On Tue, Apr 29, 2008 at 04:42:54PM +0200, Soren Hansen wrote:
> On Tue, Apr 29, 2008 at 03:17:14PM +0100, Daniel P. Berrange wrote:
> >>>> + if (!bus)
> >>>> + disk->bus = QEMUD_DISK_BUS_IDE;
> >>>> + else if (!strcmp((const char *)bus, "ide"))
> >>>> + disk->bus = QEMUD_DISK_BUS_IDE;
> >>>> + else if (!strcmp((const char *)bus, "scsi"))
> >>>> + disk->bus = QEMUD_DISK_BUS_SCSI;
> >>>> + else if (!strcmp((const char *)bus, "virtio"))
> >>>> + disk->bus = QEMUD_DISK_BUS_VIRTIO;
> >>> Can you use the STREQ macro here instead of strcmp.
> >> Erm... I *could*.. I'm curious, though, why e.g. the similar code right
> >> above it doesn't use STREQ if that's the preferred way to do it?
> > We've been slowly updating code to match these new standards when doing
> > patches.
>
> Well, if that's the way you do it, I'll follow suit.. However, I have
> to say that I pity the person that reads the code and finds these two
> sections of code that seem to do rather similar things, but use
> different functions to do it, and then has to work out what on earth the
> difference between the two might be.
Here is an update to the HACKING file intended to describe some of the
conventions in use...
Dan
Index: HACKING
===================================================================
RCS file: /data/cvs/libvirt/HACKING,v
retrieving revision 1.1
diff -r1.1 HACKING
45a46,160
>
>
> Low level memory management
> ===========================
>
> Use of the malloc/free/realloc/calloc APIs is deprecated in the libvirt
> codebase, because they encourage a number of serious coding bugs and do
> not enable compile time verification of checks for NULL. Instead of these
> routines, use the macros from memory.h
>
> - eg to allocate a single object:
>
> virDomainPtr domain;
>
> if (VIR_ALLOC(domain) < 0) {
> __virRaiseError(VIR_ERROR_NO_MEMORY)
> return NULL;
> }
>
>
> - eg to allocate an array of objects
>
> virDomainPtr domains;
> int ndomains = 10;
>
> if (VIR_ALLOC_N(domains, ndomains) < 0) {
> __virRaiseError(VIR_ERROR_NO_MEMORY)
> return NULL;
> }
>
> - eg to allocate an array of object pointers
>
> virDomainPtr *domains;
> int ndomains = 10;
>
> if (VIR_ALLOC_N(domains, ndomains) < 0) {
> __virRaiseError(VIR_ERROR_NO_MEMORY)
> return NULL;
> }
>
> - eg to re-allocate the array of domains to be longer
>
> ndomains = 20
>
> if (VIR_REALLOC_N(domains, ndomains) < 0) {
> __virRaiseError(VIR_ERROR_NO_MEMORY)
> return NULL;
> }
>
> - eg to free the domain
>
> VIR_FREE(domain);
>
>
>
> String comparisons
> ==================
>
> Do not use the strcmp, strncmp, etc functions directly. Instead use
> one of the following semantically named macros
>
> - For strict equality:
>
> STREQ(a,b)
> STRNEQ(a,b)
>
> - For case sensitive equality:
> STRCASEEQ(a,b)
> STRCASENEQ(a,b)
>
> - For strict equality of a substring:
>
> STREQLEN(a,b,n)
> STRNEQLEN(a,b,n)
>
> - For case sensitive equality of a substring:
>
> STRCASEEQLEN(a,b,n)
> STRCASENEQLEN(a,b,n)
>
> - For strict equality of a prefix:
>
> STRPREFIX(a,b)
>
>
>
> Variable length string buffer
> =============================
>
> If there is a need for complex string concatenations, avoid using
> the usual sequence of malloc/strcpy/strcat/snprintf functions and
> make use of the virBuffer API described in buf.h
>
> eg typical usage is as follows:
>
> char *
> somefunction(...) {
> virBuffer buf = VIR_BUFFER_INITIALIZER;
>
> ...
>
> virBufferAdd(&buf, "<domain>\n");
> virBufferVSprint(&buf, " <memory>%d</memory>\n", memory);
> ...
> virBufferAdd(&buf, "</domain>\n");
>
> ....
>
> if (virBufferError(&buf)) {
> __virRaiseError(...);
> return NULL;
> }
>
> return virBufferContentAndReset(&buf);
> }
--
|: Red Hat, Engineering, Boston -o- http://people.redhat.com/berrange/ :|
|: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|
--
Libvir-list mailing list
Libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list