Add some error recovery, cleanup scons-configure-cache

2 files changed, 56 insertions, 24 deletions

diff --git a/src/engine/SCons/CacheDir.py b/src/engine/SCons/CacheDir.py
index a9419862..aaf3c124 100644
--- a/src/engine/SCons/CacheDir.py
+++ b/src/engine/SCons/CacheDir.py
@@ -169,19 +169,35 @@ class CacheDir(object):
                 global warned
                 if self.path not in warned:
                     msg = "Please upgrade your cache by running " +\
-                          " scons-upgrade-cache.py " +  self.path
+                          " scons-configure-cache.py " +  self.path
                     SCons.Warnings.warn(SCons.Warnings.CacheVersionWarning, msg)
                     warned[self.path] = True
             else:
                 if not os.path.isdir(path):
-                    os.makedirs(path)
+                    try:
+                        os.makedirs(path)
+                    except OSError:
+                        # If someone else is trying to create the directory at
+                        # the same time as me, bad things will happen
+                        msg = "Failed to create cache directory " + path
+                        raise SCons.Errors.EnvironmentError(msg)
+                        
                 self.config['prefix_len'] = 2
                 if not os.path.exists(config_file):
-                    with open(config_file, 'w') as config:
-                        self.config = json.dump(self.config, config)
+                    try:
+                        with open(config_file, 'w') as config:
+                            self.config = json.dump(self.config, config)
+                    except:
+                        msg = "Failed to write cache configuration for " + path
+                        raise SCons.Errors.EnvironmentError(msg)
         else:
-            with open(config_file) as config:
-                self.config = json.load(config)
+            try:
+                with open(config_file) as config:
+                    self.config = json.load(config)
+            except ValueError:
+                msg = "Failed to read cache configuration for " + path
+                raise SCons.Errors.EnvironmentError(msg)
+            
 
     def CacheDebug(self, fmt, target, cachefile):
         if cache_debug != self.current_cache_debug:
diff --git a/src/script/scons-configure-cache.py b/src/script/scons-configure-cache.py
index ec3a9407..c1b7d591 100644
--- a/src/script/scons-configure-cache.py
+++ b/src/script/scons-configure-cache.py
@@ -60,6 +60,29 @@ def rearrange_cache_entries(current_prefix_len, new_prefix_len):
     for dir in old_dirs:

         os.rmdir(dir)

 

+# This dictionary should have one entry per entry in the cache config

+# Each entry should have the following:

+#   implicit - (optional) This is to allow adding a new config entry and also

+#              changing the behaviour of the system at the same time. This

+#              indicates the value the config entry would have had if it had been

+#              specified.

+#   default - The value the config entry should have if it wasn't previously

+#             specified

+#   command-line - parameters to pass to ArgumentParser.add_argument

+#   converter - (optional) Function to call if it's necessary to do some work

+#               if this configuration entry changes

+config_entries = {

+    'prefix_len' : { 

+        'implicit' : 1, 

+        'default' : 2 ,

+        'command-line' : {

+            'help' : 'Length of cache file name used as subdirectory prefix',

+            'metavar' : '<number>',

+            'type' : int

+            },

+        'converter' : rearrange_cache_entries

+    }

+}

 parser = argparse.ArgumentParser(

     description = 'Modify the configuration of an scons cache directory',

     epilog = '''

@@ -70,10 +93,9 @@ parser = argparse.ArgumentParser(
     )

 

 parser.add_argument('cache-dir', help='Path to scons cache directory')

-parser.add_argument('--prefix-len', 

-                    help='Length of cache file name used as subdirectory prefix',

-                    metavar = '<number>',

-                    type=int)

+for param in config_entries:

+    parser.add_argument('--' + param.replace('_', '-'), 

+                        **config_entries[param]['command-line'])

 parser.add_argument('--version', action='version', version='%(prog)s 1.0')

 

 # Get the command line as a dict without any of the unspecified entries.

@@ -84,15 +106,6 @@ args = dict(filter(lambda x: x[1], vars(parser.parse_args()).items()))
 os.chdir(args['cache-dir'])

 del args['cache-dir']

 

-# If a value isn't currently configured, this contains the way it behaves

-# currently (implied), and the way it should behave afer running this script

-# (default)

-# FIXME: I should use this to construct the parameter list and supply an

-# upgrade function

-implicit = {

-    'prefix_len' : { 'implied' : 1, 'default' : 2 }

-}

-

 if not os.path.exists('config'):

     # Validate the only files in the directory are directories 0-9, a-f

     expected = [ '{:X}'.format(x) for x in range(0, 16) ]

@@ -104,18 +117,21 @@ else:
         config = json.load(conf)

 

 # Find any keys that aren't currently set but should be

-for key in implicit:

+for key in config_entries:

     if key not in config:

-        config[key] = implicit[key]['implied']

+        if 'implicit' in config_entries[key]:

+            config[key] = config_entries[key]['implicit']

+        else:

+            config[key] = config_entries[key]['default']

         if key not in args:

-            args[key] = implicit[key]['default']

+            args[key] = config_entries[key]['default']

 

 #Now we go through each entry in args to see if it changes an existing config

 #setting.

 for key in args:

     if args[key] != config[key]:        

-        if key == 'prefix_len':

-            rearrange_cache_entries(config[key], args[key])

+        if 'converter' in config_entries[key]:

+            config_entries[key]['converter'](config[key], args[key])

         config[key] = args[key]

 

 # and write the updated config file