Move uniquePath implementation from Path to Temporary and refactor usage

- Remove uniquePath from Path and add to Temporary with new logic
- Use std::random and std::filesystem for unique path generation
- Add DEFAULT_TMP_MAX_ATTEMPTS constant for path generation attempts
- Update TempPath to use new uniquePath implementation

Author: Hubert Degaudenzi

ElementsKernel/ElementsKernel/Path.h

@@ -279,15 +279,6 @@ extern template ELEMENTS_API std::vector<Item> removeDuplicates(const std::vecto
 /// Template instantiation for the most common types
 extern template ELEMENTS_API std::vector<Item> removeDuplicates(const std::vector<std::string>& path_list);
 
-/**
- * @brief Geenrate a unique random path according to to a pattern
- * @ingroup ElementsKernel
- * @param p
- *  initial pattern
- * @return the path random path stem
- */
-ELEMENTS_API Item uniquePath(Item const& p = "%%%%-%%%%-%%%%-%%%%");
-
 }  // namespace Path
 }  // namespace Kernel
 }  // namespace Elements

ElementsKernel/ElementsKernel/Temporary.h

@@ -38,6 +38,17 @@ namespace Elements {
 const std::string DEFAULT_TMP_KEEP_VAR{"KEEPTEMPDIR"};
 /// The default random creation motif
 const std::string DEFAULT_TMP_MOTIF{"%%%%-%%%%-%%%%-%%%%"};
+/// Defualt max number of attempt to find a random path
+const int DEFAULT_TMP_MAX_ATTEMPTS{100};
+
+/**
+ * @brief Geenrate a unique random path according to to a pattern
+ * @ingroup ElementsKernel
+ * @param p
+ *  initial pattern
+ * @return the path random path stem
+ */
+ELEMENTS_API Path::Item uniquePath(Path::Item const& p = DEFAULT_TMP_MOTIF);
 
 class ELEMENTS_API TempPath {
 public:

ElementsKernel/src/Lib/Path.cpp

@@ -139,11 +139,6 @@ template vector<Item> multiPathAppend(const vector<string>& initial_locations, c
 template vector<Item> removeDuplicates(const vector<Item>& path_list);
 template vector<Item> removeDuplicates(const vector<string>& path_list);
 
-Item uniquePath(Item const& p) {
-  using boost::filesystem::unique_path;
-  return Item{unique_path(p.string()).string()};
-}
-
 }  // namespace Path
 }  // namespace Kernel
 }  // namespace Elements

ElementsKernel/src/Lib/Temporary.cpp

@@ -23,6 +23,7 @@
 
 #include <filesystem>  // for operator/, ofstream, path>
 #include <fstream>     // for ofstream>
+#include <random>      // for random_device, mt19937, uniform_int_distribution
 #include <string>      // for string
 
 #include <utility>
@@ -34,12 +35,53 @@
 using std::string;
 using std::filesystem::temp_directory_path;
 
+namespace fs = std::filesystem;
+
 namespace Elements {
 
 namespace {
 auto log = Logging::getLogger();
 }
 
+inline std::string randomHexString(const std::size_t length) {
+  static std::random_device              rd;
+  static std::mt19937                    gen(rd());
+  static std::uniform_int_distribution<> dist(0, 15);
+
+  static const char* hex_chars = "0123456789abcdef";
+
+  std::string result;
+  result.reserve(length);
+  for (std::size_t i = 0; i < length; ++i)
+    result += hex_chars[dist(gen)];
+  return result;
+}
+
+Path::Item uniquePath(Path::Item const& model) {
+
+  auto model_string = model.string();
+
+  if (model_string.empty())
+    model_string = DEFAULT_TMP_MOTIF;
+
+  string path_str;
+
+  for (int tries = 0; tries < DEFAULT_TMP_MAX_ATTEMPTS; ++tries) {  // avoid infinite loops
+    path_str.clear();
+    for (char c : model_string) {
+      if (c == '%')
+        path_str += randomHexString(1);
+      else
+        path_str += c;
+    }
+    fs::path candidate = fs::temp_directory_path() / path_str;
+    if (!fs::exists(candidate))
+      return path_str;
+  }
+
+  throw std::runtime_error("unique_path: could not find unique path");
+}
+
 TempPath::TempPath(string motif, string keep_var)
     : m_motif(std::move(motif)), m_path(temp_directory_path()), m_keep_var(std::move(keep_var)) {
 
@@ -54,7 +96,7 @@ TempPath::TempPath(string motif, string keep_var)
     pattern = DEFAULT_TMP_MOTIF;
   }
 
-  m_path /= Path::uniquePath(pattern);
+  m_path /= uniquePath(pattern);
 }
 
 TempPath::~TempPath() {

ElementsKernel/tests/src/Temporary_test.cpp

@@ -192,7 +192,7 @@ BOOST_AUTO_TEST_CASE(KeepTmpDir_test) {
 }
 
 BOOST_AUTO_TEST_CASE(Fake_test) {
-  using Path::uniquePath;
+
   using std::filesystem::temp_directory_path;
 
   const string motif1;