The CompressionType is now a scoped enum Compression.

Cython stable don't support scoped enum. (Next version will).
For now we have to use a workaround.

We declare a `zim::Compression` enum but we never use it in python.
We convert from the python value (to int) using cython and
to c++ `zim::Compression` (from int) using a small helper function.

Author: mgautierfr

libzim/libwrapper.cpp

@@ -165,3 +165,18 @@ zim::writer::Hints WriterItemWrapper::getHints() const
 {
   return callMethodOnObj<zim::writer::Hints>(m_obj, "get_hints");
 }
+
+zim::Compression comp_from_int(int compValue)
+{
+  switch(compValue) {
+    case 0:
+      return zim::Compression::None;
+    case 1:
+      return zim::Compression::Lzma;
+    case 2:
+      return zim::Compression::Zstd;
+    default:
+      // Should we raise a error ?
+      return zim::Compression::None;
+  }
+}

libzim/libwrapper.h

@@ -315,4 +315,13 @@ class ContentProviderWrapper : public zim::writer::ContentProvider, private ObjW
     zim::Blob feed() override;
 };
 
+
+// Small helpers
+
+// The current stable cython version (0.29.24) doesn't support scoped enum (next version >30 will be).
+// The cython generated __Pyx_PyInt_As_enum__zim_3a__3a_Compression(PyOobject*)
+// try to do some strange bit shifting of `zim::Compression` which doesn't compile.
+// Let's provide our own function for this
+zim::Compression comp_from_int(int compValue);
+
 #endif // LIBZIM_LIBWRAPPER_H

libzim/libzim.pyx

@@ -171,9 +171,11 @@ cdef class WritingBlob:
 class Compression(enum.Enum):
     """ Compression algorithms available to create ZIM files """
     __module__ = writer_module_name
-    none = zim.CompressionType.zimcompNone
-    lzma = zim.CompressionType.zimcompLzma
-    zstd = zim.CompressionType.zimcompZstd
+    # We don't care of the exact value. The function comp_from_int will do the right
+    # conversion to zim::Compression
+    none = 0
+    lzma = 1
+    zstd = 2
 
 
 class Hint(enum.Enum):
@@ -223,10 +225,10 @@ cdef class _Creator:
         self.c_creator.configVerbose(verbose)
         return self
 
-    def config_compression(self, comptype: Compression) -> Creator:
+    def config_compression(self, compression: Compression) -> Creator:
         if self._started:
             raise RuntimeError("ZimCreator started")
-        self.c_creator.configCompression(comptype.value)
+        self.c_creator.configCompression(zim.comp_from_int(compression.value))
         return self
 
     def config_clustersize(self, int size) -> Creator:

libzim/zim.pxd

@@ -31,12 +31,12 @@ cdef extern from "zim/zim.h" namespace "zim":
     ctypedef uint64_t size_type
     ctypedef uint64_t offset_type
     ctypedef uint32_t entry_index_type
-    ctypedef enum CompressionType:
-        zimcompNone
-        zimcompZip
-        zimcompBzip2
-        zimcompLzma
-        zimcompZstd
+    cdef enum Compression:
+        # We need to declare something here to be syntaxically correct
+        # but we don't use those values (even if they are valid).
+        None "zim::Compression::None"
+        Lzma "zim::Compression::Lzma"
+        Zstd "zim::Compression::Zstd"
 
 
 cdef extern from "zim/writer/item.h" namespace "zim::writer":
@@ -54,7 +54,7 @@ cdef extern from "zim/writer/contentProvider.h" namespace "zim::writer":
 cdef extern from "zim/writer/creator.h" namespace "zim::writer":
     cdef cppclass ZimCreator "zim::writer::Creator":
         void configVerbose(bint verbose)
-        void configCompression(CompressionType comptype)
+        void configCompression(Compression compression)
         void configClusterSize(int size)
         void configIndexing(bint indexing, string language)
         void configNbWorkers(int nbWorkers)
@@ -93,6 +93,8 @@ cdef extern from "libwrapper.h":
     cdef cppclass WriterItemWrapper:
         WriterItemWrapper(PyObject* obj) except +
 
+    Compression comp_from_int(int)
+
 
 # Import the cpp wrappers.
 cdef extern from "libwrapper.h" namespace "wrapper":