[Telemetry] Default to most recent local build if --browser is omitted.

tools/telemetry/telemetry/core/browser_finder.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Finds browsers that can be controlled by telemetry."""
 
 import logging
 
 from telemetry.core.chrome import android_browser_finder
 from telemetry.core.chrome import cros_browser_finder
 from telemetry.core.chrome import desktop_browser_finder
 
-ALL_BROWSER_TYPES = (
-    desktop_browser_finder.ALL_BROWSER_TYPES + ',' +
-    android_browser_finder.ALL_BROWSER_TYPES + ',' +
-    cros_browser_finder.ALL_BROWSER_TYPES)
+BROWSER_FINDERS = [
+  desktop_browser_finder,
+  android_browser_finder,
+  cros_browser_finder

[achuithb, 2013/07/24 01:20:07]

Why not reverse this? If the user specifies --remote but no browser, I think
cros-chrome should be the default, no?

+  ]
+
+ALL_BROWSER_TYPES = ','.join([bf.ALL_BROWSER_TYPES for bf in BROWSER_FINDERS])
+
 
 class BrowserTypeRequiredException(Exception):
   pass
 
 class BrowserFinderException(Exception):
   pass
 
 def FindBrowser(options):
   """Finds the best PossibleBrowser object to run given the provided
   BrowserOptions object. The returned possiblity object can then be used to
@@ skipping 10 matching lines @@
 
   if options.browser_type == 'cros-chrome' and options.cros_remote == None:
     raise BrowserFinderException(
         'browser_type=cros-chrome requires cros_remote be set.')
   if (options.browser_type != 'cros-chrome' and
       options.browser_type != 'cros-chrome-guest' and
       options.cros_remote != None):
     raise BrowserFinderException(
         'cros_remote requires browser_type=cros-chrome or cros-chrome-guest.')
 
+  browsers = []
+  default_browser = None
+  for finder in BROWSER_FINDERS:
+    curr_browsers = finder.FindAllAvailableBrowsers(options)
+    if not default_browser:
+      default_browser = finder.SelectDefaultBrowser(curr_browsers)
+    browsers.extend(curr_browsers)
+
   if options.browser_type == None:
-    raise BrowserTypeRequiredException('browser_type must be specified')
-
-  browsers = []
-  browsers.extend(desktop_browser_finder.FindAllAvailableBrowsers(options))
-  browsers.extend(android_browser_finder.FindAllAvailableBrowsers(options))
-  browsers.extend(cros_browser_finder.FindAllAvailableBrowsers(options))
-
-  if options.browser_type == 'any':
-    types = ALL_BROWSER_TYPES.split(',')
-    def compare_browsers_on_type_priority(x, y):
-      x_idx = types.index(x.browser_type)
-      y_idx = types.index(y.browser_type)
-      return x_idx - y_idx
-    browsers.sort(compare_browsers_on_type_priority)
-    if len(browsers) >= 1:
-      return browsers[0]
-    else:
-      return None
+    if default_browser:
+      logging.warning('--browser omitted. Using most recent local build: %s' %
+                      default_browser.browser_type)
+      return default_browser
+    raise BrowserTypeRequiredException(
+        '--browser must be specified. Available browsers:\n%s' %
+        '\n'.join(sorted(set([b.browser_type for b in browsers]))))
 
   matching_browsers = [b for b in browsers
       if b.browser_type == options.browser_type and b.SupportsOptions(options)]
 
   if len(matching_browsers) == 1:
     return matching_browsers[0]
   elif len(matching_browsers) > 1:
     logging.warning('Multiple browsers of the same type found: %s' % (
                     repr(matching_browsers)))
     return matching_browsers[0]
   else:
     return None
 
 def GetAllAvailableBrowserTypes(options):
   """Returns an array of browser types supported on this system.
   A BrowserFinderException will be raised if the BrowserOptions argument is
   improperly set or if an error occurs when finding a browser.
   """
   browsers = []
-  browsers.extend(desktop_browser_finder.FindAllAvailableBrowsers(options))
-  browsers.extend(android_browser_finder.FindAllAvailableBrowsers(options))
-  browsers.extend(cros_browser_finder.FindAllAvailableBrowsers(options))
+  for finder in BROWSER_FINDERS:
+    browsers.extend(finder.FindAllAvailableBrowsers(options))
 
   type_list = set([browser.browser_type for browser in browsers])
   type_list = list(type_list)
   type_list.sort()
   return type_list