Fix for File explorer not showing up and multiple notepads

[alekhyareddy28]

Summary of the Pull Request

This PR fixes two issues, namely File Explorer not showing up and multiple notepads showing up due to multiple shortcut files in different locations.

PR Checklist

• Applies to [Launcher, Tracker] doesn't find some apps (file explorer, windows terminal,...) #3223, PowerToys run shows Notepad en Notepad++ twice #3180, Does not find Evernote #3599
• CLA signed. If not, go over here and sign the CLA
• Tests added/passed
• Requires documentation to be updated
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

Detailed Description of the Pull Request / Additional comments

Changes made in this PR are -

• Previously we were checking if the LnkResolvedPath is null or empty, if so we were removing that program as a duplicate. However, this was true only in case of exe's and not lnk's. Hence, added an additional check to remove only the exe applications which do not have an lnkResolvedPath. This solves the issue of applications like File Explorer not showing up because they are lnk files without a resolvedPath.
• The check that we previously had wherein we removed apps with the same LnkResolvedPath was not sufficient because shortcuts in different locations have different lnkResolved paths (as mentioned in this comment - PowerToys run shows Notepad en Notepad++ twice #3180 (comment)). Therefore, using the condition that if two applications have the same name, same executable name and same FullPath, they are qualified as the same item.

Validation Steps Performed

• Created a copy of the notepad.lnk in multiple locations as mentioned PowerToys run shows Notepad en Notepad++ twice #3180 (comment) and validated that they don't show up twice.
• Added tests for all the deduplication cases.

[arjunbalgovind]

Probably unrelated to the PR, but I just noticed that start menu search doesn't actually find shortcuts on the desktop. I tried creating a shortcut to an unindexed file on desktop and Start menu doesn't find it but PT Run does.

[dsrivastavv]

The equal function takes all three variables into account but hashing doesn't. So comparison using hashing and equal would produce different results.

[alekhyareddy28]

Good catch! Used exor.

[dsrivastavv]

I don't think exor will ensure uniqueness for hashing. Swapping name and executable name will give false on using Equal but true on comparing hash codes because exor is commutative operation.

You can use something like below snippet which has a very low probability of being equal(which seems to be standard practice as per this post):

final int prime = 31;
int result = 1;
for( String s : strings )
{
    result = result * prime + s.hashCode();
}

[alekhyareddy28]

modified it as you suggested.

[htcfreek]

What will happen if two shortcuts only difference in the start parameter for the linked app?
Is this then covered by different values in LnkResolvedPath?

[alekhyareddy28]

What will happen if two shortcuts only difference in the start parameter for the linked app?
Is this then covered by different values in LnkResolvedPath?

Yes, the lnkResolved paths would be different then. The .lnk files contain information about the object that they are pointing to and also the arguments that must be passed to that object. Since they differ in their arguments, they would be different shortcuts as they do different things. Hope this clarifies your question.

Ref - https://docs.microsoft.com/en-us/windows/win32/shell/links?redirectedfrom=MSDN#link-files

[dsrivastavv]

LGTM!