git map: Add -h, --help option

git_map.py

Index: git_map.py
diff --git a/git_map.py b/git_map.py
index 22e02e74b6f411e223eeb54f5608e9af24fed3ec..abbc3b104f1ae03f3dfa571f8fce72daf9dda4d9 100755
--- a/git_map.py
+++ b/git_map.py
@@ -4,8 +4,8 @@
 # found in the LICENSE file.
 
 """
-Provides an augmented `git log --graph` view. In particular, it also annotates
-commits with branches + tags that point to them. Items are colorized as follows:
+Enhances `git log --graph` view with information on commit branches + tags that
+point to them. Items are colorized as follows:
   * Cyan    - Currently checked out branch
   * Green   - Local branch
   * Red     - Remote branches
@@ -19,7 +19,7 @@ import sys
 import subprocess2
 
 from git_common import current_branch, branches, tags, get_config_list, GIT_EXE
-from git_common import get_or_create_merge_base, root
+from git_common import get_or_create_merge_base, root, ROOT, IS_WIN
 
 from third_party import colorama
 
@@ -38,6 +38,10 @@ RESET = colorama.Fore.RESET + colorama.Back.RESET + colorama.Style.RESET_ALL
 BRIGHT_RED = '\x1b[1;31m'
 
 def main(argv):
+  if '-h' in argv or '--help' in argv:
+    sys.stdout.write(__doc__)
+    return 0
+
   map_extra = get_config_list('depot_tools.map_extra')
   fmt = '%C(red bold)%h%x09%Creset%C(green)%d%Creset %C(yellow)%ad%Creset ~ %s'
   log_proc = subprocess2.Popen(
@@ -47,6 +51,18 @@ def main(argv):
     stdout=subprocess2.PIPE,
     shell=False)
 
+  # prepare pager
+  less = 'less'
+  if IS_WIN:
+    with open(ROOT + '\\git.bat') as r:
+      for line in r:
+        start = line.find('%~dp0')
+        if start != -1:
+          GIT_DIR = line[start+5:line.find('\cmd')]
+          less = ROOT + '\\' + GIT_DIR + '\\usr\\bin\\less'
+          break
+  less_proc = subprocess2.Popen([less, '-R'], stdin=subprocess2.PIPE)

[iannucci, 2016/07/19 01:07:55]

please make this a separate CL.

That said, this all looks pretty sketchy (parsing the bat file?)

less.exe should be in the PATH if this was invoked via git. It may be better to
set GIT_PAGER in the shell script above.

+
   current = current_branch()
   all_branches = set(branches())
   merge_base_map = {b: get_or_create_merge_base(b) for b in all_branches}
@@ -100,10 +116,13 @@ def main(argv):
           line = "%s%s%s" % (line[:start-1], branches_str, line[end+5:])
           if head_marker:
             line = line.replace('*', head_marker, 1)
-      sys.stdout.write(line)
+      less_proc.stdin.write(line)
   except (IOError, KeyboardInterrupt):
     pass
   finally:
+    # wait for less to exit
+    less_proc.stdin.close()
+    less_proc.wait()
     sys.stderr.close()
     sys.stdout.close()
   return 0