Support setup on environment with no PyTorch (#843)

setup.py

@@ -2,9 +2,11 @@
 
 from setuptools import find_packages, setup
 
+EXT_TYPE = ''
 try:
     from torch.utils.cpp_extension import BuildExtension
     cmd_class = {'build_ext': BuildExtension}
+    EXT_TYPE = 'torch'
 except ModuleNotFoundError:
     cmd_class = {}
     print('Skip building ext ops due to the absence of torch.')
@@ -105,64 +107,68 @@ def gen_packages_items():
 def get_extensions():
     extensions = []
     ext_name = 'mmdeploy.backend.torchscript.ts_optimizer'
-    import glob
-    import platform
-
-    from torch.utils.cpp_extension import CppExtension
-
-    try:
-        import psutil
-        num_cpu = len(psutil.Process().cpu_affinity())
-        cpu_use = max(4, num_cpu - 1)
-    except (ModuleNotFoundError, AttributeError):
-        cpu_use = 4
-
-    os.environ.setdefault('MAX_JOBS', str(cpu_use))
-    define_macros = []
-
-    # Before PyTorch1.8.0, when compiling CUDA code, `cxx` is a
-    # required key passed to PyTorch. Even if there is no flag passed
-    # to cxx, users also need to pass an empty list to PyTorch.
-    # Since PyTorch1.8.0, it has a default value so users do not need
-    # to pass an empty list anymore.
-    # More details at https://github.com/pytorch/pytorch/pull/45956
-    extra_compile_args = {'cxx': []}
-
-    # c++14 is required.
-    # However, in the windows environment, some standard libraries
-    # will depend on c++17 or higher. In fact, for the windows
-    # environment, the compiler will choose the appropriate compiler
-    # to compile those cpp files, so there is no need to add the
-    # argument
-    if platform.system() != 'Windows':
-        extra_compile_args['cxx'] = ['-std=c++14']
-
-    include_dirs = []
-
-    op_files = glob.glob(
-        './csrc/mmdeploy/backend_ops/torchscript/optimizer/*.cpp'
-    ) + glob.glob(
-        './csrc/mmdeploy/backend_ops/torchscript/optimizer/ir/*.cpp'
-    ) + glob.glob(
-        './csrc/mmdeploy/backend_ops/torchscript/optimizer/passes/onnx/*.cpp')
-    extension = CppExtension
-
-    # c++14 is required.
-    # However, in the windows environment, some standard libraries
-    # will depend on c++17 or higher. In fact, for the windows
-    # environment, the compiler will choose the appropriate compiler
-    # to compile those cpp files, so there is no need to add the
-    # argument
-    if 'nvcc' in extra_compile_args and platform.system() != 'Windows':
-        extra_compile_args['nvcc'] += ['-std=c++14']
-
-    ext_ops = extension(
-        name=ext_name,
-        sources=op_files,
-        include_dirs=include_dirs,
-        define_macros=define_macros,
-        extra_compile_args=extra_compile_args)
-    extensions.append(ext_ops)
+
+    if EXT_TYPE == 'torch':
+        import glob
+        import platform
+
+        from torch.utils.cpp_extension import CppExtension
+
+        try:
+            import psutil
+            num_cpu = len(psutil.Process().cpu_affinity())
+            cpu_use = max(4, num_cpu - 1)
+        except (ModuleNotFoundError, AttributeError):
+            cpu_use = 4
+
+        os.environ.setdefault('MAX_JOBS', str(cpu_use))
+        define_macros = []
+
+        # Before PyTorch1.8.0, when compiling CUDA code, `cxx` is a
+        # required key passed to PyTorch. Even if there is no flag passed
+        # to cxx, users also need to pass an empty list to PyTorch.
+        # Since PyTorch1.8.0, it has a default value so users do not need
+        # to pass an empty list anymore.
+        # More details at https://github.com/pytorch/pytorch/pull/45956
+        extra_compile_args = {'cxx': []}
+
+        # c++14 is required.
+        # However, in the windows environment, some standard libraries
+        # will depend on c++17 or higher. In fact, for the windows
+        # environment, the compiler will choose the appropriate compiler
+        # to compile those cpp files, so there is no need to add the
+        # argument
+        if platform.system() != 'Windows':
+            extra_compile_args['cxx'] = ['-std=c++14']
+
+        include_dirs = []
+
+        op_files = glob.glob(
+            './csrc/mmdeploy/backend_ops/torchscript/optimizer/*.cpp'
+        ) + glob.glob(
+            './csrc/mmdeploy/backend_ops/torchscript/optimizer/ir/*.cpp'
+        ) + glob.glob(
+            './csrc/mmdeploy/backend_ops/torchscript/optimizer/passes'
+            '/onnx/*.cpp')
+        extension = CppExtension
+
+        # c++14 is required.
+        # However, in the windows environment, some standard libraries
+        # will depend on c++17 or higher. In fact, for the windows
+        # environment, the compiler will choose the appropriate compiler
+        # to compile those cpp files, so there is no need to add the
+        # argument
+        if 'nvcc' in extra_compile_args and platform.system() != 'Windows':
+            extra_compile_args['nvcc'] += ['-std=c++14']
+
+        ext_ops = extension(
+            name=ext_name,
+            sources=op_files,
+            include_dirs=include_dirs,
+            define_macros=define_macros,
+            extra_compile_args=extra_compile_args)
+        extensions.append(ext_ops)
+
     return extensions