Fix a bug in the Save to disk function that could cause saving of multiple books to fail on multi-core machines

src/calibre/debug.py

@@ -65,7 +65,14 @@ def debug_device_driver():
     from calibre.devices.scanner import DeviceScanner
     s = DeviceScanner()
     s.scan()
-    print 'USB devices on system:\n', pprint.pprint(s.devices)
+    devices = s.devices
+    if not iswindows:
+        devices = [list(x) for x in devices]
+        for d in devices:
+            for i in range(3):
+                d[i] = hex(d[i])
+
+    print 'USB devices on system:\n', pprint.pprint(devices)
     if iswindows:
         wmi = __import__('wmi', globals(), locals(), [], -1)
         drives = []

src/calibre/devices/eslick/driver.py

@@ -14,7 +14,7 @@ class ESLICK(USBMS):
     name           = 'ESlick Device Interface'
     gui_name       = 'Foxit ESlick'
     description    = _('Communicate with the ESlick eBook reader.')
-    author         = _('Kovid Goyal')
+    author         = 'Kovid Goyal'
     supported_platforms = ['windows', 'osx', 'linux']
 
     # Ordered list of supported formats

src/calibre/library/save_to_disk.py

@@ -153,8 +153,14 @@ def save_book_to_disk(id, db, root, opts, length):
     base_path = os.path.join(root, *components)
     base_name = os.path.basename(base_path)
     dirpath = os.path.dirname(base_path)
-    if not os.path.exists(dirpath):
+    # Don't test for existence first are the test could fail but
+    # another worker process could create the directory before
+    # the call to makedirs
+    try:
         os.makedirs(dirpath)
+    except BaseException:
+        if not os.path.exists(dirpath):
+            raise
 
     cdata = db.cover(id, index_is_id=True)
     if opts.save_cover: