add is_directory to file_util.h

Author: Daniel Kroening

src/util/file_util.cpp

@@ -145,3 +145,28 @@ std::string concat_dir_file(
           file_name : directory+"/"+file_name;
   #endif
 }
+
+bool is_directory(const std::string &path)
+{
+  if(path.empty())
+    return false;
+
+#ifdef _WIN32
+
+  auto attributes = ::GetFileAttributesW(widen(path).c_str());
+  if (attributes == INVALID_FILE_ATTRIBUTES)
+    return false;
+  else
+    return (attributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
+
+#else
+
+  struct stat buf;
+
+  if(stat(path.c_str(), &buf)!=0)
+    return false;
+  else
+    return (buf.st_mode & S_IFDIR) != 0;
+
+#endif
+}

src/util/file_util.h

@@ -19,4 +19,7 @@ std::string get_current_working_directory();
 std::string concat_dir_file(const std::string &directory,
                             const std::string &file_name);
 
+// C++17 will allow us to use std::filesystem::is_directory()
+bool is_directory(const std::string &path);
+
 #endif // CPROVER_UTIL_FILE_UTIL_H

unit/Makefile

@@ -28,6 +28,7 @@ SRC += unit_tests.cpp \
        solvers/refinement/string_refinement/union_find_replace.cpp \
        util/expr.cpp \
        util/expr_cast/expr_cast.cpp \
+       util/file_util.cpp \
        util/get_base_name.cpp \
        util/graph.cpp \
        util/irep.cpp \

unit/util/file_util.cpp

@@ -0,0 +1,34 @@
+/*******************************************************************\
+
+Module: Unit tests for file_util.h
+
+Author: Daniel Kroening
+
+\*******************************************************************/
+
+#include <testing-utils/catch.hpp>
+
+#include <util/file_util.h>
+#include <util/tempdir.h>
+#include <util/unicode.h>
+
+#include <fstream>
+
+TEST_CASE("is_directory functionality", "[core][util][file_util]")
+{
+  temp_dirt temp_dir("testXXXXXX");
+
+  #ifdef _WIN32
+  std::ofstream outfile(widen(temp_dir("file")));
+  #else
+  std::ofstream outfile(temp_dir("file"));
+  #endif
+
+  outfile.close();
+
+  REQUIRE(is_directory(temp_dir.path));
+  REQUIRE(is_directory(temp_dir.path+"/"));
+  REQUIRE(!is_directory(temp_dir("whatnot")));
+  REQUIRE(!is_directory(temp_dir("file")));
+  REQUIRE(!is_directory(""));
+}