Allow the lastchange target to get a hard-coded default last change

from build/LASTCHANGE.in if there's no actual svn or git change found.
BUG=none
TEST=none
Review URL: http://codereview.chromium.org/159876

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22489 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 16 insertions, 5 deletions

diff --git a/build/util/build_util.gyp b/build/util/build_util.gyp
index 7ece392..ad17be6 100644
--- a/build/util/build_util.gyp
+++ b/build/util/build_util.gyp
@@ -12,11 +12,14 @@
       'type': 'none',
       'variables': {
         'lastchange_out_path': '<(SHARED_INTERMEDIATE_DIR)/build/LASTCHANGE',
+        'default_lastchange_path': '../LASTCHANGE.in',
       },
       'actions': [
         {
           'action_name': 'lastchange',
           'inputs': [
+            # Note:  <(default_lastchange_path) is optional,
+            # so it doesn't show up in inputs.
             './lastchange.py',
           ],
           'outputs': [
@@ -24,9 +27,12 @@
             '<(lastchange_out_path).always',
           ],
           'action': [
-            'python', '<@(_inputs)', '-o', '<(lastchange_out_path)',
+            'python', '<@(_inputs)',
+            '-o', '<(lastchange_out_path)',
+            '-d', '<(default_lastchange_path)',
           ],
-          'message': 'Extracting last change to <(lastchange_out_path)'
+          'message': 'Extracting last change to <(lastchange_out_path)',
+          'process_outputs_as_sources': '1',
         },
       ],
     },
diff --git a/build/util/lastchange.py b/build/util/lastchange.py
index 1b68acd..8f1fb64 100644
--- a/build/util/lastchange.py
+++ b/build/util/lastchange.py
@@ -60,7 +60,7 @@ def git_fetch_id():
   return id
 
 
-def fetch_change():
+def fetch_change(default_lastchange):
   """
   Returns the last change, from some appropriate revision control system.
   """
@@ -68,7 +68,10 @@ def fetch_change():
   if not change and sys.platform in ('linux2',):
     change = git_fetch_id()
   if not change:
-    change = '0'
+    if default_lastchange and os.path.exists(default_lastchange):
+      change = open(default_lastchange, 'r').read().strip()
+    else:
+      change = '0'
   return change
 
 
@@ -93,6 +96,8 @@ def main(argv=None):
     argv = sys.argv
 
   parser = optparse.OptionParser(usage="lastchange.py [-h] [[-o] FILE]")
+  parser.add_option("-d", "--default-lastchange", metavar="FILE",
+                    help="default last change input FILE")
   parser.add_option("-o", "--output", metavar="FILE",
                     help="write last change to FILE")
   opts, args = parser.parse_args(argv[1:])
@@ -107,7 +112,7 @@ def main(argv=None):
     parser.print_help()
     sys.exit(2)
 
-  change = fetch_change()
+  change = fetch_change(opts.default_lastchange)
 
   contents = "LASTCHANGE=%s\n" % change