Support --find-copies-harder in the Log window

Detecting copies from unmodified files in TortoiseGit is a longed-for feature, such as #3219 .

This merge request integrates the git option --find-copies-harder into the Log Message window.

I don't have much experience in writing C++/MFC, so this feature is implemented as a command line option as the first step.

To Test

1. In Icon Overlays page, set Status cache to None. (may not be necessary)

2. Head to a resopitory where you know there are copy commits. For me

D:\Speak Easy>git log --find-copies --find-copies-harder --name-status
commit d4cdd85d4bed86fbec314989aff075eeab2bd3e3 (HEAD -> copy)
Author: Qiqi Gu <qiqigutg@gmail.com>
Date:   Mon Aug 5 16:38:07 2024 +0800

    add ep4

C085    ep3     ep4

commit 59d51a593770ba5e8b20f7c1085022691904577e
Author: Qiqi Gu <qiqigutg@gmail.com>
Date:   Sat Aug 3 20:17:50 2024 +0800

    finish ep3

M       ep3
A       ep3-30.filter

3. Run command D:\Speak Easy>D:\tortoisegit\bin\Debug64\bin\TortoiseGitProc.exe /command:log /path:"D:\Speak Easy" /findcopiesharder

Then the log window successfully picks up the copy operation from ep3 to ep4.

Design Concerns

I added LOG_INFO_FIND_COPIES_HARDER at the end of CGit::LOG_INFO_MASK. LOG_INFO_MASK is like a bitset which only has 32 seats. I'm not sure if it's a good idea to take one of these precious seats.

LogDlg.h did not have public fields. I added m_FindCopiesHarder so that LogCommand can pass information over. I don't know whether it is idiomatic in this project.

Limitations

There are limitations though.

1. I didn't implement the libgit2 way for --find-copies-harder. If users specify the /findcopiesharder option, TortoiseGit does not call libgit2, and fall back to git.exe. Nevertheless, the current version of TortoiseGit is not using libgit2 for GIT_CMD_LOGLISTDIFF in the first place.

2. I disabled m_LogCache.FetchCacheIndex() if the /findcopiesharder option is specified. The reason is that, if the cache has been created without /findcopiesharder, a new Log window with /findcopiesharder reads the existing cache which contains no copy information. A Log window with /findcopiesharder does not create or modify cache (tortoisegit.data and tortoisegit.index) either.

3. I did not change the GUI. I envision a checkbox on the Log window but this MR is the first step to add support for --find-copies-harder.

All these points lead to future work. When the community agrees on this MR, I'm very likely to work on the next step. I have a series of changes in my mind.

Anyway, please give feedback. I just started to look into this project recently and the changes I made are minimal in my opinion to bake in the feature.

Signed-off-by: Qiqi Gu qiqigutg@gmail.com