Add 'cd -' feature to change to the previous working directory.

llvm-svn: 141846

1 files changed, 30 insertions, 6 deletions

diff --git a/lldb/examples/customization/pwd-cd-and-system/utils.py b/lldb/examples/customization/pwd-cd-and-system/utils.py
index 27836f62e1c..0a29420a4ee 100644
--- a/lldb/examples/customization/pwd-cd-and-system/utils.py
+++ b/lldb/examples/customization/pwd-cd-and-system/utils.py
@@ -2,13 +2,37 @@
 
 import os, shlex, subprocess
 
+# Store the previous working directory for the 'cd -' command.
+class Holder:
+    """Holds the _prev_dir_ class attribute for chdir() function."""
+    _prev_dir_ = None
+
+    @classmethod
+    def prev_dir(cls):
+        return cls._prev_dir_
+
+    @classmethod
+    def swap(cls, dir):
+        cls._prev_dir_ = dir
+
 def chdir(debugger, args, result, dict):
-    """Change the working directory, or cd to ${HOME}."""
-    dir = args.strip()
-    if dir:
-        os.chdir(args)
-    else:
-        os.chdir(os.path.expanduser('~'))
+    """
+    Change the working directory, or cd to ${HOME}.
+    You can also issue 'cd -' to change to the previous working directory.    
+    """
+    new_dir = args.strip()
+    if not new_dir:
+        new_dir = os.path.expanduser('~')
+    elif new_dir == '-':
+        if not Holder.prev_dir():
+            # Bad directory, not changing.
+            print "bad directory, not changing"
+            return
+        else:
+            new_dir = Holder.prev_dir()
+
+    Holder.swap(os.getcwd())
+    os.chdir(new_dir)
     print "Current working directory: %s" % os.getcwd()
 
 def system(debugger, command_line, result, dict):