Make code compatible with python 3.7, removed unused imports, change static methods.

src/calibre/devices/kindle/apnx.py

@@ -2,6 +2,8 @@ __license__ = 'GPL v3'
 __copyright__ = '2011, John Schember <john at nachtimwald.com>, refactored: 2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
+from typing import Optional, Dict
+
 '''
 Generates and writes an APNX page mapping file.
 '''
@@ -17,8 +19,6 @@ from polyglot.builtins import as_unicode, as_bytes
 
 from calibre.devices.kindle.apnx_page_generator.generators.accurate_page_generator import AccuratePageGenerator
 from calibre.devices.kindle.apnx_page_generator.generators.pagebreak_page_generator import PagebreakPageGenerator
-from calibre.devices.kindle.apnx_page_generator.generators.aria_pagebreak_page_generator import \
-    AriaPagebreakPageGenerator
 from calibre.devices.kindle.apnx_page_generator.generators.exact_page_generator import ExactPageGenerator
 from calibre.devices.kindle.apnx_page_generator.generators.fast_page_generator import FastPageGenerator
 from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator
@@ -30,14 +30,14 @@ class APNXBuilder:
     Create an APNX file using a pseudo page mapping.
     """
 
-    generators: dict[str, IPageGenerator] = {
+    generators: Dict[str, IPageGenerator] = {
         FastPageGenerator.instance.name(): FastPageGenerator.instance,
         AccuratePageGenerator.instance.name(): AccuratePageGenerator.instance,
         PagebreakPageGenerator.instance.name(): PagebreakPageGenerator.instance,
         # ExactPageGenerator.instance.name(): ExactPageGenerator.instance,
     }
 
-    def write_apnx(self, mobi_file_path: str, apnx_path: str, method: str | None = None, page_count: int = 0):
+    def write_apnx(self, mobi_file_path: str, apnx_path: str, method: Optional[str] = None, page_count: int = 0):
         """
         If you want a fixed number of pages (such as from a custom column) then
         pass in a value to page_count, otherwise a count will be estimated
@@ -62,7 +62,7 @@ class APNXBuilder:
             fsync(apnxf)
 
     @staticmethod
-    def get_apnx_meta(mobi_file_path) -> dict[str, str]:
+    def get_apnx_meta(mobi_file_path) -> Dict[str, str]:
         import uuid
         apnx_meta = {
             'guid': str(uuid.uuid4()).replace('-', '')[:8],

src/calibre/devices/kindle/apnx_page_generator/generators/accurate_page_generator.py

@@ -2,20 +2,24 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
+from typing import Optional
+
 from calibre.devices.kindle.apnx_page_generator.generators.fast_page_generator import FastPageGenerator
-from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator
+from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator, mobi_html
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
 
 
 class AccuratePageGenerator(IPageGenerator):
 
+    instance = None
+
     def name(self) -> str:
         return "accurate"
 
-    def _generate_fallback(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate_fallback(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         return FastPageGenerator.instance.generate(mobi_file_path, real_count)
 
-    def _generate(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         """
         A more accurate but much more resource intensive and slower
         method to calculate the page length.
@@ -35,7 +39,7 @@ class AccuratePageGenerator(IPageGenerator):
         """
         pages = []
 
-        html = self.mobi_html(mobi_file_path)
+        html = mobi_html(mobi_file_path)
 
         # States
         in_tag = False
@@ -54,7 +58,7 @@ class AccuratePageGenerator(IPageGenerator):
         # and string functions will parse the text each
         # time they are called.
         #
-        # We can can use .lower() here because we are
+        # We can use .lower() here because we are
         # not modifying the text. In this case the case
         # doesn't matter just the absolute character and
         # the position within the stream.

src/calibre/devices/kindle/apnx_page_generator/generators/exact_page_generator.py

@@ -2,20 +2,24 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
+from typing import Optional
+
 from calibre.devices.kindle.apnx_page_generator.generators.fast_page_generator import FastPageGenerator
-from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator
+from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator, mobi_html_length
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
 
 
 class ExactPageGenerator(IPageGenerator):
 
+    instance = None
+
     def name(self) -> str:
         return "exact"
 
-    def _generate_fallback(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate_fallback(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         return FastPageGenerator.instance.generate(mobi_file_path, real_count)
 
-    def _generate(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         """
         Given a specified page count (such as from a custom column),
         create our array of pages for the apnx file by dividing by
@@ -24,7 +28,7 @@ class ExactPageGenerator(IPageGenerator):
         pages = []
         count = 0
 
-        text_length = self.mobi_html_length(mobi_file_path)
+        text_length = mobi_html_length(mobi_file_path)
 
         chars_per_page = int(text_length // real_count)
         while count < text_length:

src/calibre/devices/kindle/apnx_page_generator/generators/fast_page_generator.py

@@ -2,7 +2,9 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator
+from typing import Optional
+
+from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator, mobi_html_length
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
 
 
@@ -11,10 +13,10 @@ class FastPageGenerator(IPageGenerator):
     def name(self) -> str:
         return "fast"
 
-    def _generate_fallback(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate_fallback(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         raise Exception("Fast calculation impossible.")
 
-    def _generate(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         """
         2300 characters of uncompressed text per page. This is
         not meant to map 1 to 1 to a print book but to be a
@@ -34,7 +36,7 @@ class FastPageGenerator(IPageGenerator):
         pages = []
         count = 0
 
-        text_length = self.mobi_html_length(mobi_file_path)
+        text_length = mobi_html_length(mobi_file_path)
 
         while count < text_length:
             pages.append(count)

src/calibre/devices/kindle/apnx_page_generator/generators/pagebreak_page_generator.py

@@ -2,8 +2,10 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
+from typing import Optional
+
 from calibre.devices.kindle.apnx_page_generator.generators.fast_page_generator import FastPageGenerator
-from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator
+from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator, mobi_html
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
 import re
 
@@ -13,12 +15,12 @@ class PagebreakPageGenerator(IPageGenerator):
     def name(self) -> str:
         return "pagebreak"
 
-    def _generate_fallback(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate_fallback(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         return FastPageGenerator.instance.generate(mobi_file_path, real_count)
 
-    def _generate(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         """ Determine pages based on the presence of <*pagebreak*/>. """
-        html = self.mobi_html(mobi_file_path)
+        html = mobi_html(mobi_file_path)
         pages = []
         for m in re.finditer(b'<[^>]*pagebreak[^>]*>', html):
             pages.append(m.end())

src/calibre/devices/kindle/apnx_page_generator/i_page_generator.py

@@ -4,6 +4,8 @@ __docformat__ = 'restructuredtext en'
 
 import struct
 from abc import abstractmethod, ABCMeta
+from typing import Optional
+
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
 from calibre.ebooks.mobi.reader.mobi6 import MobiReader
 from calibre.utils.logging import default_log
@@ -14,14 +16,14 @@ from calibre.ebooks.pdb.header import PdbHeaderReader
 class IPageGenerator(metaclass=ABCMeta):
 
     @abstractmethod
-    def _generate(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         pass
 
     @abstractmethod
-    def _generate_fallback(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def _generate_fallback(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         pass
 
-    def generate(self, mobi_file_path: str, real_count: int | None) -> Pages:
+    def generate(self, mobi_file_path: str, real_count: Optional[int]) -> Pages:
         try:
             result = self._generate(mobi_file_path, real_count)
             if result.number_of_pages > 0:
@@ -36,18 +38,17 @@ class IPageGenerator(metaclass=ABCMeta):
     def name(self) -> str:
         pass
 
-    @staticmethod
-    def mobi_html(mobi_file_path: str) -> bytes:
+
+def mobi_html(mobi_file_path: str) -> bytes:
     mr = MobiReader(mobi_file_path, default_log)
     if mr.book_header.encryption_type != 0:
         raise Exception("DRMed book")
     mr.extract_text()
     return as_bytes(mr.mobi_html.lower())
 
-    @staticmethod
-    def mobi_html_length(mobi_file_path: str) -> int:
+
+def mobi_html_length(mobi_file_path: str) -> int:
     with lopen(mobi_file_path, 'rb') as mf:
         pdb_header = PdbHeaderReader(mf)
         r0 = pdb_header.section_data(0)
         return struct.unpack('>I', r0[4:8])[0]
-

src/calibre/devices/kindle/apnx_page_generator/page_group.py

@@ -2,30 +2,32 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
+from typing import Union, List, Tuple
+
 from calibre.devices.kindle.apnx_page_generator.page_number_type import PageNumberTypes
 
 
 class PageGroup:
     """Simulate constructor overloading"""
-    def __init__(self, page_locations: int | list[int], page_number_type: PageNumberTypes, first_value: int,
-                 page_labels: str | list[str] | None = None):
+    def __init__(self, page_locations: Union[int, List[int]], page_number_type: PageNumberTypes, first_value: int,
+                 page_labels: Union[str, List[str], None] = None):
         if page_locations.__class__ == int:
-            self.page_locations: list[int] = [page_locations]
+            self.page_locations: List[int] = [page_locations]
         else:
-            self.page_locations: list[int] = page_locations
+            self.page_locations: List[int] = page_locations
         self.__page_number_type: PageNumberTypes = page_number_type
         self.__first_value = first_value
         if page_number_type == PageNumberTypes.Custom:
             assert(page_labels is not None)
             if page_labels.__class__ == str:
                 assert (1 == len(self.page_locations) and len(page_labels) > 0)
-                self.__page_number_labels: list[str] = [page_labels]
+                self.__page_number_labels: List[str] = [page_labels]
             else:
                 assert (len(page_labels) == len(self.page_locations))
                 assert(all(len(label) > 0 for label in page_labels))
-                self.__page_number_labels: list[str] = page_labels
+                self.__page_number_labels: List[str] = page_labels
 
-    def append(self, page_location: int | tuple[int, str]) -> None:
+    def append(self, page_location: Union[int, Tuple[int, str]]) -> None:
         if page_location.__class__ == int:
             assert (self.__page_number_type != PageNumberTypes.Custom)
             self.page_locations.append(page_location)

src/calibre/devices/kindle/apnx_page_generator/page_number_type.py

@@ -5,7 +5,7 @@ __docformat__ = 'restructuredtext en'
 import enum
 
 
-class PageNumberTypes(str, enum.Enum):
+class PageNumberTypes(enum.Enum):
     Arabic = "a"
     Roman = "r"
-    Custom = 'c'
+    Custom = "c"

src/calibre/devices/kindle/apnx_page_generator/pages.py

@@ -3,17 +3,18 @@ __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
 import itertools
+from typing import Optional, List
 
 from calibre.devices.kindle.apnx_page_generator.page_group import PageGroup
 from calibre.devices.kindle.apnx_page_generator.page_number_type import PageNumberTypes
 
 
 class Pages:
-    def __init__(self, page_locations: list[int] | None = None):
+    def __init__(self, page_locations: Optional[List[int]] = None):
         if page_locations.__class__ == list:
-            self.__pages_groups: list[PageGroup] = [PageGroup(page_locations, PageNumberTypes.Arabic, 1)]
+            self.__pages_groups: List[PageGroup] = [PageGroup(page_locations, PageNumberTypes.Arabic, 1)]
         else:
-            self.__pages_groups: list[PageGroup] = []
+            self.__pages_groups: List[PageGroup] = []
 
     def append(self, page_location: PageGroup) -> None:
         self.__pages_groups.append(page_location)
@@ -33,7 +34,7 @@ class Pages:
         return ",".join(result)
 
     @property
-    def page_locations(self) -> list[int]:
+    def page_locations(self) -> List[int]:
         return list(itertools.chain.from_iterable(list(map(lambda pg: pg.page_locations, self.__pages_groups))))
 
     @property

src/calibre/devices/kindle/driver.py

@@ -411,7 +411,7 @@ class KINDLE2(KINDLE):
     OPT_APNX_CUST_COL        = 2
     OPT_APNX_METHOD_COL      = 3
     OPT_APNX_OVERWRITE       = 4
-    EXTRA_CUSTOMIZATION_CHOICES = {OPT_APNX_METHOD: APNXBuilder.generators.keys()}
+    EXTRA_CUSTOMIZATION_CHOICES = {OPT_APNX_METHOD: set(APNXBuilder.generators.keys())}
 
     # x330 on the PaperWhite
     # x262 on the Touch. Doesn't choke on x330, though.