Make magic_[version|setparam|getparam] optional

These aren't present in ancient versions of libmagic, so only fetch
optionally and throw NotImplementedError if called.

2 files changed, 43 insertions, 20 deletions

diff --git a/magic.py b/magic.py
index a9cab37..4828148 100644
--- a/magic.py
+++ b/magic.py
@@ -72,7 +72,8 @@ class Magic:
         # by bumping the limit up.  It's not clear if this is a general solution
         # or whether other internal limits should be increased, but given
         # the lack of other reports I'll assume this is rare.
-        self.setparam(MAGIC_PARAM_NAME_MAX, 64)
+        if _has_param:
+            self.setparam(MAGIC_PARAM_NAME_MAX, 64)
 
     def from_buffer(self, buf):
         """
@@ -301,32 +302,42 @@ magic_compile = libmagic.magic_compile
 magic_compile.restype = c_int
 magic_compile.argtypes = [magic_t, c_char_p]
 
-_magic_setparam = libmagic.magic_setparam
-_magic_setparam.restype = c_int
-_magic_setparam.argtypes = [magic_t, c_int, POINTER(c_size_t)]
-_magic_setparam.errcheck = errorcheck_negative_one
+_has_param = False
+if hasattr(libmagic, 'magic_setparam') and hasattr(libmagic, 'magic_getparam'):
+    _has_param = True
+    _magic_setparam = libmagic.magic_setparam
+    _magic_setparam.restype = c_int
+    _magic_setparam.argtypes = [magic_t, c_int, POINTER(c_size_t)]
+    _magic_setparam.errcheck = errorcheck_negative_one
 
+    _magic_getparam = libmagic.magic_getparam
+    _magic_getparam.restype = c_int
+    _magic_getparam.argtypes = [magic_t, c_int, POINTER(c_size_t)]
+    _magic_getparam.errcheck = errorcheck_negative_one
 
 def magic_setparam(cookie, param, val):
+    if not _has_param:
+        raise NotImplementedError("magic_setparam not implemented")
     v = c_size_t(val)
     return _magic_setparam(cookie, param, byref(v))
 
-_magic_getparam = libmagic.magic_getparam
-_magic_getparam.restype = c_int
-_magic_getparam.argtypes = [magic_t, c_int, POINTER(c_size_t)]
-_magic_getparam.errcheck = errorcheck_negative_one
-
-
 def magic_getparam(cookie, param):
+    if not _has_param:
+        raise NotImplementedError("magic_getparam not implemented")
     val = c_size_t()
     _magic_getparam(cookie, param, byref(val))
     return val.value
 
-magic_version = libmagic.magic_version
-magic_version.restype = c_int
-magic_version.argtypes = []
+_has_version = False
+if hasattr(libmagic, "magic_version"):
+    _has_version = True
+    magic_version = libmagic.magic_version
+    magic_version.restype = c_int
+    magic_version.argtypes = []
 
 def version():
+    if not _has_version:
+        raise NotImplementedError("magic_version not implemented")
     return magic_version()
 
 MAGIC_NONE = 0x000000 # No flags
diff --git a/test/test.py b/test/test.py
index 86a06e4..dffefd6 100755
--- a/test/test.py
+++ b/test/test.py
@@ -18,7 +18,10 @@ class MagicTest(unittest.TestCase):
     TESTDATA_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'testdata')
 
     def test_version(self):
-        self.assertTrue(magic.version() > 0)
+        try:
+            self.assertTrue(magic.version() > 0)
+        except NotImplementedError:
+            pass
 
     def test_fs_encoding(self):
         self.assertEqual('utf-8', sys.getfilesystemencoding().lower())
@@ -145,9 +148,15 @@ class MagicTest(unittest.TestCase):
         m = magic.Magic(mime=True)
         self.assertEqual(m.from_file(filename), 'image/jpeg')
 
-        m = magic.Magic(mime=True, keep_going=True)
-        self.assertEqual(m.from_file(filename),
-                         'image/jpeg\\012- application/octet-stream')
+        try:
+            # this will throw if you have an "old" version of the library
+            # I'm otherwise not sure how to query if keep_going is supported
+            magic.version()
+            m = magic.Magic(mime=True, keep_going=True)
+            self.assertEqual(m.from_file(filename),
+                             'image/jpeg\\012- application/octet-stream')
+        except NotImplementedError:
+            pass
 
     def test_rethrow(self):
         old = magic.magic_buffer
@@ -163,8 +172,11 @@ class MagicTest(unittest.TestCase):
 
     def test_getparam(self):
         m = magic.Magic(mime=True)
-        m.setparam(magic.MAGIC_PARAM_INDIR_MAX, 1)
-        self.assertEqual(m.getparam(magic.MAGIC_PARAM_INDIR_MAX), 1)
+        try:
+            m.setparam(magic.MAGIC_PARAM_INDIR_MAX, 1)
+            self.assertEqual(m.getparam(magic.MAGIC_PARAM_INDIR_MAX), 1)
+        except NotImplementedError:
+            pass
 
     def test_name_count(self):
         m = magic.Magic()