FIX: hanging stream identification #189

fido/fido.py

@@ -532,10 +532,11 @@ def blocking_read(self, file, bytes_to_read):
         buffer = b''
         while bytes_read < bytes_to_read:
             readbuffer = file.read(bytes_to_read - bytes_read)
+            last_read_len = len(readbuffer)
             buffer += readbuffer
-            bytes_read = len(buffer)
-            # break out if EOF is reached.
-            if readbuffer == '':
+            bytes_read += last_read_len
+            # break out if EOF is reached, that is zero bytes read.
+            if last_read_len < 1:
                 break
         return buffer
 

tests/test_fido.py

@@ -1,13 +1,50 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+from __future__ import print_function
 
+import io
+import tempfile
 from time import sleep
 
+from fido import fido
 from fido.fido import PerfTimer
 
+# Magic number for fmt/1000.
+MAGIC = b"\x5A\x58\x54\x61\x70\x65\x21\x1A\x01"
 
 def test_perf_timer():
     timer = PerfTimer()
     sleep(3.6)
     duration = timer.duration()
     assert duration > 0
+
+def test_file_identification():
+    """Reference for Fido-based format identification
+        1. Create a byte-stream with a known magic number and serialise to tempfile.
+        2. Call identify_file(...) to identify the file against Fido's known formats.
+    """
+    # Create a temporary file on the host operating system.
+    tmp = tempfile.mkstemp()
+    tmp_file = tmp[1]
+
+    # Write to the file our known magic-number.
+    with open(tmp_file, "wb") as new_file:
+        new_file.write(MAGIC)
+
+    # Create a Fido instance and call identify_file. The identify_file function
+    # will create and manage a file for itself.
+    f = fido.Fido()
+    f.identify_file(tmp_file)
+
+def test_stream_identification():
+    """Reference for Fido-based format identification
+        1. Create a byte-stream with a known magic number.
+        2. Call identify_stream(...) to identify the file against Fido's known formats.
+    """
+    # Create the stream object with the known magic-number.
+    fstream = io.BytesIO(MAGIC)
+    # Create a Fido instance and call identify_stream. The identify_stream function
+    # will work on the stream as-is. This could be an open file handle that the
+    # caller is managing for itself.
+    f = fido.Fido()
+    f.identify_stream(fstream, "filename to display", extension=False)