refactor: add type hints in strings.py and file.py

cve_bin_tool/file.py

@@ -11,7 +11,7 @@
 from cve_bin_tool.async_utils import FileIO, run_coroutine
 
 
-async def aio_is_binary(filename):
+async def aio_is_binary(filename: str) -> bool:
     """Read the magic bytes from a file and determine if it is an executable
     binary."""
     signature = await read_signature(filename)
@@ -24,26 +24,26 @@ async def aio_is_binary(filename):
     return False
 
 
-def is_binary(filename):
+def is_binary(filename: str) -> bool:
     return run_coroutine(aio_is_binary(filename))
 
 
-async def read_signature(filename, length=4):
+async def read_signature(filename: str, length: int = 4) -> bytes:
     """Read the signature, first length bytes, from filename."""
     async with FileIO(filename, "rb") as file_handle:
         return await file_handle.read(length)
 
 
-def check_elf(_filename, signature):
+def check_elf(_filename: str, signature: bytes) -> bool:
     """Check for an ELF signature."""
     return signature == b"\x7f\x45\x4c\x46"
 
 
-def check_pe(_filename, signature):
+def check_pe(_filename: str, signature: bytes) -> bool:
     """Check for windows/dos PE signature, aka 0x5a4d."""
     return signature[:4] == b"\x4d\x5a"
 
 
-def check_fake_test(_filename, signature):
+def check_fake_test(_filename: str, signature: bytes) -> bool:
     """check for fake tests under windows."""
     return signature == b"MZ\x90\x00"

cve_bin_tool/strings.py

@@ -16,11 +16,11 @@ class Strings:
     # add tab to the printable character
     PRINTABLE.add(9)
 
-    def __init__(self, filename=""):
-        self.filename = filename
-        self.output = ""
+    def __init__(self, filename: str = "") -> None:
+        self.filename: str = filename
+        self.output: str = ""
 
-    async def aio_parse(self):
+    async def aio_parse(self) -> str:
         async with FileIO(self.filename, "rb") as f:
             tmp = []
             async for line in f:
@@ -33,5 +33,5 @@ async def aio_parse(self):
                         tmp = []
         return self.output
 
-    def parse(self):
+    def parse(self) -> str:
         return run_coroutine(self.aio_parse())