Add hexdir handler, test

chainqueue/fs/dir.py

@@ -0,0 +1,104 @@
+# standard imports
+import os
+import stat
+import logging
+
+# external imports
+from hexathon import valid as valid_hex
+
+logg = logging.getLogger(__name__)
+
+
+class HexDir:
+
+    def __init__(self, root_path, key_length, levels=2, prefix_length=0):
+        self.path = root_path
+        self.key_length = key_length
+        self.prefix_length = prefix_length
+        self.__levels = levels + 2
+        fi = None
+        try:
+            fi = os.stat(self.path)
+            self.__verify_directory()
+        except FileNotFoundError:
+            HexDir.__setup_directory(self.path)
+        if not stat.S_ISDIR(fi.st_mode):
+            raise ValueError('{} is not a directory'.format(self.path))
+        self.master_file = os.path.join(self.path, 'master')
+
+
+    @property
+    def levels(self):
+        return self.__levels - 2
+
+
+    def add(self, key, content, prefix=b''):
+        l = len(key)
+        if l != self.key_length:
+            raise ValueError('expected key length {}, got {}'.format(self.key_length, l))
+        l = len(prefix)
+        if l != self.prefix_length:
+            raise ValueError('expected prefix length {}, got {}'.format(self.prefix_length, l))
+        if not isinstance(content, bytes):
+            raise ValueError('content must be bytes, got {}'.format(type(content).__name__))
+        if prefix != None and not isinstance(prefix, bytes):
+            raise ValueError('prefix must be bytes, got {}'.format(type(content).__name__))
+        key_hex = key.hex()
+        entry_path = self.to_filepath(key_hex)
+
+        os.makedirs(os.path.dirname(entry_path), exist_ok=True)
+        f = open(entry_path, 'wb')
+        f.write(content)
+        f.close()
+
+        f = open(self.master_file, 'ab')
+        if prefix != None:
+            f.write(prefix)
+        f.write(key)
+        f.close()
+
+        logg.info('created new entry {} in {}'.format(key_hex, entry_path)) 
+
+
+    def set_prefix(self, idx, prefix):
+        l = len(prefix)
+        if l != self.prefix_length:
+            raise ValueError('expected prefix length {}, got {}'.format(self.prefix_length, l))
+        if not isinstance(prefix, bytes):
+            raise ValueError('prefix must be bytes, got {}'.format(type(content).__name__))
+        cursor = idx * (self.prefix_length + self.key_length)
+        f = open(self.master_file, 'rb+')
+        f.seek(cursor)
+        f.write(prefix)
+        f.close()
+
+
+    def to_subpath(self, hx):
+        lead = ''
+        for i in range(0, self.__levels, 2):
+            lead += hx[i:i+2] + '/'
+        return lead.upper()
+
+
+    def to_dirpath(self, hx):
+        sub_path = self.to_subpath(hx)
+        return os.path.join(self.path, sub_path)
+
+
+    def to_filepath(self, hx):
+        dir_path = self.to_dirpath(hx)
+        file_path = os.path.join(dir_path, hx.upper())
+        return file_path
+
+
+    def __verify_directory(self):
+        return True
+
+
+    @staticmethod
+    def __prepare_directory(path):
+        os.makedirs(path, exist_ok=True)
+        state_file = os.path.join(path, 'master')
+        f = open(state_file, 'w')
+        f.close()
+