Em sex 09 maio 2014, às 11:36:08, Keith Gardner escreveu:
> I have been working on adding a class to QtCore (QVersion) to support
> storing version numbers, convert to/from QString, and having comparison
> operators. My goal was to provide an API to assist in the following use
> cases:
>
> - Plugin loading where there are multiple versions on the same system.
> - File format validation.
> - Executing an already installed command line application where the
> behavior is dependent on the called application's version.
> - Performing software installations and updates.
> - QMake support for version number comparisons.
>
> Please share other potential use cases where this might be useful.
Ok, since we can't seem to agree, let's settle on the maximum common
denominator: QVersion will only compare the numeric part of a version number.
By default, two versions with the same numeric part will compare equally,
regardless of any suffixes that may be present.
Therefore, by default, given:
QVersion a("5.3.0");
QVersion b("5.3.0pl1");
QVersion c("5.3.0beta1");
a != b != c; // since they aren't equal
QVersion::compare(a, b) == 0;
QVersion::compare(b, c) == 0;
We will also provide an overload for the QVersion::compare function taking a
functor:
template <typename SuffixCompare> static inline int
compare(const QVersion &a, const QVersion &b, SuffixCompare
suffixCompare)
{
int cmp = compare(a, b);
if (cmp)
return cmp;
return suffixCompare(a.suffix(), b.suffix());
}
Thus, if you want to implement a comparison like OpenSSL's, you can do:
QVersion::compare(a, b,
[](auto a, auto b) {
return QString::compare(a, b, Qt::CaseInsensitive);
});
If you want a more complex comparison like I had wanted, you'd do:
static int priorityOrder(const QString &suffix)
{
if (suffix.isEmpty())
return 0;
return suffix.startsWith("alpha") || suffix.startsWith("beta") ||
suffix.startsWith("rc") ? -1 : 1;
}
static int myCompare(const QString &a, const QString &b)
{
int a_prio = priorityOrder(a);
int b_prio = priorityOrder(b);
if (a_prio != b_prio || a_prio == 0)
return a_prio - b_prio;
return QString::compare(a, b, Qt::CaseInsensitive);
}
And then you'd use: QVersion::compare(a, b, myCompare);
--
Thiago Macieira - thiago.macieira (AT) intel.com
Software Architect - Intel Open Source Technology Center
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