[PATCH 03/10] Add a mergetool-lib scriptlet for holding common merge tool functions

[David Aguilar <davvid@gmail.com>]

git-mergetool-lib provides common merge tool functions.

Signed-off-by: David Aguilar <davvid@gmail.com>
---
 .gitignore                          |    1 +
 Documentation/git-mergetool-lib.txt |   42 +++++++++++++++++++++++++++++++++++
 Makefile                            |    1 +
 command-list.txt                    |    1 +
 git-mergetool-lib.sh                |   41 ++++++++++++++++++++++++++++++++++
 5 files changed, 86 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-mergetool-lib.txt
 create mode 100644 git-mergetool-lib.sh

diff --git a/.gitignore b/.gitignore
index 966c886..75c154a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -80,6 +80,7 @@ git-merge-recursive
 git-merge-resolve
 git-merge-subtree
 git-mergetool
+git-mergetool-lib
 git-mktag
 git-mktree
 git-name-rev
diff --git a/Documentation/git-mergetool-lib.txt b/Documentation/git-mergetool-lib.txt
new file mode 100644
index 0000000..a8d62f5
--- /dev/null
+++ b/Documentation/git-mergetool-lib.txt
@@ -0,0 +1,42 @@
+git-mergetool-lib(1)
+====================
+
+NAME
+----
+git-mergetool-lib - Common git merge tool shell scriptlets
+
+SYNOPSIS
+--------
+'. "$(git --exec-path)/git-mergetool-lib"'
+
+DESCRIPTION
+-----------
+
+This is not a command the end user would want to run.  Ever.
+This documentation is meant for people who are studying the
+Porcelain-ish scripts and/or are writing new ones.
+
+The 'git-mergetool-lib' scriptlet is designed to be sourced (using
+`.`) by other shell scripts to set up functions for working
+with git merge tools.
+
+Before sourcing it, your script should set up a few variables;
+`TOOL_MODE` is used to define the operation mode for various
+functions.  'diff' and 'merge' are valid values.
+
+FUNCTIONS
+---------
+get_merge_tool_path::
+	returns the `merge_tool_path` for a `merge_tool`.
+
+Author
+------
+Written by David Aguilar <davvid@gmail.com>
+
+Documentation
+--------------
+Documentation by David Aguilar and the git-list <git@vger.kernel.org>.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Makefile b/Makefile
index d77fd71..086f9e7 100644
--- a/Makefile
+++ b/Makefile
@@ -284,6 +284,7 @@ SCRIPT_SH += git-merge-octopus.sh
 SCRIPT_SH += git-merge-one-file.sh
 SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
+SCRIPT_SH += git-mergetool-lib.sh
 SCRIPT_SH += git-parse-remote.sh
 SCRIPT_SH += git-pull.sh
 SCRIPT_SH += git-quiltimport.sh
diff --git a/command-list.txt b/command-list.txt
index fb03a2e..922c815 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -69,6 +69,7 @@ git-merge-file                          plumbingmanipulators
 git-merge-index                         plumbingmanipulators
 git-merge-one-file                      purehelpers
 git-mergetool                           ancillarymanipulators
+git-mergetool-lib                       purehelpers
 git-merge-tree                          ancillaryinterrogators
 git-mktag                               plumbingmanipulators
 git-mktree                              plumbingmanipulators
diff --git a/git-mergetool-lib.sh b/git-mergetool-lib.sh
new file mode 100644
index 0000000..c307a5d
--- /dev/null
+++ b/git-mergetool-lib.sh
@@ -0,0 +1,41 @@
+# git-mergetool-lib is a library for common merge tool functions
+diff_mode() {
+	test $TOOL_MODE = "diff"
+}
+
+get_merge_tool_path () {
+	if test -z "$2"; then
+		case "$1" in
+		emerge)
+			path=emacs
+			;;
+		*)
+			path="$1"
+			;;
+		esac
+	fi
+	echo "$path"
+}
+
+valid_tool () {
+	case "$1" in
+	kdiff3 | kompare | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
+		if test "$1" = "kompare" && ! diff_mode; then
+			return 1
+		fi
+		;; # happy
+	*)
+		if ! test -n "$(get_custom_cmd "$1")"; then
+			return 1
+		fi ;;
+	esac
+}
+
+get_custom_cmd () {
+	diff_mode &&
+	custom_cmd="$(git config difftool.$1.cmd)"
+	test -z "$custom_cmd" &&
+	custom_cmd="$(git config mergetool.$1.cmd)"
+	test -n "$custom_cmd" &&
+	echo "$custom_cmd"
+}
-- 
1.6.1.3