Initial class construction

Git/mingw64/libexec/git-core/git-difftool--helper

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+#!/bin/sh
+# git-difftool--helper is a GIT_EXTERNAL_DIFF-compatible diff tool launcher.
+# This script is typically launched by using the 'git difftool'
+# convenience command.
+#
+# Copyright (c) 2009, 2010 David Aguilar
+
+TOOL_MODE=diff
+. git-mergetool--lib
+
+# difftool.prompt controls the default prompt/no-prompt behavior
+# and is overridden with $GIT_DIFFTOOL*_PROMPT.
+should_prompt () {
+	prompt_merge=$(git config --bool mergetool.prompt || echo true)
+	prompt=$(git config --bool difftool.prompt || echo $prompt_merge)
+	if test "$prompt" = true
+	then
+		test -z "$GIT_DIFFTOOL_NO_PROMPT"
+	else
+		test -n "$GIT_DIFFTOOL_PROMPT"
+	fi
+}
+
+# Indicates that --extcmd=... was specified
+use_ext_cmd () {
+	test -n "$GIT_DIFFTOOL_EXTCMD"
+}
+
+launch_merge_tool () {
+	# Merged is the filename as it appears in the work tree
+	# Local is the contents of a/filename
+	# Remote is the contents of b/filename
+	# Custom merge tool commands might use $BASE so we provide it
+	MERGED="$1"
+	LOCAL="$2"
+	REMOTE="$3"
+	BASE="$1"
+
+	# $LOCAL and $REMOTE are temporary files so prompt
+	# the user with the real $MERGED name before launching $merge_tool.
+	if should_prompt
+	then
+		printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \
+			"$GIT_DIFF_PATH_TOTAL" "$MERGED"
+		if use_ext_cmd
+		then
+			printf "Launch '%s' [Y/n]? " \
+				"$GIT_DIFFTOOL_EXTCMD"
+		else
+			printf "Launch '%s' [Y/n]? " "$merge_tool"
+		fi
+		read ans || return
+		if test "$ans" = n
+		then
+			return
+		fi
+	fi
+
+	if use_ext_cmd
+	then
+		export BASE
+		eval $GIT_DIFFTOOL_EXTCMD '"$LOCAL"' '"$REMOTE"'
+	else
+		run_merge_tool "$merge_tool"
+	fi
+}
+
+if ! use_ext_cmd
+then
+	if test -n "$GIT_DIFF_TOOL"
+	then
+		merge_tool="$GIT_DIFF_TOOL"
+	else
+		merge_tool="$(get_merge_tool)" || exit
+	fi
+fi
+
+if test -n "$GIT_DIFFTOOL_DIRDIFF"
+then
+	LOCAL="$1"
+	REMOTE="$2"
+	run_merge_tool "$merge_tool" false
+else
+	# Launch the merge tool on each path provided by 'git diff'
+	while test $# -gt 6
+	do
+		launch_merge_tool "$1" "$2" "$5"
+		status=$?
+		if test $status -ge 126
+		then
+			# Command not found (127), not executable (126) or
+			# exited via a signal (>= 128).
+			exit $status
+		fi
+
+		if test "$status" != 0 &&
+			test "$GIT_DIFFTOOL_TRUST_EXIT_CODE" = true
+		then
+			exit $status
+		fi
+		shift 7
+	done
+fi
+
+exit 0