git-cl-upload-hook: improved finding depot_tools algorithm

* also allow PATH entry to end in / (which is valid)
* in case depot_tools cannot be located in PATH, search for them using which
* added dependency on subprocess (new in python 2.4)

M      git-cl-upload-hook

TEST=run the hook manually with:
1) PATH containing the depot_tools, depot_tools/ (success)
2) checkout of depot_tools into ~/x, and PATH containing that (success)
3) PATH not containing any copy of depot_tools (fail)
4) Several PATH entries containing gclient, not called depot_tools (success)

Review URL: http://codereview.chromium.org/2852032

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@51207 0039d316-1c4b-4281-b951-d872f2087c98

git-cl-upload-hook

@@ -5,18 +5,30 @@
 
 import os
 import sys
+from subprocess import Popen, PIPE
 
 # Try locating depot_tools from the user's PATH.
 depot_tools_path = None
+
+# First parse PATH if there's a "depot_tools" inside
 for path in os.environ.get("PATH").split(os.pathsep):
- if not path.endswith("depot_tools"):
+ if not path.endswith("depot_tools") and not path.endswith("depot_tools/"):
  continue
  depot_tools_path = path
  break
 
+# If depot_tools dir is not called depot_tools, or other weirdness
+if not depot_tools_path:
+ # Grab a `which gclient', which gives first match
+ # `which' also uses PATH, but is not restricted to specific directory name
+ path = Popen(["which", "gclient"], stdout=PIPE).communicate()[0]
+ if path:
+ depot_tools_path = path.replace("/gclient","")
+
 # If we found depot_tools, add it to the script's import path.
+# Use realpath to normalize the actual path
 if depot_tools_path:
- sys.path.append(depot_tools_path)
+ sys.path.append(os.path.realpath(depot_tools_path))
 else:
  print "ERROR: Could not find depot_tools in your PATH."
  print "ERROR: Please add it to your PATH and try again."