Re: [PATCH] git-difftool-helper.sh: learn a new way skip to save point

`git difftool` only allow us to select file to view In turn.
If there is a commit with many files and we exit in search,
We will have to traverse list again to get the file diff which
we want to see.Therefore,here is a new method:every time before
we view the file diff,the current coordinates will be stored in
`GIT_DIR/difftool_skip_to`,this file will be deleted after
successful traversing.But if an unexpected exit occurred midway,
git will view the coordinates in the save point,ask user if they
want continue from the last saved point.This will improve the
user experience.

Signed-off-by: ZheNing Hu <redacted>
---
    git-difftool-helper.sh: learn a new way skip to save point
    
    this patch's origin discuss is here:
    https://lore.kernel.org/git/gOXOaoqn-E9A2ob7ykWEcDc7ZxmSwAjcP5CCFKfr5ejCOWZQ1lfAUZcbgYT9AyQCcDgJvCrnrtziXiels-Hxol3xlkGTVHk24SvAdaSUtKQ=@rtzoeller.com/ (local)
    
    git user may should travel the diff list to choice file diff to view, if
    they exit in midway,they must travel it again. I’m on the basis of the
    "difftool_skip_to" suggested by Junio,Provides a possibility for this
    user-friendly solution.
    
    Thanks!

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-870%2Fadlternative%2Fdifftool_save_point-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-870/adlternative/difftool_save_point-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/870

 git-difftool--helper.sh | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh
index 46af3e60b718..56ec1d38a7a1 100755
--- a/git-difftool--helper.sh
+++ b/git-difftool--helper.sh

@@ -6,6 +6,7 @@
 # Copyright (c) 2009, 2010 David Aguilar
 
 TOOL_MODE=diff
+GIT_DIFFTOOL_SKIP_TO_FILE="$GIT_DIR/difftool-skip-to"
 . git-mergetool--lib
 
 # difftool.prompt controls the default prompt/no-prompt behavior

@@ -40,6 +41,31 @@ launch_merge_tool () {
 	# the user with the real $MERGED name before launching $merge_tool.
 	if should_prompt
 	then
+		if test -f "$GIT_DIFFTOOL_SKIP_TO_FILE"
+		then
+			SAVE_POINT_NUM=$(cat "$GIT_DIFFTOOL_SKIP_TO_FILE")
+			if test $SAVE_POINT_NUM -le $GIT_DIFF_PATH_TOTAL &&
+				test $SAVE_POINT_NUM -gt $GIT_DIFF_PATH_COUNTER
+			then
+				# choice skip or not skip when check first file.
+				if test $GIT_DIFF_PATH_COUNTER -eq "1"
+				then
+					printf "do you want to skip to last time difftool save point($SAVE_POINT_NUM) [Y/n]?"
+					read skip_ans || return
+					if test "$skip_ans" = y
+					then
+						return
+					fi
+				else
+					return
+				fi
+			fi
+		fi
+		# write the current coordinates to .git/difftool-skip-to
+		if test !$SAVE_POINT_NUM || $SAVE_POINT_NUM -ne $GIT_DIFF_PATH_COUNTER
+		then
+			echo $GIT_DIFF_PATH_COUNTER > $GIT_DIFFTOOL_SKIP_TO_FILE
+		fi
 		printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \
 			"$GIT_DIFF_PATH_TOTAL" "$MERGED"
 		if use_ext_cmd

@@ -102,4 +128,10 @@ else
 	done
 fi
 
+if test -f $GIT_DIFFTOOL_SKIP_TO_FILE &&
+	test $GIT_DIFF_PATH_COUNTER -eq $GIT_DIFF_PATH_TOTAL
+then
+	rm $GIT_DIFFTOOL_SKIP_TO_FILE
+
+fi
 exit 0

base-commit: e6362826a0409539642a5738db61827e5978e2e4