Refactor the way that git executables are launched in depot tools.

This introduces python_git_runner.sh, and makes git-cl, git-cache, git-number,
and git-try use it.

R=agable@chromium.org, szager@chromium.org
BUG=261738

Review URL: https://codereview.chromium.org/188383002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@256131 0039d316-1c4b-4281-b951-d872f2087c98

git-cache

-#!/bin/sh
+#!/bin/bash
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# git-cache -- a git-command for managing local caches of remote repositories.
+# git_cache.py - a git-command for managing local caches of remote repositories.
 
-# Test if this script is running under a MSys install.  If it is, we will
-# hardcode the path to Python where possible.
-OUTPUT="$(uname | grep 'MINGW')"
-MINGW=$?
-
-if [ $MINGW = 0 ]; then
-  base_dir="${0%\\*}"
-else
-  base_dir=$(dirname "$0")
-fi
-
-# Uncomment this line if you never use gclient.
-# "$base_dir"/update_depot_tools
-
-if [ -e "$base_dir/python.bat" -a $MINGW = 0 ]; then
-  PYTHONDONTWRITEBYTECODE=1 cmd.exe //c "$base_dir\\python.bat" "$base_dir\\git_cache.py" "$@"
-else
-  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/git_cache.py" "$@"
-fi
+. $(type -P python_git_runner.sh)

git-cl

-#!/bin/sh
-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+#!/bin/bash
+# Copyright (c) 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# git-cl -- a git-command for integrating reviews on Rietveld
+# git_cl.py -- a git-command for integrating reviews on Rietveld
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
-# Test if this script is running under a MSys install.  If it is, we will
-# hardcode the path to Python where possible.
-OUTPUT="$(uname | grep 'MINGW')"
-MINGW=$?
-
-if [ $MINGW = 0 ]; then
-  base_dir="${0%\\*}"
-else
-  base_dir=$(dirname "$0")
-fi
-
-# Uncomment this line if you never use gclient.
-# "$base_dir"/update_depot_tools
-
-if [ -e "$base_dir/python.bat" -a $MINGW = 0 ]; then
-  PYTHONDONTWRITEBYTECODE=1 cmd.exe //c "$base_dir\\python.bat" "$base_dir\\git_cl.py" "$@"
-else
-  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/git_cl.py" "$@"
-fi
+. $(type -P python_git_runner.sh)

git-number

-#!/bin/sh
+#!/bin/bash
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# git-number -- a git-command for calculating and displaying the generation
+# git_number.py - a git-command for calculating and displaying the generation
 # number of a commit.
 
-# Test if this script is running under a MSys install.  If it is, we will
-# hardcode the path to Python where possible.
-OUTPUT="$(uname | grep 'MINGW')"
-MINGW=$?
-
-if [ $MINGW = 0 ]; then
-  base_dir="${0%\\*}"
-else
-  base_dir=$(dirname "$0")
-fi
-
-# Uncomment this line if you never use gclient.
-# "$base_dir"/update_depot_tools
-
-if [ -e "$base_dir/python.bat" -a $MINGW = 0 ]; then
-  PYTHONDONTWRITEBYTECODE=1 cmd.exe //c "$base_dir\\python.bat" "$base_dir\\git_number.py" "$@"
-else
-  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/git_number.py" "$@"
-fi
+. $(type -P python_git_runner.sh)

git-try

-#!/bin/sh
+#!/bin/bash
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# Test if this script is running under a MSys install.  If it is, we will
-# hardcode the path to Python where possible.
-OUTPUT="$(uname | grep 'MINGW')"
-MINGW=$?
+# git_try.py - Commits a patch to the SVN try patch repo.
+#              It is highly recommended to use `git cl try` instead.
 
-if [ $MINGW = 0 ]; then
-  base_dir="${0%\\*}"
-else
-  base_dir=$(dirname "$0")
-fi
-
-if [ -e "$base_dir/python.bat" -a $MINGW = 0 ]; then
-  PYTHONDONTWRITEBYTECODE=1 cmd.exe //c "$base_dir\\python.bat" "$base_dir\\git_try.py" "$@"
-else
-  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/git_try.py" "$@"
-fi
+. $(type -P python_git_runner.sh)

python_git_runner.sh

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+## This file is designed to be sourced from a bash script whose name takes the
+## form 'git-sub-command'. This script will then instead invoke
+## '[depot_tools]/git_sub_command.py' correctly under mingw as well
+## as posix-ey systems, passing along all other command line flags.
+
+## Example:
+## echo ". python_git_runner.sh" > git-foo-command
+## ./git-foo-command  #=> runs `python git_foo_command.py`
+
+## Constants
+PYTHONDONTWRITEBYTECODE=1
+
+## "Input parameters".
+# If set before the script is sourced, then we'll use the pre-set values.
+#
+# SCRIPT defaults to the basename of $0, with dashes replaced with underscores
+
+if [[ $OSTYPE = msys ]]
+then
+  DEPOT_TOOLS="${0%\\*}"
+  BASENAME="${0##*\\}"
+else
+  DEPOT_TOOLS="${0%/*}"
+  BASENAME="${0##*/}"
+fi
+SCRIPT="${SCRIPT-${BASENAME//-/_}.py}"
+
+if [[ -e "$DEPOT_TOOLS/python.bat" && $OSTYPE = msys ]]; then
+  cmd.exe //c "$DEPOT_TOOLS\\python.bat" "$DEPOT_TOOLS\\$SCRIPT" "$@"
+else
+  exec "$DEPOT_TOOLS/$SCRIPT" "$@"
+fi