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[PATCH v2 2/4] mergetool: move main program flow into a main() function

From
David Aguilar <davvid@gmail.com>
Date
Oct 7, 2016, 06:24 UTC
Message-ID
<20161007062415.21551-1-davvid@gmail.com>

Make it easier to follow the program's flow by isolating all logic into functions. Isolate the main execution code path into a single unit instead of having prompt_after_failed_merge() interrupt it partyway through.

The use of a main() function is borrowing a convention from C, Python, Perl, and many other languages. This helps readers more familiar with other languages understand the purpose of each function when diving into the codebase with fresh eyes.

Signed-off-by: David Aguilar <davvid@gmail.com>
---
As suggested by Hannes, v2 provides a better commit message.

This is a stylistic choice, but since I was about to start hacking on it, I couldn't help but notice the organic sprawl that could use some tidying before adding new features.

 git-mergetool.sh | 180 ++++++++++++++++++++++++++++---------------------------
 1 file changed, 93 insertions(+), 87 deletions(-)
diff --git a/git-mergetool.sh b/git-mergetool.sh
index 300ce7f..b2cd0a4 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -366,51 +366,6 @@ merge_file () {
 	return 0
 }
 
-prompt=$(git config --bool mergetool.prompt)
-guessed_merge_tool=false
-
-while test $# != 0
-do
-	case "$1" in
-	--tool-help=*)
-		TOOL_MODE=${1#--tool-help=}
-		show_tool_help
-		;;
-	--tool-help)
-		show_tool_help
-		;;
-	-t|--tool*)
-		case "$#,$1" in
-		*,*=*)
-			merge_tool=$(expr "z$1" : 'z-[^=]*=\(.*\)')
-			;;
-		1,*)
-			usage ;;
-		*)
-			merge_tool="$2"
-			shift ;;
-		esac
-		;;
-	-y|--no-prompt)
-		prompt=false
-		;;
-	--prompt)
-		prompt=true
-		;;
-	--)
-		shift
-		break
-		;;
-	-*)
-		usage
-		;;
-	*)
-		break
-		;;
-	esac
-	shift
-done
-
 prompt_after_failed_merge () {
 	while true
 	do
@@ -427,57 +382,108 @@ prompt_after_failed_merge () {
 	done
 }
 
-git_dir_init
-require_work_tree
+main () {
+	prompt=$(git config --bool mergetool.prompt)
+	guessed_merge_tool=false
+
+	while test $# != 0
+	do
+		case "$1" in
+		--tool-help=*)
+			TOOL_MODE=${1#--tool-help=}
+			show_tool_help
+			;;
+		--tool-help)
+			show_tool_help
+			;;
+		-t|--tool*)
+			case "$#,$1" in
+			*,*=*)
+				merge_tool=$(expr "z$1" : 'z-[^=]*=\(.*\)')
+				;;
+			1,*)
+				usage ;;
+			*)
+				merge_tool="$2"
+				shift ;;
+			esac
+			;;
+		-y|--no-prompt)
+			prompt=false
+			;;
+		--prompt)
+			prompt=true
+			;;
+		--)
+			shift
+			break
+			;;
+		-*)
+			usage
+			;;
+		*)
+			break
+			;;
+		esac
+		shift
+	done
+
+	git_dir_init
+	require_work_tree
 
-if test -z "$merge_tool"
-then
-	# Check if a merge tool has been configured
-	merge_tool=$(get_configured_merge_tool)
-	# Try to guess an appropriate merge tool if no tool has been set.
 	if test -z "$merge_tool"
 	then
-		merge_tool=$(guess_merge_tool) || exit
-		guessed_merge_tool=true
+		# Check if a merge tool has been configured
+		merge_tool=$(get_configured_merge_tool)
+		# Try to guess an appropriate merge tool if no tool has been set.
+		if test -z "$merge_tool"
+		then
+			merge_tool=$(guess_merge_tool) || exit
+			guessed_merge_tool=true
+		fi
 	fi
-fi
-merge_keep_backup="$(git config --bool mergetool.keepBackup || echo true)"
-merge_keep_temporaries="$(git config --bool mergetool.keepTemporaries || echo false)"
-
-files=
+	merge_keep_backup="$(git config --bool mergetool.keepBackup || echo true)"
+	merge_keep_temporaries="$(git config --bool mergetool.keepTemporaries || echo false)"
 
-if test $# -eq 0
-then
-	cd_to_toplevel
+	files=
 
-	if test -e "$GIT_DIR/MERGE_RR"
+	if test $# -eq 0
 	then
-		files=$(git rerere remaining)
+		cd_to_toplevel
+
+		if test -e "$GIT_DIR/MERGE_RR"
+		then
+			files=$(git rerere remaining)
+		else
+			files=$(git ls-files -u |
+				sed -e 's/^[^	]*	//' | sort -u)
+		fi
 	else
-		files=$(git ls-files -u | sed -e 's/^[^	]*	//' | sort -u)
+		files=$(git ls-files -u -- "$@" |
+			sed -e 's/^[^	]*	//' | sort -u)
 	fi
-else
-	files=$(git ls-files -u -- "$@" | sed -e 's/^[^	]*	//' | sort -u)
-fi
-
-if test -z "$files"
-then
-	echo "No files need merging"
-	exit 0
-fi
-
-printf "Merging:\n"
-printf "%s\n" "$files"
-
-rc=0
-for i in $files
-do
-	printf "\n"
-	if ! merge_file "$i"
+
+	if test -z "$files"
 	then
-		rc=1
-		prompt_after_failed_merge || exit 1
+		echo "No files need merging"
+		exit 0
 	fi
-done
 
-exit $rc
+	printf "Merging:\n"
+	printf "%s\n" "$files"
+
+	rc=0
+	for i in $files
+	do
+		printf "\n"
+		if ! merge_file "$i"
+		then
+			rc=1
+			prompt_after_failed_merge || exit 1
+		fi
+	done
+
+	exit $rc
+}
+
+main "$@"
-- 
2.10.1.386.g42aabb0
Message 1 of 1 in “mergetool: move main program flow into a main() function”
  1. 2/4 mergetool: move main program flow into a main() functionDavid Aguilar, Oct 7, 2016

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