Missing cancel option

[Bob590]

I'm missing the cancel option... but i have found a way to add it myself.

I have to zip (STORE) a lot of files of about 130MB each – they are already compressed).
I also have the specification that this long zipping activity should be aborted at any time.
The current library implementation doesn’t allow this!

The progress callback is handled but the cancel callback is missing.

I have added the cancel callback:

int progress_cancel_callback(zip archive, void ud) {
ZipArchive za = static_cast<ZipArchive>(ud);
vector<ZipProgressListener*> listeners = za->getProgressListeners();
for(vector<ZipProgressListener*>::const_iterator it=listeners.begin() ; it!=listeners.end() ; ++it) {
ZipProgressListener* listener = *it;
if(listener->cancel())
return 1;
}
return 0;
}

And registered it:

int ZipArchive::close(void) {
if (isOpen()) {

    //do not handle zipSource at all because it will be deleted by libzip
    //directly when not necessary anymore

    if(!listeners.empty()) {
        zip_register_progress_callback_with_state(zipHandle, progressPrecision, progress_callback, nullptr, this);
        zip_register_cancel_callback_with_state(zipHandle, progress_cancel_callback, nullptr, this);
    }

Finally I have modified the progress listener:

class LIBZIPPP_API ZipProgressListener {
public:

    /**
     * This method is invoked while the changes are being committed during
     * the closing of the ZipArchive.
     * The value p is a double between 0 and 1, representing the overall progression.
     * The frequency of invocation of this method depends of the precision.
     *
     * Note that libzippp enforces the first invokation to be with a p-value of zero
     * and the last invokation to be with a p-value of 1. Hence, it might be possible
     * to receive multiple invokations with the same p-value, depending on the precsion
     * set in libzip.
     */
    virtual void progression(double p) = 0;
    /**
     * This method is invoked during zip/unzip operations.
     * If this function return 1 the operation is cancelled.
     * If this function return 0 the operation will continue.
     */
    virtual int cancel() = 0;
};

I have also made some small changes (basically some cast) and then added this on top of the .cpp file:

#ifdef WIN32
// Disable compiler warning for strcpy
#define _CRT_SECURE_NO_WARNINGS
#endif

All these minor changes were done to avoid VS2017 warnings when compiling.
Now the compilation is CLEAN. ;-)

If you agree I'll make a new Pull Request for your review.

[ctabin]

Hi @Bob590,

This looks great ! I always welcome any PR :-)
It would be awesome if you could separate your feature from code compilation cleaning in two separates PRs.

[Bob590]

Hi @ctabin,
Ok. I have made two separate PR requests.
The first was missing the .h update so I have made an update adding the missng .h change.
Sorry for the extra step.
:-}

[ctabin]

Hi @Bob590,

Thanks for the PR. Unfortunately both of them are failing the Travis CI. Can you have a look ?

[Bob590]

Hi @ctabin,
the first most probably fails due to the missing .h change.
How I can do/force a new CI?

[Bob590]

I see only now that also the test.cpp must be changed in order to update the ZipProgressListener...
I'm going to do it... sorry I have missed that!

[Bob590]

Done all. Now it should compile and pass the CI. :-)

[ctabin]

Done in #167.