add read and write file validators #249

Signed-off-by: Rafi Wiener <rafiw@mellanox.com>

README.md

@@ -337,6 +337,8 @@ CLI11 has several Validators built in that perform some common checks
 -   `CLI::Transformer(...)`: 🚧 Modify the input using a map.  See [Transforming Validators](#transforming-validators) for more details.
 -   `CLI::CheckedTransformer(...)`: 🚧 Modify the input using a map, and Require that the input is either in the set or already one of the outputs of the set. See [Transforming Validators](#transforming-validators) for more details.
 -   `CLI::ExistingFile`: Requires that the file exists if given.
+-   `CLI::ExistingReadFile`: Requires that the file given exists and have permission to read it.
+-   `CLI::ExistingWriteFile`: Requires that the file given exists and have permission to write to it.
 -   `CLI::ExistingDirectory`: Requires that the directory exists.
 -   `CLI::ExistingPath`: Requires that the path (file or directory) exists.
 -   `CLI::NonexistentPath`: Requires that the path does not exist.

examples/validators.cpp

@@ -5,7 +5,7 @@ int main(int argc, char **argv) {
     CLI::App app("Validator checker");
 
     std::string file;
-    app.add_option("-f,--file,file", file, "File name")->check(CLI::ExistingFile);
+    app.add_option("-f,--file,file", file, "File name")->check(CLI::ExistingReadableFile);
 
     int count;
     app.add_option("-v,--value", count, "Value in range")->check(CLI::Range(3, 6));

include/CLI/Validators.hpp

@@ -216,8 +216,8 @@ namespace detail {
 /// Check for an existing file (returns error message if check fails)
 class ExistingFileValidator : public Validator {
   public:
-    ExistingFileValidator() : Validator("FILE") {
-        func_ = [](std::string &filename) {
+    ExistingFileValidator(unsigned short mode = 0) : Validator("FILE") {
+        func_ = [mode](std::string &filename) {
             struct stat buffer;
             bool exist = stat(filename.c_str(), &buffer) == 0;
             bool is_dir = (buffer.st_mode & S_IFDIR) != 0;
@@ -226,6 +226,9 @@ class ExistingFileValidator : public Validator {
             } else if(is_dir) {
                 return "File is actually a directory: " + filename;
             }
+            if(mode && !(buffer.st_mode & mode)) {
+                return "File doesn't have the wanted permission: " + filename;
+            }
             return std::string();
         };
     }
@@ -328,6 +331,12 @@ class PositiveNumber : public Validator {
 /// Check for existing file (returns error message if check fails)
 const detail::ExistingFileValidator ExistingFile;
 
+/// Check that the file exist and available for read
+const detail::ExistingFileValidator ExistingReadableFile(S_IREAD);
+
+/// Check that the file exist and available for write
+const detail::ExistingFileValidator ExistingWritableFile(S_IWRITE);
+
 /// Check for an existing directory (returns error message if check fails)
 const detail::ExistingDirectoryValidator ExistingDirectory;
 

tests/AppTest.cpp

@@ -1,6 +1,7 @@
 #include "app_helper.hpp"
 #include <complex>
 #include <cstdlib>
+#include <sys/stat.h>
 
 #include "gmock/gmock.h"
 
@@ -1466,6 +1467,50 @@ TEST_F(TApp, FileExists) {
     EXPECT_FALSE(CLI::ExistingFile(myfile).empty());
 }
 
+TEST_F(TApp, FileExistsForRead) {
+    std::string myfile{"TestNonFileNotUsed.txt"};
+    EXPECT_FALSE(CLI::ExistingReadableFile(myfile).empty());
+
+    bool ok = static_cast<bool>(std::ofstream(myfile.c_str()).put('a')); // create file
+    EXPECT_TRUE(ok);
+
+    std::string filename = "Failed";
+    app.add_option("--file", filename)->check(CLI::ExistingReadableFile);
+    args = {"--file", myfile};
+
+    run();
+
+    EXPECT_EQ(myfile, filename);
+#ifdef __linux__
+    my_chmod(myfile.c_str(), 0);
+    EXPECT_THROW(run(), CLI::ValidationError);
+#endif
+    std::remove(myfile.c_str());
+    EXPECT_FALSE(CLI::ExistingFile(myfile).empty());
+}
+
+TEST_F(TApp, FileExistsForWrite) {
+    std::string myfile{"TestNonFileNotUsed.txt"};
+    EXPECT_FALSE(CLI::ExistingWritableFile(myfile).empty());
+
+    bool ok = static_cast<bool>(std::ofstream(myfile.c_str()).put('a')); // create file
+    EXPECT_TRUE(ok);
+
+    std::string filename = "Failed";
+    app.add_option("--file", filename)->check(CLI::ExistingWritableFile);
+    args = {"--file", myfile};
+
+    run();
+    EXPECT_EQ(myfile, filename);
+
+    my_chmod(myfile.c_str(), S_IREAD);
+    EXPECT_THROW(run(), CLI::ValidationError);
+
+    int ret = std::remove(myfile.c_str());
+    EXPECT_EQ(ret, 0);
+    EXPECT_FALSE(CLI::ExistingFile(myfile).empty());
+}
+
 TEST_F(TApp, NotFileExists) {
     std::string myfile{"TestNonFileNotUsed.txt"};
     EXPECT_FALSE(CLI::ExistingFile(myfile).empty());

tests/app_helper.hpp

@@ -8,6 +8,7 @@
 
 #include "gtest/gtest.h"
 #include <iostream>
+#include <sys/stat.h>
 
 typedef std::vector<std::string> input_t;
 
@@ -55,3 +56,11 @@ inline void unset_env(std::string name) {
     unsetenv(name.c_str());
 #endif
 }
+
+inline int my_chmod(const char *path, int mode) {
+#ifdef _WIN32
+    return _chmod(path, mode);
+#else
+    return chmod(path, mode);
+#endif
+}