From 6cd4f21c5465be83b4503de83684bdff85f90b1f Mon Sep 17 00:00:00 2001
From: KOLANICH <kolan_n@mail.ru>
Date: Thu, 12 Dec 2019 12:51:59 +0300
Subject: [PATCH] Added support for memory mappings

---
 pgpy/pgp.py   |  3 ++-
 pgpy/types.py | 31 ++++++++++++++++---------------
 pgpy/utils.py | 23 +++++++++++++++++++++++
 3 files changed, 41 insertions(+), 16 deletions(-)
 create mode 100644 pgpy/utils.py

diff --git a/pgpy/pgp.py b/pgpy/pgp.py
index f34a25fb..4871b647 100644
--- a/pgpy/pgp.py
+++ b/pgpy/pgp.py
@@ -14,6 +14,7 @@
 import itertools
 import operator
 import os
+from mmap import mmap
 import re
 import warnings
 import weakref
@@ -2424,7 +2425,7 @@ def verify(self, subject, signature=None):
         sspairs = []
 
         # some type checking
-        if not isinstance(subject, (type(None), PGPMessage, PGPKey, PGPUID, PGPSignature, str, bytes, bytearray)):
+        if not isinstance(subject, (type(None), PGPMessage, PGPKey, PGPUID, PGPSignature, str, bytes, bytearray, mmap)):
             raise TypeError("Unexpected subject value: {:s}".format(str(type(subject))))
         if not isinstance(signature, (type(None), PGPSignature)):
             raise TypeError("Unexpected signature value: {:s}".format(str(type(signature))))
diff --git a/pgpy/types.py b/pgpy/types.py
index 187d3984..36c1c006 100644
--- a/pgpy/types.py
+++ b/pgpy/types.py
@@ -14,12 +14,16 @@
 import warnings
 import weakref
 
+from mmap import mmap
+
+
 from enum import EnumMeta
 from enum import IntEnum
 
 from .decorators import sdproperty
 
 from .errors import PGPError
+from .utils import MMap
 
 __all__ = ['Armorable',
            'ParentRef',
@@ -81,7 +85,7 @@ def is_ascii(text):
         if isinstance(text, str):
             return bool(re.match(r'^[ -~\r\n\t]*$', text, flags=re.ASCII))
 
-        if isinstance(text, (bytes, bytearray)):
+        if isinstance(text, (bytes, bytearray, mmap)):
             return bool(re.match(br'^[ -~\r\n\t]*$', text, flags=re.ASCII))
 
         raise TypeError("Expected: ASCII input of type str, bytes, or bytearray")  # pragma: no cover
@@ -94,8 +98,8 @@ def is_armor(text):
         :raises: :py:exc:`TypeError` if ``text`` is not a ``str``, ``bytes``, or ``bytearray``
         :returns: Whether the text is ASCII-armored.
         """
-        if isinstance(text, (bytes, bytearray)):  # pragma: no cover
-            text = text.decode('latin-1')
+        if isinstance(text, (bytes, bytearray, mmap)):  # pragma: no cover
+            text = codecs.latin_1_decode(text)[0]
 
         return Armorable.__armor_regex.search(text) is not None
 
@@ -115,8 +119,8 @@ def ascii_unarmor(text):
             m['body'] = bytearray(text)
             return m
 
-        if isinstance(text, (bytes, bytearray)):  # pragma: no cover
-            text = text.decode('latin-1')
+        if isinstance(text, (bytes, bytearray, mmap)):  # pragma: no cover
+            text = codecs.latin_1_decode(text)[0]
 
         m = Armorable.__armor_regex.search(text)
 
@@ -176,12 +180,9 @@ def magic(self):
 
     @classmethod
     def from_file(cls, filename):
-        with open(filename, 'rb') as file:
-            obj = cls()
-            data = bytearray(os.path.getsize(filename))
-            file.readinto(data)
-
-        po = obj.parse(data)
+        obj = cls()
+        with MMap(filename) as data:
+            po = obj.parse(data)
 
         if po is not None:
             return (obj, po)
@@ -191,7 +192,7 @@ def from_file(cls, filename):
     @classmethod
     def from_blob(cls, blob):
         obj = cls()
-        if (not isinstance(blob, bytes)) and (not isinstance(blob, bytearray)):
+        if (not isinstance(blob, bytes)) and (not isinstance(blob, (bytearray, mmap))):
             po = obj.parse(bytearray(blob, 'latin-1'))
 
         else:
@@ -691,9 +692,9 @@ def __eq__(self, other):
         if isinstance(other, Fingerprint):
             return str(self) == str(other)
 
-        if isinstance(other, (str, bytes, bytearray)):
-            if isinstance(other, (bytes, bytearray)):  # pragma: no cover
-                other = other.decode('latin-1')
+        if isinstance(other, (str, bytes, bytearray, mmap)):
+            if isinstance(other, (bytes, bytearray, mmap)):  # pragma: no cover
+                other = codecs.latin_1_decode(other)[0]
 
             other = other.replace(' ', '')
             return any([str(self) == other,
diff --git a/pgpy/utils.py b/pgpy/utils.py
new file mode 100644
index 00000000..8d8385dd
--- /dev/null
+++ b/pgpy/utils.py
@@ -0,0 +1,23 @@
+import mmap
+
+try:
+    from pathlib import Path
+except ImportError:
+    from pathlib2 import Path
+
+class MMap:
+    __slots__ = ("path", "f", "m")
+    def __init__(self, path):
+        path = Path(path)
+        self.path = path
+        self.f = None
+        self.m = None
+    
+    def __enter__(self):
+        self.f = self.path.open("rb")
+        self.m = mmap.mmap(self.f.fileno(), 0, prot=mmap.PROT_READ)
+        return self.m
+    
+    def __exit__(self, *args, **kwargs):
+        self.m.close()
+        self.f.close()