[PATCH v2 08/10] mergetool-lib: introduce run_mergetool

[David Aguilar <davvid@gmail.com>]

run_mergetool contains the common functionality for launching
mergetools.  There's some context-specific behavior but overall
it's better to have all of this stuff in one place versus multiple
places.

Signed-off-by: David Aguilar <davvid@gmail.com>
---

Include fixups from Markus

 Documentation/git-mergetool-lib.txt |   10 +++
 git-mergetool-lib.sh                |  141 +++++++++++++++++++++++++++++++++++
 2 files changed, 151 insertions(+), 0 deletions(-)

diff --git a/Documentation/git-mergetool-lib.txt b/Documentation/git-mergetool-lib.txt
index a8d62f5..7377774 100644
--- a/Documentation/git-mergetool-lib.txt
+++ b/Documentation/git-mergetool-lib.txt
@@ -29,6 +29,16 @@ FUNCTIONS
 get_merge_tool_path::
 	returns the `merge_tool_path` for a `merge_tool`.
 
+run_mergetool::
+	launches a merge tool given the tool name and a true/false
+	flag to indicate whether a merge base is present
+
+valid_tool::
+	tests whether a merge tool is setup correctly.
+
+get_custom_cmd::
+	given a merge tool, returns the custom command for that tool.
+
 Author
 ------
 Written by David Aguilar <davvid@gmail.com>
diff --git a/git-mergetool-lib.sh b/git-mergetool-lib.sh
index 5f9ba97..d28be68 100644
--- a/git-mergetool-lib.sh
+++ b/git-mergetool-lib.sh
@@ -3,7 +3,12 @@ diff_mode() {
 	test $TOOL_MODE = "diff"
 }
 
+merge_mode() {
+	test $TOOL_MODE = "merge"
+}
+
 get_merge_tool_path () {
+	path="$1"
 	if test -z "$2"; then
 		case "$1" in
 		emerge)
@@ -17,6 +22,11 @@ get_merge_tool_path () {
 	echo "$path"
 }
 
+# Overridden in git-mergetool
+check_unchanged () {
+	true
+}
+
 valid_tool () {
 	case "$1" in
 	kdiff3 | kompare | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
@@ -40,3 +50,134 @@ get_custom_cmd () {
 	test -n "$custom_cmd" &&
 	echo "$custom_cmd"
 }
+
+run_mergetool () {
+	base_present="$2"
+	if diff_mode; then
+		base_present="false"
+	fi
+	if test -z "$base_present"; then
+		base_present="true"
+	fi
+
+	case "$1" in
+	kdiff3)
+		if $base_present; then
+			("$merge_tool_path" --auto \
+			 --L1 "$MERGED (Base)" --L2 "$MERGED (Local)" --L3 "$MERGED (Remote)" \
+			 -o "$MERGED" "$BASE" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
+		else
+			("$merge_tool_path" --auto \
+			 --L1 "$MERGED (Local)" --L2 "$MERGED (Remote)" \
+			 -o "$MERGED" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
+		fi
+		status=$?
+		;;
+	kompare)
+		"$merge_tool_path" "$LOCAL" "$REMOTE"
+		status=$?
+		;;
+	tkdiff)
+		if $base_present; then
+			"$merge_tool_path" -a "$BASE" -o "$MERGED" "$LOCAL" "$REMOTE"
+		else
+			if merge_mode; then
+				"$merge_tool_path" -o "$MERGED" "$LOCAL" "$REMOTE"
+			else
+				"$merge_tool_path" "$LOCAL" "$REMOTE"
+			fi
+		fi
+		status=$?
+		;;
+	meld)
+		if merge_mode; then
+			touch "$BACKUP"
+			"$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE"
+		fi
+		check_unchanged
+		;;
+	vimdiff)
+		if merge_mode; then
+			touch "$BACKUP"
+			"$merge_tool_path" -c "wincmd l" "$LOCAL" "$MERGED" "$REMOTE"
+			check_unchanged
+		else
+			"$merge_tool_path" -c "wincmd l" "$LOCAL" "$REMOTE"
+		fi
+		;;
+	gvimdiff)
+		if merge_mode; then
+			touch "$BACKUP"
+			"$merge_tool_path" -c "wincmd l" -f "$LOCAL" "$MERGED" "$REMOTE"
+			check_unchanged
+		else
+			"$merge_tool_path" -c "wincmd l" -f "$LOCAL" "$REMOTE"
+		fi
+		;;
+	xxdiff)
+		merge_mode && touch "$BACKUP"
+		if $base_present; then
+			"$merge_tool_path" -X --show-merged-pane \
+			    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
+			    -R 'Accel.Search: "Ctrl+F"' \
+			    -R 'Accel.SearchForward: "Ctrl-G"' \
+			    --merged-file "$MERGED" "$LOCAL" "$BASE" "$REMOTE"
+		else
+			merge_mode && extra=--show-merged-pane
+			"$merge_tool_path" -X $extra \
+				-R 'Accel.SaveAsMerged: "Ctrl-S"' \
+				-R 'Accel.Search: "Ctrl+F"' \
+				-R 'Accel.SearchForward: "Ctrl-G"' \
+				--merged-file "$MERGED" "$LOCAL" "$REMOTE"
+		fi
+		check_unchanged
+		;;
+	opendiff)
+		merge_mode && touch "$BACKUP"
+		if $base_present; then
+			"$merge_tool_path" "$LOCAL" "$REMOTE" \
+				-ancestor "$BASE" -merge "$MERGED" | cat
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE" \
+				-merge "$MERGED" | cat
+		fi
+		check_unchanged
+		;;
+	ecmerge)
+		merge_mode && touch "$BACKUP"
+		if $base_present; then
+			"$merge_tool_path" "$BASE" "$LOCAL" "$REMOTE" \
+				--default --mode=merge3 --to="$MERGED"
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE" \
+				--default --mode=merge2 --to="$MERGED"
+		fi
+		check_unchanged
+		;;
+	emerge)
+		if $base_present; then
+			"$merge_tool_path" -f emerge-files-with-ancestor-command \
+				"$LOCAL" "$REMOTE" "$BASE" "$(basename "$MERGED")"
+		else
+			"$merge_tool_path" -f emerge-files-command \
+				"$LOCAL" "$REMOTE" "$(basename "$MERGED")"
+		fi
+		status=$?
+		;;
+	*)
+		if test -n "$merge_tool_cmd"; then
+			if merge_mode &&
+			test "$merge_tool_trust_exit_code" = "false"; then
+				touch "$BACKUP"
+				( eval $merge_tool_cmd )
+				check_unchanged
+			else
+				( eval $merge_tool_cmd )
+				status=$?
+			fi
+		fi
+		;;
+	esac
+}
-- 
1.6.1.3