CAB file API clarification

Since I'm not really seeing any content anywhere that doesn't point back to the original Microsoft documents on this matter, or source code that really doesn't seem to answer the questions I'm having, I thought I might ask a few things here. (Delphi tag is there because that's what my dev environment is on the code I'm making from this)

That said, I had a few questions the API document wasn't answering. First one: fdi_notify messages. What is "my responsibility" is in coding these: fdintCABINET_INFO: fdintPARTIAL_FILE: fdintNEXT_CABINET: fdintENUMERATE: ? I'll illustrate what I mean by an example. For fdintCLOSE_FIL开发者_StackOverflow中文版E_INFO, "my responsibility" is to Close a file related to handle given me, and set the file's date and time according to the data passed in fdi_notify.

I figure I'm missing something since my code isn't handling extracting spanned CAB files...any thoughts on how to do this?

---

What you're more than likely running into is that FDICopy only reads the cab you passed in. It will use fdintNEXT_CABINET to get spanned data for any files you extract in response to fdintCOPY_FILE, but it only calls fdintCOPY_FILE for files that start on that first cab.

To get a directory listing for the entire set, you need to call FDICopy in a loop. Every time you get a fdintCABINET_INFO event, save off the psz1 parameter (next cab name). When FDICopy returns, check that. If it's an empty string you're done, if not call FDICopy again with the next cab as the new path.

---

fdintCABINET_INFO: The only responsibility for this is returning 0 to continue processing. You can use the information provided (the path of the next cabinet, next disk, path name, nad set ID), but you don't need to.

fdintPARTIAL_FILE: Depending on how you're processing your cabs, you can probably ignore this. You'll only see it for the second and later images in a set, and it's to tell you that the particular entry is continued from a previous cab. If you started at the first cab in the set you'll have already seen an fdintCOPY_FILE for the file. If you're processing random .cabs, you won't really be able to use it either, since you won't have the start of the file to extract.

fdintNEXT_CABINET: You can use this to prompt the user for a new directory for the next cabinet, but for simple spanning support just return 0 if the passed in filename is valid or -1 if it isn't. If you return 0 and the cab isn't valid, or is the wrong one, this will get called again. The easiest approach (if you don't request a new disk/directory), is just to check pfdin^.fdie. If it's FDIError_None it's equal the first time being called for the requested cab, so you can return 0. If it's anything else it's already tried to open the requested cab at least once, so you can return -1 as an error.

fdintENUMERATE: I think you can ignore this. It isn't covered in the documentation, and the two cab libraries I've looked at don't use it. It may be a leftover from a previous API version.