我已将我的代码缩短为一个最小的用例。
该脚本总是完成,但大约 50% 的时间它给出了内存访问冲突/崩溃。
这是在 Windows 7 上使用 64 位 Python 3
这段代码应该遍历 7zip 的所有处理程序并说明它们支持哪些扩展(一个空格分隔的列表,可能是空的......不是 VT_EMPTY,只是 bstrVal=L"")
#!/usr/bin/python
from cffi import FFI
ffi = FFI()
ffi.cdef("""
typedef struct PROPVARIANT {
unsigned short vt;
unsigned short wReserved1;
unsigned short wReserved2;
unsigned short wReserved3;
union {
int intVal;
wchar_t* bstrVal;
/* shortened for clarity */
};
} PROPVARIANT;
typedef unsigned long long HRESULT;
typedef uint32_t PROPID;
HRESULT GetNumberOfFormats(uint32_t * numFormats);
HRESULT GetHandlerProperty2(uint32_t index, PROPID propID, PROPVARIANT * value);
""")
S_OK = 0x00000000 # Operation successful
VT_BSTR = 8
kExtension = 2
dll7z = ffi.dlopen('7z.dll')
num_formats = ffi.new('uint32_t*')
assert dll7z.GetNumberOfFormats(num_formats) == S_OK
print(num_formats[0])
tmp_pvar = ffi.new('PROPVARIANT*')
for i in range(num_formats[0]):
assert dll7z.GetHandlerProperty2(i, kExtension, tmp_pvar) == S_OK
assert tmp_pvar != ffi.NULL
assert tmp_pvar[0].vt == VT_BSTR
print(ffi.string(tmp_pvar[0].bstrVal))
令人烦恼的是,等效ctypes
代码似乎工作得很好。
from ctypes import *
class PROPVARIANT(Structure):
_fields_ = [
('vt', c_ushort),
('resrved1', c_ushort),
('resrved2', c_ushort),
('resrved3', c_ushort),
('bstrVal', c_wchar_p),
]
dll7z = windll.LoadLibrary('7z.dll')
S_OK = 0x00000000 # Operation successful
VT_BSTR = 8
kExtension = 2
num_formats = c_uint()
assert dll7z.GetNumberOfFormats(byref(num_formats)) == S_OK
print(num_formats.value)
tmp_pvar = PROPVARIANT()
for i in range(num_formats.value):
assert dll7z.GetHandlerProperty2(i, kExtension, tmp_pvar) == S_OK
assert tmp_pvar.vt == VT_BSTR
print(tmp_pvar.bstrVal)