got patch: handle git-style diffs for the 3-way merge too tweak and ok stsp@

handle blob ids without corresponding blob ids ok stsp@

got patch: use status G for merged files (and document it) Suggested by stsp@. This makes possible to tell if 'got patch' used a merge-base from the repository for the 3-way merge or did a simple search/replace operation. While here update the tests to look for the 'G' status and the manpage, which was also missing the documentation for the 'C' status in got patch. ok stsp@

got patch: ignore blobs not found since diffs are often enclosed in other formats (e.g. emails) we might parse something and think it's a blob id when it's not. This should already happens, but apply_patch is looking for the wrong error due to a leftover from previous attempts. Reported by stsp@ while here tweak the test_patch_merge_unknown_blob to also try with a dummy commit id, as now got-read-patch requires it in order to consider a blob id. ok stsp@

use the commitid in the patch diff3 conflict header suggested by and ok stsp@

got patch: use diff3 to merge the changes Parse the "blob -" metadata in diffs produced by 'got diff' and use the original file for patching. Then, use the diff3 with the current version of the file to merge the differences. This solves many failures automagically or at least turns them into a conflict. ok/improvements stsp@

patch_file: fill tmp with the patched file even in nop mode future work with diff3 merge will need the fully patched file even in the nop mode ok stsp@

patch_file: move file ownership to parent ok stsp@

style: remove double semicolon

check for errors from fclose() in patch_file()

plug memory and fd leak in got patch

got patch: use ints for line offsets instead of longs ints have the advantage that their size is more likely to be the same across the various architecture supported by OpenBSD, thus introducing less possible differences. INT_MAX is still (at least) a few order of magnitudes higher than the patches we dealt with (even abnormal ones.) suggested by stsp@

actually guarding against negative line offsets previous commit looked at some pretty zeroes returned from calloc instead of the actual numbers received.

style; set datalen only once

got patch: guard against invalid (negative) line offsets under normal circumstances got-read-patch can't send negative line offsets; that's not an excuse not to guard the main process from those as well. This makes sure we bail out early instead of trying to apply the diff.

free patch on error

got patch: ensure new and old paths are NUL-terminated

refactor got_patch / got_worktree_patch_complete let got_patch own fileindex_path and call got_worktree_patch_complete only if got_wokrtree_patch_prepare hasn't failed. suggested by stsp@

got patch: avoid open/sync/close the fileindex over and over again Instead of flushing the fileindex after every patch in the patchfile just reuse the same fileindex and sync it only at the end of the patch operation. This speeds up 'got patch' on large repositories by quite a lot.

got patch: switch from fseek() to fseeko(), use unary minus while here ok op

got patch: fail when reading empty hunks

fix wrong path in error message

got patch: allow to reverse a patch add a flag to got_patch to reverse a patch before applying and the -R flag for `got patch'. ok stsp@

got-read-patch: preserve all \ lines as a cheap optimization got-read-patch was sending only the "\ No newline at end of file" lines that follows an addition (a "+" line). To be able to reverse patches in the future got_patch needs to know about all of these lines instead. No functional changes intended. ok stsp@

got patch: resolve paths from the current working directory this allow to apply patches from subdirectories of the work tree root. Prodded by naddy@, ok stsp@.