Prevent get_archive.py from going into an infinite loop if you request a

tools/get_archive.py

Index: tools/get_archive.py
===================================================================
--- tools/get_archive.py	(revision 10904)
+++ tools/get_archive.py	(working copy)
@@ -161,6 +161,8 @@
         else:
           # Now try to find one with a nearby CL num.
           revision_num = int(revision_num) - 1
+          if revision_num <= 0:
+            too_early_error()
     return latest
     
   get_from_gsutil(name, directory, version_file, latest_pattern, osdict, 
@@ -286,6 +288,13 @@
   print 'Successfully downloaded to %s' % directory
   return 0
 
+def too_early_error():
+  """Quick shortcutting function, to return early if someone requests a revision
+  that is smaller than the earliest stored. This saves us from doing repeated
+  requests until we get down to 0."""
+  print ('Unable to download requested revision because it is earlier than the '
+      'earliest revision stored.')
+  sys.exit(1)
 
 def main():
   parser = optparse.OptionParser(usage='usage: %prog [options] download_name')
@@ -296,17 +305,25 @@
   args, positional = parser.parse_args()
 
   if positional[0] == 'dartium':
+    if args.revision < 4285:

[Emily Fortuna, 2012/08/17 19:52:02]

I'm not a fan of hard-coding the "earliest revision" numbers, but this saves us
from making, in this case 4285 requests (and in some cases 9761 requests!) to
determine that no earlier version exists. I'm certainly open to any suggested
nicer solution.

+      return too_early_error()
     get_dartium_revision('Dartium', DARTIUM_DIR, DARTIUM_VERSION,
                          DARTIUM_LATEST_PATTERN, DARTIUM_PERMANENT_PATTERN,
                          args.revision)
   elif positional[0] == 'chromedriver':
+    if args.revision < 7823:
+      return too_early_error()
     get_dartium_revision('chromedriver', CHROMEDRIVER_DIR, CHROMEDRIVER_VERSION,
                          CHROMEDRIVER_LATEST_PATTERN,
                          CHROMEDRIVER_PERMANENT_PATTERN, args.revision)
   elif positional[0] == 'sdk':
+    if args.revision < 9761:
+      return too_early_error()
     get_sdk_revision('sdk', SDK_DIR, SDK_VERSION, SDK_LATEST_PATTERN,
         SDK_PERMANENT, args.revision)
   elif positional[0] == 'drt':
+    if args.revision < 5342:
+      return too_early_error()
     get_dartium_revision('DumpRenderTree', DRT_DIR, DRT_VERSION,
                          DRT_LATEST_PATTERN, DRT_PERMANENT_PATTERN,
                          args.revision)