started with caching classes

[pywienerlinien] / gotovienna / cache.py

diff --git a/gotovienna/cache.py b/gotovienna/cache.py
new file mode 100644 (file)
index 0000000..76842c1
--- /dev/null
+++ b/gotovienna/cache.py
@@ -0,0 +1,80 @@
+from os import path
+import json
+import shutil
+import defaults
+import realtime
+
+
+def load(path):
+    if path.exists(path, typ):
+        try:
+            with open(path, 'r') as f:
+                j = json.load(f)
+                if type(j) == typ:
+                    return j
+                else:
+                    print 'Unexpected content in cache file'
+                    print 'rebuilding cache'
+                    shutil.copy(path, path + '.bak')
+        except ValueError:
+            print 'Corrupt cache file'
+            print 'rebuilding cache'
+            shutil.copy(path, path + '.bak')
+
+    return None
+
+class Lines(list):
+    def __init__(self, lines=[]):
+        l = load(defaults.cache_line)
+        if l and type(l) == list:
+            lines = l
+        self.lines = lines
+
+    def __iter__(self):
+        for line in self.lines:
+            yield line
+        raise StopIteration()
+
+    def __iadd__(self, y):
+        self.lines += y
+
+    def __add__(self, y):
+        return self.lines + y
+
+    def __getitem__(self, y):
+        return self.lines[y]
+
+    def __len__(self):
+        return len(self.lines)
+
+    def __str__(self):
+        return str(self.lines)
+
+    def __setitem__(self, i, y):
+        self.lines[i] = y
+
+class Stations(dict):
+    stations = {}
+
+    def __init__(self, line=False):
+        """ loads cache files
+        if line=False behaves as dict of all lines/stations
+        if line behaves as dict of directions/stations of line
+        """
+        if not Stations.stations:
+            s = load(defaults.cache_line, dict)
+            if s:
+                Stations.stations = st
+
+        self.current_line = line
+        if line == False:
+            self.dict = Stations.stations
+        elif line in Stations.stations:
+            self.dict = Stations.stations[line]
+        else:
+            Stations.stations[line] = {}
+            self.dict = Stations.stations[line]
+
+
+    def __getitem__(self, *args, **kwargs):
+        return self.dict.__getitem__(self, *args, **kwargs)