,7 +1,7 @@
 /*
  * datatypes.c: management of structs for public data types
  *
- * Copyright (C) 2006-2015 Red Hat, Inc.
+ * Copyright (C) 2006-2018 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -36,6 +36,7 @@ VIR_LOG_INIT("datatypes");
 virClassPtr virConnectClass;
 virClassPtr virConnectCloseCallbackDataClass;
 virClassPtr virDomainClass;
+virClassPtr virDomainCheckpointClass;
 virClassPtr virDomainSnapshotClass;
 virClassPtr virInterfaceClass;
 virClassPtr virNetworkClass;
@@ -49,6 +50,7 @@ virClassPtr virStoragePoolClass;
 static void virConnectDispose(void *obj);
 static void virConnectCloseCallbackDataDispose(void *obj);
 static void virDomainDispose(void *obj);
+static void virDomainCheckpointDispose(void *obj);
 static void virDomainSnapshotDispose(void *obj);
 static void virInterfaceDispose(void *obj);
 static void virNetworkDispose(void *obj);
@@ -84,6 +86,7 @@ virDataTypesOnceInit(void)
     DECLARE_CLASS_LOCKABLE(virConnect);
     DECLARE_CLASS_LOCKABLE(virConnectCloseCallbackData);
     DECLARE_CLASS(virDomain);
+    DECLARE_CLASS(virDomainCheckpoint);
     DECLARE_CLASS(virDomainSnapshot);
     DECLARE_CLASS(virInterface);
     DECLARE_CLASS(virNetwork);
@@ -887,6 +890,63 @@ virDomainSnapshotDispose(void *obj)
 }


+/**
+ * virGetDomainCheckpoint:
+ * @domain: the domain to checkpoint
+ * @name: pointer to the domain checkpoint name
+ *
+ * Allocates a new domain checkpoint object. When the object is no longer needed,
+ * virObjectUnref() must be called in order to not leak data.
+ *
+ * Returns a pointer to the domain checkpoint object, or NULL on error.
+ */
+virDomainCheckpointPtr
+virGetDomainCheckpoint(virDomainPtr domain, const char *name)
+{
+    virDomainCheckpointPtr ret = NULL;
+
+    if (virDataTypesInitialize() < 0)
+        return NULL;
+
+    virCheckDomainGoto(domain, error);
+    virCheckNonNullArgGoto(name, error);

+
+    if (!(ret = virObjectNew(virDomainCheckpointClass)))
+        goto error;
+    if (VIR_STRDUP(ret->name, name) < 0)
+        goto error;
+
+    ret->domain = virObjectRef(domain);
+
+    return ret;
+
+ error:
+    virObjectUnref(ret);
+    return NULL;
+}
+
+
+/**
+ * virDomainCheckpointDispose:
+ * @obj: the domain checkpoint to release
+ *
+ * Unconditionally release all memory associated with a checkpoint.
+ * The checkpoint object must not be used once this method returns.
+ *
+ * It will also unreference the associated connection object,
+ * which may also be released if its ref count hits zero.
+ */
+static void
+virDomainCheckpointDispose(void *obj)
+{
+    virDomainCheckpointPtr checkpoint = obj;
+    VIR_DEBUG("release checkpoint %p %s", checkpoint, checkpoint->name);
+
+    VIR_FREE(checkpoint->name);
+    virObjectUnref(checkpoint->domain);
+}
+
+
 virAdmConnectPtr
 virAdmConnectNew(void)
 {
diff --git a/src/datatypes.h b/src/datatypes.h
index 192c86be80..fbe842d105 100644
--- a/src/datatypes.h
+++ b/src/datatypes.h
@@ -1,7 +1,7 @@
 /*
  * datatypes.h: management of structs for public data types
  *
- * Copyright (C) 2006-2015 Red Hat, Inc.
+ * Copyright (C) 2006-2018 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -31,6 +31,7 @@

 extern virClassPtr virConnectClass;
 extern virClassPtr virDomainClass;
+extern virClassPtr virDomainCheckpointClass;
 extern virClassPtr virDomainSnapshotClass;
 extern virClassPtr virInterfaceClass;
 extern virClassPtr virNetworkClass;
@@ -292,6 +293,21 @@ extern virClassPtr virAdmClientClass;
         } \
     } while (0)

+# define virCheckDomainCheckpointReturn(obj, retval) \
+    do { \
+        virDomainCheckpointPtr _check = (obj); \
+        if (!virObjectIsClass(_check, virDomainCheckpointClass) || \
+            !virObjectIsClass(_check->domain, virDomainClass) || \
+            !virObjectIsClass(_check->domain->conn, virConnectClass)) { \
+            virReportErrorHelper(VIR_FROM_DOMAIN_CHECKPOINT, \
+                                 VIR_ERR_INVALID_DOMAIN_CHECKPOINT, \
+                                 __FILE__, __FUNCTION__, __LINE__, \
+                                 __FUNCTION__); \

+            virDispatchError(NULL); \
+            return retval; \
+        } \
+    } while (0)
+

 /* Helper macros to implement VIR_DOMAIN_DEBUG using just C99.  This
  * assumes you pass fewer than 15 arguments to VIR_DOMAIN_DEBUG, but
@@ -652,6 +668,17 @@ struct _virStream {
     void *privateData;
 };

+/**
+ * _virDomainCheckpoint
+ *
+ * Internal structure associated with a domain checkpoint
+ */
+struct _virDomainCheckpoint {
+    virObject parent;
+    char *name;
+    virDomainPtr domain;
+};
+
 /**
  * _virDomainSnapshot
  *
@@ -712,6 +739,8 @@ virStreamPtr virGetStream(virConnectPtr conn);
 virNWFilterPtr virGetNWFilter(virConnectPtr conn,
                               const char *name,
                               const unsigned char *uuid);
+virDomainCheckpointPtr virGetDomainCheckpoint(virDomainPtr domain,
+                                              const char *name);

 virDomainSnapshotPtr virGetDomainSnapshot(virDomainPtr domain,
                                           const char *name);

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index ea24f2847c..4686c775a5 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1183,10 +1183,12 @@ virConnectCloseCallbackDataClass;
 virConnectCloseCallbackDataGetCallback;
 virConnectCloseCallbackDataRegister;
 virConnectCloseCallbackDataUnregister;
+virDomainCheckpointClass;
 virDomainClass;
 virDomainSnapshotClass;
 virGetConnect;
 virGetDomain;
+virGetDomainCheckpoint;
 virGetDomainSnapshot;
 virGetInterface;
 virGetNetwork;
diff --git a/src/util/virerror.c b/src/util/virerror.c
index 93632dbdf7..1e6fd77abf 100644
--- a/src/util/virerror.c
+++ b/src/util/virerror.c
@@ -1,7 +1,7 @@
 /*
  * virerror.c: error handling and reporting code for libvirt
  *
- * Copyright (C) 2006, 2008-2016 Red Hat, Inc.
+ * Copyright (C) 2006, 2008-2018 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -140,6 +140,7 @@ VIR_ENUM_IMPL(virErrorDomain, VIR_ERR_DOMAIN_LAST,
               "Perf", /* 65 */
               "Libssh transport layer",
               "Resource control",
+              "Domain Checkpoint",
     )


@@ -1494,6 +1495,18 @@ virErrorMsg(virErrorNumber error, const char *info)
             else
                 errmsg = _("device not found: %s");
             break;
+        case VIR_ERR_INVALID_DOMAIN_CHECKPOINT:
+            if (info == NULL)
+                errmsg = _("Invalid checkpoint");
+            else
+                errmsg = _("Invalid checkpoint: %s");
+            break;
+        case VIR_ERR_NO_DOMAIN_CHECKPOINT:
+            if (info == NULL)
+                errmsg = _("Domain snapshot not found");
+            else
+                errmsg = _("Domain snapshot not found: %s");
+            break;
     }
     return errmsg;
 }
--
2.14.4