jsvn: add "externals" subcommand

jsvn

@@ -41,6 +41,8 @@
 #   - with no switches, set svn:needs-lock to '*' for file[s]
 #   - with --remove, remove svn:needs-lock' for file[s]
 #   - with --status, prepended '*' for those with svn:needs-lock set
+#  externals
+#   - print a list of the externals in the repository
 #
 # The following subcommands are executed using their native handler, but
 # have their output simplified and/or colorized:
@@ -59,6 +61,7 @@ import re
 import time
 from subprocess import *
 
+STATUS_LINE_REGEX = r'[ACDIMRX?!~ ][CM ][L ][+ ][SX ][KOTB ]'
 ###########################################################################
 # Subcommand Handler Return Values                                        #
 ###########################################################################
@@ -558,7 +561,7 @@ def status(argv, svn, out):
         if not external_printed:
             out.write("\nExternal '%s':\n" % external)
             external_printed = True
-        if re.match(r'[ACDIMRX?!~ ][CM ][L ][+ ][SX ][KOTB ]', line):
+        if re.match(STATUS_LINE_REGEX, line):
             action = line[0]
             if action == 'A' or action == 'M':
                 ansi_color(out, 'green')
@@ -576,6 +579,14 @@ def status(argv, svn, out):
         out.write(line)
     return RET_OK
 
+def externals(argv, svn, out):
+    pout = Popen([svn, 'status'], stdout=PIPE).stdout
+    for line in iter(pout.readline, ''):
+        if re.match(STATUS_LINE_REGEX, line):
+            if line[0] == 'X':
+                out.write(line[8:])
+    return RET_OK
+
 def root(argv, svn, out):
     out.write(getSVNRoot(svn) + '\n')
     return RET_OK
@@ -613,6 +624,7 @@ def main(argv):
     handlers = {
             'branch': branch,
             'branches': branch,
+            'externals': externals,
             'switch': switch,
             'sw': switch,
             'merge': merge,