Add path exists validator.

README.md

@@ -179,6 +179,7 @@ The add commands return a pointer to an internally stored `Option`. If you set t
 * `->multi_option_policy(CLI::MultiOptionPolicy::Throw)`: Set the multi-option policy. Shortcuts available: `->take_last()`, `->take_first()`, and `->join()`. This will only affect options expecting 1 argument or bool flags (which always default to take last).
 * `->check(CLI::ExistingFile)`: Requires that the file exists if given.
 * `->check(CLI::ExistingDirectory)`: Requires that the directory exists.
+* `->check(CLI::ExistingPath)`: Requires that the path (file or directory) exists.
 * `->check(CLI::NonexistentPath)`: Requires that the path does not exist.
 * `->check(CLI::Range(min,max))`: Requires that the option be between min and max (make sure to use floating point if needed). Min defaults to 0.
 * `->transform(std::string(std::string))`: Converts the input string into the output string, in-place in the parsed options.

include/CLI/Validators.hpp

@@ -50,6 +50,16 @@ inline std::string ExistingDirectory(const std::string &filename) {
     return std::string();
 }
 
+/// Check for an existing path
+inline std::string ExistingPath(const std::string &filename) {
+    struct stat buffer;
+    bool const exist = stat(filename.c_str(), &buffer) == 0;
+    if(!exist) {
+        return "Path does not exist: " + filename;
+    }
+    return std::string();
+}
+
 /// Check for a non-existing path
 inline std::string NonexistentPath(const std::string &filename) {
     struct stat buffer;

tests/HelpersTest.cpp

@@ -133,6 +133,27 @@ TEST(Validators, DirectoryIsFile) {
     EXPECT_TRUE(CLI::NonexistentPath(myfile).empty());
 }
 
+TEST(Validators, PathExistsDir) {
+    std::string mydir{"../tests"};
+    EXPECT_EQ(CLI::ExistingPath(mydir), "");
+}
+
+TEST(Validators, PathExistsFile) {
+    std::string myfile{"TestFileNotUsed.txt"};
+    EXPECT_FALSE(CLI::ExistingPath(myfile).empty());
+    bool ok = static_cast<bool>(std::ofstream(myfile.c_str()).put('a')); // create file
+    EXPECT_TRUE(ok);
+    EXPECT_TRUE(CLI::ExistingPath(myfile).empty());
+
+    std::remove(myfile.c_str());
+    EXPECT_FALSE(CLI::ExistingPath(myfile).empty());
+}
+
+TEST(Validators, PathNotExistsDir) {
+    std::string mydir{"nonpath"};
+    EXPECT_NE(CLI::ExistingPath(mydir), "");
+}
+
 // Yes, this is testing an app_helper :)
 TEST(AppHelper, TempfileCreated) {
     std::string name = "TestFileNotUsed.txt";