Merge pull request #245 from bzz/initial-cffi-python-bindings

Initial cffi bindings for python
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Alexander 2019-10-28 14:07:29 +01:00 committed by GitHub
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6 changed files with 161 additions and 0 deletions

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@ -29,6 +29,7 @@ LINUX_DIR=$(RESOURCES_DIR)/linux-x86-64
LINUX_SHARED_LIB=$(LINUX_DIR)/libenry.so
DARWIN_DIR=$(RESOURCES_DIR)/darwin
DARWIN_SHARED_LIB=$(DARWIN_DIR)/libenry.dylib
STATIC_LIB=$(RESOURCES_DIR)/libenry.a
HEADER_FILE=libenry.h
NATIVE_LIB=./shared/enry.go
@ -79,4 +80,10 @@ $(LINUX_SHARED_LIB):
CGO_ENABLED=1 GOOS=linux GOARCH=amd64 go build -buildmode=c-shared -o $(LINUX_SHARED_LIB) $(NATIVE_LIB) && \
mv $(LINUX_DIR)/$(HEADER_FILE) $(RESOURCES_DIR)/$(HEADER_FILE)
static: $(STATIC_LIB)
$(STATIC_LIB):
CGO_ENABLED=1 go build -buildmode=c-archive -o $(STATIC_LIB) $(NATIVE_LIB)
.PHONY: benchmarks benchmarks-samples benchmarks-slow

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@ -59,4 +59,6 @@ package:
clean:
rm -rf $(JAR)
rm -rf $(RESOURCES_DIR)
rm -rf $(JNAERATOR_JAR)
.PHONY: test package clean linux-shared darwin-shared os-shared-lib

29
python/README.md Normal file
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@ -0,0 +1,29 @@
# Python bindings for enry
Python bingings thoug cFFI (API, out-of-line) for calling enr Go functions though CGo wrapper.
## Build
```
$ make static
$ python enry_build.py
```
Will build static library for Cgo wrapper `libenry`, then generate and build `enry.c`
- a CPython extension that
## Run
Example for single exposed API function is provided.
```
$ python enry.py
```
## TODOs
- [ ] try ABI mode, to aviod dependency on C compiler on install (+perf test?)
- [ ] ready `libenry.h` and generate `ffibuilder.cdef` content
- [ ] helpers for sending/recieving Go slices to C
- [ ] cover the rest of enry API
- [ ] add `setup.py`
- [ ] build/release automation on CI (publish on pypi)

76
python/enry.py Normal file
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@ -0,0 +1,76 @@
"""
Python library calling enry Go implementation trough cFFI (API, out-of-line) and Cgo.
"""
from _c_enry import ffi, lib
## Helpers
def go_str_to_py(go_str):
str_len = go_str.n
if str_len > 0:
return ffi.unpack(go_str.p, go_str.n).decode()
return ""
def py_str_to_go(py_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]
def go_bool_to_py(go_bool):
return go_bool == 1
## API
def language_by_extension(filename: str) -> str:
fName = 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 = 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 = py_str_to_go(filename)
guess = lib.IsVendor(fName)
return go_bool_to_py(guess)
## Tests
def main():
files = [
"Parse.hs", "some.cpp", "and.go", "type.h", ".bashrc", ".gitignore"
]
print("strategy: extension")
for filename in files:
lang = language_by_extension(filename)
print("file: {:10s} language: '{}'".format(filename, lang))
print("\nstrategy: filename")
for filename in files:
lang = language_by_filename(filename)
print("file: {:10s} language: '{}'".format(filename, lang))
print("\ncheck: is vendor?")
for filename in files:
vendor = is_vendor(filename)
print("file: {:10s} vendor: '{}'".format(filename, vendor))
if __name__ == "__main__":
main()

43
python/enry_build.py Normal file
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@ -0,0 +1,43 @@
from cffi import FFI
ffibuilder = FFI()
# cdef() expects a single string declaring the C types, functions and
# globals needed to use the shared object. It must be in valid C syntax.
ffibuilder.cdef("""
typedef struct { const char *p; ptrdiff_t n; } _GoString_;
typedef _GoString_ GoString;
typedef unsigned char GoUint8;
/* Return type for GetLanguageByExtension */
struct GetLanguageByExtension_return {
GoString r0; /* language */
GoUint8 r1; /* safe */
};
extern struct GetLanguageByExtension_return GetLanguageByExtension(GoString p0);
/* Return type for GetLanguageByFilename */
struct GetLanguageByFilename_return {
GoString r0; /* language */
GoUint8 r1; /* safe */
};
extern struct GetLanguageByFilename_return GetLanguageByFilename(GoString p0);
extern GoUint8 IsVendor(GoString p0);
""")
# set_source() gives the name of the python extension module to
# produce, and some C source code as a string. This C code needs
# to make the declarated functions, types and globals available,
# so it is often just the "#include".
ffibuilder.set_source("_c_enry",
"""
#include "../.shared/libenry.h" // the C header of the library
""",
libraries=['enry'],
library_dirs=['../.shared'
]) # library name, for the linker
if __name__ == "__main__":
ffibuilder.compile(verbose=True)

4
python/requirements.txt Normal file
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@ -0,0 +1,4 @@
cffi==1.12.3
Click==7.0
pycparser==2.19
yapf==0.27.0