Improve object hash performance and other Various fixes

* Hash filename, timestamp, and size for obect ID.
 * Coerce all args to lowercase.
 * Ignore stat() failures and continue processing.
 * Truncate cache file when writing.
 * Close cache file after writing.
 * Catch most exceptions as Exception.

lineage-updater

@@ -58,18 +58,10 @@ def args_parse():
         arg = values.get(k, [])
         if len(arg) != 1:
             raise RuntimeError("No %s specified" % (k))
-        args[k] = arg[0]
+        args[k] = arg[0].lower()
 
     return args
 
-def file_hash(pathname):
-    f = open(pathname, 'rb')
-    buf = f.read()
-    f.close()
-    hasher = hashlib.sha1()
-    hasher.update(buf)
-    return hasher.hexdigest()
-
 def filename_properties(pathname):
     filename = os.path.basename(pathname)
     if not filename.endswith('.zip'):
@@ -111,21 +103,25 @@ def cache_refresh(cache):
             pathname = "%s/%s" % (root, filename)
             try:
                 props = filename_properties(pathname)
-            except ValueError:
+                st = os.stat(pathname)
+            except Exception:
                 continue
-            st = os.stat(pathname)
             if (not pathname in cache or
                     st.st_size != cache[pathname]['size'] or
                     int(st.st_mtime) != cache[pathname]['datetime']):
-                hash = file_hash(pathname)
                 obj = dict()
                 obj['datetime'] = int(st.st_mtime)
                 obj['filename'] = filename
-                obj['id'] = hash
                 obj['romtype'] = props['buildtype']
                 obj['size'] = st.st_size
                 obj['url'] = "%s%s/%s" % (config['baseurl'], relpath, filename)
                 obj['version'] = props['version']
+
+                str = "%s.%d.%d" % (obj['filename'], obj['datetime'], obj['size'])
+                hasher = hashlib.sha1()
+                hasher.update(str.encode())
+                obj['id'] = hasher.hexdigest()
+
                 cache[pathname] = obj
                 stale = True
 
@@ -150,8 +146,8 @@ def find_roms(device=None, buildtype=None, incremental=None):
     update_cache = False
     try:
         cache = json.load(cf)
-    except:
+    except Exception as e:
-        dbg("Failed to read cache file")
+        dbg("Failed to read cache file: %s" % (e))
         update_cache = True
 
     if cf is None or ct < time.time() - 60:
@@ -162,16 +158,19 @@ def find_roms(device=None, buildtype=None, incremental=None):
             cf.seek(0, 0)
             try:
                 json.dump(cache, cf)
+                cf.truncate()
             except:
                 pass
         fcntl.lockf(cf, fcntl.LOCK_UN)
+        cf.close()
+        cf = None
 
     roms = []
     for k, v in cache.items():
         try:
             props = filename_properties(k)
-        except ValueError:
+        except Exception as e:
-            dbg("Failed to parse cache filename")
+            dbg("Failed to parse cache filename: %s" % (e))
             continue
 
         if device and props['device'] != device:
@@ -210,12 +209,12 @@ config = dict()
 
 try:
     config_load("%s/.lineageupdaterrc" % (home))
-except RuntimeError as e:
+except Exception as e:
     die("Failed to load configuration: %s" % (str(e)))
 
 try:
     args = args_parse()
-except RuntimeError as e:
+except Exception as e:
     die("Failed to parse arguments: %s\n" % (str(e)))
 
 if cgi_method() != "GET":