Filedir checks (#341)

* add checks for files and directories so the code can be used in the config check

* add use of std::filesystem when available

* add some documentation

* try a verbatim section

* update formatting on validators

* update error call to use FileError::Missing

* add FileError test for invalid file

* format tweak

include/CLI/App.hpp

@@ -2075,8 +2075,13 @@ class App {
             }
             if(!config_name_.empty()) {
                 try {
-                    std::vector<ConfigItem> values = config_formatter_->from_file(config_name_);
-                    _parse_config(values);
+                    auto path_result = detail::check_path(config_name_.c_str());
+                    if(path_result == detail::path_type::file) {
+                        std::vector<ConfigItem> values = config_formatter_->from_file(config_name_);
+                        _parse_config(values);
+                    } else if(config_required_) {
+                        throw FileError::Missing(config_name_);
+                    }
                 } catch(const FileError &) {
                     if(config_required_)
                         throw;

include/CLI/Validators.hpp

@@ -13,11 +13,27 @@
 #include <memory>
 #include <string>
 
+// [CLI11:verbatim]
+#if(defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1)
+#define CLI11_CPP17
+#endif
+
 // C standard library
 // Only needed for existence checking
-// Could be swapped for filesystem in C++17
+#if defined CLI11_CPP17 && defined __has_include && !defined CLI11_HAS_FILESYSTEM
+#if __has_include(<filesystem>)
+#define CLI11_HAS_FILESYSTEM 1
+#endif
+#endif
+
+#if defined CLI11_HAS_FILESYSTEM && CLI11_HAS_FILESYSTEM > 0
+#include <filesystem>
+#else
 #include <sys/stat.h>
 #include <sys/types.h>
+#endif
+
+// [CLI11:verbatim]
 
 namespace CLI {
 
@@ -250,18 +266,54 @@ class CustomValidator : public Validator {
 // Therefore, this is in detail.
 namespace detail {
 
+/// CLI enumeration of different file types
+enum class path_type { nonexistant, file, directory };
+
+#if defined CLI11_HAS_FILESYSTEM && CLI11_HAS_FILESYSTEM > 0
+/// get the type of the path from a file name
+inline path_type check_path(const char *file) {
+    try {
+        auto stat = std::filesystem::status(file);
+        switch(stat.type()) {
+        case std::filesystem::file_type::none:
+        case std::filesystem::file_type::not_found:
+            return path_type::nonexistant;
+        case std::filesystem::file_type::directory:
+            return path_type::directory;
+        default:
+            return path_type::file;
+        }
+    } catch(const std::filesystem::filesystem_error &) {
+        return path_type::nonexistant;
+    }
+}
+#else
+/// get the type of the path from a file name
+inline path_type check_path(const char *file) {
+#if defined(_MSC_VER)
+    struct __stat64 buffer;
+    if(_stat64(file, &buffer) == 0) {
+        return ((buffer.st_mode & S_IFDIR) != 0) ? path_type::directory : path_type::file;
+    }
+#else
+    struct stat buffer;
+    if(stat(file, &buffer) == 0) {
+        return ((buffer.st_mode & S_IFDIR) != 0) ? path_type::directory : path_type::file;
+    }
+#endif
+    return path_type::nonexistant;
+}
+#endif
 /// Check for an existing file (returns error message if check fails)
 class ExistingFileValidator : public Validator {
   public:
     ExistingFileValidator() : Validator("FILE") {
         func_ = [](std::string &filename) {
-            struct stat buffer;
-            bool exist = stat(filename.c_str(), &buffer) == 0;
-            bool is_dir = (buffer.st_mode & S_IFDIR) != 0;
-            if(!exist) {
+            auto path_result = check_path(filename.c_str());
+            if(path_result == path_type::nonexistant) {
                 return "File does not exist: " + filename;
             }
-            if(is_dir) {
+            if(path_result == path_type::directory) {
                 return "File is actually a directory: " + filename;
             }
             return std::string();
@@ -274,13 +326,11 @@ class ExistingDirectoryValidator : public Validator {
   public:
     ExistingDirectoryValidator() : Validator("DIR") {
         func_ = [](std::string &filename) {
-            struct stat buffer;
-            bool exist = stat(filename.c_str(), &buffer) == 0;
-            bool is_dir = (buffer.st_mode & S_IFDIR) != 0;
-            if(!exist) {
+            auto path_result = check_path(filename.c_str());
+            if(path_result == path_type::nonexistant) {
                 return "Directory does not exist: " + filename;
             }
-            if(!is_dir) {
+            if(path_result == path_type::file) {
                 return "Directory is actually a file: " + filename;
             }
             return std::string();
@@ -293,9 +343,8 @@ class ExistingPathValidator : public Validator {
   public:
     ExistingPathValidator() : Validator("PATH(existing)") {
         func_ = [](std::string &filename) {
-            struct stat buffer;
-            bool const exist = stat(filename.c_str(), &buffer) == 0;
-            if(!exist) {
+            auto path_result = check_path(filename.c_str());
+            if(path_result == path_type::nonexistant) {
                 return "Path does not exist: " + filename;
             }
             return std::string();
@@ -308,9 +357,8 @@ class NonexistentPathValidator : public Validator {
   public:
     NonexistentPathValidator() : Validator("PATH(non-existing)") {
         func_ = [](std::string &filename) {
-            struct stat buffer;
-            bool exist = stat(filename.c_str(), &buffer) == 0;
-            if(exist) {
+            auto path_result = check_path(filename.c_str());
+            if(path_result != path_type::nonexistant) {
                 return "Path already exists: " + filename;
             }
             return std::string();
@@ -1017,7 +1065,7 @@ inline std::pair<std::string, std::string> split_program_name(std::string comman
     std::pair<std::string, std::string> vals;
     trim(commandline);
     auto esp = commandline.find_first_of(' ', 1);
-    while(!ExistingFile(commandline.substr(0, esp)).empty()) {
+    while(detail::check_path(commandline.substr(0, esp).c_str()) != path_type::file) {
         esp = commandline.find_first_of(' ', esp + 1);
         if(esp == std::string::npos) {
             // if we have reached the end and haven't found a valid file just assume the first argument is the

tests/IniTest.cpp

@@ -167,6 +167,10 @@ TEST(StringBased, SpacesSections) {
     EXPECT_EQ("four", output.at(1).inputs.at(0));
 }
 
+TEST(StringBased, file_error) {
+    EXPECT_THROW(std::vector<CLI::ConfigItem> output = CLI::ConfigINI().from_file("nonexist_file"), CLI::FileError);
+}
+
 TEST_F(TApp, IniNotRequired) {
 
     TempFile tmpini{"TestIniTmp.ini"};