was able to test on Linux successfully

lib7zip/__init__.py

@@ -65,13 +65,13 @@
 	def free_propvariant(void_p):
 		#TODO make smarter
 		pvar = ffi.cast('PROPVARIANT*', void_p)
-		if pvar.vt == wintypes.VT_BSTR and pvar.bstrVal != ffi.NULL:
-			C.free(pvar.bstrVal)
+		if pvar.vt == wintypes.VARTYPE.VT_BSTR and pvar.bstrVal != ffi.NULL:
+			C.free( ffi.cast('char*',pvar.bstrVal)-4 )
 
 		C.memset(pvar, 0, ffi.sizeof('PROPVARIANT'))
 
-	suffixes = '', '7z.so', 'p7zip/7z.so'
-	prefixes = ['/lib', '/usr/lib']
+	suffixes = '7z.so', 'p7zip/7z.so'
+	prefixes = ['/lib', '/usr/lib', '/usr/local/lib', '/usr/libexec', '/home/linuxbrew/.linuxbrew/lib', '/opt/local/lib', '/sw/lib']
 	for suffix in suffixes:
 		for prefix in prefixes:
 			dll_paths.append(os.path.join(prefix, suffix))
@@ -143,16 +143,22 @@ def get_format_info():
 	assert num_formats != ffi.NULL
 	log.debug('GetNumberOfFormats() == %d', num_formats[0])
 
-	return {
-		get_string_prop(i, FormatProps.kName, dll7z.GetHandlerProperty2):
-		Format(
+	retdict = {}
+	for i in range(num_formats[0]):
+		start_signature = get_bytes_prop(i, FormatProps.kSignature, dll7z.GetHandlerProperty2)
+		if start_signature is None:
+			multi_signature = get_bytes_prop(i, FormatProps.kMultiSignature, dll7z.GetHandlerProperty2)
+			if multi_signature is not None:
+				size = multi_signature[0]
+				start_signature = multi_signature[1:size+1]
+
+		retdict[get_string_prop(i, FormatProps.kName, dll7z.GetHandlerProperty2)] = Format(
 			classid=get_classid(i, FormatProps.kClassID, dll7z.GetHandlerProperty2),
 			extensions=tuple(get_string_prop(i, FormatProps.kExtension, dll7z.GetHandlerProperty2).split()),
 			index=i,
-			start_signature=get_bytes_prop(i, FormatProps.kStartSignature, dll7z.GetHandlerProperty2),
+			start_signature=start_signature,
 		)
-		for i in range(num_formats[0])
-	}
+	return retdict
 
 Method = namedtuple(
 	'Method',
@@ -181,7 +187,7 @@ def get_method_info():
 getting_meths = False
 log.debug('initializing')
 formats = get_format_info()
-max_sig_size = max(len(f.start_signature) for f in formats.values())
+max_sig_size = max(len(f.start_signature or '') for f in formats.values())
 getting_meths = True
 methods = get_method_info()
 

lib7zip/archive.py

@@ -102,7 +102,7 @@ def __del__(self):
 
 	def close(self):
 		log.debug('Archive.close()')
-		if self.archive or self.archive.vtable or self.archive.vtable.Close == ffi.NULL:
+		if self.archive == ffi.NULL or self.archive.vtable == ffi.NULL or self.archive.vtable.Close == ffi.NULL:
 			log.warn('close failed, NULLs')
 			return
 		RNOK(self.archive.vtable.Close(self.archive))
@@ -190,14 +190,10 @@ def extract(self, file, password=None):
 
 		self.callback = callback = ArchiveExtractToStreamCallback(file, self.index, password)
 		self.cb_inst = callback_inst = callback.instances[py7ziptypes.IID_IArchiveExtractCallback]
-		#indices = ffi.new('const uint32_t indices[]', [self.index])
-
-		#indices_p = C.calloc(1, ffi.sizeof('uint32_t'))
-		#indices = ffi.cast('uint32_t*', indices_p)
-		#indices[0] = self.index
+		indices = ffi.new('uint32_t indices[1]', [self.index])
 
 		log.debug('starting extract of %s!', self.path)
-		RNOK(self.archive.archive.vtable.Extract(self.archive.archive, ffi.NULL, 0xFFFFFFFF, 0, callback_inst))
+		RNOK(self.archive.archive.vtable.Extract(self.archive.archive, indices, 1, 0, callback_inst))
 		log.debug('finished extract')
 		#C.free(indices_p)
 

lib7zip/comtypes.py

@@ -1,4 +1,5 @@
 import uuid
+import sys
 
 IID_IUnknown = uuid.UUID('{00000000-0000-0000-C000-000000000046}')
 
@@ -8,6 +9,13 @@
 	uint32_t (*Release)(void*);
 """
 
+if 'win' not in sys.platform:
+	# https://forum.lazarus.freepascal.org/index.php/topic,42701.msg298820.html#msg298820
+	CDEF_IUnknown += """
+	void* Reserved1;
+	void* Reserved2;
+"""
+
 CDEFS = """
 typedef struct {
 	""" + CDEF_IUnknown + """

lib7zip/py7ziptypes.py

@@ -136,9 +136,8 @@ class FormatProps(IntEnum):
 	kAddExtension = 3
 	kUpdate = 4
 	kKeepName = 5
-	kStartSignature = 6
-	kFinishSignature = 7
-	kAssociate = 8
+	kSignature = 6
+	kMultiSignature = 7
 
 class MethodProps(IntEnum):
 	kID = 0

lib7zip/simplecom.py

@@ -40,8 +40,9 @@ def __init__(self):
 				try:
 					method = self.methods[name]
 				except KeyError:
-					ctype = ffi.typeof(getattr(vtable, name))
-					self.methods[name] = method = ffi.callback(ctype, getattr(self, name))
+					if name!='Reserved1' and name!='Reserved2':
+						ctype = ffi.typeof(getattr(vtable, name))
+						self.methods[name] = method = ffi.callback(ctype, getattr(self, name))
 
 				setattr(vtable, name, method)
 			self.vtables.append(vtable)