Re: [libvirt] [python PATCH] build: make it easier to backport event ids

In some cases, it is very easy for downstream distros to backport enum values without requiring a .so bump. Keying the conditional code off of the upstream version where the enum value was added is not ideal, because downstream then has to patch that the feature is available in their build that still reports an earlier version number. For example, if RHEL 7 backports events from 1.2.11 into a build based on 1.2.8, building the python bindings would warn: libvirt-override.c: In function ‘libvirt_virConnectDomainEventRegisterAny’: libvirt-override.c:6653:5: warning: enumeration value ‘VIR_DOMAIN_EVENT_ID_TUNABLE’ not handled in switch [-Wswitch] switch ((virDomainEventID) eventID) { ^ libvirt-override.c:6653:5: warning: enumeration value ‘VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE’ not handled in switch [-Wswitch] The solution is simple - use feature-based probes instead of version probes. Since we already scrape the XML API document of whatever libvirt build we are binding, and that XML already documents any downstream enum additions, we can use those as the features for gating conditional compilation. * generator.py (enum): Track event id names. (buildStubs): Output define wrappers for events. * libvirt-override.c (libvirt_virConnectDomainEventBalloonChangeCallback) (libvirt_virConnectDomainEventPMSuspendDiskCallback) (libvirt_virConnectDomainEventDeviceRemovedCallback) (libvirt_virConnectDomainEventTunableCallback) (libvirt_virConnectDomainEventAgentLifecycleCallback) (libvirt_virConnectDomainEventRegisterAny): Use them. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- I mentioned this idea on the list a while back, and finally got time to code it up in a much nicer way than my initial attempt that would have polluted libvirt.h proper. https://www.redhat.com/archives/libvir-list/2014-October/msg00186.html I'm relatively weak at python, and welcome to suggestions on how to avoid the long line in generator.py (maybe a regex match on VIR_.*_EVENT_ID_, but what's the canonical way to write that in python?) generator.py | 11 +++++++++-- libvirt-override.c | 46 +++++++++++++++++++++++----------------------- 2 files changed, 32 insertions(+), 25 deletions(-) diff --git a/generator.py b/generator.py index cf044c9..4fd6d55 100755 --- a/generator.py +++ b/generator.py @@ -9,6 +9,7 @@ qemu_functions = {} enums = {} # { enumType: { enumConstant: enumValue } } lxc_enums = {} # { enumType: { enumConstant: enumValue } } qemu_enums = {} # { enumType: { enumConstant: enumValue } } +event_ids = [] import os import sys @@ -219,6 +220,8 @@ def lxc_function(name, desc, ret, args, file, module, cond): def enum(type, name, value): if type not in enums: enums[type] = {} + if name.startswith('VIR_DOMAIN_EVENT_ID_') or name.startswith('VIR_NETWORK_EVENT_ID_'): + event_ids.append(name)

if value == 'VIR_TYPED_PARAM_INT': value = 1 elif value == 'VIR_TYPED_PARAM_UINT': @@ -910,10 +913,10 @@ def buildStubs(module, api_xml): wrapper_file = "build/%s.c" % module include = open(header_file, "w") - include.write("/* Generated */\n\n") + include.write("/* Generated by generator.py */\n\n") export = open(export_file, "w") - export.write("/* Generated */\n\n") + export.write("/* Generated by generator.py */\n\n") wrapper = open(wrapper_file, "w") wrapper.write("/* Generated by generator.py */\n\n") @@ -943,6 +946,10 @@ def buildStubs(module, api_xml): # Write C pointer conversion functions. for classname in primary_classes: print_c_pointer(classname, wrapper, export, include) + # Write define wrappers around event id enums + include.write("\n") + for event_id in event_ids: + include.write("#define %s %s\n" % (event_id, event_id))

include.close() export.close() diff --git a/libvirt-override.c b/libvirt-override.c index e51c44d..88cb527 100644 --- a/libvirt-override.c +++ b/libvirt-override.c @@ -4,7 +4,7 @@ * entry points where an automatically generated stub is * unpractical * - * Copyright (C) 2005, 2007-2014 Red Hat, Inc. + * Copyright (C) 2005, 2007-2015 Red Hat, Inc. * * Daniel Veillard <veillard(a)redhat.com&gt; */ @@ -6346,7 +6346,7 @@ libvirt_virConnectDomainEventPMSuspendCallback(virConnectPtr conn ATTRIBUTE_UNUS } -#if LIBVIR_CHECK_VERSION(0, 10, 0) +#ifdef VIR_DOMAIN_EVENT_ID_BALLOON_CHANGE static int libvirt_virConnectDomainEventBalloonChangeCallback(virConnectPtr conn ATTRIBUTE_UNUSED, virDomainPtr dom, @@ -6398,9 +6398,9 @@ libvirt_virConnectDomainEventBalloonChangeCallback(virConnectPtr conn ATTRIBUTE_ LIBVIRT_RELEASE_THREAD_STATE; return ret; } -#endif /* LIBVIR_CHECK_VERSION(0, 10, 0) */ +#endif /* VIR_DOMAIN_EVENT_ID_BALLOON_CHANGE */ -#if LIBVIR_CHECK_VERSION(1, 0, 0) +#ifdef VIR_DOMAIN_EVENT_ID_PMSUSPEND_DISK static int libvirt_virConnectDomainEventPMSuspendDiskCallback(virConnectPtr conn ATTRIBUTE_UNUSED, virDomainPtr dom, @@ -6452,9 +6452,9 @@ libvirt_virConnectDomainEventPMSuspendDiskCallback(virConnectPtr conn ATTRIBUTE_ LIBVIRT_RELEASE_THREAD_STATE; return ret; } -#endif /* LIBVIR_CHECK_VERSION(1, 0, 0) */ +#endif /* VIR_DOMAIN_EVENT_ID_PMSUSPEND_DISK */ -#if LIBVIR_CHECK_VERSION(1, 1, 1) +#ifdef VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED static int libvirt_virConnectDomainEventDeviceRemovedCallback(virConnectPtr conn ATTRIBUTE_UNUSED, virDomainPtr dom, @@ -6504,9 +6504,9 @@ libvirt_virConnectDomainEventDeviceRemovedCallback(virConnectPtr conn ATTRIBUTE_ LIBVIRT_RELEASE_THREAD_STATE; return ret; } -#endif /* LIBVIR_CHECK_VERSION(1, 1, 1) */ +#endif /* VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED */ -#if LIBVIR_CHECK_VERSION(1, 2, 9) +#ifdef VIR_DOMAIN_EVENT_ID_TUNABLE static int libvirt_virConnectDomainEventTunableCallback(virConnectPtr conn ATTRIBUTE_UNUSED, virDomainPtr dom, @@ -6564,9 +6564,9 @@ libvirt_virConnectDomainEventTunableCallback(virConnectPtr conn ATTRIBUTE_UNUSED return ret; } -#endif /* LIBVIR_CHECK_VERSION(1, 2, 9) */ +#endif /* VIR_DOMAIN_EVENT_ID_TUNABLE */ -#if LIBVIR_CHECK_VERSION(1, 2, 11) +#ifdef VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE static int libvirt_virConnectDomainEventAgentLifecycleCallback(virConnectPtr conn ATTRIBUTE_UNUSED, virDomainPtr dom, @@ -6618,7 +6618,7 @@ libvirt_virConnectDomainEventAgentLifecycleCallback(virConnectPtr conn ATTRIBUTE return ret; } -#endif /* LIBVIR_CHECK_VERSION(1, 2, 11) */ +#endif /* VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE */ static PyObject * @@ -6676,9 +6676,9 @@ libvirt_virConnectDomainEventRegisterAny(ATTRIBUTE_UNUSED PyObject *self, cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventGenericCallback); break; case VIR_DOMAIN_EVENT_ID_BLOCK_JOB: -#if LIBVIR_CHECK_VERSION(1, 2, 6) +#ifdef VIR_DOMAIN_EVENT_ID_BLOCK_JOB_2 case VIR_DOMAIN_EVENT_ID_BLOCK_JOB_2: -#endif /* LIBVIR_CHECK_VERSION(1, 2, 6) */ +#endif /* VIR_DOMAIN_EVENT_ID_BLOCK_JOB_2 */ cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventBlockJobCallback); break; case VIR_DOMAIN_EVENT_ID_DISK_CHANGE: @@ -6693,31 +6693,31 @@ libvirt_virConnectDomainEventRegisterAny(ATTRIBUTE_UNUSED PyObject *self, case VIR_DOMAIN_EVENT_ID_PMSUSPEND: cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventPMSuspendCallback); break; -#if LIBVIR_CHECK_VERSION(0, 10, 0) +#ifdef VIR_DOMAIN_EVENT_ID_BALLOON_CHANGE case VIR_DOMAIN_EVENT_ID_BALLOON_CHANGE: cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventBalloonChangeCallback); break; -#endif /* LIBVIR_CHECK_VERSION(0, 10, 0) */ -#if LIBVIR_CHECK_VERSION(1, 0, 0) +#endif /* VIR_DOMAIN_EVENT_ID_BALLOON_CHANGE */ +#ifdef VIR_DOMAIN_EVENT_ID_PMSUSPEND_DISK case VIR_DOMAIN_EVENT_ID_PMSUSPEND_DISK: cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventPMSuspendDiskCallback); break; -#endif /* LIBVIR_CHECK_VERSION(1, 0, 0) */ -#if LIBVIR_CHECK_VERSION(1, 1, 1) +#endif /* VIR_DOMAIN_EVENT_ID_PMSUSPEND_DISK */ +#ifdef VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED case VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED: cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventDeviceRemovedCallback); break; -#endif /* LIBVIR_CHECK_VERSION(1, 1, 1) */ -#if LIBVIR_CHECK_VERSION(1, 2, 9) +#endif /* VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED */ +#ifdef VIR_DOMAIN_EVENT_ID_TUNABLE case VIR_DOMAIN_EVENT_ID_TUNABLE: cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventTunableCallback); break; -#endif /* LIBVIR_CHECK_VERSION(1, 2, 9) */ -#if LIBVIR_CHECK_VERSION(1, 2, 11) +#endif /* VIR_DOMAIN_EVENT_ID_TUNABLE */ +#ifdef VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE case VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE: cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventAgentLifecycleCallback); break; -#endif /* LIBVIR_CHECK_VERSION(1, 2, 11) */ +#endif /* VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE */ case VIR_DOMAIN_EVENT_ID_LAST: break; } -- 2.1.0 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list