Compute all fields lazily.

1 files changed, 60 insertions, 28 deletions

diff --git a/summainlib.py b/summainlib.py
index 48127d3..3ba8529 100644
--- a/summainlib.py
+++ b/summainlib.py
@@ -161,30 +161,57 @@ class FilesystemObject(object):
     
     def __init__(self, filename, nn, pn, exclude, stat_result=None, sha1=None,
                  open_file=None, readlink=None):
-        stat_result = stat_result or os.lstat(filename)
-        sha1 = sha1 or hashlib.sha1()
+        self._filename = filename
+        self._exclude = exclude
+        self._pn = pn
+        self._nn = nn
+        self._sha1 = sha1 or hashlib.sha1()
+        self._stat_result = stat_result or os.lstat(filename)
         self.open_file = open_file or file
-        readlink = readlink or os.readlink
-        
-        self.exclude = exclude
-        
+        self.readlink = readlink or os.readlink
         self.values = dict()
-        self['Name'] = pn.normalize(filename)
-        self['Mtime'] = self.format_time(stat_result.st_mtime)
-        self['Mode'] = '%o' % stat_result.st_mode
-        self['Ino'] = '%d' % nn.get_ino(stat_result.st_ino)
-        self['Dev'] = '%d' % nn.get_dev(stat_result.st_dev)
-        self['Nlink'] = '%d' % stat_result.st_nlink
-        if not stat.S_ISDIR(stat_result.st_mode):
-            self['Size'] = '%d' % stat_result.st_size
-        self['Uid'] = '%d' % stat_result.st_uid
-        self['Username'] = self.lookup_username(stat_result.st_uid)
-        self['Gid'] = '%d' % stat_result.st_gid
-        self['Group'] = self.lookup_group(stat_result.st_gid)
-        if stat.S_ISREG(stat_result.st_mode):
-            self['Sha-1'] = self.compute_sha1(filename, sha1)
-        if stat.S_ISLNK(stat_result.st_mode):
-            self['Target'] = readlink(filename)
+
+    def _compute_name(self):
+        return urllib.quote(self._pn.normalize(self._filename))
+
+    def _compute_mtime(self):
+        return self.format_time(self._stat_result.st_mtime)
+
+    def _compute_mode(self):
+        return '%o' % self._stat_result.st_mode
+
+    def _compute_ino(self):
+        return '%d' % self._nn.get_ino(self._stat_result.st_ino)
+
+    def _compute_dev(self):
+        return '%d' % self._nn.get_dev(self._stat_result.st_dev)
+
+    def _compute_nlink(self):
+        return '%d' % self._stat_result.st_nlink
+
+    def _compute_size(self):
+        if not stat.S_ISDIR(self._stat_result.st_mode):
+            return '%d' % self._stat_result.st_size
+
+    def _compute_uid(self):
+        return '%d' % self._stat_result.st_uid
+
+    def _compute_username(self):
+        return self.lookup_username(self._stat_result.st_uid)
+
+    def _compute_gid(self):
+        return '%d' % self._stat_result.st_gid
+
+    def _compute_group(self):
+        return self.lookup_group(self._stat_result.st_gid)
+
+    def _compute_sha_1(self):
+        if stat.S_ISREG(self._stat_result.st_mode):
+            return self.compute_sha1(self._filename, self._sha1)
+
+    def _compute_target(self):
+        if stat.S_ISLNK(self._stat_result.st_mode):
+            return self.readlink(self._filename)
 
     def format_time(self, timestamp):
         return time.strftime('%Y-%m-%d %H:%M:%S +0000', 
@@ -206,16 +233,21 @@ class FilesystemObject(object):
         f.close()
         return sha1.hexdigest()
 
-    def hook_name(self, value):
-        return urllib.quote(value)
-
     def __setitem__(self, key, value):
-        hook_name = 'hook_%s' % key.lower()
-        if hasattr(self, hook_name):
-            value = getattr(self, hook_name)(value)
         self.values[key] = value
         
+    def _normalize_key(self, key):
+        key = key.lower()
+        key = '_'.join(key.split('-'))
+        return key
+        
     def __getitem__(self, key):
+        if key not in self.values:
+            method = '_compute_%s' % self._normalize_key(key)
+            if hasattr(self, method):
+                value = getattr(self, method)()
+                if value is not None:
+                    self.values[key] = value
         return self.values.get(key, '')
 
     def _isdir(self):