def has_function()

in modules/SwissArmyTransformer/sat/ops/ops_builder/builder.py [0:0]

• 49 lines of code
• 16 McCabe index (conditional complexity)

    def has_function(self, funcname, libraries, verbose=False):
        '''
        Test for existence of a function within a tuple of libraries.

        This is used as a smoke test to check whether a certain library is available.
        As a test, this creates a simple C program that calls the specified function,
        and then distutils is used to compile that program and link it with the specified libraries.
        Returns True if both the compile and link are successful, False otherwise.
        '''
        tempdir = None  # we create a temporary directory to hold various files
        filestderr = None  # handle to open file to which we redirect stderr
        oldstderr = None  # file descriptor for stderr
        try:
            # Echo compile and link commands that are used.
            if verbose:
                distutils.log.set_verbosity(1)

            # Create a compiler object.
            compiler = distutils.ccompiler.new_compiler(verbose=verbose)

            # Configure compiler and linker to build according to Python install.
            distutils.sysconfig.customize_compiler(compiler)

            # Create a temporary directory to hold test files.
            tempdir = tempfile.mkdtemp()

            # Define a simple C program that calls the function in question
            prog = "void %s(void); int main(int argc, char** argv) { %s(); return 0; }" % (funcname, funcname)

            # Write the test program to a file.
            filename = os.path.join(tempdir, 'test.c')
            with open(filename, 'w') as f:
                f.write(prog)

            # Redirect stderr file descriptor to a file to silence compile/link warnings.
            if not verbose:
                filestderr = open(os.path.join(tempdir, 'stderr.txt'), 'w')
                oldstderr = os.dup(sys.stderr.fileno())
                os.dup2(filestderr.fileno(), sys.stderr.fileno())

            # Workaround for behavior in distutils.ccompiler.CCompiler.object_filenames()
            # Otherwise, a local directory will be used instead of tempdir
            drive, driveless_filename = os.path.splitdrive(filename)
            root_dir = driveless_filename[0] if os.path.isabs(driveless_filename) else ''
            output_dir = os.path.join(drive, root_dir)

            # Attempt to compile the C program into an object file.
            cflags = shlex.split(os.environ.get('CFLAGS', ""))
            objs = compiler.compile([filename], output_dir=output_dir, extra_preargs=self.strip_empty_entries(cflags))

            # Attempt to link the object file into an executable.
            # Be sure to tack on any libraries that have been specified.
            ldflags = shlex.split(os.environ.get('LDFLAGS', ""))
            compiler.link_executable(objs,
                                     os.path.join(tempdir, 'a.out'),
                                     extra_preargs=self.strip_empty_entries(ldflags),
                                     libraries=libraries)

            # Compile and link succeeded
            return True

        except CompileError:
            return False

        except LinkError:
            return False

        except:
            return False

        finally:
            # Restore stderr file descriptor and close the stderr redirect file.
            if oldstderr is not None:
                os.dup2(oldstderr, sys.stderr.fileno())
            if filestderr is not None:
                filestderr.close()

            # Delete the temporary directory holding the test program and stderr files.
            if tempdir is not None:
                shutil.rmtree(tempdir)