Check for missing files using .sfv file

Patch that should work. I haven't tried it yet though.

The patch adds an if clause in dcpp/HashManager.cpp on line 769, right before the CRC32 inconsistency check. It tries to open the file; if it can, close the handle and continue, otherwise write to the log that it couldn't find the file (will also say so if the permissions are wrong, but then it wouldn't be shared anyway...).

Code follows:

FILE* fp = NULL;
fp = fopen(fname, "rb");
if(fp == NULL) {
 LogManager::getInstance()->message(str(F_("%1% not found but found in SFV file.") % fname));
} else {
 fclose(fp);
}

Instead of using the functions from <cstdio>, you should use the File class already in DC++ (which strangely doesn't seem to have a static exists() function... adding that might be a good precursor patch to this one). Additionally, it's a good idea to generate the patch from within bzr instead of using diff manually.

In DC++ File::getSize() is used for checking the existence of a file...

the patch reports after each file so if a sfv contains 10 files it'll show 9 files missing when 1 has downloaded and the rest is in the queue...
probably, the way to go about this is to check the queue and disk when the .sfv has downloaded and then report missing files

What about this then? I don't know if this is the correct function to use. How much would this slow down sfv-checking?

if(dcpp::File::getSize(path) == -1 && QueueManager::FileQueue::find(fname) == NULL) {
 LogManager::getInstance()->message(str(F_("%1% not found but found in SFV file.") % fname));
}