go-enry/python/enry.py
Miguel Molina 8ff885a3a8
implement IsGenerated helper to filter out generated files
Closes #17

Implements the IsGenerated helper function to filter out generated
files using the rules and matchers in:
- https://github.com/github/linguist/blob/master/lib/linguist/generated.rb

Since the vast majority of matchers have very different logic, it cannot
be autogenerated directly from linguist like other logics in enry, so it's
translated by hand.

There are three different types of matchers in this implementation:
- By extension, which mark as generated based only in the extension. These
  are the fastest matchers, so they're done first.
- By file name, which matches patterns against the filename. These
  are performed in second place. Unlike linguist, we try to use string
  functions instead of regexps as much as possible.
- Finally, the rest of the matchers, which go into the content and try
  to identify if they're generated or not based on the content. Unlike
  linguist, we try to only read the content we need and not split it
  all unless it's necessary and use byte functions instead of regexps
  as much as possible.

Signed-off-by: Miguel Molina <miguel@erizocosmi.co>
2020-05-28 08:55:13 +02:00

95 lines
2.8 KiB
Python

"""
Python library calling enry Go implementation trough cFFI (API, out-of-line) and Cgo.
"""
from _c_enry import ffi, lib
## cgo -> ffi helpers
def py_bytes_to_go(py_bytes: bytes):
c_bytes = ffi.new("char[]", len(py_bytes))
go_slice = ffi.new("GoSlice *", [c_bytes, len(py_bytes), len(py_bytes)])
return (go_slice[0], c_bytes)
def py_str_to_go(py_str: str):
str_bytes = py_str.encode()
c_str = ffi.new("char[]", str_bytes)
go_str = ffi.new("_GoString_ *", [c_str, len(str_bytes)])
return (go_str[0], c_str)
def go_str_to_py(go_str: str):
str_len = go_str.n
if str_len > 0:
return ffi.unpack(go_str.p, go_str.n).decode()
return ""
def go_bool_to_py(go_bool: bool):
return go_bool == 1
## API, TODO(bzz): add docstrings
def language(filename: str, content: bytes) -> str:
fName, c_str = py_str_to_go(filename)
fContent, c_bytes = py_bytes_to_go(content)
guess = lib.GetLanguage(fName, fContent)
lang = go_str_to_py(guess)
return lang
def language_by_extension(filename: str) -> str:
fName, c_str = py_str_to_go(filename)
guess = lib.GetLanguageByExtension(fName)
lang = go_str_to_py(guess.r0)
return lang
def language_by_filename(filename: str) -> str:
fName, c_str = py_str_to_go(filename)
guess = lib.GetLanguageByFilename(fName)
lang = go_str_to_py(guess.r0)
return lang
def is_vendor(filename: str) -> bool:
fName, c_str = py_str_to_go(filename)
guess = lib.IsVendor(fName)
return go_bool_to_py(guess)
def is_generated(filename: str, content: bytes) -> bool:
fname, c_str = py_str_to_go(filename)
fcontent, c_bytes = py_bytes_to_go(content)
guess = lib.IsGenerated(fname, fcontent)
return go_bool_to_py(guess)
## Tests
from collections import namedtuple
def main():
TestFile = namedtuple("TestFile", "name, content, lang")
files = [
TestFile("Parse.hs", b"", "Haskell"), TestFile("some.cpp", b"", "C++"),
TestFile("orand.go", b"", "Go"), TestFile("type.h", b"", "C"),
TestFile(".bashrc", b"", "Shell"), TestFile(".gitignore", b"", "Ignore List")
]
print("\nstrategy: extension")
for f in files:
lang = language_by_extension(f.name)
print("\tfile: {:10s} language: '{}'".format(f.name, lang))
print("\nstrategy: filename")
for f in files:
lang = language_by_filename(f.name)
print("\tfile: {:10s} language: '{}'".format(f.name, lang))
print("\ncheck: is vendor?")
for f in files:
vendor = is_vendor(f.name)
print("\tfile: {:10s} vendor: '{}'".format(f.name, vendor))
print("\nstrategy: all")
for f in files:
lang = language(f.name, f.content)
print("\tfile: {:10s} language: '{}'".format(f.name, lang))
assert lang == f.lang, "Expected '{}' but got '{}'".format(f.lang, lang)
if __name__ == "__main__":
main()